[PATCH v4 19/20] nvme: fix context analysis warning in tcp.c

[Nilay Shroff]

After adding Clang context annotations, compiling tcp.c reports the
following warning while context analysis is enabled:

drivers/nvme/host/tcp.c:2572:24: warning: passing pointer to variable 'list' requires holding mutex 'nvme_tcp_ctrl_mutex'
	  [-Wthread-safety-pointer]
2572 |         if (list_empty(&ctrl->list))
     |                               ^

The above warning is triggered because ctrl->list is guarded with mutex
nvme_tcp_ctrl_mutex but when list_empty(&ctrl->list) is invoked it
doesn't acquire nvme_tcp_ctrl_mutex.

Replace list_empty() with list_empty_careful(), which is intended
for lockless inspection of list heads during teardown when no concurrent
list modifications are expected. This suppresses the corresponding
Clang context analysis warning while preserving the existing behavior.

Signed-off-by: Nilay Shroff <nilay at linux.ibm.com>
---
 drivers/nvme/host/tcp.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/nvme/host/tcp.c b/drivers/nvme/host/tcp.c
index 8d2fbfc7cd8d..87d8067f3283 100644
--- a/drivers/nvme/host/tcp.c
+++ b/drivers/nvme/host/tcp.c
@@ -2579,7 +2579,7 @@ static void nvme_tcp_free_ctrl(struct nvme_ctrl *nctrl)
 {
 	struct nvme_tcp_ctrl *ctrl = to_tcp_ctrl(nctrl);
 
-	if (list_empty(&ctrl->list))
+	if (list_empty_careful(&ctrl->list))
 		goto free_ctrl;
 
 	mutex_lock(&nvme_tcp_ctrl_mutex);
-- 
2.53.0