From 83a13a4181b0e874d1f196e11b953c3c9f009f68 Mon Sep 17 00:00:00 2001
From: Pavel Begunkov <asml.silence@gmail.com>
Date: Sun, 5 Dec 2021 14:37:59 +0000
Subject: [PATCH] io_uring: tweak iopoll CQE_SKIP event counting
Git-commit: 83a13a4181b0e874d1f196e11b953c3c9f009f68
Patch-mainline: v5.17-rc1
References: bsc#1205205

When iopolling the userspace specifies the minimum number of "events" it
expects. Previously, we had one CQE per request, so the definition of
an "event" was unequivocal, but that's not more the case anymore with
REQ_F_CQE_SKIP.

Currently it counts the number of completed requests, replace it with
the number of posted CQEs. This allows users of the "one CQE per link"
scheme to wait for all N links in a single syscall, which is not
possible without the patch and requires extra context switches.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/d5a965c4d2249827392037bbd0186f87fea49c55.1638714983.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Gabriel Krisman Bertazi <krisman@suse.de>
---
 fs/io_uring.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 64add8260abb..ea7a0daa0b3b 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -2538,10 +2538,10 @@ static int io_do_iopoll(struct io_ring_ctx *ctx, bool force_nonspin)
 		/* order with io_complete_rw_iopoll(), e.g. ->result updates */
 		if (!smp_load_acquire(&req->iopoll_completed))
 			break;
+		if (unlikely(req->flags & REQ_F_CQE_SKIP))
+			continue;
 
-		if (!(req->flags & REQ_F_CQE_SKIP))
-			__io_fill_cqe(ctx, req->user_data, req->result,
-				      io_put_kbuf(req));
+		__io_fill_cqe(ctx, req->user_data, req->result, io_put_kbuf(req));
 		nr_events++;
 	}
 
-- 
2.35.3