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io_uring: set -EINTR directly when a signal wakes up in io_cqring_wait 

We didn't use -ERESTARTSYS to tell the application layer to restart the
system call, but instead return -EINTR. we can set -EINTR directly when
wakeup by the signal, which can help us save an assignment operation and
comparison operation.

Reviewed-by: Bob Liu <bob.liu@oracle.com>
Signed-off-by: Jackie Liu <liuyun01@kylinos.cn>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Jackie Liu 2019-10-29 11:16:42 +08:00 committed by Jens Axboe
parent 62755e35df
commit e9ffa5c2b7
1 changed files with 3 additions and 6 deletions
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9
fs/io_uring.c
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@ -2976,7 +2976,7 @@ static int io_cqring_wait(struct io_ring_ctx *ctx, int min_events,
.to_wait = min_events,
};
struct io_rings *rings = ctx->rings;
int ret;
int ret = 0;
if (io_cqring_events(rings) >= min_events)
return 0;
@ -2994,7 +2994,6 @@ static int io_cqring_wait(struct io_ring_ctx *ctx, int min_events,
return ret;
}
ret = 0;
iowq.nr_timeouts = atomic_read(&ctx->cq_timeouts);
trace_io_uring_cqring_wait(ctx, min_events);
do {
@ -3004,15 +3003,13 @@ static int io_cqring_wait(struct io_ring_ctx *ctx, int min_events,
break;
schedule();
if (signal_pending(current)) {
ret = -ERESTARTSYS;
ret = -EINTR;
break;
}
} while (1);
finish_wait(&ctx->wait, &iowq.wq);
restore_saved_sigmask_unless(ret == -ERESTARTSYS);
if (ret == -ERESTARTSYS)
ret = -EINTR;
restore_saved_sigmask_unless(ret == -EINTR);
return READ_ONCE(rings->cq.head) == READ_ONCE(rings->cq.tail) ? ret : 0;
}