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| author | Jens Axboe <axboe@kernel.dk> | 2024-01-04 20:21:08 +0100 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2024-01-04 20:21:08 +0100 |
| commit | 6ff1407e24e6fdfa4a16ba9ba551e3d253a26391 (patch) | |
| tree | 5a905e6c11599e8b25b5fd25d86f359fc7907f32 /io_uring | |
| parent | io_uring/kbuf: add method for returning provided buffer ring head (diff) | |
| download | linux-6ff1407e24e6fdfa4a16ba9ba551e3d253a26391.tar.xz linux-6ff1407e24e6fdfa4a16ba9ba551e3d253a26391.zip | |
io_uring: ensure local task_work is run on wait timeout
A previous commit added an earlier break condition here, which is fine if
we're using non-local task_work as it'll be run on return to userspace.
However, if DEFER_TASKRUN is used, then we could be leaving local
task_work that is ready to process in the ctx list until next time that
we enter the kernel to wait for events.
Move the break condition to _after_ we have run task_work.
Cc: stable@vger.kernel.org
Fixes: 846072f16eed ("io_uring: mimimise io_cqring_wait_schedule")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'io_uring')
| -rw-r--r-- | io_uring/io_uring.c | 14 |
1 files changed, 12 insertions, 2 deletions
diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c index a9a519fa9926..4afb911fc042 100644 --- a/io_uring/io_uring.c +++ b/io_uring/io_uring.c @@ -2615,8 +2615,6 @@ static int io_cqring_wait(struct io_ring_ctx *ctx, int min_events, __set_current_state(TASK_RUNNING); atomic_set(&ctx->cq_wait_nr, 0); - if (ret < 0) - break; /* * Run task_work after scheduling and before io_should_wake(). * If we got woken because of task_work being processed, run it @@ -2626,6 +2624,18 @@ static int io_cqring_wait(struct io_ring_ctx *ctx, int min_events, if (!llist_empty(&ctx->work_llist)) io_run_local_work(ctx); + /* + * Non-local task_work will be run on exit to userspace, but + * if we're using DEFER_TASKRUN, then we could have waited + * with a timeout for a number of requests. If the timeout + * hits, we could have some requests ready to process. Ensure + * this break is _after_ we have run task_work, to avoid + * deferring running potentially pending requests until the + * next time we wait for events. + */ + if (ret < 0) + break; + check_cq = READ_ONCE(ctx->check_cq); if (unlikely(check_cq)) { /* let the caller flush overflows, retry */ |