diff mbox series

[net-next,2/4] net: add pskb_may_pull_reason() helper

Message ID 20230210184708.2172562-3-edumazet@google.com (mailing list archive)
State Accepted
Commit 1fb2d41501f38192d8a19da585cd441cf8845697
Delegated to: Netdev Maintainers
Headers show
Series ipv6: more drop reason | expand

Checks

Context Check Description
netdev/tree_selection success Clearly marked for net-next
netdev/fixes_present success Fixes tag not required for -next series
netdev/subject_prefix success Link
netdev/cover_letter success Series has a cover letter
netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 5335 this patch: 5335
netdev/cc_maintainers warning 1 maintainers not CCed: imagedong@tencent.com
netdev/build_clang success Errors and warnings before: 1084 this patch: 1084
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 5550 this patch: 5550
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 28 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Eric Dumazet Feb. 10, 2023, 6:47 p.m. UTC 
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@google.com>
---
 include/linux/skbuff.h | 19 +++++++++++++++----
 1 file changed, 15 insertions(+), 4 deletions(-)

Comments

David Ahern Feb. 10, 2023, 7:24 p.m. UTC | #1 
On 2/10/23 11:47 AM, Eric Dumazet wrote:
> 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@google.com>
> ---
>  include/linux/skbuff.h | 19 +++++++++++++++----
>  1 file changed, 15 insertions(+), 4 deletions(-)
> 

Reviewed-by: David Ahern <dsahern@kernel.org>
diff mbox series

Patch

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 47ab28a37f2f1f9fb25e575fffe2db1cfd884f65..d5602b15c714fa3bd67d56793857b2bb5c21542e 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -2631,13 +2631,24 @@  void *skb_pull_data(struct sk_buff *skb, size_t len);
 
 void *__pskb_pull_tail(struct sk_buff *skb, int delta);
 
-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;
 }
 
 static inline void *pskb_pull(struct sk_buff *skb, unsigned int len)