linux-kernel - [PATCH v2] io_uring: remove WRITE_ONCE() in io_uring

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Message-ID: <20250904161223.2600435-1-csander@purestorage.com>
Date: Thu,  4 Sep 2025 10:12:22 -0600
From: Caleb Sander Mateos <csander@...estorage.com>
To: Jens Axboe <axboe@...nel.dk>
Cc: Caleb Sander Mateos <csander@...estorage.com>,
	io-uring@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH v2] io_uring: remove WRITE_ONCE() in io_uring_create()

There's no need to use WRITE_ONCE() to set ctx->submitter_task in
io_uring_create() since no other task can access the io_ring_ctx until a
file descriptor is associated with it. So use a normal assignment
instead of WRITE_ONCE().

Signed-off-by: Caleb Sander Mateos <csander@...estorage.com>
---
 io_uring/io_uring.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
index 6c07efac977c..20dfa5ef75dc 100644
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -3889,12 +3889,17 @@ static __cold int io_uring_create(unsigned entries, struct io_uring_params *p,
 		ret = -EFAULT;
 		goto err;
 	}
 
 	if (ctx->flags & IORING_SETUP_SINGLE_ISSUER
-	    && !(ctx->flags & IORING_SETUP_R_DISABLED))
-		WRITE_ONCE(ctx->submitter_task, get_task_struct(current));
+	    && !(ctx->flags & IORING_SETUP_R_DISABLED)) {
+		/*
+		 * Unlike io_register_enable_rings(), don't need WRITE_ONCE()
+		 * since ctx isn't yet accessible from other tasks
+		 */
+		ctx->submitter_task = get_task_struct(current);
+	}
 
 	file = io_uring_get_file(ctx);
 	if (IS_ERR(file)) {
 		ret = PTR_ERR(file);
 		goto err;
-- 
2.45.2