scsi: target: iscsi: Drop unnecessary container_of()

The structure pointer passed to container_of() is never NULL; that was
already checked. That means that the result of container_of() operations
on it is also never NULL, even though se_node_acl is the first element
of the structure embedding it. On top of that, it is misleading to perform
a NULL check on the result of container_of() because the position of the
contained element could change, which would make the test invalid.
Remove the unnecessary NULL check.

As it turns out, the container_of operation was only made for the purpose
of the NULL check. If the container_of is actually needed, it is repeated
later. Remove the container_of operation as well.

The NULL check was identified and removed with the following Coccinelle
script.

@@
type t;
identifier v;
statement s;
@@

<+...
(
  t v = container_of(...);
|
  v = container_of(...);
)
  ...
  when != v
- if (\( !v \| v == NULL \) ) s
...+>

Link: https://lore.kernel.org/r/20210510040817.2050266-1-linux@roeck-us.net
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: Hou Pu <houpu@bytedance.com>
Cc: Mike Christie <michael.christie@oracle.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

diff --git a/drivers/target/iscsi/iscsi_target_nego.c b/drivers/target/iscsi/iscsi_target_nego.c
index 9a4a632..c0ed6f8 100644 (file)
--- a/drivers/target/iscsi/iscsi_target_nego.c
+++ b/drivers/target/iscsi/iscsi_target_nego.c
@@ -118,13 +118,6 @@ static u32 iscsi_handle_authentication(
                                        " CHAP auth\n");
                        return -1;
                }
-               iscsi_nacl = container_of(se_nacl, struct iscsi_node_acl,
-                               se_node_acl);
-               if (!iscsi_nacl) {
-                       pr_err("Unable to locate struct iscsi_node_acl for"
-                                       " CHAP auth\n");
-                       return -1;
-               }
 
                if (se_nacl->dynamic_node_acl) {
                        iscsi_tpg = container_of(se_nacl->se_tpg,