Messages in this thread Patch in this message | | | Date | Wed, 05 Jun 2013 08:54:22 +0800 | From | Chen Gang <> | Subject | [PATCH v3] include/linux/skbuff.h: using '(__u16) ~0U' instead of '~0U' |
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Both 'transport_header' and 'mac_header' are __u16, which are never equal to '~0U'.
So need use '(__u16) ~0U' instead of '~0U'.
The related warning (with EXTRA_CFLAGS=-W ARCH=m68k for allmodconfig) include/linux/skbuff.h:1587:2: warning: comparison is always true due to limited range of data type [-Wtype-limits] ...
Use meaningful macro instead of hard code number, and better to initialize 'skb->transport_header' in __alloc_skb_head(), too.
Signed-off-by: Chen Gang <gang.chen@asianux.com> --- include/linux/skbuff.h | 6 ++++-- net/core/skbuff.c | 11 ++++++----- 2 files changed, 10 insertions(+), 7 deletions(-)
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 5f93119..3314911 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -40,6 +40,8 @@ #define CHECKSUM_COMPLETE 2 #define CHECKSUM_PARTIAL 3 +#define SKB_HEADER_OFFSET_UNSET ((__u16) ~0U) + #define SKB_DATA_ALIGN(X) (((X) + (SMP_CACHE_BYTES - 1)) & \ ~(SMP_CACHE_BYTES - 1)) #define SKB_WITH_OVERHEAD(X) \ @@ -1593,7 +1595,7 @@ static inline void skb_set_inner_mac_header(struct sk_buff *skb, } static inline bool skb_transport_header_was_set(const struct sk_buff *skb) { - return skb->transport_header != ~0U; + return skb->transport_header != SKB_HEADER_OFFSET_UNSET; } static inline unsigned char *skb_transport_header(const struct sk_buff *skb) @@ -1636,7 +1638,7 @@ static inline unsigned char *skb_mac_header(const struct sk_buff *skb) static inline int skb_mac_header_was_set(const struct sk_buff *skb) { - return skb->mac_header != ~0U; + return skb->mac_header != SKB_HEADER_OFFSET_UNSET; } static inline void skb_reset_mac_header(struct sk_buff *skb) diff --git a/net/core/skbuff.c b/net/core/skbuff.c index f45de07..6808433 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -200,7 +200,8 @@ struct sk_buff *__alloc_skb_head(gfp_t gfp_mask, int node) atomic_set(&skb->users, 1); #ifdef NET_SKBUFF_DATA_USES_OFFSET - skb->mac_header = (__u16) ~0U; + skb->mac_header = SKB_HEADER_OFFSET_UNSET; + skb->transport_header = SKB_HEADER_OFFSET_UNSET; #endif out: return skb; @@ -276,8 +277,8 @@ struct sk_buff *__alloc_skb(unsigned int size, gfp_t gfp_mask, skb_reset_tail_pointer(skb); skb->end = skb->tail + size; #ifdef NET_SKBUFF_DATA_USES_OFFSET - skb->mac_header = (__u16) ~0U; - skb->transport_header = (__u16) ~0U; + skb->mac_header = SKB_HEADER_OFFSET_UNSET; + skb->transport_header = SKB_HEADER_OFFSET_UNSET; #endif /* make sure we initialize shinfo sequentially */ @@ -345,8 +346,8 @@ struct sk_buff *build_skb(void *data, unsigned int frag_size) skb_reset_tail_pointer(skb); skb->end = skb->tail + size; #ifdef NET_SKBUFF_DATA_USES_OFFSET - skb->mac_header = (__u16) ~0U; - skb->transport_header = (__u16) ~0U; + skb->mac_header = SKB_HEADER_OFFSET_UNSET; + skb->transport_header = SKB_HEADER_OFFSET_UNSET; #endif /* make sure we initialize shinfo sequentially */ -- 1.7.7.6
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