From f0a4e62bb5343b3b7163bc851cfb4bebfefcc4e7 Mon Sep 17 00:00:00 2001
From: Nathan Chancellor <nathan@kernel.org>
Date: Mon, 7 Feb 2022 09:24:11 -0700
Subject: [PATCH] io_uring: Fix use of uninitialized ret in
 io_eventfd_register()
Git-commit: f0a4e62bb5343b3b7163bc851cfb4bebfefcc4e7
Patch-mainline: v5.18-rc1
References: bsc#1205205

Clang warns:

  fs/io_uring.c:9396:9: warning: variable 'ret' is uninitialized when used here [-Wuninitialized]
          return ret;
                 ^~~
  fs/io_uring.c:9373:13: note: initialize the variable 'ret' to silence this warning
          int fd, ret;
                     ^
                      = 0
  1 warning generated.

Just return 0 directly and reduce the scope of ret to the if statement,
as that is the only place that it is used, which is how the function was
before the fixes commit.

Fixes: 1a75fac9a0f9 ("io_uring: avoid ring quiesce while registering/unregistering eventfd")
Link: https://github.com/ClangBuiltLinux/linux/issues/1579
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Link: https://lore.kernel.org/r/20220207162410.1013466-1-nathan@kernel.org
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 49bcc5fc688d..1dce3f6e7031 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -9378,7 +9378,7 @@ static int io_eventfd_register(struct io_ring_ctx *ctx, void __user *arg,
 {
 	struct io_ev_fd *ev_fd;
 	__s32 __user *fds = arg;
-	int fd, ret;
+	int fd;
 
 	ev_fd = rcu_dereference_protected(ctx->io_ev_fd,
 					lockdep_is_held(&ctx->uring_lock));
@@ -9394,14 +9394,14 @@ static int io_eventfd_register(struct io_ring_ctx *ctx, void __user *arg,
 
 	ev_fd->cq_ev_fd = eventfd_ctx_fdget(fd);
 	if (IS_ERR(ev_fd->cq_ev_fd)) {
-		ret = PTR_ERR(ev_fd->cq_ev_fd);
+		int ret = PTR_ERR(ev_fd->cq_ev_fd);
 		kfree(ev_fd);
 		return ret;
 	}
 	ev_fd->eventfd_async = eventfd_async;
 
 	rcu_assign_pointer(ctx->io_ev_fd, ev_fd);
-	return ret;
+	return 0;
 }
 
 static void io_eventfd_put(struct rcu_head *rcu)
-- 
2.35.3