On Fri, Oct 04, 2024 at 10:03:27AM -0700, Sherry Yang wrote:
> From: Eric Dumazet <edumazet@xxxxxxxxxx>
>
> [ Upstream commit 1fb2d41501f38192d8a19da585cd441cf8845697 ]
>
> pskb_may_pull() can fail for two different reasons.
>
> Provide pskb_may_pull_reason() helper to distinguish
> between these reasons.
>
> It returns:
>
> SKB_NOT_DROPPED_YET : Success
> SKB_DROP_REASON_PKT_TOO_SMALL : packet too small
> SKB_DROP_REASON_NOMEM : skb->head could not be resized
>
> Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
> Reviewed-by: David Ahern <dsahern@xxxxxxxxxx>
> Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
> Stable-dep-of: 8bd67ebb50c0 ("net: bridge: xmit: make sure we have at least eth header len bytes")
> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
> [Sherry: bp to 5.15.y. Minor conflicts due to missing commit
> d427c8999b07 ("net-next: skbuff: refactor pskb_pull") which is not
> necessary in 5.15.y. Ignore context change.
> Signed-off-by: Sherry Yang <sherry.yang@xxxxxxxxxx>
> ---
> include/linux/skbuff.h | 19 +++++++++++++++----
> 1 file changed, 15 insertions(+), 4 deletions(-)
>
> diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
> index b230c422dc3b..f92e8fe4f5eb 100644
> --- a/include/linux/skbuff.h
> +++ b/include/linux/skbuff.h
> @@ -2465,13 +2465,24 @@ static inline void *pskb_pull(struct sk_buff *skb, unsigned int len)
> return unlikely(len > skb->len) ? NULL : __pskb_pull(skb, len);
> }
>
> -static inline bool pskb_may_pull(struct sk_buff *skb, unsigned int len)
> +static inline enum skb_drop_reason
> +pskb_may_pull_reason(struct sk_buff *skb, unsigned int len)
> {
> if (likely(len <= skb_headlen(skb)))
> - return true;
> + return SKB_NOT_DROPPED_YET;
> +
> if (unlikely(len > skb->len))
> - return false;
> - return __pskb_pull_tail(skb, len - skb_headlen(skb)) != NULL;
> + return SKB_DROP_REASON_PKT_TOO_SMALL;
> +
> + if (unlikely(!__pskb_pull_tail(skb, len - skb_headlen(skb))))
> + return SKB_DROP_REASON_NOMEM;
> +
> + return SKB_NOT_DROPPED_YET;
> +}
> +
> +static inline bool pskb_may_pull(struct sk_buff *skb, unsigned int len)
> +{
> + return pskb_may_pull_reason(skb, len) == SKB_NOT_DROPPED_YET;
> }
>
> void skb_condense(struct sk_buff *skb);
> --
> 2.46.0
>
>
Any specific reason why you didn't test build this patch?
It breaks the build into thousands of tiny pieces.
greg k-h
