[PATCH] net: caif: Drop unnecessary NULL check after container_of

[PATCH] net: caif: Drop unnecessary NULL check after container_of

[Guenter Roeck]

The first parameter passed to chnl_recv_cb() can never be NULL since all
callers dereferenced it. Consequently, container_of() on it is also never
NULL, even though the reference into the structure points to the first
element of the structure. The NULL check is therefore unnecessary.
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.

This change was made automatically 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
...+>

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
 net/caif/chnl_net.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/net/caif/chnl_net.c b/net/caif/chnl_net.c
index fadc7c8a3107..37b67194c0df 100644
--- a/net/caif/chnl_net.c
+++ b/net/caif/chnl_net.c
@@ -76,8 +76,6 @@ static int chnl_recv_cb(struct cflayer *layr, struct cfpkt *pkt)
 	u8 buf;
 
 	priv = container_of(layr, struct chnl_net, chnl);
-	if (!priv)
-		return -EINVAL;
 
 	skb = (struct sk_buff *) cfpkt_tonative(pkt);
 
-- 
2.25.1

Re: [PATCH] net: caif: Drop unnecessary NULL check after container_of

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net-next.git (refs/heads/master):

On Thu, 13 May 2021 09:58:40 -0700 you wrote:
> The first parameter passed to chnl_recv_cb() can never be NULL since all
> callers dereferenced it. Consequently, container_of() on it is also never
> NULL, even though the reference into the structure points to the first
> element of the structure. The NULL check is therefore unnecessary.
> 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.
> 
> [...]

Here is the summary with links:
  - net: caif: Drop unnecessary NULL check after container_of
    https://git.kernel.org/netdev/net-next/c/0f3ee280331e

You are awesome, thank you!
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