diff options
Diffstat (limited to 'io_uring/rsrc.c')
| -rw-r--r-- | io_uring/rsrc.c | 1371 |
1 files changed, 1371 insertions, 0 deletions
diff --git a/io_uring/rsrc.c b/io_uring/rsrc.c new file mode 100644 index 000000000..7ada0339b --- /dev/null +++ b/io_uring/rsrc.c @@ -0,0 +1,1371 @@ +// 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 int io_sqe_buffer_register(struct io_ring_ctx *ctx, struct iovec *iov, + struct io_mapped_ubuf **pimu, + struct page **last_hpage); + +#define IO_RSRC_REF_BATCH 100 + +/* only define max */ +#define IORING_MAX_FIXED_FILES (1U << 20) +#define IORING_MAX_REG_BUFFERS (1U << 14) + +void io_rsrc_refs_drop(struct io_ring_ctx *ctx) + __must_hold(&ctx->uring_lock) +{ + if (ctx->rsrc_cached_refs) { + io_rsrc_put_node(ctx->rsrc_node, ctx->rsrc_cached_refs); + ctx->rsrc_cached_refs = 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 != ctx->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; +} + +void io_rsrc_refs_refill(struct io_ring_ctx *ctx) + __must_hold(&ctx->uring_lock) +{ + ctx->rsrc_cached_refs += IO_RSRC_REF_BATCH; + percpu_ref_get_many(&ctx->rsrc_node->refs, IO_RSRC_REF_BATCH); +} + +static void __io_rsrc_put_work(struct io_rsrc_node *ref_node) +{ + struct io_rsrc_data *rsrc_data = ref_node->rsrc_data; + struct io_ring_ctx *ctx = rsrc_data->ctx; + struct io_rsrc_put *prsrc, *tmp; + + list_for_each_entry_safe(prsrc, tmp, &ref_node->rsrc_list, list) { + list_del(&prsrc->list); + + if (prsrc->tag) { + if (ctx->flags & IORING_SETUP_IOPOLL) { + mutex_lock(&ctx->uring_lock); + io_post_aux_cqe(ctx, prsrc->tag, 0, 0, true); + mutex_unlock(&ctx->uring_lock); + } else { + io_post_aux_cqe(ctx, prsrc->tag, 0, 0, true); + } + } + + rsrc_data->do_put(ctx, prsrc); + kfree(prsrc); + } + + io_rsrc_node_destroy(ref_node); + if (atomic_dec_and_test(&rsrc_data->refs)) + complete(&rsrc_data->done); +} + +void io_rsrc_put_work(struct work_struct *work) +{ + struct io_ring_ctx *ctx; + struct llist_node *node; + + ctx = container_of(work, struct io_ring_ctx, rsrc_put_work.work); + node = llist_del_all(&ctx->rsrc_put_llist); + + while (node) { + struct io_rsrc_node *ref_node; + struct llist_node *next = node->next; + + ref_node = llist_entry(node, struct io_rsrc_node, llist); + __io_rsrc_put_work(ref_node); + node = next; + } +} + +void io_wait_rsrc_data(struct io_rsrc_data *data) +{ + if (data && !atomic_dec_and_test(&data->refs)) + wait_for_completion(&data->done); +} + +void io_rsrc_node_destroy(struct io_rsrc_node *ref_node) +{ + percpu_ref_exit(&ref_node->refs); + kfree(ref_node); +} + +static __cold void io_rsrc_node_ref_zero(struct percpu_ref *ref) +{ + struct io_rsrc_node *node = container_of(ref, struct io_rsrc_node, refs); + struct io_ring_ctx *ctx = node->rsrc_data->ctx; + unsigned long flags; + bool first_add = false; + unsigned long delay = HZ; + + spin_lock_irqsave(&ctx->rsrc_ref_lock, flags); + node->done = true; + + /* if we are mid-quiesce then do not delay */ + if (node->rsrc_data->quiesce) + delay = 0; + + 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->done) + break; + list_del(&node->node); + first_add |= llist_add(&node->llist, &ctx->rsrc_put_llist); + } + spin_unlock_irqrestore(&ctx->rsrc_ref_lock, flags); + + if (first_add) + mod_delayed_work(system_wq, &ctx->rsrc_put_work, delay); +} + +static struct io_rsrc_node *io_rsrc_node_alloc(void) +{ + struct io_rsrc_node *ref_node; + + ref_node = kzalloc(sizeof(*ref_node), GFP_KERNEL); + if (!ref_node) + return NULL; + + if (percpu_ref_init(&ref_node->refs, io_rsrc_node_ref_zero, + 0, GFP_KERNEL)) { + kfree(ref_node); + return NULL; + } + INIT_LIST_HEAD(&ref_node->node); + INIT_LIST_HEAD(&ref_node->rsrc_list); + ref_node->done = false; + return ref_node; +} + +void io_rsrc_node_switch(struct io_ring_ctx *ctx, + struct io_rsrc_data *data_to_kill) + __must_hold(&ctx->uring_lock) +{ + WARN_ON_ONCE(!ctx->rsrc_backup_node); + WARN_ON_ONCE(data_to_kill && !ctx->rsrc_node); + + io_rsrc_refs_drop(ctx); + + if (data_to_kill) { + struct io_rsrc_node *rsrc_node = ctx->rsrc_node; + + rsrc_node->rsrc_data = data_to_kill; + spin_lock_irq(&ctx->rsrc_ref_lock); + list_add_tail(&rsrc_node->node, &ctx->rsrc_ref_list); + spin_unlock_irq(&ctx->rsrc_ref_lock); + + atomic_inc(&data_to_kill->refs); + percpu_ref_kill(&rsrc_node->refs); + ctx->rsrc_node = NULL; + } + + if (!ctx->rsrc_node) { + ctx->rsrc_node = ctx->rsrc_backup_node; + ctx->rsrc_backup_node = NULL; + } +} + +int io_rsrc_node_switch_start(struct io_ring_ctx *ctx) +{ + if (ctx->rsrc_backup_node) + return 0; + ctx->rsrc_backup_node = io_rsrc_node_alloc(); + return ctx->rsrc_backup_node ? 0 : -ENOMEM; +} + +__cold static int io_rsrc_ref_quiesce(struct io_rsrc_data *data, + struct io_ring_ctx *ctx) +{ + int ret; + + /* As we may drop ->uring_lock, other task may have started quiesce */ + if (data->quiesce) + return -ENXIO; + + data->quiesce = true; + do { + ret = io_rsrc_node_switch_start(ctx); + if (ret) + break; + io_rsrc_node_switch(ctx, data); + + /* kill initial ref, already quiesced if zero */ + if (atomic_dec_and_test(&data->refs)) + break; + mutex_unlock(&ctx->uring_lock); + flush_delayed_work(&ctx->rsrc_put_work); + ret = wait_for_completion_interruptible(&data->done); + if (!ret) { + mutex_lock(&ctx->uring_lock); + if (atomic_read(&data->refs) > 0) { + /* + * it has been revived by another thread while + * we were unlocked + */ + mutex_unlock(&ctx->uring_lock); + } else { + break; + } + } + + atomic_inc(&data->refs); + /* wait for all works potentially completing data->done */ + flush_delayed_work(&ctx->rsrc_put_work); + reinit_completion(&data->done); + + ret = io_run_task_work_sig(ctx); + mutex_lock(&ctx->uring_lock); + } while (ret >= 0); + data->quiesce = false; + + 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, + rsrc_put_fn *do_put, u64 __user *utags, + unsigned nr, struct io_rsrc_data **pdata) +{ + struct io_rsrc_data *data; + int ret = -ENOMEM; + 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->do_put = do_put; + 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; + } + } + + atomic_set(&data->refs, 1); + init_completion(&data->done); + *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; + struct file *file; + int fd, i, err = 0; + unsigned int done; + bool needs_switch = false; + + 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) { + file = (struct file *)(file_slot->file_ptr & FFS_MASK); + err = io_queue_rsrc_removal(data, i, ctx->rsrc_node, file); + if (err) + break; + file_slot->file_ptr = 0; + io_file_bitmap_clear(&ctx->file_table, i); + needs_switch = true; + } + if (fd != -1) { + 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); + } + } + + if (needs_switch) + io_rsrc_node_switch(ctx, data); + 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; + bool needs_switch = false; + __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; + int offset = up->offset + done; + 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(offset, ctx->nr_user_bufs); + if (ctx->user_bufs[i] != ctx->dummy_ubuf) { + err = io_queue_rsrc_removal(ctx->buf_data, i, + ctx->rsrc_node, ctx->user_bufs[i]); + if (unlikely(err)) { + io_buffer_unmap(ctx, &imu); + break; + } + ctx->user_bufs[i] = ctx->dummy_ubuf; + needs_switch = true; + } + + ctx->user_bufs[i] = imu; + *io_get_tag_slot(ctx->buf_data, i) = tag; + } + + if (needs_switch) + io_rsrc_node_switch(ctx, ctx->buf_data); + 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; + int err; + + if (check_add_overflow(up->offset, nr_args, &tmp)) + return -EOVERFLOW; + err = io_rsrc_node_switch_start(ctx); + if (err) + return err; + + 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, + struct io_rsrc_node *node, void *rsrc) +{ + u64 *tag_slot = io_get_tag_slot(data, idx); + struct io_rsrc_put *prsrc; + + prsrc = kzalloc(sizeof(*prsrc), GFP_KERNEL); + if (!prsrc) + return -ENOMEM; + + prsrc->tag = *tag_slot; + *tag_slot = 0; + prsrc->rsrc = rsrc; + list_add(&prsrc->list, &node->rsrc_list); + 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->scm_io_uring = 1; + skb->destructor = unix_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 void io_rsrc_file_put(struct io_ring_ctx *ctx, struct io_rsrc_put *prsrc) +{ + struct file *file = prsrc->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; + + if (!io_file_need_scm(file)) { + fput(file); + return; + } + + __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); + } +#else + fput(file); +#endif +} + +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_node_switch_start(ctx); + if (ret) + return ret; + ret = io_rsrc_data_alloc(ctx, io_rsrc_file_put, 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); + io_rsrc_node_switch(ctx, NULL); + 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 vm_area_struct **vmas = NULL; + struct page **pages = NULL; + int i, 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; + + vmas = kvmalloc_array(nr_pages, sizeof(struct vm_area_struct *), + GFP_KERNEL); + if (!vmas) + goto done; + + ret = 0; + mmap_read_lock(current->mm); + pret = pin_user_pages(ubuf, nr_pages, FOLL_WRITE | FOLL_LONGTERM, + pages, vmas); + if (pret == nr_pages) { + struct file *file = vmas[0]->vm_file; + + /* don't support file backed memory */ + for (i = 0; i < nr_pages; i++) { + if (vmas[i]->vm_file != file) { + ret = -EINVAL; + break; + } + if (!file) + continue; + if (!vma_is_shmem(vmas[i]) && !is_file_hugepages(file)) { + ret = -EOPNOTSUPP; + break; + } + } + *npages = nr_pages; + } else { + ret = pret < 0 ? pret : -EFAULT; + } + mmap_read_unlock(current->mm); + if (ret) { + /* + * if we did partial map, or found file backed vmas, + * release any pages we did get + */ + if (pret > 0) + unpin_user_pages(pages, pret); + goto done; + } + ret = 0; +done: + kvfree(vmas); + 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; + + *pimu = ctx->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; + } + + 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; + for (i = 0; i < nr_pages; i++) { + size_t vec_len; + + vec_len = min_t(size_t, size, PAGE_SIZE - off); + imu->bvec[i].bv_page = pages[i]; + imu->bvec[i].bv_len = vec_len; + imu->bvec[i].bv_offset = off; + off = 0; + size -= vec_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; +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_node_switch_start(ctx); + if (ret) + return ret; + ret = io_rsrc_data_alloc(ctx, io_rsrc_buf_put, 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); + else + io_rsrc_node_switch(ctx, NULL); + 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; + + /* + * May 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) { + iov_iter_advance(iter, 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; +} |