All of lore.kernel.org
 help / color / mirror / Atom feed
From: Guenter Roeck <linux@roeck-us.net>
To: "Martin K . Petersen" <martin.petersen@oracle.com>
Cc: linux-scsi@vger.kernel.org, target-devel@vger.kernel.org,
	linux-kernel@vger.kernel.org, Guenter Roeck <linux@roeck-us.net>,
	Hou Pu <houpu@bytedance.com>,
	Mike Christie <michael.christie@oracle.com>
Subject: [PATCH] scsi: target: iscsi: Drop unnecessary container_of
Date: Sun,  9 May 2021 21:08:17 -0700	[thread overview]
Message-ID: <20210510040817.2050266-1-linux@roeck-us.net> (raw)

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
...+>

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>
---
 drivers/target/iscsi/iscsi_target_nego.c | 7 -------
 1 file changed, 7 deletions(-)

diff --git a/drivers/target/iscsi/iscsi_target_nego.c b/drivers/target/iscsi/iscsi_target_nego.c
index 151e2949bb75..fb1b5816a5b6 100644
--- 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,
-- 
2.25.1


             reply	other threads:[~2021-05-10  4:08 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-10  4:08 Guenter Roeck [this message]
2021-05-15  2:42 ` [PATCH] scsi: target: iscsi: Drop unnecessary container_of Martin K. Petersen

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20210510040817.2050266-1-linux@roeck-us.net \
    --to=linux@roeck-us.net \
    --cc=houpu@bytedance.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-scsi@vger.kernel.org \
    --cc=martin.petersen@oracle.com \
    --cc=michael.christie@oracle.com \
    --cc=target-devel@vger.kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.