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-rw-r--r--io_uring/io_uring.c4247
1 files changed, 4247 insertions, 0 deletions
diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
new file mode 100644
index 000000000..35894955b
--- /dev/null
+++ b/io_uring/io_uring.c
@@ -0,0 +1,4247 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Shared application/kernel submission and completion ring pairs, for
+ * supporting fast/efficient IO.
+ *
+ * A note on the read/write ordering memory barriers that are matched between
+ * the application and kernel side.
+ *
+ * After the application reads the CQ ring tail, it must use an
+ * appropriate smp_rmb() to pair with the smp_wmb() the kernel uses
+ * before writing the tail (using smp_load_acquire to read the tail will
+ * do). It also needs a smp_mb() before updating CQ head (ordering the
+ * entry load(s) with the head store), pairing with an implicit barrier
+ * through a control-dependency in io_get_cqe (smp_store_release to
+ * store head will do). Failure to do so could lead to reading invalid
+ * CQ entries.
+ *
+ * Likewise, the application must use an appropriate smp_wmb() before
+ * writing the SQ tail (ordering SQ entry stores with the tail store),
+ * which pairs with smp_load_acquire in io_get_sqring (smp_store_release
+ * to store the tail will do). And it needs a barrier ordering the SQ
+ * head load before writing new SQ entries (smp_load_acquire to read
+ * head will do).
+ *
+ * When using the SQ poll thread (IORING_SETUP_SQPOLL), the application
+ * needs to check the SQ flags for IORING_SQ_NEED_WAKEUP *after*
+ * updating the SQ tail; a full memory barrier smp_mb() is needed
+ * between.
+ *
+ * Also see the examples in the liburing library:
+ *
+ * git://git.kernel.dk/liburing
+ *
+ * io_uring also uses READ/WRITE_ONCE() for _any_ store or load that happens
+ * from data shared between the kernel and application. This is done both
+ * for ordering purposes, but also to ensure that once a value is loaded from
+ * data that the application could potentially modify, it remains stable.
+ *
+ * Copyright (C) 2018-2019 Jens Axboe
+ * Copyright (c) 2018-2019 Christoph Hellwig
+ */
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/errno.h>
+#include <linux/syscalls.h>
+#include <net/compat.h>
+#include <linux/refcount.h>
+#include <linux/uio.h>
+#include <linux/bits.h>
+
+#include <linux/sched/signal.h>
+#include <linux/fs.h>
+#include <linux/file.h>
+#include <linux/fdtable.h>
+#include <linux/mm.h>
+#include <linux/mman.h>
+#include <linux/percpu.h>
+#include <linux/slab.h>
+#include <linux/bvec.h>
+#include <linux/net.h>
+#include <net/sock.h>
+#include <net/af_unix.h>
+#include <net/scm.h>
+#include <linux/anon_inodes.h>
+#include <linux/sched/mm.h>
+#include <linux/uaccess.h>
+#include <linux/nospec.h>
+#include <linux/highmem.h>
+#include <linux/fsnotify.h>
+#include <linux/fadvise.h>
+#include <linux/task_work.h>
+#include <linux/io_uring.h>
+#include <linux/audit.h>
+#include <linux/security.h>
+#include <asm/shmparam.h>
+
+#define CREATE_TRACE_POINTS
+#include <trace/events/io_uring.h>
+
+#include <uapi/linux/io_uring.h>
+
+#include "io-wq.h"
+
+#include "io_uring.h"
+#include "opdef.h"
+#include "refs.h"
+#include "tctx.h"
+#include "sqpoll.h"
+#include "fdinfo.h"
+#include "kbuf.h"
+#include "rsrc.h"
+#include "cancel.h"
+#include "net.h"
+#include "notif.h"
+
+#include "timeout.h"
+#include "poll.h"
+#include "alloc_cache.h"
+
+#define IORING_MAX_ENTRIES 32768
+#define IORING_MAX_CQ_ENTRIES (2 * IORING_MAX_ENTRIES)
+
+#define IORING_MAX_RESTRICTIONS (IORING_RESTRICTION_LAST + \
+ IORING_REGISTER_LAST + IORING_OP_LAST)
+
+#define SQE_COMMON_FLAGS (IOSQE_FIXED_FILE | IOSQE_IO_LINK | \
+ IOSQE_IO_HARDLINK | IOSQE_ASYNC)
+
+#define SQE_VALID_FLAGS (SQE_COMMON_FLAGS | IOSQE_BUFFER_SELECT | \
+ IOSQE_IO_DRAIN | IOSQE_CQE_SKIP_SUCCESS)
+
+#define IO_REQ_CLEAN_FLAGS (REQ_F_BUFFER_SELECTED | REQ_F_NEED_CLEANUP | \
+ REQ_F_POLLED | REQ_F_INFLIGHT | REQ_F_CREDS | \
+ REQ_F_ASYNC_DATA)
+
+#define IO_REQ_CLEAN_SLOW_FLAGS (REQ_F_REFCOUNT | REQ_F_LINK | REQ_F_HARDLINK |\
+ IO_REQ_CLEAN_FLAGS)
+
+#define IO_TCTX_REFS_CACHE_NR (1U << 10)
+
+#define IO_COMPL_BATCH 32
+#define IO_REQ_ALLOC_BATCH 8
+
+enum {
+ IO_CHECK_CQ_OVERFLOW_BIT,
+ IO_CHECK_CQ_DROPPED_BIT,
+};
+
+enum {
+ IO_EVENTFD_OP_SIGNAL_BIT,
+ IO_EVENTFD_OP_FREE_BIT,
+};
+
+struct io_defer_entry {
+ struct list_head list;
+ struct io_kiocb *req;
+ u32 seq;
+};
+
+/* requests with any of those set should undergo io_disarm_next() */
+#define IO_DISARM_MASK (REQ_F_ARM_LTIMEOUT | REQ_F_LINK_TIMEOUT | REQ_F_FAIL)
+#define IO_REQ_LINK_FLAGS (REQ_F_LINK | REQ_F_HARDLINK)
+
+static bool io_uring_try_cancel_requests(struct io_ring_ctx *ctx,
+ struct task_struct *task,
+ bool cancel_all);
+
+static void io_dismantle_req(struct io_kiocb *req);
+static void io_clean_op(struct io_kiocb *req);
+static void io_queue_sqe(struct io_kiocb *req);
+static void io_move_task_work_from_local(struct io_ring_ctx *ctx);
+static void __io_submit_flush_completions(struct io_ring_ctx *ctx);
+
+static struct kmem_cache *req_cachep;
+
+struct sock *io_uring_get_socket(struct file *file)
+{
+#if defined(CONFIG_UNIX)
+ if (io_is_uring_fops(file)) {
+ struct io_ring_ctx *ctx = file->private_data;
+
+ return ctx->ring_sock->sk;
+ }
+#endif
+ return NULL;
+}
+EXPORT_SYMBOL(io_uring_get_socket);
+
+static inline void io_submit_flush_completions(struct io_ring_ctx *ctx)
+{
+ if (!wq_list_empty(&ctx->submit_state.compl_reqs))
+ __io_submit_flush_completions(ctx);
+}
+
+static inline unsigned int __io_cqring_events(struct io_ring_ctx *ctx)
+{
+ return ctx->cached_cq_tail - READ_ONCE(ctx->rings->cq.head);
+}
+
+static inline unsigned int __io_cqring_events_user(struct io_ring_ctx *ctx)
+{
+ return READ_ONCE(ctx->rings->cq.tail) - READ_ONCE(ctx->rings->cq.head);
+}
+
+static bool io_match_linked(struct io_kiocb *head)
+{
+ struct io_kiocb *req;
+
+ io_for_each_link(req, head) {
+ if (req->flags & REQ_F_INFLIGHT)
+ return true;
+ }
+ return false;
+}
+
+/*
+ * As io_match_task() but protected against racing with linked timeouts.
+ * User must not hold timeout_lock.
+ */
+bool io_match_task_safe(struct io_kiocb *head, struct task_struct *task,
+ bool cancel_all)
+{
+ bool matched;
+
+ if (task && head->task != task)
+ return false;
+ if (cancel_all)
+ return true;
+
+ if (head->flags & REQ_F_LINK_TIMEOUT) {
+ struct io_ring_ctx *ctx = head->ctx;
+
+ /* protect against races with linked timeouts */
+ spin_lock_irq(&ctx->timeout_lock);
+ matched = io_match_linked(head);
+ spin_unlock_irq(&ctx->timeout_lock);
+ } else {
+ matched = io_match_linked(head);
+ }
+ return matched;
+}
+
+static inline void req_fail_link_node(struct io_kiocb *req, int res)
+{
+ req_set_fail(req);
+ io_req_set_res(req, res, 0);
+}
+
+static inline void io_req_add_to_cache(struct io_kiocb *req, struct io_ring_ctx *ctx)
+{
+ wq_stack_add_head(&req->comp_list, &ctx->submit_state.free_list);
+}
+
+static __cold void io_ring_ctx_ref_free(struct percpu_ref *ref)
+{
+ struct io_ring_ctx *ctx = container_of(ref, struct io_ring_ctx, refs);
+
+ complete(&ctx->ref_comp);
+}
+
+static __cold void io_fallback_req_func(struct work_struct *work)
+{
+ struct io_ring_ctx *ctx = container_of(work, struct io_ring_ctx,
+ fallback_work.work);
+ struct llist_node *node = llist_del_all(&ctx->fallback_llist);
+ struct io_kiocb *req, *tmp;
+ bool locked = false;
+
+ percpu_ref_get(&ctx->refs);
+ llist_for_each_entry_safe(req, tmp, node, io_task_work.node)
+ req->io_task_work.func(req, &locked);
+
+ if (locked) {
+ io_submit_flush_completions(ctx);
+ mutex_unlock(&ctx->uring_lock);
+ }
+ percpu_ref_put(&ctx->refs);
+}
+
+static int io_alloc_hash_table(struct io_hash_table *table, unsigned bits)
+{
+ unsigned hash_buckets = 1U << bits;
+ size_t hash_size = hash_buckets * sizeof(table->hbs[0]);
+
+ table->hbs = kmalloc(hash_size, GFP_KERNEL);
+ if (!table->hbs)
+ return -ENOMEM;
+
+ table->hash_bits = bits;
+ init_hash_table(table, hash_buckets);
+ return 0;
+}
+
+static __cold struct io_ring_ctx *io_ring_ctx_alloc(struct io_uring_params *p)
+{
+ struct io_ring_ctx *ctx;
+ int hash_bits;
+
+ ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
+ if (!ctx)
+ return NULL;
+
+ xa_init(&ctx->io_bl_xa);
+
+ /*
+ * Use 5 bits less than the max cq entries, that should give us around
+ * 32 entries per hash list if totally full and uniformly spread, but
+ * don't keep too many buckets to not overconsume memory.
+ */
+ hash_bits = ilog2(p->cq_entries) - 5;
+ hash_bits = clamp(hash_bits, 1, 8);
+ if (io_alloc_hash_table(&ctx->cancel_table, hash_bits))
+ goto err;
+ if (io_alloc_hash_table(&ctx->cancel_table_locked, hash_bits))
+ goto err;
+
+ ctx->dummy_ubuf = kzalloc(sizeof(*ctx->dummy_ubuf), GFP_KERNEL);
+ if (!ctx->dummy_ubuf)
+ goto err;
+ /* set invalid range, so io_import_fixed() fails meeting it */
+ ctx->dummy_ubuf->ubuf = -1UL;
+
+ if (percpu_ref_init(&ctx->refs, io_ring_ctx_ref_free,
+ 0, GFP_KERNEL))
+ goto err;
+
+ ctx->flags = p->flags;
+ init_waitqueue_head(&ctx->sqo_sq_wait);
+ INIT_LIST_HEAD(&ctx->sqd_list);
+ INIT_LIST_HEAD(&ctx->cq_overflow_list);
+ INIT_LIST_HEAD(&ctx->io_buffers_cache);
+ io_alloc_cache_init(&ctx->apoll_cache);
+ io_alloc_cache_init(&ctx->netmsg_cache);
+ init_completion(&ctx->ref_comp);
+ xa_init_flags(&ctx->personalities, XA_FLAGS_ALLOC1);
+ mutex_init(&ctx->uring_lock);
+ init_waitqueue_head(&ctx->cq_wait);
+ spin_lock_init(&ctx->completion_lock);
+ spin_lock_init(&ctx->timeout_lock);
+ INIT_WQ_LIST(&ctx->iopoll_list);
+ INIT_LIST_HEAD(&ctx->io_buffers_pages);
+ INIT_LIST_HEAD(&ctx->io_buffers_comp);
+ INIT_LIST_HEAD(&ctx->defer_list);
+ INIT_LIST_HEAD(&ctx->timeout_list);
+ INIT_LIST_HEAD(&ctx->ltimeout_list);
+ spin_lock_init(&ctx->rsrc_ref_lock);
+ INIT_LIST_HEAD(&ctx->rsrc_ref_list);
+ INIT_DELAYED_WORK(&ctx->rsrc_put_work, io_rsrc_put_work);
+ init_llist_head(&ctx->rsrc_put_llist);
+ init_llist_head(&ctx->work_llist);
+ INIT_LIST_HEAD(&ctx->tctx_list);
+ ctx->submit_state.free_list.next = NULL;
+ INIT_WQ_LIST(&ctx->locked_free_list);
+ INIT_DELAYED_WORK(&ctx->fallback_work, io_fallback_req_func);
+ INIT_WQ_LIST(&ctx->submit_state.compl_reqs);
+ return ctx;
+err:
+ kfree(ctx->dummy_ubuf);
+ kfree(ctx->cancel_table.hbs);
+ kfree(ctx->cancel_table_locked.hbs);
+ kfree(ctx->io_bl);
+ xa_destroy(&ctx->io_bl_xa);
+ kfree(ctx);
+ return NULL;
+}
+
+static void io_account_cq_overflow(struct io_ring_ctx *ctx)
+{
+ struct io_rings *r = ctx->rings;
+
+ WRITE_ONCE(r->cq_overflow, READ_ONCE(r->cq_overflow) + 1);
+ ctx->cq_extra--;
+}
+
+static bool req_need_defer(struct io_kiocb *req, u32 seq)
+{
+ if (unlikely(req->flags & REQ_F_IO_DRAIN)) {
+ struct io_ring_ctx *ctx = req->ctx;
+
+ return seq + READ_ONCE(ctx->cq_extra) != ctx->cached_cq_tail;
+ }
+
+ return false;
+}
+
+static inline void io_req_track_inflight(struct io_kiocb *req)
+{
+ if (!(req->flags & REQ_F_INFLIGHT)) {
+ req->flags |= REQ_F_INFLIGHT;
+ atomic_inc(&req->task->io_uring->inflight_tracked);
+ }
+}
+
+static struct io_kiocb *__io_prep_linked_timeout(struct io_kiocb *req)
+{
+ if (WARN_ON_ONCE(!req->link))
+ return NULL;
+
+ req->flags &= ~REQ_F_ARM_LTIMEOUT;
+ req->flags |= REQ_F_LINK_TIMEOUT;
+
+ /* linked timeouts should have two refs once prep'ed */
+ io_req_set_refcount(req);
+ __io_req_set_refcount(req->link, 2);
+ return req->link;
+}
+
+static inline struct io_kiocb *io_prep_linked_timeout(struct io_kiocb *req)
+{
+ if (likely(!(req->flags & REQ_F_ARM_LTIMEOUT)))
+ return NULL;
+ return __io_prep_linked_timeout(req);
+}
+
+static noinline void __io_arm_ltimeout(struct io_kiocb *req)
+{
+ io_queue_linked_timeout(__io_prep_linked_timeout(req));
+}
+
+static inline void io_arm_ltimeout(struct io_kiocb *req)
+{
+ if (unlikely(req->flags & REQ_F_ARM_LTIMEOUT))
+ __io_arm_ltimeout(req);
+}
+
+static void io_prep_async_work(struct io_kiocb *req)
+{
+ const struct io_op_def *def = &io_op_defs[req->opcode];
+ struct io_ring_ctx *ctx = req->ctx;
+
+ if (!(req->flags & REQ_F_CREDS)) {
+ req->flags |= REQ_F_CREDS;
+ req->creds = get_current_cred();
+ }
+
+ req->work.list.next = NULL;
+ req->work.flags = 0;
+ req->work.cancel_seq = atomic_read(&ctx->cancel_seq);
+ if (req->flags & REQ_F_FORCE_ASYNC)
+ req->work.flags |= IO_WQ_WORK_CONCURRENT;
+
+ if (req->file && !io_req_ffs_set(req))
+ req->flags |= io_file_get_flags(req->file) << REQ_F_SUPPORT_NOWAIT_BIT;
+
+ if (req->flags & REQ_F_ISREG) {
+ if (def->hash_reg_file || (ctx->flags & IORING_SETUP_IOPOLL))
+ io_wq_hash_work(&req->work, file_inode(req->file));
+ } else if (!req->file || !S_ISBLK(file_inode(req->file)->i_mode)) {
+ if (def->unbound_nonreg_file)
+ req->work.flags |= IO_WQ_WORK_UNBOUND;
+ }
+}
+
+static void io_prep_async_link(struct io_kiocb *req)
+{
+ struct io_kiocb *cur;
+
+ if (req->flags & REQ_F_LINK_TIMEOUT) {
+ struct io_ring_ctx *ctx = req->ctx;
+
+ spin_lock_irq(&ctx->timeout_lock);
+ io_for_each_link(cur, req)
+ io_prep_async_work(cur);
+ spin_unlock_irq(&ctx->timeout_lock);
+ } else {
+ io_for_each_link(cur, req)
+ io_prep_async_work(cur);
+ }
+}
+
+void io_queue_iowq(struct io_kiocb *req, bool *dont_use)
+{
+ struct io_kiocb *link = io_prep_linked_timeout(req);
+ struct io_uring_task *tctx = req->task->io_uring;
+
+ BUG_ON(!tctx);
+ BUG_ON(!tctx->io_wq);
+
+ /* init ->work of the whole link before punting */
+ io_prep_async_link(req);
+
+ /*
+ * Not expected to happen, but if we do have a bug where this _can_
+ * happen, catch it here and ensure the request is marked as
+ * canceled. That will make io-wq go through the usual work cancel
+ * procedure rather than attempt to run this request (or create a new
+ * worker for it).
+ */
+ if (WARN_ON_ONCE(!same_thread_group(req->task, current)))
+ req->work.flags |= IO_WQ_WORK_CANCEL;
+
+ trace_io_uring_queue_async_work(req, io_wq_is_hashed(&req->work));
+ io_wq_enqueue(tctx->io_wq, &req->work);
+ if (link)
+ io_queue_linked_timeout(link);
+}
+
+static __cold void io_queue_deferred(struct io_ring_ctx *ctx)
+{
+ while (!list_empty(&ctx->defer_list)) {
+ struct io_defer_entry *de = list_first_entry(&ctx->defer_list,
+ struct io_defer_entry, list);
+
+ if (req_need_defer(de->req, de->seq))
+ break;
+ list_del_init(&de->list);
+ io_req_task_queue(de->req);
+ kfree(de);
+ }
+}
+
+
+static void io_eventfd_ops(struct rcu_head *rcu)
+{
+ struct io_ev_fd *ev_fd = container_of(rcu, struct io_ev_fd, rcu);
+ int ops = atomic_xchg(&ev_fd->ops, 0);
+
+ if (ops & BIT(IO_EVENTFD_OP_SIGNAL_BIT))
+ eventfd_signal_mask(ev_fd->cq_ev_fd, 1, EPOLL_URING_WAKE);
+
+ /* IO_EVENTFD_OP_FREE_BIT may not be set here depending on callback
+ * ordering in a race but if references are 0 we know we have to free
+ * it regardless.
+ */
+ if (atomic_dec_and_test(&ev_fd->refs)) {
+ eventfd_ctx_put(ev_fd->cq_ev_fd);
+ kfree(ev_fd);
+ }
+}
+
+static void io_eventfd_signal(struct io_ring_ctx *ctx)
+{
+ struct io_ev_fd *ev_fd = NULL;
+
+ rcu_read_lock();
+ /*
+ * rcu_dereference ctx->io_ev_fd once and use it for both for checking
+ * and eventfd_signal
+ */
+ ev_fd = rcu_dereference(ctx->io_ev_fd);
+
+ /*
+ * Check again if ev_fd exists incase an io_eventfd_unregister call
+ * completed between the NULL check of ctx->io_ev_fd at the start of
+ * the function and rcu_read_lock.
+ */
+ if (unlikely(!ev_fd))
+ goto out;
+ if (READ_ONCE(ctx->rings->cq_flags) & IORING_CQ_EVENTFD_DISABLED)
+ goto out;
+ if (ev_fd->eventfd_async && !io_wq_current_is_worker())
+ goto out;
+
+ if (likely(eventfd_signal_allowed())) {
+ eventfd_signal_mask(ev_fd->cq_ev_fd, 1, EPOLL_URING_WAKE);
+ } else {
+ atomic_inc(&ev_fd->refs);
+ if (!atomic_fetch_or(BIT(IO_EVENTFD_OP_SIGNAL_BIT), &ev_fd->ops))
+ call_rcu(&ev_fd->rcu, io_eventfd_ops);
+ else
+ atomic_dec(&ev_fd->refs);
+ }
+
+out:
+ rcu_read_unlock();
+}
+
+static void io_eventfd_flush_signal(struct io_ring_ctx *ctx)
+{
+ bool skip;
+
+ spin_lock(&ctx->completion_lock);
+
+ /*
+ * Eventfd should only get triggered when at least one event has been
+ * posted. Some applications rely on the eventfd notification count
+ * only changing IFF a new CQE has been added to the CQ ring. There's
+ * no depedency on 1:1 relationship between how many times this
+ * function is called (and hence the eventfd count) and number of CQEs
+ * posted to the CQ ring.
+ */
+ skip = ctx->cached_cq_tail == ctx->evfd_last_cq_tail;
+ ctx->evfd_last_cq_tail = ctx->cached_cq_tail;
+ spin_unlock(&ctx->completion_lock);
+ if (skip)
+ return;
+
+ io_eventfd_signal(ctx);
+}
+
+void __io_commit_cqring_flush(struct io_ring_ctx *ctx)
+{
+ if (ctx->off_timeout_used || ctx->drain_active) {
+ spin_lock(&ctx->completion_lock);
+ if (ctx->off_timeout_used)
+ io_flush_timeouts(ctx);
+ if (ctx->drain_active)
+ io_queue_deferred(ctx);
+ spin_unlock(&ctx->completion_lock);
+ }
+ if (ctx->has_evfd)
+ io_eventfd_flush_signal(ctx);
+}
+
+static inline void io_cqring_ev_posted(struct io_ring_ctx *ctx)
+{
+ io_commit_cqring_flush(ctx);
+ io_cqring_wake(ctx);
+}
+
+static inline void __io_cq_unlock_post(struct io_ring_ctx *ctx)
+ __releases(ctx->completion_lock)
+{
+ io_commit_cqring(ctx);
+ spin_unlock(&ctx->completion_lock);
+ io_cqring_ev_posted(ctx);
+}
+
+void io_cq_unlock_post(struct io_ring_ctx *ctx)
+{
+ __io_cq_unlock_post(ctx);
+}
+
+/* Returns true if there are no backlogged entries after the flush */
+static bool __io_cqring_overflow_flush(struct io_ring_ctx *ctx, bool force)
+{
+ bool all_flushed;
+ size_t cqe_size = sizeof(struct io_uring_cqe);
+
+ if (!force && __io_cqring_events(ctx) == ctx->cq_entries)
+ return false;
+
+ if (ctx->flags & IORING_SETUP_CQE32)
+ cqe_size <<= 1;
+
+ io_cq_lock(ctx);
+ while (!list_empty(&ctx->cq_overflow_list)) {
+ struct io_uring_cqe *cqe = io_get_cqe_overflow(ctx, true);
+ struct io_overflow_cqe *ocqe;
+
+ if (!cqe && !force)
+ break;
+ ocqe = list_first_entry(&ctx->cq_overflow_list,
+ struct io_overflow_cqe, list);
+ if (cqe)
+ memcpy(cqe, &ocqe->cqe, cqe_size);
+ else
+ io_account_cq_overflow(ctx);
+
+ list_del(&ocqe->list);
+ kfree(ocqe);
+ }
+
+ all_flushed = list_empty(&ctx->cq_overflow_list);
+ if (all_flushed) {
+ clear_bit(IO_CHECK_CQ_OVERFLOW_BIT, &ctx->check_cq);
+ atomic_andnot(IORING_SQ_CQ_OVERFLOW, &ctx->rings->sq_flags);
+ }
+
+ io_cq_unlock_post(ctx);
+ return all_flushed;
+}
+
+static bool io_cqring_overflow_flush(struct io_ring_ctx *ctx)
+{
+ bool ret = true;
+
+ if (test_bit(IO_CHECK_CQ_OVERFLOW_BIT, &ctx->check_cq)) {
+ /* iopoll syncs against uring_lock, not completion_lock */
+ if (ctx->flags & IORING_SETUP_IOPOLL)
+ mutex_lock(&ctx->uring_lock);
+ ret = __io_cqring_overflow_flush(ctx, false);
+ if (ctx->flags & IORING_SETUP_IOPOLL)
+ mutex_unlock(&ctx->uring_lock);
+ }
+
+ return ret;
+}
+
+void __io_put_task(struct task_struct *task, int nr)
+{
+ struct io_uring_task *tctx = task->io_uring;
+
+ percpu_counter_sub(&tctx->inflight, nr);
+ if (unlikely(atomic_read(&tctx->in_idle)))
+ wake_up(&tctx->wait);
+ put_task_struct_many(task, nr);
+}
+
+void io_task_refs_refill(struct io_uring_task *tctx)
+{
+ unsigned int refill = -tctx->cached_refs + IO_TCTX_REFS_CACHE_NR;
+
+ percpu_counter_add(&tctx->inflight, refill);
+ refcount_add(refill, &current->usage);
+ tctx->cached_refs += refill;
+}
+
+static __cold void io_uring_drop_tctx_refs(struct task_struct *task)
+{
+ struct io_uring_task *tctx = task->io_uring;
+ unsigned int refs = tctx->cached_refs;
+
+ if (refs) {
+ tctx->cached_refs = 0;
+ percpu_counter_sub(&tctx->inflight, refs);
+ put_task_struct_many(task, refs);
+ }
+}
+
+static bool io_cqring_event_overflow(struct io_ring_ctx *ctx, u64 user_data,
+ s32 res, u32 cflags, u64 extra1, u64 extra2)
+{
+ struct io_overflow_cqe *ocqe;
+ size_t ocq_size = sizeof(struct io_overflow_cqe);
+ bool is_cqe32 = (ctx->flags & IORING_SETUP_CQE32);
+
+ if (is_cqe32)
+ ocq_size += sizeof(struct io_uring_cqe);
+
+ ocqe = kmalloc(ocq_size, GFP_ATOMIC | __GFP_ACCOUNT);
+ trace_io_uring_cqe_overflow(ctx, user_data, res, cflags, ocqe);
+ if (!ocqe) {
+ /*
+ * If we're in ring overflow flush mode, or in task cancel mode,
+ * or cannot allocate an overflow entry, then we need to drop it
+ * on the floor.
+ */
+ io_account_cq_overflow(ctx);
+ set_bit(IO_CHECK_CQ_DROPPED_BIT, &ctx->check_cq);
+ return false;
+ }
+ if (list_empty(&ctx->cq_overflow_list)) {
+ set_bit(IO_CHECK_CQ_OVERFLOW_BIT, &ctx->check_cq);
+ atomic_or(IORING_SQ_CQ_OVERFLOW, &ctx->rings->sq_flags);
+
+ }
+ ocqe->cqe.user_data = user_data;
+ ocqe->cqe.res = res;
+ ocqe->cqe.flags = cflags;
+ if (is_cqe32) {
+ ocqe->cqe.big_cqe[0] = extra1;
+ ocqe->cqe.big_cqe[1] = extra2;
+ }
+ list_add_tail(&ocqe->list, &ctx->cq_overflow_list);
+ return true;
+}
+
+bool io_req_cqe_overflow(struct io_kiocb *req)
+{
+ if (!(req->flags & REQ_F_CQE32_INIT)) {
+ req->extra1 = 0;
+ req->extra2 = 0;
+ }
+ return io_cqring_event_overflow(req->ctx, req->cqe.user_data,
+ req->cqe.res, req->cqe.flags,
+ req->extra1, req->extra2);
+}
+
+/*
+ * writes to the cq entry need to come after reading head; the
+ * control dependency is enough as we're using WRITE_ONCE to
+ * fill the cq entry
+ */
+struct io_uring_cqe *__io_get_cqe(struct io_ring_ctx *ctx, bool overflow)
+{
+ struct io_rings *rings = ctx->rings;
+ unsigned int off = ctx->cached_cq_tail & (ctx->cq_entries - 1);
+ unsigned int free, queued, len;
+
+ /*
+ * Posting into the CQ when there are pending overflowed CQEs may break
+ * ordering guarantees, which will affect links, F_MORE users and more.
+ * Force overflow the completion.
+ */
+ if (!overflow && (ctx->check_cq & BIT(IO_CHECK_CQ_OVERFLOW_BIT)))
+ return NULL;
+
+ /* userspace may cheat modifying the tail, be safe and do min */
+ queued = min(__io_cqring_events(ctx), ctx->cq_entries);
+ free = ctx->cq_entries - queued;
+ /* we need a contiguous range, limit based on the current array offset */
+ len = min(free, ctx->cq_entries - off);
+ if (!len)
+ return NULL;
+
+ if (ctx->flags & IORING_SETUP_CQE32) {
+ off <<= 1;
+ len <<= 1;
+ }
+
+ ctx->cqe_cached = &rings->cqes[off];
+ ctx->cqe_sentinel = ctx->cqe_cached + len;
+
+ ctx->cached_cq_tail++;
+ ctx->cqe_cached++;
+ if (ctx->flags & IORING_SETUP_CQE32)
+ ctx->cqe_cached++;
+ return &rings->cqes[off];
+}
+
+bool io_fill_cqe_aux(struct io_ring_ctx *ctx, u64 user_data, s32 res, u32 cflags,
+ bool allow_overflow)
+{
+ struct io_uring_cqe *cqe;
+
+ ctx->cq_extra++;
+
+ /*
+ * If we can't get a cq entry, userspace overflowed the
+ * submission (by quite a lot). Increment the overflow count in
+ * the ring.
+ */
+ cqe = io_get_cqe(ctx);
+ if (likely(cqe)) {
+ trace_io_uring_complete(ctx, NULL, user_data, res, cflags, 0, 0);
+
+ WRITE_ONCE(cqe->user_data, user_data);
+ WRITE_ONCE(cqe->res, res);
+ WRITE_ONCE(cqe->flags, cflags);
+
+ if (ctx->flags & IORING_SETUP_CQE32) {
+ WRITE_ONCE(cqe->big_cqe[0], 0);
+ WRITE_ONCE(cqe->big_cqe[1], 0);
+ }
+ return true;
+ }
+
+ if (allow_overflow)
+ return io_cqring_event_overflow(ctx, user_data, res, cflags, 0, 0);
+
+ return false;
+}
+
+bool io_post_aux_cqe(struct io_ring_ctx *ctx,
+ u64 user_data, s32 res, u32 cflags,
+ bool allow_overflow)
+{
+ bool filled;
+
+ io_cq_lock(ctx);
+ filled = io_fill_cqe_aux(ctx, user_data, res, cflags, allow_overflow);
+ io_cq_unlock_post(ctx);
+ return filled;
+}
+
+void io_req_complete_post(struct io_kiocb *req)
+{
+ struct io_ring_ctx *ctx = req->ctx;
+
+ io_cq_lock(ctx);
+ if (!(req->flags & REQ_F_CQE_SKIP))
+ __io_fill_cqe_req(ctx, req);
+
+ /*
+ * If we're the last reference to this request, add to our locked
+ * free_list cache.
+ */
+ if (req_ref_put_and_test(req)) {
+ if (req->flags & IO_REQ_LINK_FLAGS) {
+ if (req->flags & IO_DISARM_MASK)
+ io_disarm_next(req);
+ if (req->link) {
+ io_req_task_queue(req->link);
+ req->link = NULL;
+ }
+ }
+ io_req_put_rsrc(req);
+ /*
+ * Selected buffer deallocation in io_clean_op() assumes that
+ * we don't hold ->completion_lock. Clean them here to avoid
+ * deadlocks.
+ */
+ io_put_kbuf_comp(req);
+ io_dismantle_req(req);
+ io_put_task(req->task, 1);
+ wq_list_add_head(&req->comp_list, &ctx->locked_free_list);
+ ctx->locked_free_nr++;
+ }
+ io_cq_unlock_post(ctx);
+}
+
+inline void __io_req_complete(struct io_kiocb *req, unsigned issue_flags)
+{
+ io_req_complete_post(req);
+}
+
+void io_req_complete_failed(struct io_kiocb *req, s32 res)
+ __must_hold(&ctx->uring_lock)
+{
+ const struct io_op_def *def = &io_op_defs[req->opcode];
+
+ lockdep_assert_held(&req->ctx->uring_lock);
+
+ req_set_fail(req);
+ io_req_set_res(req, res, io_put_kbuf(req, IO_URING_F_UNLOCKED));
+ if (def->fail)
+ def->fail(req);
+ io_req_complete_post(req);
+}
+
+/*
+ * Don't initialise the fields below on every allocation, but do that in
+ * advance and keep them valid across allocations.
+ */
+static void io_preinit_req(struct io_kiocb *req, struct io_ring_ctx *ctx)
+{
+ req->ctx = ctx;
+ req->link = NULL;
+ req->async_data = NULL;
+ /* not necessary, but safer to zero */
+ req->cqe.res = 0;
+}
+
+static void io_flush_cached_locked_reqs(struct io_ring_ctx *ctx,
+ struct io_submit_state *state)
+{
+ spin_lock(&ctx->completion_lock);
+ wq_list_splice(&ctx->locked_free_list, &state->free_list);
+ ctx->locked_free_nr = 0;
+ spin_unlock(&ctx->completion_lock);
+}
+
+/*
+ * A request might get retired back into the request caches even before opcode
+ * handlers and io_issue_sqe() are done with it, e.g. inline completion path.
+ * Because of that, io_alloc_req() should be called only under ->uring_lock
+ * and with extra caution to not get a request that is still worked on.
+ */
+__cold bool __io_alloc_req_refill(struct io_ring_ctx *ctx)
+ __must_hold(&ctx->uring_lock)
+{
+ gfp_t gfp = GFP_KERNEL | __GFP_NOWARN;
+ void *reqs[IO_REQ_ALLOC_BATCH];
+ int ret, i;
+
+ /*
+ * If we have more than a batch's worth of requests in our IRQ side
+ * locked cache, grab the lock and move them over to our submission
+ * side cache.
+ */
+ if (data_race(ctx->locked_free_nr) > IO_COMPL_BATCH) {
+ io_flush_cached_locked_reqs(ctx, &ctx->submit_state);
+ if (!io_req_cache_empty(ctx))
+ return true;
+ }
+
+ ret = kmem_cache_alloc_bulk(req_cachep, gfp, ARRAY_SIZE(reqs), reqs);
+
+ /*
+ * Bulk alloc is all-or-nothing. If we fail to get a batch,
+ * retry single alloc to be on the safe side.
+ */
+ if (unlikely(ret <= 0)) {
+ reqs[0] = kmem_cache_alloc(req_cachep, gfp);
+ if (!reqs[0])
+ return false;
+ ret = 1;
+ }
+
+ percpu_ref_get_many(&ctx->refs, ret);
+ for (i = 0; i < ret; i++) {
+ struct io_kiocb *req = reqs[i];
+
+ io_preinit_req(req, ctx);
+ io_req_add_to_cache(req, ctx);
+ }
+ return true;
+}
+
+static inline void io_dismantle_req(struct io_kiocb *req)
+{
+ unsigned int flags = req->flags;
+
+ if (unlikely(flags & IO_REQ_CLEAN_FLAGS))
+ io_clean_op(req);
+ if (!(flags & REQ_F_FIXED_FILE))
+ io_put_file(req->file);
+}
+
+__cold void io_free_req(struct io_kiocb *req)
+{
+ struct io_ring_ctx *ctx = req->ctx;
+
+ io_req_put_rsrc(req);
+ io_dismantle_req(req);
+ io_put_task(req->task, 1);
+
+ spin_lock(&ctx->completion_lock);
+ wq_list_add_head(&req->comp_list, &ctx->locked_free_list);
+ ctx->locked_free_nr++;
+ spin_unlock(&ctx->completion_lock);
+}
+
+static void __io_req_find_next_prep(struct io_kiocb *req)
+{
+ struct io_ring_ctx *ctx = req->ctx;
+
+ io_cq_lock(ctx);
+ io_disarm_next(req);
+ io_cq_unlock_post(ctx);
+}
+
+static inline struct io_kiocb *io_req_find_next(struct io_kiocb *req)
+{
+ struct io_kiocb *nxt;
+
+ /*
+ * If LINK is set, we have dependent requests in this chain. If we
+ * didn't fail this request, queue the first one up, moving any other
+ * dependencies to the next request. In case of failure, fail the rest
+ * of the chain.
+ */
+ if (unlikely(req->flags & IO_DISARM_MASK))
+ __io_req_find_next_prep(req);
+ nxt = req->link;
+ req->link = NULL;
+ return nxt;
+}
+
+static void ctx_flush_and_put(struct io_ring_ctx *ctx, bool *locked)
+{
+ if (!ctx)
+ return;
+ if (ctx->flags & IORING_SETUP_TASKRUN_FLAG)
+ atomic_andnot(IORING_SQ_TASKRUN, &ctx->rings->sq_flags);
+ if (*locked) {
+ io_submit_flush_completions(ctx);
+ mutex_unlock(&ctx->uring_lock);
+ *locked = false;
+ }
+ percpu_ref_put(&ctx->refs);
+}
+
+static unsigned int handle_tw_list(struct llist_node *node,
+ struct io_ring_ctx **ctx, bool *locked,
+ struct llist_node *last)
+{
+ unsigned int count = 0;
+
+ while (node != last) {
+ struct llist_node *next = node->next;
+ struct io_kiocb *req = container_of(node, struct io_kiocb,
+ io_task_work.node);
+
+ prefetch(container_of(next, struct io_kiocb, io_task_work.node));
+
+ if (req->ctx != *ctx) {
+ ctx_flush_and_put(*ctx, locked);
+ *ctx = req->ctx;
+ /* if not contended, grab and improve batching */
+ *locked = mutex_trylock(&(*ctx)->uring_lock);
+ percpu_ref_get(&(*ctx)->refs);
+ } else if (!*locked)
+ *locked = mutex_trylock(&(*ctx)->uring_lock);
+ req->io_task_work.func(req, locked);
+ node = next;
+ count++;
+ if (unlikely(need_resched())) {
+ ctx_flush_and_put(*ctx, locked);
+ *ctx = NULL;
+ cond_resched();
+ }
+ }
+
+ return count;
+}
+
+/**
+ * io_llist_xchg - swap all entries in a lock-less list
+ * @head: the head of lock-less list to delete all entries
+ * @new: new entry as the head of the list
+ *
+ * If list is empty, return NULL, otherwise, return the pointer to the first entry.
+ * The order of entries returned is from the newest to the oldest added one.
+ */
+static inline struct llist_node *io_llist_xchg(struct llist_head *head,
+ struct llist_node *new)
+{
+ return xchg(&head->first, new);
+}
+
+/**
+ * io_llist_cmpxchg - possibly swap all entries in a lock-less list
+ * @head: the head of lock-less list to delete all entries
+ * @old: expected old value of the first entry of the list
+ * @new: new entry as the head of the list
+ *
+ * perform a cmpxchg on the first entry of the list.
+ */
+
+static inline struct llist_node *io_llist_cmpxchg(struct llist_head *head,
+ struct llist_node *old,
+ struct llist_node *new)
+{
+ return cmpxchg(&head->first, old, new);
+}
+
+void tctx_task_work(struct callback_head *cb)
+{
+ bool uring_locked = false;
+ struct io_ring_ctx *ctx = NULL;
+ struct io_uring_task *tctx = container_of(cb, struct io_uring_task,
+ task_work);
+ struct llist_node fake = {};
+ struct llist_node *node = io_llist_xchg(&tctx->task_list, &fake);
+ unsigned int loops = 1;
+ unsigned int count = handle_tw_list(node, &ctx, &uring_locked, NULL);
+
+ node = io_llist_cmpxchg(&tctx->task_list, &fake, NULL);
+ while (node != &fake) {
+ loops++;
+ node = io_llist_xchg(&tctx->task_list, &fake);
+ count += handle_tw_list(node, &ctx, &uring_locked, &fake);
+ node = io_llist_cmpxchg(&tctx->task_list, &fake, NULL);
+ }
+
+ ctx_flush_and_put(ctx, &uring_locked);
+
+ /* relaxed read is enough as only the task itself sets ->in_idle */
+ if (unlikely(atomic_read(&tctx->in_idle)))
+ io_uring_drop_tctx_refs(current);
+
+ trace_io_uring_task_work_run(tctx, count, loops);
+}
+
+static void io_req_local_work_add(struct io_kiocb *req)
+{
+ struct io_ring_ctx *ctx = req->ctx;
+
+ percpu_ref_get(&ctx->refs);
+
+ if (!llist_add(&req->io_task_work.node, &ctx->work_llist)) {
+ percpu_ref_put(&ctx->refs);
+ return;
+ }
+ /* need it for the following io_cqring_wake() */
+ smp_mb__after_atomic();
+
+ if (unlikely(atomic_read(&req->task->io_uring->in_idle))) {
+ io_move_task_work_from_local(ctx);
+ percpu_ref_put(&ctx->refs);
+ return;
+ }
+
+ if (ctx->flags & IORING_SETUP_TASKRUN_FLAG)
+ atomic_or(IORING_SQ_TASKRUN, &ctx->rings->sq_flags);
+
+ if (ctx->has_evfd)
+ io_eventfd_signal(ctx);
+ __io_cqring_wake(ctx);
+ percpu_ref_put(&ctx->refs);
+}
+
+void __io_req_task_work_add(struct io_kiocb *req, bool allow_local)
+{
+ struct io_uring_task *tctx = req->task->io_uring;
+ struct io_ring_ctx *ctx = req->ctx;
+ struct llist_node *node;
+
+ if (allow_local && ctx->flags & IORING_SETUP_DEFER_TASKRUN) {
+ io_req_local_work_add(req);
+ return;
+ }
+
+ /* task_work already pending, we're done */
+ if (!llist_add(&req->io_task_work.node, &tctx->task_list))
+ return;
+
+ if (ctx->flags & IORING_SETUP_TASKRUN_FLAG)
+ atomic_or(IORING_SQ_TASKRUN, &ctx->rings->sq_flags);
+
+ if (likely(!task_work_add(req->task, &tctx->task_work, ctx->notify_method)))
+ return;
+
+ node = llist_del_all(&tctx->task_list);
+
+ while (node) {
+ req = container_of(node, struct io_kiocb, io_task_work.node);
+ node = node->next;
+ if (llist_add(&req->io_task_work.node,
+ &req->ctx->fallback_llist))
+ schedule_delayed_work(&req->ctx->fallback_work, 1);
+ }
+}
+
+static void __cold io_move_task_work_from_local(struct io_ring_ctx *ctx)
+{
+ struct llist_node *node;
+
+ node = llist_del_all(&ctx->work_llist);
+ while (node) {
+ struct io_kiocb *req = container_of(node, struct io_kiocb,
+ io_task_work.node);
+
+ node = node->next;
+ __io_req_task_work_add(req, false);
+ }
+}
+
+int __io_run_local_work(struct io_ring_ctx *ctx, bool *locked)
+{
+ struct llist_node *node;
+ struct llist_node fake;
+ struct llist_node *current_final = NULL;
+ int ret;
+ unsigned int loops = 1;
+
+ if (unlikely(ctx->submitter_task != current))
+ return -EEXIST;
+
+ node = io_llist_xchg(&ctx->work_llist, &fake);
+ ret = 0;
+again:
+ while (node != current_final) {
+ struct llist_node *next = node->next;
+ struct io_kiocb *req = container_of(node, struct io_kiocb,
+ io_task_work.node);
+ prefetch(container_of(next, struct io_kiocb, io_task_work.node));
+ req->io_task_work.func(req, locked);
+ ret++;
+ node = next;
+ }
+
+ if (ctx->flags & IORING_SETUP_TASKRUN_FLAG)
+ atomic_andnot(IORING_SQ_TASKRUN, &ctx->rings->sq_flags);
+
+ node = io_llist_cmpxchg(&ctx->work_llist, &fake, NULL);
+ if (node != &fake) {
+ loops++;
+ current_final = &fake;
+ node = io_llist_xchg(&ctx->work_llist, &fake);
+ goto again;
+ }
+
+ if (*locked)
+ io_submit_flush_completions(ctx);
+ trace_io_uring_local_work_run(ctx, ret, loops);
+ return ret;
+
+}
+
+int io_run_local_work(struct io_ring_ctx *ctx)
+{
+ bool locked;
+ int ret;
+
+ if (llist_empty(&ctx->work_llist))
+ return 0;
+
+ __set_current_state(TASK_RUNNING);
+ locked = mutex_trylock(&ctx->uring_lock);
+ ret = __io_run_local_work(ctx, &locked);
+ if (locked)
+ mutex_unlock(&ctx->uring_lock);
+
+ return ret;
+}
+
+static void io_req_task_cancel(struct io_kiocb *req, bool *locked)
+{
+ /* not needed for normal modes, but SQPOLL depends on it */
+ io_tw_lock(req->ctx, locked);
+ io_req_complete_failed(req, req->cqe.res);
+}
+
+void io_req_task_submit(struct io_kiocb *req, bool *locked)
+{
+ io_tw_lock(req->ctx, locked);
+ /* req->task == current here, checking PF_EXITING is safe */
+ if (likely(!(req->task->flags & PF_EXITING)))
+ io_queue_sqe(req);
+ else
+ io_req_complete_failed(req, -EFAULT);
+}
+
+void io_req_task_queue_fail(struct io_kiocb *req, int ret)
+{
+ io_req_set_res(req, ret, 0);
+ req->io_task_work.func = io_req_task_cancel;
+ io_req_task_work_add(req);
+}
+
+void io_req_task_queue(struct io_kiocb *req)
+{
+ req->io_task_work.func = io_req_task_submit;
+ io_req_task_work_add(req);
+}
+
+void io_queue_next(struct io_kiocb *req)
+{
+ struct io_kiocb *nxt = io_req_find_next(req);
+
+ if (nxt)
+ io_req_task_queue(nxt);
+}
+
+void io_free_batch_list(struct io_ring_ctx *ctx, struct io_wq_work_node *node)
+ __must_hold(&ctx->uring_lock)
+{
+ struct task_struct *task = NULL;
+ int task_refs = 0;
+
+ do {
+ struct io_kiocb *req = container_of(node, struct io_kiocb,
+ comp_list);
+
+ if (unlikely(req->flags & IO_REQ_CLEAN_SLOW_FLAGS)) {
+ if (req->flags & REQ_F_REFCOUNT) {
+ node = req->comp_list.next;
+ if (!req_ref_put_and_test(req))
+ continue;
+ }
+ if ((req->flags & REQ_F_POLLED) && req->apoll) {
+ struct async_poll *apoll = req->apoll;
+
+ if (apoll->double_poll)
+ kfree(apoll->double_poll);
+ if (!io_alloc_cache_put(&ctx->apoll_cache, &apoll->cache))
+ kfree(apoll);
+ req->flags &= ~REQ_F_POLLED;
+ }
+ if (req->flags & IO_REQ_LINK_FLAGS)
+ io_queue_next(req);
+ if (unlikely(req->flags & IO_REQ_CLEAN_FLAGS))
+ io_clean_op(req);
+ }
+ if (!(req->flags & REQ_F_FIXED_FILE))
+ io_put_file(req->file);
+
+ io_req_put_rsrc_locked(req, ctx);
+
+ if (req->task != task) {
+ if (task)
+ io_put_task(task, task_refs);
+ task = req->task;
+ task_refs = 0;
+ }
+ task_refs++;
+ node = req->comp_list.next;
+ io_req_add_to_cache(req, ctx);
+ } while (node);
+
+ if (task)
+ io_put_task(task, task_refs);
+}
+
+static void __io_submit_flush_completions(struct io_ring_ctx *ctx)
+ __must_hold(&ctx->uring_lock)
+{
+ struct io_wq_work_node *node, *prev;
+ struct io_submit_state *state = &ctx->submit_state;
+
+ io_cq_lock(ctx);
+ wq_list_for_each(node, prev, &state->compl_reqs) {
+ struct io_kiocb *req = container_of(node, struct io_kiocb,
+ comp_list);
+
+ if (!(req->flags & REQ_F_CQE_SKIP))
+ __io_fill_cqe_req(ctx, req);
+ }
+ __io_cq_unlock_post(ctx);
+
+ io_free_batch_list(ctx, state->compl_reqs.first);
+ INIT_WQ_LIST(&state->compl_reqs);
+}
+
+/*
+ * Drop reference to request, return next in chain (if there is one) if this
+ * was the last reference to this request.
+ */
+static inline struct io_kiocb *io_put_req_find_next(struct io_kiocb *req)
+{
+ struct io_kiocb *nxt = NULL;
+
+ if (req_ref_put_and_test(req)) {
+ if (unlikely(req->flags & IO_REQ_LINK_FLAGS))
+ nxt = io_req_find_next(req);
+ io_free_req(req);
+ }
+ return nxt;
+}
+
+static unsigned io_cqring_events(struct io_ring_ctx *ctx)
+{
+ /* See comment at the top of this file */
+ smp_rmb();
+ return __io_cqring_events(ctx);
+}
+
+/*
+ * We can't just wait for polled events to come to us, we have to actively
+ * find and complete them.
+ */
+static __cold void io_iopoll_try_reap_events(struct io_ring_ctx *ctx)
+{
+ if (!(ctx->flags & IORING_SETUP_IOPOLL))
+ return;
+
+ percpu_ref_get(&ctx->refs);
+ mutex_lock(&ctx->uring_lock);
+ while (!wq_list_empty(&ctx->iopoll_list)) {
+ /* let it sleep and repeat later if can't complete a request */
+ if (io_do_iopoll(ctx, true) == 0)
+ break;
+ /*
+ * Ensure we allow local-to-the-cpu processing to take place,
+ * in this case we need to ensure that we reap all events.
+ * Also let task_work, etc. to progress by releasing the mutex
+ */
+ if (need_resched()) {
+ mutex_unlock(&ctx->uring_lock);
+ cond_resched();
+ mutex_lock(&ctx->uring_lock);
+ }
+ }
+ mutex_unlock(&ctx->uring_lock);
+ percpu_ref_put(&ctx->refs);
+}
+
+static int io_iopoll_check(struct io_ring_ctx *ctx, long min)
+{
+ unsigned int nr_events = 0;
+ int ret = 0;
+ unsigned long check_cq;
+
+ if (!io_allowed_run_tw(ctx))
+ return -EEXIST;
+
+ check_cq = READ_ONCE(ctx->check_cq);
+ if (unlikely(check_cq)) {
+ if (check_cq & BIT(IO_CHECK_CQ_OVERFLOW_BIT))
+ __io_cqring_overflow_flush(ctx, false);
+ /*
+ * Similarly do not spin if we have not informed the user of any
+ * dropped CQE.
+ */
+ if (check_cq & BIT(IO_CHECK_CQ_DROPPED_BIT))
+ return -EBADR;
+ }
+ /*
+ * Don't enter poll loop if we already have events pending.
+ * If we do, we can potentially be spinning for commands that
+ * already triggered a CQE (eg in error).
+ */
+ if (io_cqring_events(ctx))
+ return 0;
+
+ do {
+ /*
+ * If a submit got punted to a workqueue, we can have the
+ * application entering polling for a command before it gets
+ * issued. That app will hold the uring_lock for the duration
+ * of the poll right here, so we need to take a breather every
+ * now and then to ensure that the issue has a chance to add
+ * the poll to the issued list. Otherwise we can spin here
+ * forever, while the workqueue is stuck trying to acquire the
+ * very same mutex.
+ */
+ if (wq_list_empty(&ctx->iopoll_list) ||
+ io_task_work_pending(ctx)) {
+ u32 tail = ctx->cached_cq_tail;
+
+ (void) io_run_local_work_locked(ctx);
+
+ if (task_work_pending(current) ||
+ wq_list_empty(&ctx->iopoll_list)) {
+ mutex_unlock(&ctx->uring_lock);
+ io_run_task_work();
+ mutex_lock(&ctx->uring_lock);
+ }
+ /* some requests don't go through iopoll_list */
+ if (tail != ctx->cached_cq_tail ||
+ wq_list_empty(&ctx->iopoll_list))
+ break;
+ }
+ ret = io_do_iopoll(ctx, !min);
+ if (ret < 0)
+ break;
+ nr_events += ret;
+ ret = 0;
+
+ if (task_sigpending(current))
+ return -EINTR;
+ } while (nr_events < min && !need_resched());
+
+ return ret;
+}
+
+void io_req_task_complete(struct io_kiocb *req, bool *locked)
+{
+ if (req->flags & (REQ_F_BUFFER_SELECTED|REQ_F_BUFFER_RING)) {
+ unsigned issue_flags = *locked ? 0 : IO_URING_F_UNLOCKED;
+
+ req->cqe.flags |= io_put_kbuf(req, issue_flags);
+ }
+
+ if (*locked)
+ io_req_complete_defer(req);
+ else
+ io_req_complete_post(req);
+}
+
+/*
+ * After the iocb has been issued, it's safe to be found on the poll list.
+ * Adding the kiocb to the list AFTER submission ensures that we don't
+ * find it from a io_do_iopoll() thread before the issuer is done
+ * accessing the kiocb cookie.
+ */
+static void io_iopoll_req_issued(struct io_kiocb *req, unsigned int issue_flags)
+{
+ struct io_ring_ctx *ctx = req->ctx;
+ const bool needs_lock = issue_flags & IO_URING_F_UNLOCKED;
+
+ /* workqueue context doesn't hold uring_lock, grab it now */
+ if (unlikely(needs_lock))
+ mutex_lock(&ctx->uring_lock);
+
+ /*
+ * Track whether we have multiple files in our lists. This will impact
+ * how we do polling eventually, not spinning if we're on potentially
+ * different devices.
+ */
+ if (wq_list_empty(&ctx->iopoll_list)) {
+ ctx->poll_multi_queue = false;
+ } else if (!ctx->poll_multi_queue) {
+ struct io_kiocb *list_req;
+
+ list_req = container_of(ctx->iopoll_list.first, struct io_kiocb,
+ comp_list);
+ if (list_req->file != req->file)
+ ctx->poll_multi_queue = true;
+ }
+
+ /*
+ * For fast devices, IO may have already completed. If it has, add
+ * it to the front so we find it first.
+ */
+ if (READ_ONCE(req->iopoll_completed))
+ wq_list_add_head(&req->comp_list, &ctx->iopoll_list);
+ else
+ wq_list_add_tail(&req->comp_list, &ctx->iopoll_list);
+
+ if (unlikely(needs_lock)) {
+ /*
+ * If IORING_SETUP_SQPOLL is enabled, sqes are either handle
+ * in sq thread task context or in io worker task context. If
+ * current task context is sq thread, we don't need to check
+ * whether should wake up sq thread.
+ */
+ if ((ctx->flags & IORING_SETUP_SQPOLL) &&
+ wq_has_sleeper(&ctx->sq_data->wait))
+ wake_up(&ctx->sq_data->wait);
+
+ mutex_unlock(&ctx->uring_lock);
+ }
+}
+
+static bool io_bdev_nowait(struct block_device *bdev)
+{
+ return !bdev || bdev_nowait(bdev);
+}
+
+/*
+ * If we tracked the file through the SCM inflight mechanism, we could support
+ * any file. For now, just ensure that anything potentially problematic is done
+ * inline.
+ */
+static bool __io_file_supports_nowait(struct file *file, umode_t mode)
+{
+ if (S_ISBLK(mode)) {
+ if (IS_ENABLED(CONFIG_BLOCK) &&
+ io_bdev_nowait(I_BDEV(file->f_mapping->host)))
+ return true;
+ return false;
+ }
+ if (S_ISSOCK(mode))
+ return true;
+ if (S_ISREG(mode)) {
+ if (IS_ENABLED(CONFIG_BLOCK) &&
+ io_bdev_nowait(file->f_inode->i_sb->s_bdev) &&
+ !io_is_uring_fops(file))
+ return true;
+ return false;
+ }
+
+ /* any ->read/write should understand O_NONBLOCK */
+ if (file->f_flags & O_NONBLOCK)
+ return true;
+ return file->f_mode & FMODE_NOWAIT;
+}
+
+/*
+ * If we tracked the file through the SCM inflight mechanism, we could support
+ * any file. For now, just ensure that anything potentially problematic is done
+ * inline.
+ */
+unsigned int io_file_get_flags(struct file *file)
+{
+ umode_t mode = file_inode(file)->i_mode;
+ unsigned int res = 0;
+
+ if (S_ISREG(mode))
+ res |= FFS_ISREG;
+ if (__io_file_supports_nowait(file, mode))
+ res |= FFS_NOWAIT;
+ return res;
+}
+
+bool io_alloc_async_data(struct io_kiocb *req)
+{
+ WARN_ON_ONCE(!io_op_defs[req->opcode].async_size);
+ req->async_data = kmalloc(io_op_defs[req->opcode].async_size, GFP_KERNEL);
+ if (req->async_data) {
+ req->flags |= REQ_F_ASYNC_DATA;
+ return false;
+ }
+ return true;
+}
+
+int io_req_prep_async(struct io_kiocb *req)
+{
+ const struct io_op_def *def = &io_op_defs[req->opcode];
+
+ /* assign early for deferred execution for non-fixed file */
+ if (def->needs_file && !(req->flags & REQ_F_FIXED_FILE) && !req->file)
+ req->file = io_file_get_normal(req, req->cqe.fd);
+ if (!def->prep_async)
+ return 0;
+ if (WARN_ON_ONCE(req_has_async_data(req)))
+ return -EFAULT;
+ if (!io_op_defs[req->opcode].manual_alloc) {
+ if (io_alloc_async_data(req))
+ return -EAGAIN;
+ }
+ return def->prep_async(req);
+}
+
+static u32 io_get_sequence(struct io_kiocb *req)
+{
+ u32 seq = req->ctx->cached_sq_head;
+ struct io_kiocb *cur;
+
+ /* need original cached_sq_head, but it was increased for each req */
+ io_for_each_link(cur, req)
+ seq--;
+ return seq;
+}
+
+static __cold void io_drain_req(struct io_kiocb *req)
+ __must_hold(&ctx->uring_lock)
+{
+ struct io_ring_ctx *ctx = req->ctx;
+ struct io_defer_entry *de;
+ int ret;
+ u32 seq = io_get_sequence(req);
+
+ /* Still need defer if there is pending req in defer list. */
+ spin_lock(&ctx->completion_lock);
+ if (!req_need_defer(req, seq) && list_empty_careful(&ctx->defer_list)) {
+ spin_unlock(&ctx->completion_lock);
+queue:
+ ctx->drain_active = false;
+ io_req_task_queue(req);
+ return;
+ }
+ spin_unlock(&ctx->completion_lock);
+
+ io_prep_async_link(req);
+ de = kmalloc(sizeof(*de), GFP_KERNEL);
+ if (!de) {
+ ret = -ENOMEM;
+ io_req_complete_failed(req, ret);
+ return;
+ }
+
+ spin_lock(&ctx->completion_lock);
+ if (!req_need_defer(req, seq) && list_empty(&ctx->defer_list)) {
+ spin_unlock(&ctx->completion_lock);
+ kfree(de);
+ goto queue;
+ }
+
+ trace_io_uring_defer(req);
+ de->req = req;
+ de->seq = seq;
+ list_add_tail(&de->list, &ctx->defer_list);
+ spin_unlock(&ctx->completion_lock);
+}
+
+static void io_clean_op(struct io_kiocb *req)
+{
+ if (req->flags & REQ_F_BUFFER_SELECTED) {
+ spin_lock(&req->ctx->completion_lock);
+ io_put_kbuf_comp(req);
+ spin_unlock(&req->ctx->completion_lock);
+ }
+
+ if (req->flags & REQ_F_NEED_CLEANUP) {
+ const struct io_op_def *def = &io_op_defs[req->opcode];
+
+ if (def->cleanup)
+ def->cleanup(req);
+ }
+ if ((req->flags & REQ_F_POLLED) && req->apoll) {
+ kfree(req->apoll->double_poll);
+ kfree(req->apoll);
+ req->apoll = NULL;
+ }
+ if (req->flags & REQ_F_INFLIGHT) {
+ struct io_uring_task *tctx = req->task->io_uring;
+
+ atomic_dec(&tctx->inflight_tracked);
+ }
+ if (req->flags & REQ_F_CREDS)
+ put_cred(req->creds);
+ if (req->flags & REQ_F_ASYNC_DATA) {
+ kfree(req->async_data);
+ req->async_data = NULL;
+ }
+ req->flags &= ~IO_REQ_CLEAN_FLAGS;
+}
+
+static bool io_assign_file(struct io_kiocb *req, unsigned int issue_flags)
+{
+ if (req->file || !io_op_defs[req->opcode].needs_file)
+ return true;
+
+ if (req->flags & REQ_F_FIXED_FILE)
+ req->file = io_file_get_fixed(req, req->cqe.fd, issue_flags);
+ else
+ req->file = io_file_get_normal(req, req->cqe.fd);
+
+ return !!req->file;
+}
+
+static int io_issue_sqe(struct io_kiocb *req, unsigned int issue_flags)
+{
+ const struct io_op_def *def = &io_op_defs[req->opcode];
+ const struct cred *creds = NULL;
+ int ret;
+
+ if (unlikely(!io_assign_file(req, issue_flags)))
+ return -EBADF;
+
+ if (unlikely((req->flags & REQ_F_CREDS) && req->creds != current_cred()))
+ creds = override_creds(req->creds);
+
+ if (!def->audit_skip)
+ audit_uring_entry(req->opcode);
+
+ ret = def->issue(req, issue_flags);
+
+ if (!def->audit_skip)
+ audit_uring_exit(!ret, ret);
+
+ if (creds)
+ revert_creds(creds);
+
+ if (ret == IOU_OK) {
+ if (issue_flags & IO_URING_F_COMPLETE_DEFER)
+ io_req_complete_defer(req);
+ else
+ io_req_complete_post(req);
+ } else if (ret != IOU_ISSUE_SKIP_COMPLETE)
+ return ret;
+
+ /* If the op doesn't have a file, we're not polling for it */
+ if ((req->ctx->flags & IORING_SETUP_IOPOLL) && def->iopoll_queue)
+ io_iopoll_req_issued(req, issue_flags);
+
+ return 0;
+}
+
+int io_poll_issue(struct io_kiocb *req, bool *locked)
+{
+ io_tw_lock(req->ctx, locked);
+ if (unlikely(req->task->flags & PF_EXITING))
+ return -EFAULT;
+ return io_issue_sqe(req, IO_URING_F_NONBLOCK|IO_URING_F_MULTISHOT);
+}
+
+struct io_wq_work *io_wq_free_work(struct io_wq_work *work)
+{
+ struct io_kiocb *req = container_of(work, struct io_kiocb, work);
+
+ req = io_put_req_find_next(req);
+ return req ? &req->work : NULL;
+}
+
+void io_wq_submit_work(struct io_wq_work *work)
+{
+ struct io_kiocb *req = container_of(work, struct io_kiocb, work);
+ const struct io_op_def *def = &io_op_defs[req->opcode];
+ unsigned int issue_flags = IO_URING_F_UNLOCKED;
+ bool needs_poll = false;
+ int ret = 0, err = -ECANCELED;
+
+ /* one will be dropped by ->io_free_work() after returning to io-wq */
+ if (!(req->flags & REQ_F_REFCOUNT))
+ __io_req_set_refcount(req, 2);
+ else
+ req_ref_get(req);
+
+ io_arm_ltimeout(req);
+
+ /* either cancelled or io-wq is dying, so don't touch tctx->iowq */
+ if (work->flags & IO_WQ_WORK_CANCEL) {
+fail:
+ io_req_task_queue_fail(req, err);
+ return;
+ }
+ if (!io_assign_file(req, issue_flags)) {
+ err = -EBADF;
+ work->flags |= IO_WQ_WORK_CANCEL;
+ goto fail;
+ }
+
+ if (req->flags & REQ_F_FORCE_ASYNC) {
+ bool opcode_poll = def->pollin || def->pollout;
+
+ if (opcode_poll && file_can_poll(req->file)) {
+ needs_poll = true;
+ issue_flags |= IO_URING_F_NONBLOCK;
+ }
+ }
+
+ do {
+ ret = io_issue_sqe(req, issue_flags);
+ if (ret != -EAGAIN)
+ break;
+
+ /*
+ * If REQ_F_NOWAIT is set, then don't wait or retry with
+ * poll. -EAGAIN is final for that case.
+ */
+ if (req->flags & REQ_F_NOWAIT)
+ break;
+
+ /*
+ * We can get EAGAIN for iopolled IO even though we're
+ * forcing a sync submission from here, since we can't
+ * wait for request slots on the block side.
+ */
+ if (!needs_poll) {
+ if (!(req->ctx->flags & IORING_SETUP_IOPOLL))
+ break;
+ if (io_wq_worker_stopped())
+ break;
+ cond_resched();
+ continue;
+ }
+
+ if (io_arm_poll_handler(req, issue_flags) == IO_APOLL_OK)
+ return;
+ /* aborted or ready, in either case retry blocking */
+ needs_poll = false;
+ issue_flags &= ~IO_URING_F_NONBLOCK;
+ } while (1);
+
+ /* avoid locking problems by failing it from a clean context */
+ if (ret < 0)
+ io_req_task_queue_fail(req, ret);
+}
+
+inline struct file *io_file_get_fixed(struct io_kiocb *req, int fd,
+ unsigned int issue_flags)
+{
+ struct io_ring_ctx *ctx = req->ctx;
+ struct file *file = NULL;
+ unsigned long file_ptr;
+
+ io_ring_submit_lock(ctx, issue_flags);
+
+ if (unlikely((unsigned int)fd >= ctx->nr_user_files))
+ goto out;
+ fd = array_index_nospec(fd, ctx->nr_user_files);
+ file_ptr = io_fixed_file_slot(&ctx->file_table, fd)->file_ptr;
+ file = (struct file *) (file_ptr & FFS_MASK);
+ file_ptr &= ~FFS_MASK;
+ /* mask in overlapping REQ_F and FFS bits */
+ req->flags |= (file_ptr << REQ_F_SUPPORT_NOWAIT_BIT);
+ io_req_set_rsrc_node(req, ctx, 0);
+out:
+ io_ring_submit_unlock(ctx, issue_flags);
+ return file;
+}
+
+struct file *io_file_get_normal(struct io_kiocb *req, int fd)
+{
+ struct file *file = fget(fd);
+
+ trace_io_uring_file_get(req, fd);
+
+ /* we don't allow fixed io_uring files */
+ if (file && io_is_uring_fops(file))
+ io_req_track_inflight(req);
+ return file;
+}
+
+static void io_queue_async(struct io_kiocb *req, int ret)
+ __must_hold(&req->ctx->uring_lock)
+{
+ struct io_kiocb *linked_timeout;
+
+ if (ret != -EAGAIN || (req->flags & REQ_F_NOWAIT)) {
+ io_req_complete_failed(req, ret);
+ return;
+ }
+
+ linked_timeout = io_prep_linked_timeout(req);
+
+ switch (io_arm_poll_handler(req, 0)) {
+ case IO_APOLL_READY:
+ io_kbuf_recycle(req, 0);
+ io_req_task_queue(req);
+ break;
+ case IO_APOLL_ABORTED:
+ io_kbuf_recycle(req, 0);
+ io_queue_iowq(req, NULL);
+ break;
+ case IO_APOLL_OK:
+ break;
+ }
+
+ if (linked_timeout)
+ io_queue_linked_timeout(linked_timeout);
+}
+
+static inline void io_queue_sqe(struct io_kiocb *req)
+ __must_hold(&req->ctx->uring_lock)
+{
+ int ret;
+
+ ret = io_issue_sqe(req, IO_URING_F_NONBLOCK|IO_URING_F_COMPLETE_DEFER);
+
+ /*
+ * We async punt it if the file wasn't marked NOWAIT, or if the file
+ * doesn't support non-blocking read/write attempts
+ */
+ if (likely(!ret))
+ io_arm_ltimeout(req);
+ else
+ io_queue_async(req, ret);
+}
+
+static void io_queue_sqe_fallback(struct io_kiocb *req)
+ __must_hold(&req->ctx->uring_lock)
+{
+ if (unlikely(req->flags & REQ_F_FAIL)) {
+ /*
+ * We don't submit, fail them all, for that replace hardlinks
+ * with normal links. Extra REQ_F_LINK is tolerated.
+ */
+ req->flags &= ~REQ_F_HARDLINK;
+ req->flags |= REQ_F_LINK;
+ io_req_complete_failed(req, req->cqe.res);
+ } else {
+ int ret = io_req_prep_async(req);
+
+ if (unlikely(ret)) {
+ io_req_complete_failed(req, ret);
+ return;
+ }
+
+ if (unlikely(req->ctx->drain_active))
+ io_drain_req(req);
+ else
+ io_queue_iowq(req, NULL);
+ }
+}
+
+/*
+ * Check SQE restrictions (opcode and flags).
+ *
+ * Returns 'true' if SQE is allowed, 'false' otherwise.
+ */
+static inline bool io_check_restriction(struct io_ring_ctx *ctx,
+ struct io_kiocb *req,
+ unsigned int sqe_flags)
+{
+ if (!test_bit(req->opcode, ctx->restrictions.sqe_op))
+ return false;
+
+ if ((sqe_flags & ctx->restrictions.sqe_flags_required) !=
+ ctx->restrictions.sqe_flags_required)
+ return false;
+
+ if (sqe_flags & ~(ctx->restrictions.sqe_flags_allowed |
+ ctx->restrictions.sqe_flags_required))
+ return false;
+
+ return true;
+}
+
+static void io_init_req_drain(struct io_kiocb *req)
+{
+ struct io_ring_ctx *ctx = req->ctx;
+ struct io_kiocb *head = ctx->submit_state.link.head;
+
+ ctx->drain_active = true;
+ if (head) {
+ /*
+ * If we need to drain a request in the middle of a link, drain
+ * the head request and the next request/link after the current
+ * link. Considering sequential execution of links,
+ * REQ_F_IO_DRAIN will be maintained for every request of our
+ * link.
+ */
+ head->flags |= REQ_F_IO_DRAIN | REQ_F_FORCE_ASYNC;
+ ctx->drain_next = true;
+ }
+}
+
+static int io_init_req(struct io_ring_ctx *ctx, struct io_kiocb *req,
+ const struct io_uring_sqe *sqe)
+ __must_hold(&ctx->uring_lock)
+{
+ const struct io_op_def *def;
+ unsigned int sqe_flags;
+ int personality;
+ u8 opcode;
+
+ /* req is partially pre-initialised, see io_preinit_req() */
+ req->opcode = opcode = READ_ONCE(sqe->opcode);
+ /* same numerical values with corresponding REQ_F_*, safe to copy */
+ req->flags = sqe_flags = READ_ONCE(sqe->flags);
+ req->cqe.user_data = READ_ONCE(sqe->user_data);
+ req->file = NULL;
+ req->rsrc_node = NULL;
+ req->task = current;
+
+ if (unlikely(opcode >= IORING_OP_LAST)) {
+ req->opcode = 0;
+ return -EINVAL;
+ }
+ def = &io_op_defs[opcode];
+ if (unlikely(sqe_flags & ~SQE_COMMON_FLAGS)) {
+ /* enforce forwards compatibility on users */
+ if (sqe_flags & ~SQE_VALID_FLAGS)
+ return -EINVAL;
+ if (sqe_flags & IOSQE_BUFFER_SELECT) {
+ if (!def->buffer_select)
+ return -EOPNOTSUPP;
+ req->buf_index = READ_ONCE(sqe->buf_group);
+ }
+ if (sqe_flags & IOSQE_CQE_SKIP_SUCCESS)
+ ctx->drain_disabled = true;
+ if (sqe_flags & IOSQE_IO_DRAIN) {
+ if (ctx->drain_disabled)
+ return -EOPNOTSUPP;
+ io_init_req_drain(req);
+ }
+ }
+ if (unlikely(ctx->restricted || ctx->drain_active || ctx->drain_next)) {
+ if (ctx->restricted && !io_check_restriction(ctx, req, sqe_flags))
+ return -EACCES;
+ /* knock it to the slow queue path, will be drained there */
+ if (ctx->drain_active)
+ req->flags |= REQ_F_FORCE_ASYNC;
+ /* if there is no link, we're at "next" request and need to drain */
+ if (unlikely(ctx->drain_next) && !ctx->submit_state.link.head) {
+ ctx->drain_next = false;
+ ctx->drain_active = true;
+ req->flags |= REQ_F_IO_DRAIN | REQ_F_FORCE_ASYNC;
+ }
+ }
+
+ if (!def->ioprio && sqe->ioprio)
+ return -EINVAL;
+ if (!def->iopoll && (ctx->flags & IORING_SETUP_IOPOLL))
+ return -EINVAL;
+
+ if (def->needs_file) {
+ struct io_submit_state *state = &ctx->submit_state;
+
+ req->cqe.fd = READ_ONCE(sqe->fd);
+
+ /*
+ * Plug now if we have more than 2 IO left after this, and the
+ * target is potentially a read/write to block based storage.
+ */
+ if (state->need_plug && def->plug) {
+ state->plug_started = true;
+ state->need_plug = false;
+ blk_start_plug_nr_ios(&state->plug, state->submit_nr);
+ }
+ }
+
+ personality = READ_ONCE(sqe->personality);
+ if (personality) {
+ int ret;
+
+ req->creds = xa_load(&ctx->personalities, personality);
+ if (!req->creds)
+ return -EINVAL;
+ get_cred(req->creds);
+ ret = security_uring_override_creds(req->creds);
+ if (ret) {
+ put_cred(req->creds);
+ return ret;
+ }
+ req->flags |= REQ_F_CREDS;
+ }
+
+ return def->prep(req, sqe);
+}
+
+static __cold int io_submit_fail_init(const struct io_uring_sqe *sqe,
+ struct io_kiocb *req, int ret)
+{
+ struct io_ring_ctx *ctx = req->ctx;
+ struct io_submit_link *link = &ctx->submit_state.link;
+ struct io_kiocb *head = link->head;
+
+ trace_io_uring_req_failed(sqe, req, ret);
+
+ /*
+ * Avoid breaking links in the middle as it renders links with SQPOLL
+ * unusable. Instead of failing eagerly, continue assembling the link if
+ * applicable and mark the head with REQ_F_FAIL. The link flushing code
+ * should find the flag and handle the rest.
+ */
+ req_fail_link_node(req, ret);
+ if (head && !(head->flags & REQ_F_FAIL))
+ req_fail_link_node(head, -ECANCELED);
+
+ if (!(req->flags & IO_REQ_LINK_FLAGS)) {
+ if (head) {
+ link->last->link = req;
+ link->head = NULL;
+ req = head;
+ }
+ io_queue_sqe_fallback(req);
+ return ret;
+ }
+
+ if (head)
+ link->last->link = req;
+ else
+ link->head = req;
+ link->last = req;
+ return 0;
+}
+
+static inline int io_submit_sqe(struct io_ring_ctx *ctx, struct io_kiocb *req,
+ const struct io_uring_sqe *sqe)
+ __must_hold(&ctx->uring_lock)
+{
+ struct io_submit_link *link = &ctx->submit_state.link;
+ int ret;
+
+ ret = io_init_req(ctx, req, sqe);
+ if (unlikely(ret))
+ return io_submit_fail_init(sqe, req, ret);
+
+ /* don't need @sqe from now on */
+ trace_io_uring_submit_sqe(req, true);
+
+ /*
+ * If we already have a head request, queue this one for async
+ * submittal once the head completes. If we don't have a head but
+ * IOSQE_IO_LINK is set in the sqe, start a new head. This one will be
+ * submitted sync once the chain is complete. If none of those
+ * conditions are true (normal request), then just queue it.
+ */
+ if (unlikely(link->head)) {
+ ret = io_req_prep_async(req);
+ if (unlikely(ret))
+ return io_submit_fail_init(sqe, req, ret);
+
+ trace_io_uring_link(req, link->head);
+ link->last->link = req;
+ link->last = req;
+
+ if (req->flags & IO_REQ_LINK_FLAGS)
+ return 0;
+ /* last request of the link, flush it */
+ req = link->head;
+ link->head = NULL;
+ if (req->flags & (REQ_F_FORCE_ASYNC | REQ_F_FAIL))
+ goto fallback;
+
+ } else if (unlikely(req->flags & (IO_REQ_LINK_FLAGS |
+ REQ_F_FORCE_ASYNC | REQ_F_FAIL))) {
+ if (req->flags & IO_REQ_LINK_FLAGS) {
+ link->head = req;
+ link->last = req;
+ } else {
+fallback:
+ io_queue_sqe_fallback(req);
+ }
+ return 0;
+ }
+
+ io_queue_sqe(req);
+ return 0;
+}
+
+/*
+ * Batched submission is done, ensure local IO is flushed out.
+ */
+static void io_submit_state_end(struct io_ring_ctx *ctx)
+{
+ struct io_submit_state *state = &ctx->submit_state;
+
+ if (unlikely(state->link.head))
+ io_queue_sqe_fallback(state->link.head);
+ /* flush only after queuing links as they can generate completions */
+ io_submit_flush_completions(ctx);
+ if (state->plug_started)
+ blk_finish_plug(&state->plug);
+}
+
+/*
+ * Start submission side cache.
+ */
+static void io_submit_state_start(struct io_submit_state *state,
+ unsigned int max_ios)
+{
+ state->plug_started = false;
+ state->need_plug = max_ios > 2;
+ state->submit_nr = max_ios;
+ /* set only head, no need to init link_last in advance */
+ state->link.head = NULL;
+}
+
+static void io_commit_sqring(struct io_ring_ctx *ctx)
+{
+ struct io_rings *rings = ctx->rings;
+
+ /*
+ * Ensure any loads from the SQEs are done at this point,
+ * since once we write the new head, the application could
+ * write new data to them.
+ */
+ smp_store_release(&rings->sq.head, ctx->cached_sq_head);
+}
+
+/*
+ * Fetch an sqe, if one is available. Note this returns a pointer to memory
+ * that is mapped by userspace. This means that care needs to be taken to
+ * ensure that reads are stable, as we cannot rely on userspace always
+ * being a good citizen. If members of the sqe are validated and then later
+ * used, it's important that those reads are done through READ_ONCE() to
+ * prevent a re-load down the line.
+ */
+static const struct io_uring_sqe *io_get_sqe(struct io_ring_ctx *ctx)
+{
+ unsigned head, mask = ctx->sq_entries - 1;
+ unsigned sq_idx = ctx->cached_sq_head++ & mask;
+
+ /*
+ * The cached sq head (or cq tail) serves two purposes:
+ *
+ * 1) allows us to batch the cost of updating the user visible
+ * head updates.
+ * 2) allows the kernel side to track the head on its own, even
+ * though the application is the one updating it.
+ */
+ head = READ_ONCE(ctx->sq_array[sq_idx]);
+ if (likely(head < ctx->sq_entries)) {
+ /* double index for 128-byte SQEs, twice as long */
+ if (ctx->flags & IORING_SETUP_SQE128)
+ head <<= 1;
+ return &ctx->sq_sqes[head];
+ }
+
+ /* drop invalid entries */
+ spin_lock(&ctx->completion_lock);
+ ctx->cq_extra--;
+ spin_unlock(&ctx->completion_lock);
+ WRITE_ONCE(ctx->rings->sq_dropped,
+ READ_ONCE(ctx->rings->sq_dropped) + 1);
+ return NULL;
+}
+
+int io_submit_sqes(struct io_ring_ctx *ctx, unsigned int nr)
+ __must_hold(&ctx->uring_lock)
+{
+ unsigned int entries = io_sqring_entries(ctx);
+ unsigned int left;
+ int ret;
+
+ if (unlikely(!entries))
+ return 0;
+ /* make sure SQ entry isn't read before tail */
+ ret = left = min3(nr, ctx->sq_entries, entries);
+ io_get_task_refs(left);
+ io_submit_state_start(&ctx->submit_state, left);
+
+ do {
+ const struct io_uring_sqe *sqe;
+ struct io_kiocb *req;
+
+ if (unlikely(!io_alloc_req_refill(ctx)))
+ break;
+ req = io_alloc_req(ctx);
+ sqe = io_get_sqe(ctx);
+ if (unlikely(!sqe)) {
+ io_req_add_to_cache(req, ctx);
+ break;
+ }
+
+ /*
+ * Continue submitting even for sqe failure if the
+ * ring was setup with IORING_SETUP_SUBMIT_ALL
+ */
+ if (unlikely(io_submit_sqe(ctx, req, sqe)) &&
+ !(ctx->flags & IORING_SETUP_SUBMIT_ALL)) {
+ left--;
+ break;
+ }
+ } while (--left);
+
+ if (unlikely(left)) {
+ ret -= left;
+ /* try again if it submitted nothing and can't allocate a req */
+ if (!ret && io_req_cache_empty(ctx))
+ ret = -EAGAIN;
+ current->io_uring->cached_refs += left;
+ }
+
+ io_submit_state_end(ctx);
+ /* Commit SQ ring head once we've consumed and submitted all SQEs */
+ io_commit_sqring(ctx);
+ return ret;
+}
+
+struct io_wait_queue {
+ struct wait_queue_entry wq;
+ struct io_ring_ctx *ctx;
+ unsigned cq_tail;
+ unsigned nr_timeouts;
+};
+
+static inline bool io_has_work(struct io_ring_ctx *ctx)
+{
+ return test_bit(IO_CHECK_CQ_OVERFLOW_BIT, &ctx->check_cq) ||
+ ((ctx->flags & IORING_SETUP_DEFER_TASKRUN) &&
+ !llist_empty(&ctx->work_llist));
+}
+
+static inline bool io_should_wake(struct io_wait_queue *iowq)
+{
+ struct io_ring_ctx *ctx = iowq->ctx;
+ int dist = READ_ONCE(ctx->rings->cq.tail) - (int) iowq->cq_tail;
+
+ /*
+ * Wake up if we have enough events, or if a timeout occurred since we
+ * started waiting. For timeouts, we always want to return to userspace,
+ * regardless of event count.
+ */
+ return dist >= 0 || atomic_read(&ctx->cq_timeouts) != iowq->nr_timeouts;
+}
+
+static int io_wake_function(struct wait_queue_entry *curr, unsigned int mode,
+ int wake_flags, void *key)
+{
+ struct io_wait_queue *iowq = container_of(curr, struct io_wait_queue,
+ wq);
+ struct io_ring_ctx *ctx = iowq->ctx;
+
+ /*
+ * Cannot safely flush overflowed CQEs from here, ensure we wake up
+ * the task, and the next invocation will do it.
+ */
+ if (io_should_wake(iowq) || io_has_work(ctx))
+ return autoremove_wake_function(curr, mode, wake_flags, key);
+ return -1;
+}
+
+int io_run_task_work_sig(struct io_ring_ctx *ctx)
+{
+ if (io_run_task_work_ctx(ctx) > 0)
+ return 1;
+ if (task_sigpending(current))
+ return -EINTR;
+ return 0;
+}
+
+static bool current_pending_io(void)
+{
+ struct io_uring_task *tctx = current->io_uring;
+
+ if (!tctx)
+ return false;
+ return percpu_counter_read_positive(&tctx->inflight);
+}
+
+/* when returns >0, the caller should retry */
+static inline int io_cqring_wait_schedule(struct io_ring_ctx *ctx,
+ struct io_wait_queue *iowq,
+ ktime_t *timeout)
+{
+ int io_wait, ret;
+ unsigned long check_cq;
+
+ /* make sure we run task_work before checking for signals */
+ ret = io_run_task_work_sig(ctx);
+ if (ret || io_should_wake(iowq))
+ return ret;
+
+ check_cq = READ_ONCE(ctx->check_cq);
+ if (unlikely(check_cq)) {
+ /* let the caller flush overflows, retry */
+ if (check_cq & BIT(IO_CHECK_CQ_OVERFLOW_BIT))
+ return 1;
+ if (check_cq & BIT(IO_CHECK_CQ_DROPPED_BIT))
+ return -EBADR;
+ }
+
+ /*
+ * Mark us as being in io_wait if we have pending requests, so cpufreq
+ * can take into account that the task is waiting for IO - turns out
+ * to be important for low QD IO.
+ */
+ io_wait = current->in_iowait;
+ if (current_pending_io())
+ current->in_iowait = 1;
+ ret = 1;
+ if (!schedule_hrtimeout(timeout, HRTIMER_MODE_ABS))
+ ret = -ETIME;
+ current->in_iowait = io_wait;
+ return ret;
+}
+
+/*
+ * Wait until events become available, if we don't already have some. The
+ * application must reap them itself, as they reside on the shared cq ring.
+ */
+static int io_cqring_wait(struct io_ring_ctx *ctx, int min_events,
+ const sigset_t __user *sig, size_t sigsz,
+ struct __kernel_timespec __user *uts)
+{
+ struct io_wait_queue iowq;
+ struct io_rings *rings = ctx->rings;
+ ktime_t timeout = KTIME_MAX;
+ int ret;
+
+ if (!io_allowed_run_tw(ctx))
+ return -EEXIST;
+
+ do {
+ /* always run at least 1 task work to process local work */
+ ret = io_run_task_work_ctx(ctx);
+ if (ret < 0)
+ return ret;
+ io_cqring_overflow_flush(ctx);
+
+ /* if user messes with these they will just get an early return */
+ if (__io_cqring_events_user(ctx) >= min_events)
+ return 0;
+ } while (ret > 0);
+
+ if (sig) {
+#ifdef CONFIG_COMPAT
+ if (in_compat_syscall())
+ ret = set_compat_user_sigmask((const compat_sigset_t __user *)sig,
+ sigsz);
+ else
+#endif
+ ret = set_user_sigmask(sig, sigsz);
+
+ if (ret)
+ return ret;
+ }
+
+ if (uts) {
+ struct timespec64 ts;
+
+ if (get_timespec64(&ts, uts))
+ return -EFAULT;
+ timeout = ktime_add_ns(timespec64_to_ktime(ts), ktime_get_ns());
+ }
+
+ init_waitqueue_func_entry(&iowq.wq, io_wake_function);
+ iowq.wq.private = current;
+ INIT_LIST_HEAD(&iowq.wq.entry);
+ iowq.ctx = ctx;
+ iowq.nr_timeouts = atomic_read(&ctx->cq_timeouts);
+ iowq.cq_tail = READ_ONCE(ctx->rings->cq.head) + min_events;
+
+ trace_io_uring_cqring_wait(ctx, min_events);
+ do {
+ /* if we can't even flush overflow, don't wait for more */
+ if (!io_cqring_overflow_flush(ctx)) {
+ ret = -EBUSY;
+ break;
+ }
+ prepare_to_wait_exclusive(&ctx->cq_wait, &iowq.wq,
+ TASK_INTERRUPTIBLE);
+ ret = io_cqring_wait_schedule(ctx, &iowq, &timeout);
+ cond_resched();
+ } while (ret > 0);
+
+ finish_wait(&ctx->cq_wait, &iowq.wq);
+ restore_saved_sigmask_unless(ret == -EINTR);
+
+ return READ_ONCE(rings->cq.head) == READ_ONCE(rings->cq.tail) ? ret : 0;
+}
+
+static void io_mem_free(void *ptr)
+{
+ struct page *page;
+
+ if (!ptr)
+ return;
+
+ page = virt_to_head_page(ptr);
+ if (put_page_testzero(page))
+ free_compound_page(page);
+}
+
+static void *io_mem_alloc(size_t size)
+{
+ gfp_t gfp = GFP_KERNEL_ACCOUNT | __GFP_ZERO | __GFP_NOWARN | __GFP_COMP;
+
+ return (void *) __get_free_pages(gfp, get_order(size));
+}
+
+static unsigned long rings_size(struct io_ring_ctx *ctx, unsigned int sq_entries,
+ unsigned int cq_entries, size_t *sq_offset)
+{
+ struct io_rings *rings;
+ size_t off, sq_array_size;
+
+ off = struct_size(rings, cqes, cq_entries);
+ if (off == SIZE_MAX)
+ return SIZE_MAX;
+ if (ctx->flags & IORING_SETUP_CQE32) {
+ if (check_shl_overflow(off, 1, &off))
+ return SIZE_MAX;
+ }
+
+#ifdef CONFIG_SMP
+ off = ALIGN(off, SMP_CACHE_BYTES);
+ if (off == 0)
+ return SIZE_MAX;
+#endif
+
+ if (sq_offset)
+ *sq_offset = off;
+
+ sq_array_size = array_size(sizeof(u32), sq_entries);
+ if (sq_array_size == SIZE_MAX)
+ return SIZE_MAX;
+
+ if (check_add_overflow(off, sq_array_size, &off))
+ return SIZE_MAX;
+
+ return off;
+}
+
+static int io_eventfd_register(struct io_ring_ctx *ctx, void __user *arg,
+ unsigned int eventfd_async)
+{
+ struct io_ev_fd *ev_fd;
+ __s32 __user *fds = arg;
+ int fd;
+
+ ev_fd = rcu_dereference_protected(ctx->io_ev_fd,
+ lockdep_is_held(&ctx->uring_lock));
+ if (ev_fd)
+ return -EBUSY;
+
+ if (copy_from_user(&fd, fds, sizeof(*fds)))
+ return -EFAULT;
+
+ ev_fd = kmalloc(sizeof(*ev_fd), GFP_KERNEL);
+ if (!ev_fd)
+ return -ENOMEM;
+
+ ev_fd->cq_ev_fd = eventfd_ctx_fdget(fd);
+ if (IS_ERR(ev_fd->cq_ev_fd)) {
+ int ret = PTR_ERR(ev_fd->cq_ev_fd);
+ kfree(ev_fd);
+ return ret;
+ }
+
+ spin_lock(&ctx->completion_lock);
+ ctx->evfd_last_cq_tail = ctx->cached_cq_tail;
+ spin_unlock(&ctx->completion_lock);
+
+ ev_fd->eventfd_async = eventfd_async;
+ ctx->has_evfd = true;
+ rcu_assign_pointer(ctx->io_ev_fd, ev_fd);
+ atomic_set(&ev_fd->refs, 1);
+ atomic_set(&ev_fd->ops, 0);
+ return 0;
+}
+
+static int io_eventfd_unregister(struct io_ring_ctx *ctx)
+{
+ struct io_ev_fd *ev_fd;
+
+ ev_fd = rcu_dereference_protected(ctx->io_ev_fd,
+ lockdep_is_held(&ctx->uring_lock));
+ if (ev_fd) {
+ ctx->has_evfd = false;
+ rcu_assign_pointer(ctx->io_ev_fd, NULL);
+ if (!atomic_fetch_or(BIT(IO_EVENTFD_OP_FREE_BIT), &ev_fd->ops))
+ call_rcu(&ev_fd->rcu, io_eventfd_ops);
+ return 0;
+ }
+
+ return -ENXIO;
+}
+
+static void io_req_caches_free(struct io_ring_ctx *ctx)
+{
+ int nr = 0;
+
+ mutex_lock(&ctx->uring_lock);
+ io_flush_cached_locked_reqs(ctx, &ctx->submit_state);
+
+ while (!io_req_cache_empty(ctx)) {
+ struct io_kiocb *req = io_alloc_req(ctx);
+
+ kmem_cache_free(req_cachep, req);
+ nr++;
+ }
+ if (nr)
+ percpu_ref_put_many(&ctx->refs, nr);
+ mutex_unlock(&ctx->uring_lock);
+}
+
+static __cold void io_ring_ctx_free(struct io_ring_ctx *ctx)
+{
+ io_sq_thread_finish(ctx);
+ io_rsrc_refs_drop(ctx);
+ /* __io_rsrc_put_work() may need uring_lock to progress, wait w/o it */
+ io_wait_rsrc_data(ctx->buf_data);
+ io_wait_rsrc_data(ctx->file_data);
+
+ mutex_lock(&ctx->uring_lock);
+ if (ctx->buf_data)
+ __io_sqe_buffers_unregister(ctx);
+ if (ctx->file_data)
+ __io_sqe_files_unregister(ctx);
+ if (ctx->rings)
+ __io_cqring_overflow_flush(ctx, true);
+ io_eventfd_unregister(ctx);
+ io_alloc_cache_free(&ctx->apoll_cache, io_apoll_cache_free);
+ io_alloc_cache_free(&ctx->netmsg_cache, io_netmsg_cache_free);
+ io_destroy_buffers(ctx);
+ mutex_unlock(&ctx->uring_lock);
+ if (ctx->sq_creds)
+ put_cred(ctx->sq_creds);
+ if (ctx->submitter_task)
+ put_task_struct(ctx->submitter_task);
+
+ /* there are no registered resources left, nobody uses it */
+ if (ctx->rsrc_node)
+ io_rsrc_node_destroy(ctx->rsrc_node);
+ if (ctx->rsrc_backup_node)
+ io_rsrc_node_destroy(ctx->rsrc_backup_node);
+ flush_delayed_work(&ctx->rsrc_put_work);
+ flush_delayed_work(&ctx->fallback_work);
+
+ WARN_ON_ONCE(!list_empty(&ctx->rsrc_ref_list));
+ WARN_ON_ONCE(!llist_empty(&ctx->rsrc_put_llist));
+
+#if defined(CONFIG_UNIX)
+ if (ctx->ring_sock) {
+ ctx->ring_sock->file = NULL; /* so that iput() is called */
+ sock_release(ctx->ring_sock);
+ }
+#endif
+ WARN_ON_ONCE(!list_empty(&ctx->ltimeout_list));
+
+ if (ctx->mm_account) {
+ mmdrop(ctx->mm_account);
+ ctx->mm_account = NULL;
+ }
+ io_mem_free(ctx->rings);
+ io_mem_free(ctx->sq_sqes);
+
+ percpu_ref_exit(&ctx->refs);
+ free_uid(ctx->user);
+ io_req_caches_free(ctx);
+ if (ctx->hash_map)
+ io_wq_put_hash(ctx->hash_map);
+ kfree(ctx->cancel_table.hbs);
+ kfree(ctx->cancel_table_locked.hbs);
+ kfree(ctx->dummy_ubuf);
+ kfree(ctx->io_bl);
+ xa_destroy(&ctx->io_bl_xa);
+ kfree(ctx);
+}
+
+static __poll_t io_uring_poll(struct file *file, poll_table *wait)
+{
+ struct io_ring_ctx *ctx = file->private_data;
+ __poll_t mask = 0;
+
+ poll_wait(file, &ctx->cq_wait, wait);
+ /*
+ * synchronizes with barrier from wq_has_sleeper call in
+ * io_commit_cqring
+ */
+ smp_rmb();
+ if (!io_sqring_full(ctx))
+ mask |= EPOLLOUT | EPOLLWRNORM;
+
+ /*
+ * Don't flush cqring overflow list here, just do a simple check.
+ * Otherwise there could possible be ABBA deadlock:
+ * CPU0 CPU1
+ * ---- ----
+ * lock(&ctx->uring_lock);
+ * lock(&ep->mtx);
+ * lock(&ctx->uring_lock);
+ * lock(&ep->mtx);
+ *
+ * Users may get EPOLLIN meanwhile seeing nothing in cqring, this
+ * pushs them to do the flush.
+ */
+
+ if (__io_cqring_events_user(ctx) || io_has_work(ctx))
+ mask |= EPOLLIN | EPOLLRDNORM;
+
+ return mask;
+}
+
+static int io_unregister_personality(struct io_ring_ctx *ctx, unsigned id)
+{
+ const struct cred *creds;
+
+ creds = xa_erase(&ctx->personalities, id);
+ if (creds) {
+ put_cred(creds);
+ return 0;
+ }
+
+ return -EINVAL;
+}
+
+struct io_tctx_exit {
+ struct callback_head task_work;
+ struct completion completion;
+ struct io_ring_ctx *ctx;
+};
+
+static __cold void io_tctx_exit_cb(struct callback_head *cb)
+{
+ struct io_uring_task *tctx = current->io_uring;
+ struct io_tctx_exit *work;
+
+ work = container_of(cb, struct io_tctx_exit, task_work);
+ /*
+ * When @in_idle, we're in cancellation and it's racy to remove the
+ * node. It'll be removed by the end of cancellation, just ignore it.
+ * tctx can be NULL if the queueing of this task_work raced with
+ * work cancelation off the exec path.
+ */
+ if (tctx && !atomic_read(&tctx->in_idle))
+ io_uring_del_tctx_node((unsigned long)work->ctx);
+ complete(&work->completion);
+}
+
+static __cold bool io_cancel_ctx_cb(struct io_wq_work *work, void *data)
+{
+ struct io_kiocb *req = container_of(work, struct io_kiocb, work);
+
+ return req->ctx == data;
+}
+
+static __cold void io_ring_exit_work(struct work_struct *work)
+{
+ struct io_ring_ctx *ctx = container_of(work, struct io_ring_ctx, exit_work);
+ unsigned long timeout = jiffies + HZ * 60 * 5;
+ unsigned long interval = HZ / 20;
+ struct io_tctx_exit exit;
+ struct io_tctx_node *node;
+ int ret;
+
+ /*
+ * If we're doing polled IO and end up having requests being
+ * submitted async (out-of-line), then completions can come in while
+ * we're waiting for refs to drop. We need to reap these manually,
+ * as nobody else will be looking for them.
+ */
+ do {
+ if (ctx->flags & IORING_SETUP_DEFER_TASKRUN)
+ io_move_task_work_from_local(ctx);
+
+ while (io_uring_try_cancel_requests(ctx, NULL, true))
+ cond_resched();
+
+ if (ctx->sq_data) {
+ struct io_sq_data *sqd = ctx->sq_data;
+ struct task_struct *tsk;
+
+ io_sq_thread_park(sqd);
+ tsk = sqd->thread;
+ if (tsk && tsk->io_uring && tsk->io_uring->io_wq)
+ io_wq_cancel_cb(tsk->io_uring->io_wq,
+ io_cancel_ctx_cb, ctx, true);
+ io_sq_thread_unpark(sqd);
+ }
+
+ io_req_caches_free(ctx);
+
+ if (WARN_ON_ONCE(time_after(jiffies, timeout))) {
+ /* there is little hope left, don't run it too often */
+ interval = HZ * 60;
+ }
+ /*
+ * This is really an uninterruptible wait, as it has to be
+ * complete. But it's also run from a kworker, which doesn't
+ * take signals, so it's fine to make it interruptible. This
+ * avoids scenarios where we knowingly can wait much longer
+ * on completions, for example if someone does a SIGSTOP on
+ * a task that needs to finish task_work to make this loop
+ * complete. That's a synthetic situation that should not
+ * cause a stuck task backtrace, and hence a potential panic
+ * on stuck tasks if that is enabled.
+ */
+ } while (!wait_for_completion_interruptible_timeout(&ctx->ref_comp, interval));
+
+ init_completion(&exit.completion);
+ init_task_work(&exit.task_work, io_tctx_exit_cb);
+ exit.ctx = ctx;
+
+ mutex_lock(&ctx->uring_lock);
+ while (!list_empty(&ctx->tctx_list)) {
+ WARN_ON_ONCE(time_after(jiffies, timeout));
+
+ node = list_first_entry(&ctx->tctx_list, struct io_tctx_node,
+ ctx_node);
+ /* don't spin on a single task if cancellation failed */
+ list_rotate_left(&ctx->tctx_list);
+ ret = task_work_add(node->task, &exit.task_work, TWA_SIGNAL);
+ if (WARN_ON_ONCE(ret))
+ continue;
+
+ mutex_unlock(&ctx->uring_lock);
+ /*
+ * See comment above for
+ * wait_for_completion_interruptible_timeout() on why this
+ * wait is marked as interruptible.
+ */
+ wait_for_completion_interruptible(&exit.completion);
+ mutex_lock(&ctx->uring_lock);
+ }
+ mutex_unlock(&ctx->uring_lock);
+ spin_lock(&ctx->completion_lock);
+ spin_unlock(&ctx->completion_lock);
+
+ io_ring_ctx_free(ctx);
+}
+
+static __cold void io_ring_ctx_wait_and_kill(struct io_ring_ctx *ctx)
+{
+ unsigned long index;
+ struct creds *creds;
+
+ mutex_lock(&ctx->uring_lock);
+ percpu_ref_kill(&ctx->refs);
+ if (ctx->rings)
+ __io_cqring_overflow_flush(ctx, true);
+ xa_for_each(&ctx->personalities, index, creds)
+ io_unregister_personality(ctx, index);
+ if (ctx->rings)
+ io_poll_remove_all(ctx, NULL, true);
+ mutex_unlock(&ctx->uring_lock);
+
+ /*
+ * If we failed setting up the ctx, we might not have any rings
+ * and therefore did not submit any requests
+ */
+ if (ctx->rings)
+ io_kill_timeouts(ctx, NULL, true);
+
+ INIT_WORK(&ctx->exit_work, io_ring_exit_work);
+ /*
+ * Use system_unbound_wq to avoid spawning tons of event kworkers
+ * if we're exiting a ton of rings at the same time. It just adds
+ * noise and overhead, there's no discernable change in runtime
+ * over using system_wq.
+ */
+ queue_work(system_unbound_wq, &ctx->exit_work);
+}
+
+static int io_uring_release(struct inode *inode, struct file *file)
+{
+ struct io_ring_ctx *ctx = file->private_data;
+
+ file->private_data = NULL;
+ io_ring_ctx_wait_and_kill(ctx);
+ return 0;
+}
+
+struct io_task_cancel {
+ struct task_struct *task;
+ bool all;
+};
+
+static bool io_cancel_task_cb(struct io_wq_work *work, void *data)
+{
+ struct io_kiocb *req = container_of(work, struct io_kiocb, work);
+ struct io_task_cancel *cancel = data;
+
+ return io_match_task_safe(req, cancel->task, cancel->all);
+}
+
+static __cold bool io_cancel_defer_files(struct io_ring_ctx *ctx,
+ struct task_struct *task,
+ bool cancel_all)
+{
+ struct io_defer_entry *de;
+ LIST_HEAD(list);
+
+ spin_lock(&ctx->completion_lock);
+ list_for_each_entry_reverse(de, &ctx->defer_list, list) {
+ if (io_match_task_safe(de->req, task, cancel_all)) {
+ list_cut_position(&list, &ctx->defer_list, &de->list);
+ break;
+ }
+ }
+ spin_unlock(&ctx->completion_lock);
+ if (list_empty(&list))
+ return false;
+
+ while (!list_empty(&list)) {
+ de = list_first_entry(&list, struct io_defer_entry, list);
+ list_del_init(&de->list);
+ io_req_task_queue_fail(de->req, -ECANCELED);
+ kfree(de);
+ }
+ return true;
+}
+
+static __cold bool io_uring_try_cancel_iowq(struct io_ring_ctx *ctx)
+{
+ struct io_tctx_node *node;
+ enum io_wq_cancel cret;
+ bool ret = false;
+
+ mutex_lock(&ctx->uring_lock);
+ list_for_each_entry(node, &ctx->tctx_list, ctx_node) {
+ struct io_uring_task *tctx = node->task->io_uring;
+
+ /*
+ * io_wq will stay alive while we hold uring_lock, because it's
+ * killed after ctx nodes, which requires to take the lock.
+ */
+ if (!tctx || !tctx->io_wq)
+ continue;
+ cret = io_wq_cancel_cb(tctx->io_wq, io_cancel_ctx_cb, ctx, true);
+ ret |= (cret != IO_WQ_CANCEL_NOTFOUND);
+ }
+ mutex_unlock(&ctx->uring_lock);
+
+ return ret;
+}
+
+static __cold bool io_uring_try_cancel_requests(struct io_ring_ctx *ctx,
+ struct task_struct *task,
+ bool cancel_all)
+{
+ struct io_task_cancel cancel = { .task = task, .all = cancel_all, };
+ struct io_uring_task *tctx = task ? task->io_uring : NULL;
+ enum io_wq_cancel cret;
+ bool ret = false;
+
+ /* failed during ring init, it couldn't have issued any requests */
+ if (!ctx->rings)
+ return false;
+
+ if (!task) {
+ ret |= io_uring_try_cancel_iowq(ctx);
+ } else if (tctx && tctx->io_wq) {
+ /*
+ * Cancels requests of all rings, not only @ctx, but
+ * it's fine as the task is in exit/exec.
+ */
+ cret = io_wq_cancel_cb(tctx->io_wq, io_cancel_task_cb,
+ &cancel, true);
+ ret |= (cret != IO_WQ_CANCEL_NOTFOUND);
+ }
+
+ /* SQPOLL thread does its own polling */
+ if ((!(ctx->flags & IORING_SETUP_SQPOLL) && cancel_all) ||
+ (ctx->sq_data && ctx->sq_data->thread == current)) {
+ while (!wq_list_empty(&ctx->iopoll_list)) {
+ io_iopoll_try_reap_events(ctx);
+ ret = true;
+ cond_resched();
+ }
+ }
+
+ if (ctx->flags & IORING_SETUP_DEFER_TASKRUN)
+ ret |= io_run_local_work(ctx) > 0;
+ ret |= io_cancel_defer_files(ctx, task, cancel_all);
+ mutex_lock(&ctx->uring_lock);
+ ret |= io_poll_remove_all(ctx, task, cancel_all);
+ mutex_unlock(&ctx->uring_lock);
+ ret |= io_kill_timeouts(ctx, task, cancel_all);
+ if (task)
+ ret |= io_run_task_work() > 0;
+ return ret;
+}
+
+static s64 tctx_inflight(struct io_uring_task *tctx, bool tracked)
+{
+ if (tracked)
+ return atomic_read(&tctx->inflight_tracked);
+ return percpu_counter_sum(&tctx->inflight);
+}
+
+/*
+ * Find any io_uring ctx that this task has registered or done IO on, and cancel
+ * requests. @sqd should be not-null IFF it's an SQPOLL thread cancellation.
+ */
+__cold void io_uring_cancel_generic(bool cancel_all, struct io_sq_data *sqd)
+{
+ struct io_uring_task *tctx = current->io_uring;
+ struct io_ring_ctx *ctx;
+ s64 inflight;
+ DEFINE_WAIT(wait);
+
+ WARN_ON_ONCE(sqd && sqd->thread != current);
+
+ if (!current->io_uring)
+ return;
+ if (tctx->io_wq)
+ io_wq_exit_start(tctx->io_wq);
+
+ atomic_inc(&tctx->in_idle);
+ do {
+ bool loop = false;
+
+ io_uring_drop_tctx_refs(current);
+ /* read completions before cancelations */
+ inflight = tctx_inflight(tctx, !cancel_all);
+ if (!inflight)
+ break;
+
+ if (!sqd) {
+ struct io_tctx_node *node;
+ unsigned long index;
+
+ xa_for_each(&tctx->xa, index, node) {
+ /* sqpoll task will cancel all its requests */
+ if (node->ctx->sq_data)
+ continue;
+ loop |= io_uring_try_cancel_requests(node->ctx,
+ current, cancel_all);
+ }
+ } else {
+ list_for_each_entry(ctx, &sqd->ctx_list, sqd_list)
+ loop |= io_uring_try_cancel_requests(ctx,
+ current,
+ cancel_all);
+ }
+
+ if (loop) {
+ cond_resched();
+ continue;
+ }
+
+ prepare_to_wait(&tctx->wait, &wait, TASK_INTERRUPTIBLE);
+ io_run_task_work();
+ io_uring_drop_tctx_refs(current);
+
+ /*
+ * If we've seen completions, retry without waiting. This
+ * avoids a race where a completion comes in before we did
+ * prepare_to_wait().
+ */
+ if (inflight == tctx_inflight(tctx, !cancel_all))
+ schedule();
+ finish_wait(&tctx->wait, &wait);
+ } while (1);
+
+ io_uring_clean_tctx(tctx);
+ if (cancel_all) {
+ /*
+ * We shouldn't run task_works after cancel, so just leave
+ * ->in_idle set for normal exit.
+ */
+ atomic_dec(&tctx->in_idle);
+ /* for exec all current's requests should be gone, kill tctx */
+ __io_uring_free(current);
+ }
+}
+
+void __io_uring_cancel(bool cancel_all)
+{
+ io_uring_cancel_generic(cancel_all, NULL);
+}
+
+static void *io_uring_validate_mmap_request(struct file *file,
+ loff_t pgoff, size_t sz)
+{
+ struct io_ring_ctx *ctx = file->private_data;
+ loff_t offset = pgoff << PAGE_SHIFT;
+ struct page *page;
+ void *ptr;
+
+ switch (offset) {
+ case IORING_OFF_SQ_RING:
+ case IORING_OFF_CQ_RING:
+ ptr = ctx->rings;
+ break;
+ case IORING_OFF_SQES:
+ ptr = ctx->sq_sqes;
+ break;
+ default:
+ return ERR_PTR(-EINVAL);
+ }
+
+ page = virt_to_head_page(ptr);
+ if (sz > page_size(page))
+ return ERR_PTR(-EINVAL);
+
+ return ptr;
+}
+
+#ifdef CONFIG_MMU
+
+static __cold int io_uring_mmap(struct file *file, struct vm_area_struct *vma)
+{
+ size_t sz = vma->vm_end - vma->vm_start;
+ unsigned long pfn;
+ void *ptr;
+
+ ptr = io_uring_validate_mmap_request(file, vma->vm_pgoff, sz);
+ if (IS_ERR(ptr))
+ return PTR_ERR(ptr);
+
+ pfn = virt_to_phys(ptr) >> PAGE_SHIFT;
+ return remap_pfn_range(vma, vma->vm_start, pfn, sz, vma->vm_page_prot);
+}
+
+static unsigned long io_uring_mmu_get_unmapped_area(struct file *filp,
+ unsigned long addr, unsigned long len,
+ unsigned long pgoff, unsigned long flags)
+{
+ void *ptr;
+
+ /*
+ * Do not allow to map to user-provided address to avoid breaking the
+ * aliasing rules. Userspace is not able to guess the offset address of
+ * kernel kmalloc()ed memory area.
+ */
+ if (addr)
+ return -EINVAL;
+
+ ptr = io_uring_validate_mmap_request(filp, pgoff, len);
+ if (IS_ERR(ptr))
+ return -ENOMEM;
+
+ /*
+ * Some architectures have strong cache aliasing requirements.
+ * For such architectures we need a coherent mapping which aliases
+ * kernel memory *and* userspace memory. To achieve that:
+ * - use a NULL file pointer to reference physical memory, and
+ * - use the kernel virtual address of the shared io_uring context
+ * (instead of the userspace-provided address, which has to be 0UL
+ * anyway).
+ * - use the same pgoff which the get_unmapped_area() uses to
+ * calculate the page colouring.
+ * For architectures without such aliasing requirements, the
+ * architecture will return any suitable mapping because addr is 0.
+ */
+ filp = NULL;
+ flags |= MAP_SHARED;
+ pgoff = 0; /* has been translated to ptr above */
+#ifdef SHM_COLOUR
+ addr = (uintptr_t) ptr;
+ pgoff = addr >> PAGE_SHIFT;
+#else
+ addr = 0UL;
+#endif
+ return current->mm->get_unmapped_area(filp, addr, len, pgoff, flags);
+}
+
+#else /* !CONFIG_MMU */
+
+static int io_uring_mmap(struct file *file, struct vm_area_struct *vma)
+{
+ return vma->vm_flags & (VM_SHARED | VM_MAYSHARE) ? 0 : -EINVAL;
+}
+
+static unsigned int io_uring_nommu_mmap_capabilities(struct file *file)
+{
+ return NOMMU_MAP_DIRECT | NOMMU_MAP_READ | NOMMU_MAP_WRITE;
+}
+
+static unsigned long io_uring_nommu_get_unmapped_area(struct file *file,
+ unsigned long addr, unsigned long len,
+ unsigned long pgoff, unsigned long flags)
+{
+ void *ptr;
+
+ ptr = io_uring_validate_mmap_request(file, pgoff, len);
+ if (IS_ERR(ptr))
+ return PTR_ERR(ptr);
+
+ return (unsigned long) ptr;
+}
+
+#endif /* !CONFIG_MMU */
+
+static int io_validate_ext_arg(unsigned flags, const void __user *argp, size_t argsz)
+{
+ if (flags & IORING_ENTER_EXT_ARG) {
+ struct io_uring_getevents_arg arg;
+
+ if (argsz != sizeof(arg))
+ return -EINVAL;
+ if (copy_from_user(&arg, argp, sizeof(arg)))
+ return -EFAULT;
+ }
+ return 0;
+}
+
+static int io_get_ext_arg(unsigned flags, const void __user *argp, size_t *argsz,
+ struct __kernel_timespec __user **ts,
+ const sigset_t __user **sig)
+{
+ struct io_uring_getevents_arg arg;
+
+ /*
+ * If EXT_ARG isn't set, then we have no timespec and the argp pointer
+ * is just a pointer to the sigset_t.
+ */
+ if (!(flags & IORING_ENTER_EXT_ARG)) {
+ *sig = (const sigset_t __user *) argp;
+ *ts = NULL;
+ return 0;
+ }
+
+ /*
+ * EXT_ARG is set - ensure we agree on the size of it and copy in our
+ * timespec and sigset_t pointers if good.
+ */
+ if (*argsz != sizeof(arg))
+ return -EINVAL;
+ if (copy_from_user(&arg, argp, sizeof(arg)))
+ return -EFAULT;
+ if (arg.pad)
+ return -EINVAL;
+ *sig = u64_to_user_ptr(arg.sigmask);
+ *argsz = arg.sigmask_sz;
+ *ts = u64_to_user_ptr(arg.ts);
+ return 0;
+}
+
+SYSCALL_DEFINE6(io_uring_enter, unsigned int, fd, u32, to_submit,
+ u32, min_complete, u32, flags, const void __user *, argp,
+ size_t, argsz)
+{
+ struct io_ring_ctx *ctx;
+ struct fd f;
+ long ret;
+
+ if (unlikely(flags & ~(IORING_ENTER_GETEVENTS | IORING_ENTER_SQ_WAKEUP |
+ IORING_ENTER_SQ_WAIT | IORING_ENTER_EXT_ARG |
+ IORING_ENTER_REGISTERED_RING)))
+ return -EINVAL;
+
+ /*
+ * Ring fd has been registered via IORING_REGISTER_RING_FDS, we
+ * need only dereference our task private array to find it.
+ */
+ if (flags & IORING_ENTER_REGISTERED_RING) {
+ struct io_uring_task *tctx = current->io_uring;
+
+ if (unlikely(!tctx || fd >= IO_RINGFD_REG_MAX))
+ return -EINVAL;
+ fd = array_index_nospec(fd, IO_RINGFD_REG_MAX);
+ f.file = tctx->registered_rings[fd];
+ f.flags = 0;
+ if (unlikely(!f.file))
+ return -EBADF;
+ } else {
+ f = fdget(fd);
+ if (unlikely(!f.file))
+ return -EBADF;
+ ret = -EOPNOTSUPP;
+ if (unlikely(!io_is_uring_fops(f.file)))
+ goto out;
+ }
+
+ ctx = f.file->private_data;
+ ret = -EBADFD;
+ if (unlikely(ctx->flags & IORING_SETUP_R_DISABLED))
+ goto out;
+
+ /*
+ * For SQ polling, the thread will do all submissions and completions.
+ * Just return the requested submit count, and wake the thread if
+ * we were asked to.
+ */
+ ret = 0;
+ if (ctx->flags & IORING_SETUP_SQPOLL) {
+ io_cqring_overflow_flush(ctx);
+
+ if (unlikely(ctx->sq_data->thread == NULL)) {
+ ret = -EOWNERDEAD;
+ goto out;
+ }
+ if (flags & IORING_ENTER_SQ_WAKEUP)
+ wake_up(&ctx->sq_data->wait);
+ if (flags & IORING_ENTER_SQ_WAIT) {
+ ret = io_sqpoll_wait_sq(ctx);
+ if (ret)
+ goto out;
+ }
+ ret = to_submit;
+ } else if (to_submit) {
+ ret = io_uring_add_tctx_node(ctx);
+ if (unlikely(ret))
+ goto out;
+
+ mutex_lock(&ctx->uring_lock);
+ ret = io_submit_sqes(ctx, to_submit);
+ if (ret != to_submit) {
+ mutex_unlock(&ctx->uring_lock);
+ goto out;
+ }
+ if (flags & IORING_ENTER_GETEVENTS) {
+ if (ctx->syscall_iopoll)
+ goto iopoll_locked;
+ /*
+ * Ignore errors, we'll soon call io_cqring_wait() and
+ * it should handle ownership problems if any.
+ */
+ if (ctx->flags & IORING_SETUP_DEFER_TASKRUN)
+ (void)io_run_local_work_locked(ctx);
+ }
+ mutex_unlock(&ctx->uring_lock);
+ }
+
+ if (flags & IORING_ENTER_GETEVENTS) {
+ int ret2;
+
+ if (ctx->syscall_iopoll) {
+ /*
+ * We disallow the app entering submit/complete with
+ * polling, but we still need to lock the ring to
+ * prevent racing with polled issue that got punted to
+ * a workqueue.
+ */
+ mutex_lock(&ctx->uring_lock);
+iopoll_locked:
+ ret2 = io_validate_ext_arg(flags, argp, argsz);
+ if (likely(!ret2)) {
+ min_complete = min(min_complete,
+ ctx->cq_entries);
+ ret2 = io_iopoll_check(ctx, min_complete);
+ }
+ mutex_unlock(&ctx->uring_lock);
+ } else {
+ const sigset_t __user *sig;
+ struct __kernel_timespec __user *ts;
+
+ ret2 = io_get_ext_arg(flags, argp, &argsz, &ts, &sig);
+ if (likely(!ret2)) {
+ min_complete = min(min_complete,
+ ctx->cq_entries);
+ ret2 = io_cqring_wait(ctx, min_complete, sig,
+ argsz, ts);
+ }
+ }
+
+ if (!ret) {
+ ret = ret2;
+
+ /*
+ * EBADR indicates that one or more CQE were dropped.
+ * Once the user has been informed we can clear the bit
+ * as they are obviously ok with those drops.
+ */
+ if (unlikely(ret2 == -EBADR))
+ clear_bit(IO_CHECK_CQ_DROPPED_BIT,
+ &ctx->check_cq);
+ }
+ }
+out:
+ fdput(f);
+ return ret;
+}
+
+static const struct file_operations io_uring_fops = {
+ .release = io_uring_release,
+ .mmap = io_uring_mmap,
+#ifndef CONFIG_MMU
+ .get_unmapped_area = io_uring_nommu_get_unmapped_area,
+ .mmap_capabilities = io_uring_nommu_mmap_capabilities,
+#else
+ .get_unmapped_area = io_uring_mmu_get_unmapped_area,
+#endif
+ .poll = io_uring_poll,
+#ifdef CONFIG_PROC_FS
+ .show_fdinfo = io_uring_show_fdinfo,
+#endif
+};
+
+bool io_is_uring_fops(struct file *file)
+{
+ return file->f_op == &io_uring_fops;
+}
+
+static __cold int io_allocate_scq_urings(struct io_ring_ctx *ctx,
+ struct io_uring_params *p)
+{
+ struct io_rings *rings;
+ size_t size, sq_array_offset;
+
+ /* make sure these are sane, as we already accounted them */
+ ctx->sq_entries = p->sq_entries;
+ ctx->cq_entries = p->cq_entries;
+
+ size = rings_size(ctx, p->sq_entries, p->cq_entries, &sq_array_offset);
+ if (size == SIZE_MAX)
+ return -EOVERFLOW;
+
+ rings = io_mem_alloc(size);
+ if (!rings)
+ return -ENOMEM;
+
+ ctx->rings = rings;
+ ctx->sq_array = (u32 *)((char *)rings + sq_array_offset);
+ rings->sq_ring_mask = p->sq_entries - 1;
+ rings->cq_ring_mask = p->cq_entries - 1;
+ rings->sq_ring_entries = p->sq_entries;
+ rings->cq_ring_entries = p->cq_entries;
+
+ if (p->flags & IORING_SETUP_SQE128)
+ size = array_size(2 * sizeof(struct io_uring_sqe), p->sq_entries);
+ else
+ size = array_size(sizeof(struct io_uring_sqe), p->sq_entries);
+ if (size == SIZE_MAX) {
+ io_mem_free(ctx->rings);
+ ctx->rings = NULL;
+ return -EOVERFLOW;
+ }
+
+ ctx->sq_sqes = io_mem_alloc(size);
+ if (!ctx->sq_sqes) {
+ io_mem_free(ctx->rings);
+ ctx->rings = NULL;
+ return -ENOMEM;
+ }
+
+ return 0;
+}
+
+static int io_uring_install_fd(struct io_ring_ctx *ctx, struct file *file)
+{
+ int ret, fd;
+
+ fd = get_unused_fd_flags(O_RDWR | O_CLOEXEC);
+ if (fd < 0)
+ return fd;
+
+ ret = __io_uring_add_tctx_node(ctx);
+ if (ret) {
+ put_unused_fd(fd);
+ return ret;
+ }
+ fd_install(fd, file);
+ return fd;
+}
+
+/*
+ * Allocate an anonymous fd, this is what constitutes the application
+ * visible backing of an io_uring instance. The application mmaps this
+ * fd to gain access to the SQ/CQ ring details. If UNIX sockets are enabled,
+ * we have to tie this fd to a socket for file garbage collection purposes.
+ */
+static struct file *io_uring_get_file(struct io_ring_ctx *ctx)
+{
+ struct file *file;
+#if defined(CONFIG_UNIX)
+ int ret;
+
+ ret = sock_create_kern(&init_net, PF_UNIX, SOCK_RAW, IPPROTO_IP,
+ &ctx->ring_sock);
+ if (ret)
+ return ERR_PTR(ret);
+#endif
+
+ file = anon_inode_getfile_secure("[io_uring]", &io_uring_fops, ctx,
+ O_RDWR | O_CLOEXEC, NULL);
+#if defined(CONFIG_UNIX)
+ if (IS_ERR(file)) {
+ sock_release(ctx->ring_sock);
+ ctx->ring_sock = NULL;
+ } else {
+ ctx->ring_sock->file = file;
+ }
+#endif
+ return file;
+}
+
+static __cold int io_uring_create(unsigned entries, struct io_uring_params *p,
+ struct io_uring_params __user *params)
+{
+ struct io_ring_ctx *ctx;
+ struct file *file;
+ int ret;
+
+ if (!entries)
+ return -EINVAL;
+ if (entries > IORING_MAX_ENTRIES) {
+ if (!(p->flags & IORING_SETUP_CLAMP))
+ return -EINVAL;
+ entries = IORING_MAX_ENTRIES;
+ }
+
+ /*
+ * Use twice as many entries for the CQ ring. It's possible for the
+ * application to drive a higher depth than the size of the SQ ring,
+ * since the sqes are only used at submission time. This allows for
+ * some flexibility in overcommitting a bit. If the application has
+ * set IORING_SETUP_CQSIZE, it will have passed in the desired number
+ * of CQ ring entries manually.
+ */
+ p->sq_entries = roundup_pow_of_two(entries);
+ if (p->flags & IORING_SETUP_CQSIZE) {
+ /*
+ * If IORING_SETUP_CQSIZE is set, we do the same roundup
+ * to a power-of-two, if it isn't already. We do NOT impose
+ * any cq vs sq ring sizing.
+ */
+ if (!p->cq_entries)
+ return -EINVAL;
+ if (p->cq_entries > IORING_MAX_CQ_ENTRIES) {
+ if (!(p->flags & IORING_SETUP_CLAMP))
+ return -EINVAL;
+ p->cq_entries = IORING_MAX_CQ_ENTRIES;
+ }
+ p->cq_entries = roundup_pow_of_two(p->cq_entries);
+ if (p->cq_entries < p->sq_entries)
+ return -EINVAL;
+ } else {
+ p->cq_entries = 2 * p->sq_entries;
+ }
+
+ ctx = io_ring_ctx_alloc(p);
+ if (!ctx)
+ return -ENOMEM;
+
+ /*
+ * When SETUP_IOPOLL and SETUP_SQPOLL are both enabled, user
+ * space applications don't need to do io completion events
+ * polling again, they can rely on io_sq_thread to do polling
+ * work, which can reduce cpu usage and uring_lock contention.
+ */
+ if (ctx->flags & IORING_SETUP_IOPOLL &&
+ !(ctx->flags & IORING_SETUP_SQPOLL))
+ ctx->syscall_iopoll = 1;
+
+ ctx->compat = in_compat_syscall();
+ if (!ns_capable_noaudit(&init_user_ns, CAP_IPC_LOCK))
+ ctx->user = get_uid(current_user());
+
+ /*
+ * For SQPOLL, we just need a wakeup, always. For !SQPOLL, if
+ * COOP_TASKRUN is set, then IPIs are never needed by the app.
+ */
+ ret = -EINVAL;
+ if (ctx->flags & IORING_SETUP_SQPOLL) {
+ /* IPI related flags don't make sense with SQPOLL */
+ if (ctx->flags & (IORING_SETUP_COOP_TASKRUN |
+ IORING_SETUP_TASKRUN_FLAG |
+ IORING_SETUP_DEFER_TASKRUN))
+ goto err;
+ ctx->notify_method = TWA_SIGNAL_NO_IPI;
+ } else if (ctx->flags & IORING_SETUP_COOP_TASKRUN) {
+ ctx->notify_method = TWA_SIGNAL_NO_IPI;
+ } else {
+ if (ctx->flags & IORING_SETUP_TASKRUN_FLAG &&
+ !(ctx->flags & IORING_SETUP_DEFER_TASKRUN))
+ goto err;
+ ctx->notify_method = TWA_SIGNAL;
+ }
+
+ /*
+ * For DEFER_TASKRUN we require the completion task to be the same as the
+ * submission task. This implies that there is only one submitter, so enforce
+ * that.
+ */
+ if (ctx->flags & IORING_SETUP_DEFER_TASKRUN &&
+ !(ctx->flags & IORING_SETUP_SINGLE_ISSUER)) {
+ goto err;
+ }
+
+ /*
+ * This is just grabbed for accounting purposes. When a process exits,
+ * the mm is exited and dropped before the files, hence we need to hang
+ * on to this mm purely for the purposes of being able to unaccount
+ * memory (locked/pinned vm). It's not used for anything else.
+ */
+ mmgrab(current->mm);
+ ctx->mm_account = current->mm;
+
+ ret = io_allocate_scq_urings(ctx, p);
+ if (ret)
+ goto err;
+
+ ret = io_sq_offload_create(ctx, p);
+ if (ret)
+ goto err;
+ /* always set a rsrc node */
+ ret = io_rsrc_node_switch_start(ctx);
+ if (ret)
+ goto err;
+ io_rsrc_node_switch(ctx, NULL);
+
+ memset(&p->sq_off, 0, sizeof(p->sq_off));
+ p->sq_off.head = offsetof(struct io_rings, sq.head);
+ p->sq_off.tail = offsetof(struct io_rings, sq.tail);
+ p->sq_off.ring_mask = offsetof(struct io_rings, sq_ring_mask);
+ p->sq_off.ring_entries = offsetof(struct io_rings, sq_ring_entries);
+ p->sq_off.flags = offsetof(struct io_rings, sq_flags);
+ p->sq_off.dropped = offsetof(struct io_rings, sq_dropped);
+ p->sq_off.array = (char *)ctx->sq_array - (char *)ctx->rings;
+
+ memset(&p->cq_off, 0, sizeof(p->cq_off));
+ p->cq_off.head = offsetof(struct io_rings, cq.head);
+ p->cq_off.tail = offsetof(struct io_rings, cq.tail);
+ p->cq_off.ring_mask = offsetof(struct io_rings, cq_ring_mask);
+ p->cq_off.ring_entries = offsetof(struct io_rings, cq_ring_entries);
+ p->cq_off.overflow = offsetof(struct io_rings, cq_overflow);
+ p->cq_off.cqes = offsetof(struct io_rings, cqes);
+ p->cq_off.flags = offsetof(struct io_rings, cq_flags);
+
+ p->features = IORING_FEAT_SINGLE_MMAP | IORING_FEAT_NODROP |
+ IORING_FEAT_SUBMIT_STABLE | IORING_FEAT_RW_CUR_POS |
+ IORING_FEAT_CUR_PERSONALITY | IORING_FEAT_FAST_POLL |
+ IORING_FEAT_POLL_32BITS | IORING_FEAT_SQPOLL_NONFIXED |
+ IORING_FEAT_EXT_ARG | IORING_FEAT_NATIVE_WORKERS |
+ IORING_FEAT_RSRC_TAGS | IORING_FEAT_CQE_SKIP |
+ IORING_FEAT_LINKED_FILE;
+
+ if (copy_to_user(params, p, sizeof(*p))) {
+ ret = -EFAULT;
+ goto err;
+ }
+
+ if (ctx->flags & IORING_SETUP_SINGLE_ISSUER
+ && !(ctx->flags & IORING_SETUP_R_DISABLED))
+ ctx->submitter_task = get_task_struct(current);
+
+ file = io_uring_get_file(ctx);
+ if (IS_ERR(file)) {
+ ret = PTR_ERR(file);
+ goto err;
+ }
+
+ /*
+ * Install ring fd as the very last thing, so we don't risk someone
+ * having closed it before we finish setup
+ */
+ ret = io_uring_install_fd(ctx, file);
+ if (ret < 0) {
+ /* fput will clean it up */
+ fput(file);
+ return ret;
+ }
+
+ trace_io_uring_create(ret, ctx, p->sq_entries, p->cq_entries, p->flags);
+ return ret;
+err:
+ io_ring_ctx_wait_and_kill(ctx);
+ return ret;
+}
+
+/*
+ * Sets up an aio uring context, and returns the fd. Applications asks for a
+ * ring size, we return the actual sq/cq ring sizes (among other things) in the
+ * params structure passed in.
+ */
+static long io_uring_setup(u32 entries, struct io_uring_params __user *params)
+{
+ struct io_uring_params p;
+ int i;
+
+ if (copy_from_user(&p, params, sizeof(p)))
+ return -EFAULT;
+ for (i = 0; i < ARRAY_SIZE(p.resv); i++) {
+ if (p.resv[i])
+ return -EINVAL;
+ }
+
+ if (p.flags & ~(IORING_SETUP_IOPOLL | IORING_SETUP_SQPOLL |
+ IORING_SETUP_SQ_AFF | IORING_SETUP_CQSIZE |
+ IORING_SETUP_CLAMP | IORING_SETUP_ATTACH_WQ |
+ IORING_SETUP_R_DISABLED | IORING_SETUP_SUBMIT_ALL |
+ IORING_SETUP_COOP_TASKRUN | IORING_SETUP_TASKRUN_FLAG |
+ IORING_SETUP_SQE128 | IORING_SETUP_CQE32 |
+ IORING_SETUP_SINGLE_ISSUER | IORING_SETUP_DEFER_TASKRUN))
+ return -EINVAL;
+
+ return io_uring_create(entries, &p, params);
+}
+
+SYSCALL_DEFINE2(io_uring_setup, u32, entries,
+ struct io_uring_params __user *, params)
+{
+ return io_uring_setup(entries, params);
+}
+
+static __cold int io_probe(struct io_ring_ctx *ctx, void __user *arg,
+ unsigned nr_args)
+{
+ struct io_uring_probe *p;
+ size_t size;
+ int i, ret;
+
+ size = struct_size(p, ops, nr_args);
+ if (size == SIZE_MAX)
+ return -EOVERFLOW;
+ p = kzalloc(size, GFP_KERNEL);
+ if (!p)
+ return -ENOMEM;
+
+ ret = -EFAULT;
+ if (copy_from_user(p, arg, size))
+ goto out;
+ ret = -EINVAL;
+ if (memchr_inv(p, 0, size))
+ goto out;
+
+ p->last_op = IORING_OP_LAST - 1;
+ if (nr_args > IORING_OP_LAST)
+ nr_args = IORING_OP_LAST;
+
+ for (i = 0; i < nr_args; i++) {
+ p->ops[i].op = i;
+ if (!io_op_defs[i].not_supported)
+ p->ops[i].flags = IO_URING_OP_SUPPORTED;
+ }
+ p->ops_len = i;
+
+ ret = 0;
+ if (copy_to_user(arg, p, size))
+ ret = -EFAULT;
+out:
+ kfree(p);
+ return ret;
+}
+
+static int io_register_personality(struct io_ring_ctx *ctx)
+{
+ const struct cred *creds;
+ u32 id;
+ int ret;
+
+ creds = get_current_cred();
+
+ ret = xa_alloc_cyclic(&ctx->personalities, &id, (void *)creds,
+ XA_LIMIT(0, USHRT_MAX), &ctx->pers_next, GFP_KERNEL);
+ if (ret < 0) {
+ put_cred(creds);
+ return ret;
+ }
+ return id;
+}
+
+static __cold int io_register_restrictions(struct io_ring_ctx *ctx,
+ void __user *arg, unsigned int nr_args)
+{
+ struct io_uring_restriction *res;
+ size_t size;
+ int i, ret;
+
+ /* Restrictions allowed only if rings started disabled */
+ if (!(ctx->flags & IORING_SETUP_R_DISABLED))
+ return -EBADFD;
+
+ /* We allow only a single restrictions registration */
+ if (ctx->restrictions.registered)
+ return -EBUSY;
+
+ if (!arg || nr_args > IORING_MAX_RESTRICTIONS)
+ return -EINVAL;
+
+ size = array_size(nr_args, sizeof(*res));
+ if (size == SIZE_MAX)
+ return -EOVERFLOW;
+
+ res = memdup_user(arg, size);
+ if (IS_ERR(res))
+ return PTR_ERR(res);
+
+ ret = 0;
+
+ for (i = 0; i < nr_args; i++) {
+ switch (res[i].opcode) {
+ case IORING_RESTRICTION_REGISTER_OP:
+ if (res[i].register_op >= IORING_REGISTER_LAST) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ __set_bit(res[i].register_op,
+ ctx->restrictions.register_op);
+ break;
+ case IORING_RESTRICTION_SQE_OP:
+ if (res[i].sqe_op >= IORING_OP_LAST) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ __set_bit(res[i].sqe_op, ctx->restrictions.sqe_op);
+ break;
+ case IORING_RESTRICTION_SQE_FLAGS_ALLOWED:
+ ctx->restrictions.sqe_flags_allowed = res[i].sqe_flags;
+ break;
+ case IORING_RESTRICTION_SQE_FLAGS_REQUIRED:
+ ctx->restrictions.sqe_flags_required = res[i].sqe_flags;
+ break;
+ default:
+ ret = -EINVAL;
+ goto out;
+ }
+ }
+
+out:
+ /* Reset all restrictions if an error happened */
+ if (ret != 0)
+ memset(&ctx->restrictions, 0, sizeof(ctx->restrictions));
+ else
+ ctx->restrictions.registered = true;
+
+ kfree(res);
+ return ret;
+}
+
+static int io_register_enable_rings(struct io_ring_ctx *ctx)
+{
+ if (!(ctx->flags & IORING_SETUP_R_DISABLED))
+ return -EBADFD;
+
+ if (ctx->flags & IORING_SETUP_SINGLE_ISSUER && !ctx->submitter_task)
+ ctx->submitter_task = get_task_struct(current);
+
+ if (ctx->restrictions.registered)
+ ctx->restricted = 1;
+
+ ctx->flags &= ~IORING_SETUP_R_DISABLED;
+ if (ctx->sq_data && wq_has_sleeper(&ctx->sq_data->wait))
+ wake_up(&ctx->sq_data->wait);
+ return 0;
+}
+
+static __cold int __io_register_iowq_aff(struct io_ring_ctx *ctx,
+ cpumask_var_t new_mask)
+{
+ int ret;
+
+ if (!(ctx->flags & IORING_SETUP_SQPOLL)) {
+ ret = io_wq_cpu_affinity(current->io_uring, new_mask);
+ } else {
+ mutex_unlock(&ctx->uring_lock);
+ ret = io_sqpoll_wq_cpu_affinity(ctx, new_mask);
+ mutex_lock(&ctx->uring_lock);
+ }
+
+ return ret;
+}
+
+static __cold int io_register_iowq_aff(struct io_ring_ctx *ctx,
+ void __user *arg, unsigned len)
+{
+ cpumask_var_t new_mask;
+ int ret;
+
+ if (!alloc_cpumask_var(&new_mask, GFP_KERNEL))
+ return -ENOMEM;
+
+ cpumask_clear(new_mask);
+ if (len > cpumask_size())
+ len = cpumask_size();
+
+ if (in_compat_syscall()) {
+ ret = compat_get_bitmap(cpumask_bits(new_mask),
+ (const compat_ulong_t __user *)arg,
+ len * 8 /* CHAR_BIT */);
+ } else {
+ ret = copy_from_user(new_mask, arg, len);
+ }
+
+ if (ret) {
+ free_cpumask_var(new_mask);
+ return -EFAULT;
+ }
+
+ ret = __io_register_iowq_aff(ctx, new_mask);
+ free_cpumask_var(new_mask);
+ return ret;
+}
+
+static __cold int io_unregister_iowq_aff(struct io_ring_ctx *ctx)
+{
+ return __io_register_iowq_aff(ctx, NULL);
+}
+
+static __cold int io_register_iowq_max_workers(struct io_ring_ctx *ctx,
+ void __user *arg)
+ __must_hold(&ctx->uring_lock)
+{
+ struct io_tctx_node *node;
+ struct io_uring_task *tctx = NULL;
+ struct io_sq_data *sqd = NULL;
+ __u32 new_count[2];
+ int i, ret;
+
+ if (copy_from_user(new_count, arg, sizeof(new_count)))
+ return -EFAULT;
+ for (i = 0; i < ARRAY_SIZE(new_count); i++)
+ if (new_count[i] > INT_MAX)
+ return -EINVAL;
+
+ if (ctx->flags & IORING_SETUP_SQPOLL) {
+ sqd = ctx->sq_data;
+ if (sqd) {
+ /*
+ * Observe the correct sqd->lock -> ctx->uring_lock
+ * ordering. Fine to drop uring_lock here, we hold
+ * a ref to the ctx.
+ */
+ refcount_inc(&sqd->refs);
+ mutex_unlock(&ctx->uring_lock);
+ mutex_lock(&sqd->lock);
+ mutex_lock(&ctx->uring_lock);
+ if (sqd->thread)
+ tctx = sqd->thread->io_uring;
+ }
+ } else {
+ tctx = current->io_uring;
+ }
+
+ BUILD_BUG_ON(sizeof(new_count) != sizeof(ctx->iowq_limits));
+
+ for (i = 0; i < ARRAY_SIZE(new_count); i++)
+ if (new_count[i])
+ ctx->iowq_limits[i] = new_count[i];
+ ctx->iowq_limits_set = true;
+
+ if (tctx && tctx->io_wq) {
+ ret = io_wq_max_workers(tctx->io_wq, new_count);
+ if (ret)
+ goto err;
+ } else {
+ memset(new_count, 0, sizeof(new_count));
+ }
+
+ if (sqd) {
+ mutex_unlock(&sqd->lock);
+ io_put_sq_data(sqd);
+ }
+
+ if (copy_to_user(arg, new_count, sizeof(new_count)))
+ return -EFAULT;
+
+ /* that's it for SQPOLL, only the SQPOLL task creates requests */
+ if (sqd)
+ return 0;
+
+ /* now propagate the restriction to all registered users */
+ list_for_each_entry(node, &ctx->tctx_list, ctx_node) {
+ struct io_uring_task *tctx = node->task->io_uring;
+
+ if (WARN_ON_ONCE(!tctx->io_wq))
+ continue;
+
+ for (i = 0; i < ARRAY_SIZE(new_count); i++)
+ new_count[i] = ctx->iowq_limits[i];
+ /* ignore errors, it always returns zero anyway */
+ (void)io_wq_max_workers(tctx->io_wq, new_count);
+ }
+ return 0;
+err:
+ if (sqd) {
+ mutex_unlock(&sqd->lock);
+ io_put_sq_data(sqd);
+ }
+ return ret;
+}
+
+static int __io_uring_register(struct io_ring_ctx *ctx, unsigned opcode,
+ void __user *arg, unsigned nr_args)
+ __releases(ctx->uring_lock)
+ __acquires(ctx->uring_lock)
+{
+ int ret;
+
+ /*
+ * We don't quiesce the refs for register anymore and so it can't be
+ * dying as we're holding a file ref here.
+ */
+ if (WARN_ON_ONCE(percpu_ref_is_dying(&ctx->refs)))
+ return -ENXIO;
+
+ if (ctx->submitter_task && ctx->submitter_task != current)
+ return -EEXIST;
+
+ if (ctx->restricted) {
+ opcode = array_index_nospec(opcode, IORING_REGISTER_LAST);
+ if (!test_bit(opcode, ctx->restrictions.register_op))
+ return -EACCES;
+ }
+
+ switch (opcode) {
+ case IORING_REGISTER_BUFFERS:
+ ret = -EFAULT;
+ if (!arg)
+ break;
+ ret = io_sqe_buffers_register(ctx, arg, nr_args, NULL);
+ break;
+ case IORING_UNREGISTER_BUFFERS:
+ ret = -EINVAL;
+ if (arg || nr_args)
+ break;
+ ret = io_sqe_buffers_unregister(ctx);
+ break;
+ case IORING_REGISTER_FILES:
+ ret = -EFAULT;
+ if (!arg)
+ break;
+ ret = io_sqe_files_register(ctx, arg, nr_args, NULL);
+ break;
+ case IORING_UNREGISTER_FILES:
+ ret = -EINVAL;
+ if (arg || nr_args)
+ break;
+ ret = io_sqe_files_unregister(ctx);
+ break;
+ case IORING_REGISTER_FILES_UPDATE:
+ ret = io_register_files_update(ctx, arg, nr_args);
+ break;
+ case IORING_REGISTER_EVENTFD:
+ ret = -EINVAL;
+ if (nr_args != 1)
+ break;
+ ret = io_eventfd_register(ctx, arg, 0);
+ break;
+ case IORING_REGISTER_EVENTFD_ASYNC:
+ ret = -EINVAL;
+ if (nr_args != 1)
+ break;
+ ret = io_eventfd_register(ctx, arg, 1);
+ break;
+ case IORING_UNREGISTER_EVENTFD:
+ ret = -EINVAL;
+ if (arg || nr_args)
+ break;
+ ret = io_eventfd_unregister(ctx);
+ break;
+ case IORING_REGISTER_PROBE:
+ ret = -EINVAL;
+ if (!arg || nr_args > 256)
+ break;
+ ret = io_probe(ctx, arg, nr_args);
+ break;
+ case IORING_REGISTER_PERSONALITY:
+ ret = -EINVAL;
+ if (arg || nr_args)
+ break;
+ ret = io_register_personality(ctx);
+ break;
+ case IORING_UNREGISTER_PERSONALITY:
+ ret = -EINVAL;
+ if (arg)
+ break;
+ ret = io_unregister_personality(ctx, nr_args);
+ break;
+ case IORING_REGISTER_ENABLE_RINGS:
+ ret = -EINVAL;
+ if (arg || nr_args)
+ break;
+ ret = io_register_enable_rings(ctx);
+ break;
+ case IORING_REGISTER_RESTRICTIONS:
+ ret = io_register_restrictions(ctx, arg, nr_args);
+ break;
+ case IORING_REGISTER_FILES2:
+ ret = io_register_rsrc(ctx, arg, nr_args, IORING_RSRC_FILE);
+ break;
+ case IORING_REGISTER_FILES_UPDATE2:
+ ret = io_register_rsrc_update(ctx, arg, nr_args,
+ IORING_RSRC_FILE);
+ break;
+ case IORING_REGISTER_BUFFERS2:
+ ret = io_register_rsrc(ctx, arg, nr_args, IORING_RSRC_BUFFER);
+ break;
+ case IORING_REGISTER_BUFFERS_UPDATE:
+ ret = io_register_rsrc_update(ctx, arg, nr_args,
+ IORING_RSRC_BUFFER);
+ break;
+ case IORING_REGISTER_IOWQ_AFF:
+ ret = -EINVAL;
+ if (!arg || !nr_args)
+ break;
+ ret = io_register_iowq_aff(ctx, arg, nr_args);
+ break;
+ case IORING_UNREGISTER_IOWQ_AFF:
+ ret = -EINVAL;
+ if (arg || nr_args)
+ break;
+ ret = io_unregister_iowq_aff(ctx);
+ break;
+ case IORING_REGISTER_IOWQ_MAX_WORKERS:
+ ret = -EINVAL;
+ if (!arg || nr_args != 2)
+ break;
+ ret = io_register_iowq_max_workers(ctx, arg);
+ break;
+ case IORING_REGISTER_RING_FDS:
+ ret = io_ringfd_register(ctx, arg, nr_args);
+ break;
+ case IORING_UNREGISTER_RING_FDS:
+ ret = io_ringfd_unregister(ctx, arg, nr_args);
+ break;
+ case IORING_REGISTER_PBUF_RING:
+ ret = -EINVAL;
+ if (!arg || nr_args != 1)
+ break;
+ ret = io_register_pbuf_ring(ctx, arg);
+ break;
+ case IORING_UNREGISTER_PBUF_RING:
+ ret = -EINVAL;
+ if (!arg || nr_args != 1)
+ break;
+ ret = io_unregister_pbuf_ring(ctx, arg);
+ break;
+ case IORING_REGISTER_SYNC_CANCEL:
+ ret = -EINVAL;
+ if (!arg || nr_args != 1)
+ break;
+ ret = io_sync_cancel(ctx, arg);
+ break;
+ case IORING_REGISTER_FILE_ALLOC_RANGE:
+ ret = -EINVAL;
+ if (!arg || nr_args)
+ break;
+ ret = io_register_file_alloc_range(ctx, arg);
+ break;
+ default:
+ ret = -EINVAL;
+ break;
+ }
+
+ return ret;
+}
+
+SYSCALL_DEFINE4(io_uring_register, unsigned int, fd, unsigned int, opcode,
+ void __user *, arg, unsigned int, nr_args)
+{
+ struct io_ring_ctx *ctx;
+ long ret = -EBADF;
+ struct fd f;
+
+ if (opcode >= IORING_REGISTER_LAST)
+ return -EINVAL;
+
+ f = fdget(fd);
+ if (!f.file)
+ return -EBADF;
+
+ ret = -EOPNOTSUPP;
+ if (!io_is_uring_fops(f.file))
+ goto out_fput;
+
+ ctx = f.file->private_data;
+
+ io_run_task_work_ctx(ctx);
+
+ mutex_lock(&ctx->uring_lock);
+ ret = __io_uring_register(ctx, opcode, arg, nr_args);
+ mutex_unlock(&ctx->uring_lock);
+ trace_io_uring_register(ctx, opcode, ctx->nr_user_files, ctx->nr_user_bufs, ret);
+out_fput:
+ fdput(f);
+ return ret;
+}
+
+static int __init io_uring_init(void)
+{
+#define __BUILD_BUG_VERIFY_OFFSET_SIZE(stype, eoffset, esize, ename) do { \
+ BUILD_BUG_ON(offsetof(stype, ename) != eoffset); \
+ BUILD_BUG_ON(sizeof_field(stype, ename) != esize); \
+} while (0)
+
+#define BUILD_BUG_SQE_ELEM(eoffset, etype, ename) \
+ __BUILD_BUG_VERIFY_OFFSET_SIZE(struct io_uring_sqe, eoffset, sizeof(etype), ename)
+#define BUILD_BUG_SQE_ELEM_SIZE(eoffset, esize, ename) \
+ __BUILD_BUG_VERIFY_OFFSET_SIZE(struct io_uring_sqe, eoffset, esize, ename)
+ BUILD_BUG_ON(sizeof(struct io_uring_sqe) != 64);
+ BUILD_BUG_SQE_ELEM(0, __u8, opcode);
+ BUILD_BUG_SQE_ELEM(1, __u8, flags);
+ BUILD_BUG_SQE_ELEM(2, __u16, ioprio);
+ BUILD_BUG_SQE_ELEM(4, __s32, fd);
+ BUILD_BUG_SQE_ELEM(8, __u64, off);
+ BUILD_BUG_SQE_ELEM(8, __u64, addr2);
+ BUILD_BUG_SQE_ELEM(8, __u32, cmd_op);
+ BUILD_BUG_SQE_ELEM(12, __u32, __pad1);
+ BUILD_BUG_SQE_ELEM(16, __u64, addr);
+ BUILD_BUG_SQE_ELEM(16, __u64, splice_off_in);
+ BUILD_BUG_SQE_ELEM(24, __u32, len);
+ BUILD_BUG_SQE_ELEM(28, __kernel_rwf_t, rw_flags);
+ BUILD_BUG_SQE_ELEM(28, /* compat */ int, rw_flags);
+ BUILD_BUG_SQE_ELEM(28, /* compat */ __u32, rw_flags);
+ BUILD_BUG_SQE_ELEM(28, __u32, fsync_flags);
+ BUILD_BUG_SQE_ELEM(28, /* compat */ __u16, poll_events);
+ BUILD_BUG_SQE_ELEM(28, __u32, poll32_events);
+ BUILD_BUG_SQE_ELEM(28, __u32, sync_range_flags);
+ BUILD_BUG_SQE_ELEM(28, __u32, msg_flags);
+ BUILD_BUG_SQE_ELEM(28, __u32, timeout_flags);
+ BUILD_BUG_SQE_ELEM(28, __u32, accept_flags);
+ BUILD_BUG_SQE_ELEM(28, __u32, cancel_flags);
+ BUILD_BUG_SQE_ELEM(28, __u32, open_flags);
+ BUILD_BUG_SQE_ELEM(28, __u32, statx_flags);
+ BUILD_BUG_SQE_ELEM(28, __u32, fadvise_advice);
+ BUILD_BUG_SQE_ELEM(28, __u32, splice_flags);
+ BUILD_BUG_SQE_ELEM(28, __u32, rename_flags);
+ BUILD_BUG_SQE_ELEM(28, __u32, unlink_flags);
+ BUILD_BUG_SQE_ELEM(28, __u32, hardlink_flags);
+ BUILD_BUG_SQE_ELEM(28, __u32, xattr_flags);
+ BUILD_BUG_SQE_ELEM(28, __u32, msg_ring_flags);
+ BUILD_BUG_SQE_ELEM(32, __u64, user_data);
+ BUILD_BUG_SQE_ELEM(40, __u16, buf_index);
+ BUILD_BUG_SQE_ELEM(40, __u16, buf_group);
+ BUILD_BUG_SQE_ELEM(42, __u16, personality);
+ BUILD_BUG_SQE_ELEM(44, __s32, splice_fd_in);
+ BUILD_BUG_SQE_ELEM(44, __u32, file_index);
+ BUILD_BUG_SQE_ELEM(44, __u16, addr_len);
+ BUILD_BUG_SQE_ELEM(46, __u16, __pad3[0]);
+ BUILD_BUG_SQE_ELEM(48, __u64, addr3);
+ BUILD_BUG_SQE_ELEM_SIZE(48, 0, cmd);
+ BUILD_BUG_SQE_ELEM(56, __u64, __pad2);
+
+ BUILD_BUG_ON(sizeof(struct io_uring_files_update) !=
+ sizeof(struct io_uring_rsrc_update));
+ BUILD_BUG_ON(sizeof(struct io_uring_rsrc_update) >
+ sizeof(struct io_uring_rsrc_update2));
+
+ /* ->buf_index is u16 */
+ BUILD_BUG_ON(offsetof(struct io_uring_buf_ring, bufs) != 0);
+ BUILD_BUG_ON(offsetof(struct io_uring_buf, resv) !=
+ offsetof(struct io_uring_buf_ring, tail));
+
+ /* should fit into one byte */
+ BUILD_BUG_ON(SQE_VALID_FLAGS >= (1 << 8));
+ BUILD_BUG_ON(SQE_COMMON_FLAGS >= (1 << 8));
+ BUILD_BUG_ON((SQE_VALID_FLAGS | SQE_COMMON_FLAGS) != SQE_VALID_FLAGS);
+
+ BUILD_BUG_ON(__REQ_F_LAST_BIT > 8 * sizeof(int));
+
+ BUILD_BUG_ON(sizeof(atomic_t) != sizeof(u32));
+
+ io_uring_optable_init();
+
+ req_cachep = KMEM_CACHE(io_kiocb, SLAB_HWCACHE_ALIGN | SLAB_PANIC |
+ SLAB_ACCOUNT);
+ return 0;
+};
+__initcall(io_uring_init);