io_uring: don't save/restore iowait state

[ Upstream commit 6f0974eccbf78baead1735722c4f1ee3eb9422cd ]

This kind of state is per-syscall, and since we're doing the waiting off
entering the io_uring_enter(2) syscall, there's no way that iowait can
already be set for this case. Simplify it by setting it if we need to,
and always clearing it to 0 when done.

Fixes: 7b72d661f1f2 ("io_uring: gate iowait schedule on having pending requests")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
index 67a355f27ad80545539c0f362aca968c563dfe98..fc60396c9039616d85fe6ec5786f377cfa930daa 100644 (file)
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -7640,7 +7640,7 @@ static inline int io_cqring_wait_schedule(struct io_ring_ctx *ctx,
                                          struct io_wait_queue *iowq,
                                          ktime_t *timeout)
 {
-       int io_wait, ret;
+       int ret;
 
        /* make sure we run task_work before checking for signals */
        ret = io_run_task_work_sig();
@@ -7655,13 +7655,12 @@ static inline int io_cqring_wait_schedule(struct io_ring_ctx *ctx,
         * can take into account that the task is waiting for IO - turns out
         * to be important for low QD IO.
         */
-       io_wait = current->in_iowait;
        if (current_pending_io())
                current->in_iowait = 1;
        ret = 1;
        if (!schedule_hrtimeout(timeout, HRTIMER_MODE_ABS))
                ret = -ETIME;
-       current->in_iowait = io_wait;
+       current->in_iowait = 0;
        return ret;
 }