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From:   Nathan Chancellor <nathan@kernel.org>
To:     Jens Axboe <axboe@fb.com>, Christoph Hellwig <hch@lst.de>,
        Keith Busch <kbusch@kernel.org>,
        Sagi Grimberg <sagi@grimberg.me>
Cc:     Nick Desaulniers <ndesaulniers@google.com>,
        Tom Rix <trix@redhat.com>, Kanchan Joshi <joshi.k@samsung.com>,
        Anuj Gupta <anuj20.g@samsung.com>,
        linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org,
        llvm@lists.linux.dev, Nathan Chancellor <nathan@kernel.org>,
        kernel test robot <lkp@intel.com>
Subject: [PATCH] nvme: Ensure ret is always initialized in
Date:   Fri,  6 May 2022 08:03:58 -0700
Message-Id: <20220506150357.2443040-1-nathan@kernel.org>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

Clang warns:

  drivers/nvme/host/ioctl.c:674:6: error: variable 'ret' is used uninitialized whenever 'if' condition is false [-Werror,-Wsometimes-uninitialized]
          if (ns)
              ^~
  drivers/nvme/host/ioctl.c:677:9: note: uninitialized use occurs here
          return ret;
                 ^~~
  drivers/nvme/host/ioctl.c:674:2: note: remove the 'if' if its condition is always true
          if (ns)
          ^~~~~~~
  drivers/nvme/host/ioctl.c:672:9: note: initialize the variable 'ret' to silence this warning
          int ret;
                 ^
                  = 0
  1 error generated.

Initialize ret to zero so that it cannot be used uninitialized.

Fixes: 271ee3df5cca ("nvme: wire-up uring-cmd support for io-passthru on char-device.")
Link: https://github.com/ClangBuiltLinux/linux/issues/1630
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
---

Or alternatively, remove the 'if (ns)' if ns can never be NULL; I tried
going down the rabbit hole to see if that is possible but I got a little
lost :^)

 drivers/nvme/host/ioctl.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/nvme/host/ioctl.c b/drivers/nvme/host/ioctl.c
index 9db88f2c15f8..3ad5285c1f96 100644
--- a/drivers/nvme/host/ioctl.c
+++ b/drivers/nvme/host/ioctl.c
@@ -669,7 +669,7 @@ int nvme_ns_head_chr_uring_cmd(struct io_uring_cmd *ioucmd,
 	struct nvme_ns_head *head = container_of(cdev, struct nvme_ns_head, cdev);
 	int srcu_idx = srcu_read_lock(&head->srcu);
 	struct nvme_ns *ns = nvme_find_path(head);
-	int ret;
+	int ret = 0;
 
 	if (ns)
 		ret = nvme_ns_uring_cmd(ns, ioucmd, issue_flags);

base-commit: 002b149a51a53facaf26d7c6f2c1fe718673683c
-- 
2.36.0