[PATCH 5.11 05/36] io_uring: deduplicate failing task_work_add

gregkh
2021-03-10T13:25:10Z

From: Pavel Begunkov <asml.silence@gmail.com>

commit eab30c4d20dc761d463445e5130421863ff81505 upstream

When io_req_task_work_add() fails, the request will be cancelled by
enqueueing via task_works of io-wq. Extract a function for that.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
fs/io_uring.c | 46 +++++++++++++++++-----------------------------
1 file changed, 17 insertions(+), 29 deletions(-)

--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -2172,6 +2172,16 @@ static int io_req_task_work_add(struct i
return ret;
}

+static void io_req_task_work_add_fallback(struct io_kiocb *req,
+ void (*cb)(struct callback_head *))
+{
+ struct task_struct *tsk = io_wq_get_task(req->ctx->io_wq);
+
+ init_task_work(&req->task_work, cb);
+ task_work_add(tsk, &req->task_work, TWA_NONE);
+ wake_up_process(tsk);
+}
+
static void __io_req_task_cancel(struct io_kiocb *req, int error)
{
struct io_ring_ctx *ctx = req->ctx;
@@ -2229,14 +2239,8 @@ static void io_req_task_queue(struct io_
percpu_ref_get(&req->ctx->refs);

ret = io_req_task_work_add(req);
- if (unlikely(ret)) {
- struct task_struct *tsk;
-
- init_task_work(&req->task_work, io_req_task_cancel);
- tsk = io_wq_get_task(req->ctx->io_wq);
- task_work_add(tsk, &req->task_work, TWA_NONE);
- wake_up_process(tsk);
- }
+ if (unlikely(ret))
+ io_req_task_work_add_fallback(req, io_req_task_cancel);
}

static inline void io_queue_next(struct io_kiocb *req)
@@ -2354,13 +2358,8 @@ static void io_free_req_deferred(struct

init_task_work(&req->task_work, io_put_req_deferred_cb);
ret = io_req_task_work_add(req);
- if (unlikely(ret)) {
- struct task_struct *tsk;
-
- tsk = io_wq_get_task(req->ctx->io_wq);
- task_work_add(tsk, &req->task_work, TWA_NONE);
- wake_up_process(tsk);
- }
+ if (unlikely(ret))
+ io_req_task_work_add_fallback(req, io_put_req_deferred_cb);
}

static inline void io_put_req_deferred(struct io_kiocb *req, int refs)
@@ -3439,15 +3438,8 @@ static int io_async_buf_func(struct wait
/* submit ref gets dropped, acquire a new one */
refcount_inc(&req->refs);
ret = io_req_task_work_add(req);
- if (unlikely(ret)) {
- struct task_struct *tsk;
-
- /* queue just for cancelation */
- init_task_work(&req->task_work, io_req_task_cancel);
- tsk = io_wq_get_task(req->ctx->io_wq);
- task_work_add(tsk, &req->task_work, TWA_NONE);
- wake_up_process(tsk);
- }
+ if (unlikely(ret))
+ io_req_task_work_add_fallback(req, io_req_task_cancel);
return 1;
}

@@ -5159,12 +5151,8 @@ static int __io_async_wake(struct io_kio
*/
ret = io_req_task_work_add(req);
if (unlikely(ret)) {
- struct task_struct *tsk;
-
WRITE_ONCE(poll->canceled, true);
- tsk = io_wq_get_task(req->ctx->io_wq);
- task_work_add(tsk, &req->task_work, TWA_NONE);
- wake_up_process(tsk);
+ io_req_task_work_add_fallback(req, func);
}
return 1;
}