From: Caleb Sander Mateos <csander@purestorage.com>
Date: Thu, 4 Sep 2025 16:12:22 +0000 (-0600)
Subject: io_uring: remove WRITE_ONCE() in io_uring_create()
X-Git-Tag: v6.18-rc1~137^2~35
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=c2685729fa5463e5fc493244a2ba7e260217fc76;p=thirdparty%2Fkernel%2Fstable.git

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@purestorage.com>
Link: https://lore.kernel.org/r/20250904161223.2600435-1-csander@purestorage.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
---

diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
index 6c07efac977ce..20dfa5ef75dcc 100644
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -3891,8 +3891,13 @@ static __cold int io_uring_create(unsigned entries, struct io_uring_params *p,
 	}
 
 	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)) {