From: Jens Axboe <axboe@kernel.dk>
Date: Thu, 12 Sep 2019 20:19:16 +0000 (-0600)
Subject: io_uring: make sqpoll wakeup possible with getevents
X-Git-Tag: v5.4-rc1~150^2~1
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=b2a9eadab85730935f5a6fe19f3f61faaaced601;p=thirdparty%2Fkernel%2Flinux.git

io_uring: make sqpoll wakeup possible with getevents

The way the logic is setup in io_uring_enter() means that you can't wake
up the SQ poller thread while at the same time waiting (or polling) for
completions afterwards. There's no reason for that to be the case.

Reported-by: Lewis Baker <lbaker@fb.com>
Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
---

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 4bc3ee4ea81ff..3c8859d417eb5 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -3356,15 +3356,12 @@ SYSCALL_DEFINE6(io_uring_enter, unsigned int, fd, u32, to_submit,
 	 * Just return the requested submit count, and wake the thread if
 	 * we were asked to.
 	 */
+	ret = 0;
 	if (ctx->flags & IORING_SETUP_SQPOLL) {
 		if (flags & IORING_ENTER_SQ_WAKEUP)
 			wake_up(&ctx->sqo_wait);
 		submitted = to_submit;
-		goto out_ctx;
-	}
-
-	ret = 0;
-	if (to_submit) {
+	} else if (to_submit) {
 		bool block_for_last = false;
 
 		to_submit = min(to_submit, ctx->sq_entries);
@@ -3394,7 +3391,6 @@ SYSCALL_DEFINE6(io_uring_enter, unsigned int, fd, u32, to_submit,
 		}
 	}
 
-out_ctx:
 	io_ring_drop_ctx_refs(ctx, 1);
 out_fput:
 	fdput(f);