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From:   =?UTF-8?q?Michal=20Koutn=C3=BD?= <mkoutny@suse.com>
To:     axboe@kernel.dk
Cc:     asml.silence@gmail.com, fam.zheng@bytedance.com,
        io-uring@vger.kernel.org, linux-kernel@vger.kernel.org,
        roman.gushchin@linux.dev, usama.arif@bytedance.com
Subject: [PATCH] io_uring: Don't require reinitable percpu_ref
Date:   Fri, 15 Jul 2022 19:45:01 +0200
Message-Id: <20220715174501.25216-1-mkoutny@suse.com>
In-Reply-To: <8a9adb78-d9bb-a511-e4c1-c94cca392c9b@kernel.dk>
References: <8a9adb78-d9bb-a511-e4c1-c94cca392c9b@kernel.dk>
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Precedence: bulk

The commit 8bb649ee1da3 ("io_uring: remove ring quiesce for
io_uring_register") removed the worklow relying on reinit/resurrection
of the percpu_ref, hence, initialization with that requested is a relic.

This is based on code review, this causes no real bug (and theoretically
can't). Technically it's a revert of commit 214828962dea ("io_uring:
initialize percpu refcounters using PERCU_REF_ALLOW_REINIT") but since
the flag omission is now justified, I'm not making this a revert.

Fixes: 8bb649ee1da3 ("io_uring: remove ring quiesce for io_uring_register")
Signed-off-by: Michal Koutný <mkoutny@suse.com>
---
 fs/io_uring.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index a01ea49f3017..563f2266c674 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -1911,7 +1911,7 @@ static __cold struct io_ring_ctx *io_ring_ctx_alloc(struct io_uring_params *p)
 	ctx->dummy_ubuf->ubuf = -1UL;
 
 	if (percpu_ref_init(&ctx->refs, io_ring_ctx_ref_free,
-			    PERCPU_REF_ALLOW_REINIT, GFP_KERNEL))
+			    0, GFP_KERNEL))
 		goto err;
 
 	ctx->flags = p->flags;
-- 
2.37.0