Commit 4bf94615 authored by Jens Axboe's avatar Jens Axboe
Browse files

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: default avatarJens Axboe <axboe@kernel.dk>
Link: https://lore.kernel.org/r/20220418164402.75259-5-axboe@kernel.dk
parent 8e29da69

fs/io_uring.c

+60 −7
Original line number Diff line number Diff line
@@ -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;

	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 (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;
@@ -6851,6 +6887,7 @@ 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;

	if (!(cd->flags & IORING_ASYNC_CANCEL_FD))

		ret = io_timeout_cancel(ctx, cd);

out:

	spin_unlock(&ctx->completion_lock);
@@ -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);

include/uapi/linux/io_uring.h

+3 −0
Original line number Diff line number Diff line
@@ -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)