[PATCH net-next] net: remove redundant check in skb_shift()

[PATCH net-next] net: remove redundant check in skb_shift()

[Zhang Changzhong]

The check for '!to' is redundant here, since skb_can_coalesce() already
contains this check.

Signed-off-by: Zhang Changzhong <zhangchangzhong@huawei.com>
---
 net/core/skbuff.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 83f8cd8..f915234 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -4169,8 +4169,7 @@ int skb_shift(struct sk_buff *tgt, struct sk_buff *skb, int shiftlen)
 	/* Actual merge is delayed until the point when we know we can
 	 * commit all, so that we don't have to undo partial changes
 	 */
-	if (!to ||
-	    !skb_can_coalesce(tgt, to, skb_frag_page(fragfrom),
+	if (!skb_can_coalesce(tgt, to, skb_frag_page(fragfrom),
 			      skb_frag_off(fragfrom))) {
 		merge = -1;
 	} else {
-- 
2.9.5

Re: [PATCH net-next] net: remove redundant check in skb_shift()

[Simon Horman]

On Thu, Aug 15, 2024 at 10:09:42PM +0800, Zhang Changzhong wrote:
> The check for '!to' is redundant here, since skb_can_coalesce() already
> contains this check.

It would be nice to mention here how this was found (e.g. found by
inspection, flagged by private static analysis tool, ...) and how it was
tested (e.g. compile tested only).

> Signed-off-by: Zhang Changzhong <zhangchangzhong@huawei.com>

In any case, this looks good to me.

Reviewed-by: Simon Horman <horms@kernel.org>

Re: [PATCH net-next] net: remove redundant check in skb_shift()

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net-next.git (main)
by Jakub Kicinski <kuba@kernel.org>:

On Thu, 15 Aug 2024 22:09:42 +0800 you wrote:
> The check for '!to' is redundant here, since skb_can_coalesce() already
> contains this check.
> 
> Signed-off-by: Zhang Changzhong <zhangchangzhong@huawei.com>
> ---
>  net/core/skbuff.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)

Here is the summary with links:
  - [net-next] net: remove redundant check in skb_shift()
    https://git.kernel.org/netdev/net-next/c/dca9d62a0d76

You are awesome, thank you!
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