Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1289 insertions, 0 deletions

diff --git a/io_uring/rsrc.c b/io_uring/rsrc.c
new file mode 100644
index 000000000..dde501abd
--- /dev/null
+++ b/io_uring/rsrc.c
@@ -0,0 +1,1289 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/fs.h>
+#include <linux/file.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include <linux/nospec.h>
+#include <linux/hugetlb.h>
+#include <linux/compat.h>
+#include <linux/io_uring.h>
+
+#include <uapi/linux/io_uring.h>
+
+#include "io_uring.h"
+#include "openclose.h"
+#include "rsrc.h"
+
+struct io_rsrc_update {
+	struct file			*file;
+	u64				arg;
+	u32				nr_args;
+	u32				offset;
+};
+
+static void io_rsrc_buf_put(struct io_ring_ctx *ctx, struct io_rsrc_put *prsrc);
+static void io_rsrc_file_put(struct io_ring_ctx *ctx, struct io_rsrc_put *prsrc);
+static int io_sqe_buffer_register(struct io_ring_ctx *ctx, struct iovec *iov,
+				  struct io_mapped_ubuf **pimu,
+				  struct page **last_hpage);
+
+/* only define max */
+#define IORING_MAX_FIXED_FILES	(1U << 20)
+#define IORING_MAX_REG_BUFFERS	(1U << 14)
+
+static const struct io_mapped_ubuf dummy_ubuf = {
+	/* set invalid range, so io_import_fixed() fails meeting it */
+	.ubuf = -1UL,
+	.ubuf_end = 0,
+};
+
+int __io_account_mem(struct user_struct *user, unsigned long nr_pages)
+{
+	unsigned long page_limit, cur_pages, new_pages;
+
+	if (!nr_pages)
+		return 0;
+
+	/* Don't allow more pages than we can safely lock */
+	page_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
+
+	cur_pages = atomic_long_read(&user->locked_vm);
+	do {
+		new_pages = cur_pages + nr_pages;
+		if (new_pages > page_limit)
+			return -ENOMEM;
+	} while (!atomic_long_try_cmpxchg(&user->locked_vm,
+					  &cur_pages, new_pages));
+	return 0;
+}
+
+static void io_unaccount_mem(struct io_ring_ctx *ctx, unsigned long nr_pages)
+{
+	if (ctx->user)
+		__io_unaccount_mem(ctx->user, nr_pages);
+
+	if (ctx->mm_account)
+		atomic64_sub(nr_pages, &ctx->mm_account->pinned_vm);
+}
+
+static int io_account_mem(struct io_ring_ctx *ctx, unsigned long nr_pages)
+{
+	int ret;
+
+	if (ctx->user) {
+		ret = __io_account_mem(ctx->user, nr_pages);
+		if (ret)
+			return ret;
+	}
+
+	if (ctx->mm_account)
+		atomic64_add(nr_pages, &ctx->mm_account->pinned_vm);
+
+	return 0;
+}
+
+static int io_copy_iov(struct io_ring_ctx *ctx, struct iovec *dst,
+		       void __user *arg, unsigned index)
+{
+	struct iovec __user *src;
+
+#ifdef CONFIG_COMPAT
+	if (ctx->compat) {
+		struct compat_iovec __user *ciovs;
+		struct compat_iovec ciov;
+
+		ciovs = (struct compat_iovec __user *) arg;
+		if (copy_from_user(&ciov, &ciovs[index], sizeof(ciov)))
+			return -EFAULT;
+
+		dst->iov_base = u64_to_user_ptr((u64)ciov.iov_base);
+		dst->iov_len = ciov.iov_len;
+		return 0;
+	}
+#endif
+	src = (struct iovec __user *) arg;
+	if (copy_from_user(dst, &src[index], sizeof(*dst)))
+		return -EFAULT;
+	return 0;
+}
+
+static int io_buffer_validate(struct iovec *iov)
+{
+	unsigned long tmp, acct_len = iov->iov_len + (PAGE_SIZE - 1);
+
+	/*
+	 * Don't impose further limits on the size and buffer
+	 * constraints here, we'll -EINVAL later when IO is
+	 * submitted if they are wrong.
+	 */
+	if (!iov->iov_base)
+		return iov->iov_len ? -EFAULT : 0;
+	if (!iov->iov_len)
+		return -EFAULT;
+
+	/* arbitrary limit, but we need something */
+	if (iov->iov_len > SZ_1G)
+		return -EFAULT;
+
+	if (check_add_overflow((unsigned long)iov->iov_base, acct_len, &tmp))
+		return -EOVERFLOW;
+
+	return 0;
+}
+
+static void io_buffer_unmap(struct io_ring_ctx *ctx, struct io_mapped_ubuf **slot)
+{
+	struct io_mapped_ubuf *imu = *slot;
+	unsigned int i;
+
+	if (imu != &dummy_ubuf) {
+		for (i = 0; i < imu->nr_bvecs; i++)
+			unpin_user_page(imu->bvec[i].bv_page);
+		if (imu->acct_pages)
+			io_unaccount_mem(ctx, imu->acct_pages);
+		kvfree(imu);
+	}
+	*slot = NULL;
+}
+
+static void io_rsrc_put_work(struct io_rsrc_node *node)
+{
+	struct io_rsrc_put *prsrc = &node->item;
+
+	if (prsrc->tag)
+		io_post_aux_cqe(node->ctx, prsrc->tag, 0, 0);
+
+	switch (node->type) {
+	case IORING_RSRC_FILE:
+		io_rsrc_file_put(node->ctx, prsrc);
+		break;
+	case IORING_RSRC_BUFFER:
+		io_rsrc_buf_put(node->ctx, prsrc);
+		break;
+	default:
+		WARN_ON_ONCE(1);
+		break;
+	}
+}
+
+void io_rsrc_node_destroy(struct io_ring_ctx *ctx, struct io_rsrc_node *node)
+{
+	if (!io_alloc_cache_put(&ctx->rsrc_node_cache, &node->cache))
+		kfree(node);
+}
+
+void io_rsrc_node_ref_zero(struct io_rsrc_node *node)
+	__must_hold(&node->ctx->uring_lock)
+{
+	struct io_ring_ctx *ctx = node->ctx;
+
+	while (!list_empty(&ctx->rsrc_ref_list)) {
+		node = list_first_entry(&ctx->rsrc_ref_list,
+					    struct io_rsrc_node, node);
+		/* recycle ref nodes in order */
+		if (node->refs)
+			break;
+		list_del(&node->node);
+
+		if (likely(!node->empty))
+			io_rsrc_put_work(node);
+		io_rsrc_node_destroy(ctx, node);
+	}
+	if (list_empty(&ctx->rsrc_ref_list) && unlikely(ctx->rsrc_quiesce))
+		wake_up_all(&ctx->rsrc_quiesce_wq);
+}
+
+struct io_rsrc_node *io_rsrc_node_alloc(struct io_ring_ctx *ctx)
+{
+	struct io_rsrc_node *ref_node;
+	struct io_cache_entry *entry;
+
+	entry = io_alloc_cache_get(&ctx->rsrc_node_cache);
+	if (entry) {
+		ref_node = container_of(entry, struct io_rsrc_node, cache);
+	} else {
+		ref_node = kzalloc(sizeof(*ref_node), GFP_KERNEL);
+		if (!ref_node)
+			return NULL;
+	}
+
+	ref_node->ctx = ctx;
+	ref_node->empty = 0;
+	ref_node->refs = 1;
+	return ref_node;
+}
+
+__cold static int io_rsrc_ref_quiesce(struct io_rsrc_data *data,
+				      struct io_ring_ctx *ctx)
+{
+	struct io_rsrc_node *backup;
+	DEFINE_WAIT(we);
+	int ret;
+
+	/* As We may drop ->uring_lock, other task may have started quiesce */
+	if (data->quiesce)
+		return -ENXIO;
+
+	backup = io_rsrc_node_alloc(ctx);
+	if (!backup)
+		return -ENOMEM;
+	ctx->rsrc_node->empty = true;
+	ctx->rsrc_node->type = -1;
+	list_add_tail(&ctx->rsrc_node->node, &ctx->rsrc_ref_list);
+	io_put_rsrc_node(ctx, ctx->rsrc_node);
+	ctx->rsrc_node = backup;
+
+	if (list_empty(&ctx->rsrc_ref_list))
+		return 0;
+
+	if (ctx->flags & IORING_SETUP_DEFER_TASKRUN) {
+		atomic_set(&ctx->cq_wait_nr, 1);
+		smp_mb();
+	}
+
+	ctx->rsrc_quiesce++;
+	data->quiesce = true;
+	do {
+		prepare_to_wait(&ctx->rsrc_quiesce_wq, &we, TASK_INTERRUPTIBLE);
+		mutex_unlock(&ctx->uring_lock);
+
+		ret = io_run_task_work_sig(ctx);
+		if (ret < 0) {
+			mutex_lock(&ctx->uring_lock);
+			if (list_empty(&ctx->rsrc_ref_list))
+				ret = 0;
+			break;
+		}
+
+		schedule();
+		__set_current_state(TASK_RUNNING);
+		mutex_lock(&ctx->uring_lock);
+		ret = 0;
+	} while (!list_empty(&ctx->rsrc_ref_list));
+
+	finish_wait(&ctx->rsrc_quiesce_wq, &we);
+	data->quiesce = false;
+	ctx->rsrc_quiesce--;
+
+	if (ctx->flags & IORING_SETUP_DEFER_TASKRUN) {
+		atomic_set(&ctx->cq_wait_nr, 0);
+		smp_mb();
+	}
+	return ret;
+}
+
+static void io_free_page_table(void **table, size_t size)
+{
+	unsigned i, nr_tables = DIV_ROUND_UP(size, PAGE_SIZE);
+
+	for (i = 0; i < nr_tables; i++)
+		kfree(table[i]);
+	kfree(table);
+}
+
+static void io_rsrc_data_free(struct io_rsrc_data *data)
+{
+	size_t size = data->nr * sizeof(data->tags[0][0]);
+
+	if (data->tags)
+		io_free_page_table((void **)data->tags, size);
+	kfree(data);
+}
+
+static __cold void **io_alloc_page_table(size_t size)
+{
+	unsigned i, nr_tables = DIV_ROUND_UP(size, PAGE_SIZE);
+	size_t init_size = size;
+	void **table;
+
+	table = kcalloc(nr_tables, sizeof(*table), GFP_KERNEL_ACCOUNT);
+	if (!table)
+		return NULL;
+
+	for (i = 0; i < nr_tables; i++) {
+		unsigned int this_size = min_t(size_t, size, PAGE_SIZE);
+
+		table[i] = kzalloc(this_size, GFP_KERNEL_ACCOUNT);
+		if (!table[i]) {
+			io_free_page_table(table, init_size);
+			return NULL;
+		}
+		size -= this_size;
+	}
+	return table;
+}
+
+__cold static int io_rsrc_data_alloc(struct io_ring_ctx *ctx, int type,
+				     u64 __user *utags,
+				     unsigned nr, struct io_rsrc_data **pdata)
+{
+	struct io_rsrc_data *data;
+	int ret = 0;
+	unsigned i;
+
+	data = kzalloc(sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+	data->tags = (u64 **)io_alloc_page_table(nr * sizeof(data->tags[0][0]));
+	if (!data->tags) {
+		kfree(data);
+		return -ENOMEM;
+	}
+
+	data->nr = nr;
+	data->ctx = ctx;
+	data->rsrc_type = type;
+	if (utags) {
+		ret = -EFAULT;
+		for (i = 0; i < nr; i++) {
+			u64 *tag_slot = io_get_tag_slot(data, i);
+
+			if (copy_from_user(tag_slot, &utags[i],
+					   sizeof(*tag_slot)))
+				goto fail;
+		}
+	}
+	*pdata = data;
+	return 0;
+fail:
+	io_rsrc_data_free(data);
+	return ret;
+}
+
+static int __io_sqe_files_update(struct io_ring_ctx *ctx,
+				 struct io_uring_rsrc_update2 *up,
+				 unsigned nr_args)
+{
+	u64 __user *tags = u64_to_user_ptr(up->tags);
+	__s32 __user *fds = u64_to_user_ptr(up->data);
+	struct io_rsrc_data *data = ctx->file_data;
+	struct io_fixed_file *file_slot;
+	int fd, i, err = 0;
+	unsigned int done;
+
+	if (!ctx->file_data)
+		return -ENXIO;
+	if (up->offset + nr_args > ctx->nr_user_files)
+		return -EINVAL;
+
+	for (done = 0; done < nr_args; done++) {
+		u64 tag = 0;
+
+		if ((tags && copy_from_user(&tag, &tags[done], sizeof(tag))) ||
+		    copy_from_user(&fd, &fds[done], sizeof(fd))) {
+			err = -EFAULT;
+			break;
+		}
+		if ((fd == IORING_REGISTER_FILES_SKIP || fd == -1) && tag) {
+			err = -EINVAL;
+			break;
+		}
+		if (fd == IORING_REGISTER_FILES_SKIP)
+			continue;
+
+		i = array_index_nospec(up->offset + done, ctx->nr_user_files);
+		file_slot = io_fixed_file_slot(&ctx->file_table, i);
+
+		if (file_slot->file_ptr) {
+			err = io_queue_rsrc_removal(data, i,
+						    io_slot_file(file_slot));
+			if (err)
+				break;
+			file_slot->file_ptr = 0;
+			io_file_bitmap_clear(&ctx->file_table, i);
+		}
+		if (fd != -1) {
+			struct file *file = fget(fd);
+
+			if (!file) {
+				err = -EBADF;
+				break;
+			}
+			/*
+			 * Don't allow io_uring instances to be registered. If
+			 * UNIX isn't enabled, then this causes a reference
+			 * cycle and this instance can never get freed. If UNIX
+			 * is enabled we'll handle it just fine, but there's
+			 * still no point in allowing a ring fd as it doesn't
+			 * support regular read/write anyway.
+			 */
+			if (io_is_uring_fops(file)) {
+				fput(file);
+				err = -EBADF;
+				break;
+			}
+			err = io_scm_file_account(ctx, file);
+			if (err) {
+				fput(file);
+				break;
+			}
+			*io_get_tag_slot(data, i) = tag;
+			io_fixed_file_set(file_slot, file);
+			io_file_bitmap_set(&ctx->file_table, i);
+		}
+	}
+	return done ? done : err;
+}
+
+static int __io_sqe_buffers_update(struct io_ring_ctx *ctx,
+				   struct io_uring_rsrc_update2 *up,
+				   unsigned int nr_args)
+{
+	u64 __user *tags = u64_to_user_ptr(up->tags);
+	struct iovec iov, __user *iovs = u64_to_user_ptr(up->data);
+	struct page *last_hpage = NULL;
+	__u32 done;
+	int i, err;
+
+	if (!ctx->buf_data)
+		return -ENXIO;
+	if (up->offset + nr_args > ctx->nr_user_bufs)
+		return -EINVAL;
+
+	for (done = 0; done < nr_args; done++) {
+		struct io_mapped_ubuf *imu;
+		u64 tag = 0;
+
+		err = io_copy_iov(ctx, &iov, iovs, done);
+		if (err)
+			break;
+		if (tags && copy_from_user(&tag, &tags[done], sizeof(tag))) {
+			err = -EFAULT;
+			break;
+		}
+		err = io_buffer_validate(&iov);
+		if (err)
+			break;
+		if (!iov.iov_base && tag) {
+			err = -EINVAL;
+			break;
+		}
+		err = io_sqe_buffer_register(ctx, &iov, &imu, &last_hpage);
+		if (err)
+			break;
+
+		i = array_index_nospec(up->offset + done, ctx->nr_user_bufs);
+		if (ctx->user_bufs[i] != &dummy_ubuf) {
+			err = io_queue_rsrc_removal(ctx->buf_data, i,
+						    ctx->user_bufs[i]);
+			if (unlikely(err)) {
+				io_buffer_unmap(ctx, &imu);
+				break;
+			}
+			ctx->user_bufs[i] = (struct io_mapped_ubuf *)&dummy_ubuf;
+		}
+
+		ctx->user_bufs[i] = imu;
+		*io_get_tag_slot(ctx->buf_data, i) = tag;
+	}
+	return done ? done : err;
+}
+
+static int __io_register_rsrc_update(struct io_ring_ctx *ctx, unsigned type,
+				     struct io_uring_rsrc_update2 *up,
+				     unsigned nr_args)
+{
+	__u32 tmp;
+
+	lockdep_assert_held(&ctx->uring_lock);
+
+	if (check_add_overflow(up->offset, nr_args, &tmp))
+		return -EOVERFLOW;
+
+	switch (type) {
+	case IORING_RSRC_FILE:
+		return __io_sqe_files_update(ctx, up, nr_args);
+	case IORING_RSRC_BUFFER:
+		return __io_sqe_buffers_update(ctx, up, nr_args);
+	}
+	return -EINVAL;
+}
+
+int io_register_files_update(struct io_ring_ctx *ctx, void __user *arg,
+			     unsigned nr_args)
+{
+	struct io_uring_rsrc_update2 up;
+
+	if (!nr_args)
+		return -EINVAL;
+	memset(&up, 0, sizeof(up));
+	if (copy_from_user(&up, arg, sizeof(struct io_uring_rsrc_update)))
+		return -EFAULT;
+	if (up.resv || up.resv2)
+		return -EINVAL;
+	return __io_register_rsrc_update(ctx, IORING_RSRC_FILE, &up, nr_args);
+}
+
+int io_register_rsrc_update(struct io_ring_ctx *ctx, void __user *arg,
+			    unsigned size, unsigned type)
+{
+	struct io_uring_rsrc_update2 up;
+
+	if (size != sizeof(up))
+		return -EINVAL;
+	if (copy_from_user(&up, arg, sizeof(up)))
+		return -EFAULT;
+	if (!up.nr || up.resv || up.resv2)
+		return -EINVAL;
+	return __io_register_rsrc_update(ctx, type, &up, up.nr);
+}
+
+__cold int io_register_rsrc(struct io_ring_ctx *ctx, void __user *arg,
+			    unsigned int size, unsigned int type)
+{
+	struct io_uring_rsrc_register rr;
+
+	/* keep it extendible */
+	if (size != sizeof(rr))
+		return -EINVAL;
+
+	memset(&rr, 0, sizeof(rr));
+	if (copy_from_user(&rr, arg, size))
+		return -EFAULT;
+	if (!rr.nr || rr.resv2)
+		return -EINVAL;
+	if (rr.flags & ~IORING_RSRC_REGISTER_SPARSE)
+		return -EINVAL;
+
+	switch (type) {
+	case IORING_RSRC_FILE:
+		if (rr.flags & IORING_RSRC_REGISTER_SPARSE && rr.data)
+			break;
+		return io_sqe_files_register(ctx, u64_to_user_ptr(rr.data),
+					     rr.nr, u64_to_user_ptr(rr.tags));
+	case IORING_RSRC_BUFFER:
+		if (rr.flags & IORING_RSRC_REGISTER_SPARSE && rr.data)
+			break;
+		return io_sqe_buffers_register(ctx, u64_to_user_ptr(rr.data),
+					       rr.nr, u64_to_user_ptr(rr.tags));
+	}
+	return -EINVAL;
+}
+
+int io_files_update_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
+{
+	struct io_rsrc_update *up = io_kiocb_to_cmd(req, struct io_rsrc_update);
+
+	if (unlikely(req->flags & (REQ_F_FIXED_FILE | REQ_F_BUFFER_SELECT)))
+		return -EINVAL;
+	if (sqe->rw_flags || sqe->splice_fd_in)
+		return -EINVAL;
+
+	up->offset = READ_ONCE(sqe->off);
+	up->nr_args = READ_ONCE(sqe->len);
+	if (!up->nr_args)
+		return -EINVAL;
+	up->arg = READ_ONCE(sqe->addr);
+	return 0;
+}
+
+static int io_files_update_with_index_alloc(struct io_kiocb *req,
+					    unsigned int issue_flags)
+{
+	struct io_rsrc_update *up = io_kiocb_to_cmd(req, struct io_rsrc_update);
+	__s32 __user *fds = u64_to_user_ptr(up->arg);
+	unsigned int done;
+	struct file *file;
+	int ret, fd;
+
+	if (!req->ctx->file_data)
+		return -ENXIO;
+
+	for (done = 0; done < up->nr_args; done++) {
+		if (copy_from_user(&fd, &fds[done], sizeof(fd))) {
+			ret = -EFAULT;
+			break;
+		}
+
+		file = fget(fd);
+		if (!file) {
+			ret = -EBADF;
+			break;
+		}
+		ret = io_fixed_fd_install(req, issue_flags, file,
+					  IORING_FILE_INDEX_ALLOC);
+		if (ret < 0)
+			break;
+		if (copy_to_user(&fds[done], &ret, sizeof(ret))) {
+			__io_close_fixed(req->ctx, issue_flags, ret);
+			ret = -EFAULT;
+			break;
+		}
+	}
+
+	if (done)
+		return done;
+	return ret;
+}
+
+int io_files_update(struct io_kiocb *req, unsigned int issue_flags)
+{
+	struct io_rsrc_update *up = io_kiocb_to_cmd(req, struct io_rsrc_update);
+	struct io_ring_ctx *ctx = req->ctx;
+	struct io_uring_rsrc_update2 up2;
+	int ret;
+
+	up2.offset = up->offset;
+	up2.data = up->arg;
+	up2.nr = 0;
+	up2.tags = 0;
+	up2.resv = 0;
+	up2.resv2 = 0;
+
+	if (up->offset == IORING_FILE_INDEX_ALLOC) {
+		ret = io_files_update_with_index_alloc(req, issue_flags);
+	} else {
+		io_ring_submit_lock(ctx, issue_flags);
+		ret = __io_register_rsrc_update(ctx, IORING_RSRC_FILE,
+						&up2, up->nr_args);
+		io_ring_submit_unlock(ctx, issue_flags);
+	}
+
+	if (ret < 0)
+		req_set_fail(req);
+	io_req_set_res(req, ret, 0);
+	return IOU_OK;
+}
+
+int io_queue_rsrc_removal(struct io_rsrc_data *data, unsigned idx, void *rsrc)
+{
+	struct io_ring_ctx *ctx = data->ctx;
+	struct io_rsrc_node *node = ctx->rsrc_node;
+	u64 *tag_slot = io_get_tag_slot(data, idx);
+
+	ctx->rsrc_node = io_rsrc_node_alloc(ctx);
+	if (unlikely(!ctx->rsrc_node)) {
+		ctx->rsrc_node = node;
+		return -ENOMEM;
+	}
+
+	node->item.rsrc = rsrc;
+	node->type = data->rsrc_type;
+	node->item.tag = *tag_slot;
+	*tag_slot = 0;
+	list_add_tail(&node->node, &ctx->rsrc_ref_list);
+	io_put_rsrc_node(ctx, node);
+	return 0;
+}
+
+void __io_sqe_files_unregister(struct io_ring_ctx *ctx)
+{
+	int i;
+
+	for (i = 0; i < ctx->nr_user_files; i++) {
+		struct file *file = io_file_from_index(&ctx->file_table, i);
+
+		/* skip scm accounted files, they'll be freed by ->ring_sock */
+		if (!file || io_file_need_scm(file))
+			continue;
+		io_file_bitmap_clear(&ctx->file_table, i);
+		fput(file);
+	}
+
+#if defined(CONFIG_UNIX)
+	if (ctx->ring_sock) {
+		struct sock *sock = ctx->ring_sock->sk;
+		struct sk_buff *skb;
+
+		while ((skb = skb_dequeue(&sock->sk_receive_queue)) != NULL)
+			kfree_skb(skb);
+	}
+#endif
+	io_free_file_tables(&ctx->file_table);
+	io_file_table_set_alloc_range(ctx, 0, 0);
+	io_rsrc_data_free(ctx->file_data);
+	ctx->file_data = NULL;
+	ctx->nr_user_files = 0;
+}
+
+int io_sqe_files_unregister(struct io_ring_ctx *ctx)
+{
+	unsigned nr = ctx->nr_user_files;
+	int ret;
+
+	if (!ctx->file_data)
+		return -ENXIO;
+
+	/*
+	 * Quiesce may unlock ->uring_lock, and while it's not held
+	 * prevent new requests using the table.
+	 */
+	ctx->nr_user_files = 0;
+	ret = io_rsrc_ref_quiesce(ctx->file_data, ctx);
+	ctx->nr_user_files = nr;
+	if (!ret)
+		__io_sqe_files_unregister(ctx);
+	return ret;
+}
+
+/*
+ * Ensure the UNIX gc is aware of our file set, so we are certain that
+ * the io_uring can be safely unregistered on process exit, even if we have
+ * loops in the file referencing. We account only files that can hold other
+ * files because otherwise they can't form a loop and so are not interesting
+ * for GC.
+ */
+int __io_scm_file_account(struct io_ring_ctx *ctx, struct file *file)
+{
+#if defined(CONFIG_UNIX)
+	struct sock *sk = ctx->ring_sock->sk;
+	struct sk_buff_head *head = &sk->sk_receive_queue;
+	struct scm_fp_list *fpl;
+	struct sk_buff *skb;
+
+	if (likely(!io_file_need_scm(file)))
+		return 0;
+
+	/*
+	 * See if we can merge this file into an existing skb SCM_RIGHTS
+	 * file set. If there's no room, fall back to allocating a new skb
+	 * and filling it in.
+	 */
+	spin_lock_irq(&head->lock);
+	skb = skb_peek(head);
+	if (skb && UNIXCB(skb).fp->count < SCM_MAX_FD)
+		__skb_unlink(skb, head);
+	else
+		skb = NULL;
+	spin_unlock_irq(&head->lock);
+
+	if (!skb) {
+		fpl = kzalloc(sizeof(*fpl), GFP_KERNEL);
+		if (!fpl)
+			return -ENOMEM;
+
+		skb = alloc_skb(0, GFP_KERNEL);
+		if (!skb) {
+			kfree(fpl);
+			return -ENOMEM;
+		}
+
+		fpl->user = get_uid(current_user());
+		fpl->max = SCM_MAX_FD;
+		fpl->count = 0;
+
+		UNIXCB(skb).fp = fpl;
+		skb->sk = sk;
+		skb->destructor = io_uring_destruct_scm;
+		refcount_add(skb->truesize, &sk->sk_wmem_alloc);
+	}
+
+	fpl = UNIXCB(skb).fp;
+	fpl->fp[fpl->count++] = get_file(file);
+	unix_inflight(fpl->user, file);
+	skb_queue_head(head, skb);
+	fput(file);
+#endif
+	return 0;
+}
+
+static __cold void io_rsrc_file_scm_put(struct io_ring_ctx *ctx, struct file *file)
+{
+#if defined(CONFIG_UNIX)
+	struct sock *sock = ctx->ring_sock->sk;
+	struct sk_buff_head list, *head = &sock->sk_receive_queue;
+	struct sk_buff *skb;
+	int i;
+
+	__skb_queue_head_init(&list);
+
+	/*
+	 * Find the skb that holds this file in its SCM_RIGHTS. When found,
+	 * remove this entry and rearrange the file array.
+	 */
+	skb = skb_dequeue(head);
+	while (skb) {
+		struct scm_fp_list *fp;
+
+		fp = UNIXCB(skb).fp;
+		for (i = 0; i < fp->count; i++) {
+			int left;
+
+			if (fp->fp[i] != file)
+				continue;
+
+			unix_notinflight(fp->user, fp->fp[i]);
+			left = fp->count - 1 - i;
+			if (left) {
+				memmove(&fp->fp[i], &fp->fp[i + 1],
+						left * sizeof(struct file *));
+			}
+			fp->count--;
+			if (!fp->count) {
+				kfree_skb(skb);
+				skb = NULL;
+			} else {
+				__skb_queue_tail(&list, skb);
+			}
+			fput(file);
+			file = NULL;
+			break;
+		}
+
+		if (!file)
+			break;
+
+		__skb_queue_tail(&list, skb);
+
+		skb = skb_dequeue(head);
+	}
+
+	if (skb_peek(&list)) {
+		spin_lock_irq(&head->lock);
+		while ((skb = __skb_dequeue(&list)) != NULL)
+			__skb_queue_tail(head, skb);
+		spin_unlock_irq(&head->lock);
+	}
+#endif
+}
+
+static void io_rsrc_file_put(struct io_ring_ctx *ctx, struct io_rsrc_put *prsrc)
+{
+	struct file *file = prsrc->file;
+
+	if (likely(!io_file_need_scm(file)))
+		fput(file);
+	else
+		io_rsrc_file_scm_put(ctx, file);
+}
+
+int io_sqe_files_register(struct io_ring_ctx *ctx, void __user *arg,
+			  unsigned nr_args, u64 __user *tags)
+{
+	__s32 __user *fds = (__s32 __user *) arg;
+	struct file *file;
+	int fd, ret;
+	unsigned i;
+
+	if (ctx->file_data)
+		return -EBUSY;
+	if (!nr_args)
+		return -EINVAL;
+	if (nr_args > IORING_MAX_FIXED_FILES)
+		return -EMFILE;
+	if (nr_args > rlimit(RLIMIT_NOFILE))
+		return -EMFILE;
+	ret = io_rsrc_data_alloc(ctx, IORING_RSRC_FILE, tags, nr_args,
+				 &ctx->file_data);
+	if (ret)
+		return ret;
+
+	if (!io_alloc_file_tables(&ctx->file_table, nr_args)) {
+		io_rsrc_data_free(ctx->file_data);
+		ctx->file_data = NULL;
+		return -ENOMEM;
+	}
+
+	for (i = 0; i < nr_args; i++, ctx->nr_user_files++) {
+		struct io_fixed_file *file_slot;
+
+		if (fds && copy_from_user(&fd, &fds[i], sizeof(fd))) {
+			ret = -EFAULT;
+			goto fail;
+		}
+		/* allow sparse sets */
+		if (!fds || fd == -1) {
+			ret = -EINVAL;
+			if (unlikely(*io_get_tag_slot(ctx->file_data, i)))
+				goto fail;
+			continue;
+		}
+
+		file = fget(fd);
+		ret = -EBADF;
+		if (unlikely(!file))
+			goto fail;
+
+		/*
+		 * Don't allow io_uring instances to be registered. If UNIX
+		 * isn't enabled, then this causes a reference cycle and this
+		 * instance can never get freed. If UNIX is enabled we'll
+		 * handle it just fine, but there's still no point in allowing
+		 * a ring fd as it doesn't support regular read/write anyway.
+		 */
+		if (io_is_uring_fops(file)) {
+			fput(file);
+			goto fail;
+		}
+		ret = io_scm_file_account(ctx, file);
+		if (ret) {
+			fput(file);
+			goto fail;
+		}
+		file_slot = io_fixed_file_slot(&ctx->file_table, i);
+		io_fixed_file_set(file_slot, file);
+		io_file_bitmap_set(&ctx->file_table, i);
+	}
+
+	/* default it to the whole table */
+	io_file_table_set_alloc_range(ctx, 0, ctx->nr_user_files);
+	return 0;
+fail:
+	__io_sqe_files_unregister(ctx);
+	return ret;
+}
+
+static void io_rsrc_buf_put(struct io_ring_ctx *ctx, struct io_rsrc_put *prsrc)
+{
+	io_buffer_unmap(ctx, &prsrc->buf);
+	prsrc->buf = NULL;
+}
+
+void __io_sqe_buffers_unregister(struct io_ring_ctx *ctx)
+{
+	unsigned int i;
+
+	for (i = 0; i < ctx->nr_user_bufs; i++)
+		io_buffer_unmap(ctx, &ctx->user_bufs[i]);
+	kfree(ctx->user_bufs);
+	io_rsrc_data_free(ctx->buf_data);
+	ctx->user_bufs = NULL;
+	ctx->buf_data = NULL;
+	ctx->nr_user_bufs = 0;
+}
+
+int io_sqe_buffers_unregister(struct io_ring_ctx *ctx)
+{
+	unsigned nr = ctx->nr_user_bufs;
+	int ret;
+
+	if (!ctx->buf_data)
+		return -ENXIO;
+
+	/*
+	 * Quiesce may unlock ->uring_lock, and while it's not held
+	 * prevent new requests using the table.
+	 */
+	ctx->nr_user_bufs = 0;
+	ret = io_rsrc_ref_quiesce(ctx->buf_data, ctx);
+	ctx->nr_user_bufs = nr;
+	if (!ret)
+		__io_sqe_buffers_unregister(ctx);
+	return ret;
+}
+
+/*
+ * Not super efficient, but this is just a registration time. And we do cache
+ * the last compound head, so generally we'll only do a full search if we don't
+ * match that one.
+ *
+ * We check if the given compound head page has already been accounted, to
+ * avoid double accounting it. This allows us to account the full size of the
+ * page, not just the constituent pages of a huge page.
+ */
+static bool headpage_already_acct(struct io_ring_ctx *ctx, struct page **pages,
+				  int nr_pages, struct page *hpage)
+{
+	int i, j;
+
+	/* check current page array */
+	for (i = 0; i < nr_pages; i++) {
+		if (!PageCompound(pages[i]))
+			continue;
+		if (compound_head(pages[i]) == hpage)
+			return true;
+	}
+
+	/* check previously registered pages */
+	for (i = 0; i < ctx->nr_user_bufs; i++) {
+		struct io_mapped_ubuf *imu = ctx->user_bufs[i];
+
+		for (j = 0; j < imu->nr_bvecs; j++) {
+			if (!PageCompound(imu->bvec[j].bv_page))
+				continue;
+			if (compound_head(imu->bvec[j].bv_page) == hpage)
+				return true;
+		}
+	}
+
+	return false;
+}
+
+static int io_buffer_account_pin(struct io_ring_ctx *ctx, struct page **pages,
+				 int nr_pages, struct io_mapped_ubuf *imu,
+				 struct page **last_hpage)
+{
+	int i, ret;
+
+	imu->acct_pages = 0;
+	for (i = 0; i < nr_pages; i++) {
+		if (!PageCompound(pages[i])) {
+			imu->acct_pages++;
+		} else {
+			struct page *hpage;
+
+			hpage = compound_head(pages[i]);
+			if (hpage == *last_hpage)
+				continue;
+			*last_hpage = hpage;
+			if (headpage_already_acct(ctx, pages, i, hpage))
+				continue;
+			imu->acct_pages += page_size(hpage) >> PAGE_SHIFT;
+		}
+	}
+
+	if (!imu->acct_pages)
+		return 0;
+
+	ret = io_account_mem(ctx, imu->acct_pages);
+	if (ret)
+		imu->acct_pages = 0;
+	return ret;
+}
+
+struct page **io_pin_pages(unsigned long ubuf, unsigned long len, int *npages)
+{
+	unsigned long start, end, nr_pages;
+	struct page **pages = NULL;
+	int pret, ret = -ENOMEM;
+
+	end = (ubuf + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
+	start = ubuf >> PAGE_SHIFT;
+	nr_pages = end - start;
+
+	pages = kvmalloc_array(nr_pages, sizeof(struct page *), GFP_KERNEL);
+	if (!pages)
+		goto done;
+
+	ret = 0;
+	mmap_read_lock(current->mm);
+	pret = pin_user_pages(ubuf, nr_pages, FOLL_WRITE | FOLL_LONGTERM,
+			      pages);
+	if (pret == nr_pages)
+		*npages = nr_pages;
+	else
+		ret = pret < 0 ? pret : -EFAULT;
+
+	mmap_read_unlock(current->mm);
+	if (ret) {
+		/* if we did partial map, release any pages we did get */
+		if (pret > 0)
+			unpin_user_pages(pages, pret);
+		goto done;
+	}
+	ret = 0;
+done:
+	if (ret < 0) {
+		kvfree(pages);
+		pages = ERR_PTR(ret);
+	}
+	return pages;
+}
+
+static int io_sqe_buffer_register(struct io_ring_ctx *ctx, struct iovec *iov,
+				  struct io_mapped_ubuf **pimu,
+				  struct page **last_hpage)
+{
+	struct io_mapped_ubuf *imu = NULL;
+	struct page **pages = NULL;
+	unsigned long off;
+	size_t size;
+	int ret, nr_pages, i;
+	struct folio *folio = NULL;
+
+	*pimu = (struct io_mapped_ubuf *)&dummy_ubuf;
+	if (!iov->iov_base)
+		return 0;
+
+	ret = -ENOMEM;
+	pages = io_pin_pages((unsigned long) iov->iov_base, iov->iov_len,
+				&nr_pages);
+	if (IS_ERR(pages)) {
+		ret = PTR_ERR(pages);
+		pages = NULL;
+		goto done;
+	}
+
+	/* If it's a huge page, try to coalesce them into a single bvec entry */
+	if (nr_pages > 1) {
+		folio = page_folio(pages[0]);
+		for (i = 1; i < nr_pages; i++) {
+			/*
+			 * Pages must be consecutive and on the same folio for
+			 * this to work
+			 */
+			if (page_folio(pages[i]) != folio ||
+			    pages[i] != pages[i - 1] + 1) {
+				folio = NULL;
+				break;
+			}
+		}
+		if (folio) {
+			/*
+			 * The pages are bound to the folio, it doesn't
+			 * actually unpin them but drops all but one reference,
+			 * which is usually put down by io_buffer_unmap().
+			 * Note, needs a better helper.
+			 */
+			unpin_user_pages(&pages[1], nr_pages - 1);
+			nr_pages = 1;
+		}
+	}
+
+	imu = kvmalloc(struct_size(imu, bvec, nr_pages), GFP_KERNEL);
+	if (!imu)
+		goto done;
+
+	ret = io_buffer_account_pin(ctx, pages, nr_pages, imu, last_hpage);
+	if (ret) {
+		unpin_user_pages(pages, nr_pages);
+		goto done;
+	}
+
+	off = (unsigned long) iov->iov_base & ~PAGE_MASK;
+	size = iov->iov_len;
+	/* store original address for later verification */
+	imu->ubuf = (unsigned long) iov->iov_base;
+	imu->ubuf_end = imu->ubuf + iov->iov_len;
+	imu->nr_bvecs = nr_pages;
+	*pimu = imu;
+	ret = 0;
+
+	if (folio) {
+		bvec_set_page(&imu->bvec[0], pages[0], size, off);
+		goto done;
+	}
+	for (i = 0; i < nr_pages; i++) {
+		size_t vec_len;
+
+		vec_len = min_t(size_t, size, PAGE_SIZE - off);
+		bvec_set_page(&imu->bvec[i], pages[i], vec_len, off);
+		off = 0;
+		size -= vec_len;
+	}
+done:
+	if (ret)
+		kvfree(imu);
+	kvfree(pages);
+	return ret;
+}
+
+static int io_buffers_map_alloc(struct io_ring_ctx *ctx, unsigned int nr_args)
+{
+	ctx->user_bufs = kcalloc(nr_args, sizeof(*ctx->user_bufs), GFP_KERNEL);
+	return ctx->user_bufs ? 0 : -ENOMEM;
+}
+
+int io_sqe_buffers_register(struct io_ring_ctx *ctx, void __user *arg,
+			    unsigned int nr_args, u64 __user *tags)
+{
+	struct page *last_hpage = NULL;
+	struct io_rsrc_data *data;
+	int i, ret;
+	struct iovec iov;
+
+	BUILD_BUG_ON(IORING_MAX_REG_BUFFERS >= (1u << 16));
+
+	if (ctx->user_bufs)
+		return -EBUSY;
+	if (!nr_args || nr_args > IORING_MAX_REG_BUFFERS)
+		return -EINVAL;
+	ret = io_rsrc_data_alloc(ctx, IORING_RSRC_BUFFER, tags, nr_args, &data);
+	if (ret)
+		return ret;
+	ret = io_buffers_map_alloc(ctx, nr_args);
+	if (ret) {
+		io_rsrc_data_free(data);
+		return ret;
+	}
+
+	for (i = 0; i < nr_args; i++, ctx->nr_user_bufs++) {
+		if (arg) {
+			ret = io_copy_iov(ctx, &iov, arg, i);
+			if (ret)
+				break;
+			ret = io_buffer_validate(&iov);
+			if (ret)
+				break;
+		} else {
+			memset(&iov, 0, sizeof(iov));
+		}
+
+		if (!iov.iov_base && *io_get_tag_slot(data, i)) {
+			ret = -EINVAL;
+			break;
+		}
+
+		ret = io_sqe_buffer_register(ctx, &iov, &ctx->user_bufs[i],
+					     &last_hpage);
+		if (ret)
+			break;
+	}
+
+	WARN_ON_ONCE(ctx->buf_data);
+
+	ctx->buf_data = data;
+	if (ret)
+		__io_sqe_buffers_unregister(ctx);
+	return ret;
+}
+
+int io_import_fixed(int ddir, struct iov_iter *iter,
+			   struct io_mapped_ubuf *imu,
+			   u64 buf_addr, size_t len)
+{
+	u64 buf_end;
+	size_t offset;
+
+	if (WARN_ON_ONCE(!imu))
+		return -EFAULT;
+	if (unlikely(check_add_overflow(buf_addr, (u64)len, &buf_end)))
+		return -EFAULT;
+	/* not inside the mapped region */
+	if (unlikely(buf_addr < imu->ubuf || buf_end > imu->ubuf_end))
+		return -EFAULT;
+
+	/*
+	 * Might not be a start of buffer, set size appropriately
+	 * and advance us to the beginning.
+	 */
+	offset = buf_addr - imu->ubuf;
+	iov_iter_bvec(iter, ddir, imu->bvec, imu->nr_bvecs, offset + len);
+
+	if (offset) {
+		/*
+		 * Don't use iov_iter_advance() here, as it's really slow for
+		 * using the latter parts of a big fixed buffer - it iterates
+		 * over each segment manually. We can cheat a bit here, because
+		 * we know that:
+		 *
+		 * 1) it's a BVEC iter, we set it up
+		 * 2) all bvecs are PAGE_SIZE in size, except potentially the
+		 *    first and last bvec
+		 *
+		 * So just find our index, and adjust the iterator afterwards.
+		 * If the offset is within the first bvec (or the whole first
+		 * bvec, just use iov_iter_advance(). This makes it easier
+		 * since we can just skip the first segment, which may not
+		 * be PAGE_SIZE aligned.
+		 */
+		const struct bio_vec *bvec = imu->bvec;
+
+		if (offset < bvec->bv_len) {
+			/*
+			 * Note, huge pages buffers consists of one large
+			 * bvec entry and should always go this way. The other
+			 * branch doesn't expect non PAGE_SIZE'd chunks.
+			 */
+			iter->bvec = bvec;
+			iter->nr_segs = bvec->bv_len;
+			iter->count -= offset;
+			iter->iov_offset = offset;
+		} else {
+			unsigned long seg_skip;
+
+			/* skip first vec */
+			offset -= bvec->bv_len;
+			seg_skip = 1 + (offset >> PAGE_SHIFT);
+
+			iter->bvec = bvec + seg_skip;
+			iter->nr_segs -= seg_skip;
+			iter->count -= bvec->bv_len + offset;
+			iter->iov_offset = offset & ~PAGE_MASK;
+		}
+	}
+
+	return 0;
+}