[SRU OEM-6.1 3/4] io_uring/msg_ring: move double lock/unlock helpers higher up

[Thadeu Lima de Souza Cascardo]

From: Jens Axboe <axboe at kernel.dk>

In preparation for needing them somewhere else, move them and get rid of
the unused 'issue_flags' for the unlock side.

No functional changes in this patch.

Signed-off-by: Jens Axboe <axboe at kernel.dk>
(cherry picked from commit 423d5081d0451faa59a707e57373801da5b40141)
CVE-2023-2430
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo at canonical.com>
---
 io_uring/msg_ring.c | 47 ++++++++++++++++++++++-----------------------
 1 file changed, 23 insertions(+), 24 deletions(-)

diff --git a/io_uring/msg_ring.c b/io_uring/msg_ring.c
index fc0752446116..59a0e5f9fdf9 100644
--- a/io_uring/msg_ring.c
+++ b/io_uring/msg_ring.c
@@ -24,6 +24,28 @@ struct io_msg {
 	u32 flags;
 };
 
+static void io_double_unlock_ctx(struct io_ring_ctx *octx)
+{
+	mutex_unlock(&octx->uring_lock);
+}
+
+static int io_double_lock_ctx(struct io_ring_ctx *octx,
+			      unsigned int issue_flags)
+{
+	/*
+	 * To ensure proper ordering between the two ctxs, we can only
+	 * attempt a trylock on the target. If that fails and we already have
+	 * the source ctx lock, punt to io-wq.
+	 */
+	if (!(issue_flags & IO_URING_F_UNLOCKED)) {
+		if (!mutex_trylock(&octx->uring_lock))
+			return -EAGAIN;
+		return 0;
+	}
+	mutex_lock(&octx->uring_lock);
+	return 0;
+}
+
 void io_msg_ring_cleanup(struct io_kiocb *req)
 {
 	struct io_msg *msg = io_kiocb_to_cmd(req, struct io_msg);
@@ -51,29 +73,6 @@ static int io_msg_ring_data(struct io_kiocb *req)
 	return -EOVERFLOW;
 }
 
-static void io_double_unlock_ctx(struct io_ring_ctx *octx,
-				 unsigned int issue_flags)
-{
-	mutex_unlock(&octx->uring_lock);
-}
-
-static int io_double_lock_ctx(struct io_ring_ctx *octx,
-			      unsigned int issue_flags)
-{
-	/*
-	 * To ensure proper ordering between the two ctxs, we can only
-	 * attempt a trylock on the target. If that fails and we already have
-	 * the source ctx lock, punt to io-wq.
-	 */
-	if (!(issue_flags & IO_URING_F_UNLOCKED)) {
-		if (!mutex_trylock(&octx->uring_lock))
-			return -EAGAIN;
-		return 0;
-	}
-	mutex_lock(&octx->uring_lock);
-	return 0;
-}
-
 static struct file *io_msg_grab_file(struct io_kiocb *req, unsigned int issue_flags)
 {
 	struct io_msg *msg = io_kiocb_to_cmd(req, struct io_msg);
@@ -122,7 +121,7 @@ static int io_msg_install_complete(struct io_kiocb *req, unsigned int issue_flag
 	if (!io_post_aux_cqe(target_ctx, msg->user_data, ret, 0, true))
 		ret = -EOVERFLOW;
 out_unlock:
-	io_double_unlock_ctx(target_ctx, issue_flags);
+	io_double_unlock_ctx(target_ctx);
 	return ret;
 }
 
-- 
2.34.1