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io_uring: allow IORING_OP_ASYNC_CANCEL with 'fd' key

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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 <axboe@kernel.dk>
Link: https://lore.kernel.org/r/20220418164402.75259-5-axboe@kernel.dk
This commit is contained in:
Jens Axboe 2022-04-18 10:44:01 -06:00
parent 8e29da69fe
commit 4bf94615b8
2 changed files with 63 additions and 7 deletions
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67
fs/io_uring.c
View File

@ -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);

3
include/uapi/linux/io_uring.h
View File

@ -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)