From 4bf94615b8886305199ed5755cb72fea88258d15 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Mon, 18 Apr 2022 10:44:01 -0600 Subject: [PATCH] io_uring: allow IORING_OP_ASYNC_CANCEL with 'fd' key Currently sqe->addr must contain the user_data of the request being canceled. Introduce the IORING_ASYNC_CANCEL_FD flag, which tells the kernel that we're keying off the file fd instead for cancelation. This allows canceling any request that a) uses a file, and b) was assigned the file based on the value being passed in. Signed-off-by: Jens Axboe Link: https://lore.kernel.org/r/20220418164402.75259-5-axboe@kernel.dk --- fs/io_uring.c | 67 +++++++++++++++++++++++++++++++---- include/uapi/linux/io_uring.h | 3 ++ 2 files changed, 63 insertions(+), 7 deletions(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index b43cdf1a4555..cf0d5437b77d 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -587,6 +587,7 @@ struct io_cancel { struct file *file; u64 addr; u32 flags; + s32 fd; }; struct io_timeout { @@ -992,7 +993,10 @@ struct io_defer_entry { struct io_cancel_data { struct io_ring_ctx *ctx; - u64 data; + union { + u64 data; + struct file *file; + }; u32 flags; int seq; }; @@ -6332,6 +6336,29 @@ static struct io_kiocb *io_poll_find(struct io_ring_ctx *ctx, bool poll_only, return NULL; } +static struct io_kiocb *io_poll_file_find(struct io_ring_ctx *ctx, + struct io_cancel_data *cd) + __must_hold(&ctx->completion_lock) +{ + struct io_kiocb *req; + int i; + + for (i = 0; i < (1U << ctx->cancel_hash_bits); i++) { + struct hlist_head *list; + + list = &ctx->cancel_hash[i]; + hlist_for_each_entry(req, list, hash_node) { + if (req->file != cd->file) + continue; + if (cd->seq == req->work.cancel_seq) + continue; + req->work.cancel_seq = cd->seq; + return req; + } + } + return NULL; +} + static bool io_poll_disarm(struct io_kiocb *req) __must_hold(&ctx->completion_lock) { @@ -6345,8 +6372,12 @@ static bool io_poll_disarm(struct io_kiocb *req) static int io_poll_cancel(struct io_ring_ctx *ctx, struct io_cancel_data *cd) __must_hold(&ctx->completion_lock) { - struct io_kiocb *req = io_poll_find(ctx, false, cd); + struct io_kiocb *req; + if (cd->flags & IORING_ASYNC_CANCEL_FD) + req = io_poll_file_find(ctx, cd); + else + req = io_poll_find(ctx, false, cd); if (!req) return -ENOENT; io_poll_cancel_req(req); @@ -6796,8 +6827,13 @@ static bool io_cancel_cb(struct io_wq_work *work, void *data) if (req->ctx != cd->ctx) return false; - if (req->cqe.user_data != cd->data) - return false; + if (cd->flags & IORING_ASYNC_CANCEL_FD) { + if (req->file != cd->file) + return false; + } else { + if (req->cqe.user_data != cd->data) + return false; + } if (cd->flags & IORING_ASYNC_CANCEL_ALL) { if (cd->seq == req->work.cancel_seq) return false; @@ -6851,7 +6887,8 @@ static int io_try_cancel(struct io_kiocb *req, struct io_cancel_data *cd) ret = io_poll_cancel(ctx, cd); if (ret != -ENOENT) goto out; - ret = io_timeout_cancel(ctx, cd); + if (!(cd->flags & IORING_ASYNC_CANCEL_FD)) + ret = io_timeout_cancel(ctx, cd); out: spin_unlock(&ctx->completion_lock); return ret; @@ -6862,15 +6899,17 @@ static int io_async_cancel_prep(struct io_kiocb *req, { if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL)) return -EINVAL; - if (unlikely(req->flags & (REQ_F_FIXED_FILE | REQ_F_BUFFER_SELECT))) + if (unlikely(req->flags & REQ_F_BUFFER_SELECT)) return -EINVAL; if (sqe->ioprio || sqe->off || sqe->len || sqe->splice_fd_in) return -EINVAL; req->cancel.addr = READ_ONCE(sqe->addr); req->cancel.flags = READ_ONCE(sqe->cancel_flags); - if (req->cancel.flags & ~IORING_ASYNC_CANCEL_ALL) + if (req->cancel.flags & ~(IORING_ASYNC_CANCEL_ALL|IORING_ASYNC_CANCEL_FD)) return -EINVAL; + if (req->cancel.flags & IORING_ASYNC_CANCEL_FD) + req->cancel.fd = READ_ONCE(sqe->fd); return 0; } @@ -6919,7 +6958,21 @@ static int io_async_cancel(struct io_kiocb *req, unsigned int issue_flags) }; int ret; + if (cd.flags & IORING_ASYNC_CANCEL_FD) { + if (req->flags & REQ_F_FIXED_FILE) + req->file = io_file_get_fixed(req, req->cancel.fd, + issue_flags); + else + req->file = io_file_get_normal(req, req->cancel.fd); + if (!req->file) { + ret = -EBADF; + goto done; + } + cd.file = req->file; + } + ret = __io_async_cancel(&cd, req, issue_flags); +done: if (ret < 0) req_set_fail(req); io_req_complete_post(req, ret, 0); diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h index 476e58a2837f..cc7fe82a1798 100644 --- a/include/uapi/linux/io_uring.h +++ b/include/uapi/linux/io_uring.h @@ -191,8 +191,11 @@ enum { * ASYNC_CANCEL flags. * * IORING_ASYNC_CANCEL_ALL Cancel all requests that match the given key + * IORING_ASYNC_CANCEL_FD Key off 'fd' for cancelation rather than the + * request 'user_data' */ #define IORING_ASYNC_CANCEL_ALL (1U << 0) +#define IORING_ASYNC_CANCEL_FD (1U << 1) /* * IO completion data structure (Completion Queue Entry)