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io_uring: don't recycle provided buffer if punted to async worker

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We only really need to recycle the buffer when going async for a file
type that has an indefinite reponse time (eg non-file/bdev). And for
files that to arm poll, the async worker will arm poll anyway and the
buffer will get recycled there.

In that latter case, we're not holding ctx->uring_lock. Ensure we take
the issue_flags into account and acquire it if we need to.

Fixes: b1c6264575 ("io_uring: recycle provided buffers if request goes async")
Reported-by: Stefan Roesch <shr@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Jens Axboe 2022-03-22 14:12:33 -06:00
parent d89a4fac0f
commit 4d55f238f8
1 changed files with 8 additions and 3 deletions
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11
fs/io_uring.c
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@ -1383,7 +1383,7 @@ static struct io_buffer_list *io_buffer_get_list(struct io_ring_ctx *ctx,
return NULL;
}
static void io_kbuf_recycle(struct io_kiocb *req)
static void io_kbuf_recycle(struct io_kiocb *req, unsigned issue_flags)
{
struct io_ring_ctx *ctx = req->ctx;
struct io_buffer_list *bl;
@ -1392,6 +1392,9 @@ static void io_kbuf_recycle(struct io_kiocb *req)
if (likely(!(req->flags & REQ_F_BUFFER_SELECTED)))
return;
if (issue_flags & IO_URING_F_UNLOCKED)
mutex_lock(&ctx->uring_lock);
lockdep_assert_held(&ctx->uring_lock);
buf = req->kbuf;
@ -1399,6 +1402,9 @@ static void io_kbuf_recycle(struct io_kiocb *req)
list_add(&buf->list, &bl->buf_list);
req->flags &= ~REQ_F_BUFFER_SELECTED;
req->kbuf = NULL;
if (issue_flags & IO_URING_F_UNLOCKED)
mutex_unlock(&ctx->uring_lock);
}
static bool io_match_task(struct io_kiocb *head, struct task_struct *task,
@ -6254,7 +6260,7 @@ static int io_arm_poll_handler(struct io_kiocb *req, unsigned issue_flags)
req->flags |= REQ_F_POLLED;
ipt.pt._qproc = io_async_queue_proc;
io_kbuf_recycle(req);
io_kbuf_recycle(req, issue_flags);
ret = __io_arm_poll_handler(req, &apoll->poll, &ipt, mask);
if (ret || ipt.error)
@ -7504,7 +7510,6 @@ static void io_queue_sqe_arm_apoll(struct io_kiocb *req)
* Queued up for async execution, worker will release
* submit reference when the iocb is actually submitted.
*/
io_kbuf_recycle(req);
io_queue_async_work(req, NULL);
break;
case IO_APOLL_OK: