Re: [PATCH] staging: net: core: skbuff.c: Added do-while pair for complex macros

[Joe Perches <joe@perches.com>]

On Thu, 2015-11-26 at 22:06 +0530, Jitendra Kumar Khasdev wrote:
> This patch is to file skbuff.c that fixes up following error,
> reported by checkpatch.pl tool,

Your subject title is not correct.
This is not a staging patch.

> 1. ERROR: Macros with multiple statements should be enclosed
>    in a do - while loop.

checkpatch is brainless.
Not every message it emits needs fixing.


> diff --git a/net/core/skbuff.c b/net/core/skbuff.c
[]
> @@ -748,11 +748,13 @@ void consume_skb(struct sk_buff *skb)
>  EXPORT_SYMBOL(consume_skb);
>  
>  /* Make sure a field is enclosed inside headers_start/headers_end section */
> -#define CHECK_SKB_FIELD(field) \
> -	BUILD_BUG_ON(offsetof(struct sk_buff, field) <		\
> -		     offsetof(struct sk_buff, headers_start));	\
> -	BUILD_BUG_ON(offsetof(struct sk_buff, field) >		\
> -		     offsetof(struct sk_buff, headers_end));	\
> +#define CHECK_SKB_FIELD(field)						\
> +	do {								\
> +		BUILD_BUG_ON(offsetof(struct sk_buff, field) <		\
> +			offsetof(struct sk_buff, headers_start));	\
> +		BUILD_BUG_ON(offsetof(struct sk_buff, field) >		\
> +			offsetof(struct sk_buff, headers_end));		\
> +	} while (0)							\

Perhaps the last check should add a sizeof(field)

	BUILD_BUG_ON((offsetof(struct sk_buff, field) +
		      FIELD_SIZEOF(struct sk_buff, field)) >
		     offsetof(struct sk_buff, headers_end));