Re: [PATCH 4.19 17/36] cxgb4: use correct type for all-mask IP address comparison

[Pavel Machek]

Hi!

> From: Rahul Lakkireddy <rahul.lakkireddy@xxxxxxxxxxx>
> 
> [ Upstream commit f286dd8eaad5a2758750f407ab079298e0bcc8a5 ]
> 
> Use correct type to check for all-mask exact match IP addresses.
> 
> Fixes following sparse warnings due to big endian value checks
> against 0xffffffff in is_addr_all_mask():
> cxgb4_filter.c:977:25: warning: restricted __be32 degrades to integer
> cxgb4_filter.c:983:37: warning: restricted __be32 degrades to integer
> cxgb4_filter.c:984:37: warning: restricted __be32 degrades to integer
> cxgb4_filter.c:985:37: warning: restricted __be32 degrades to integer
> cxgb4_filter.c:986:37: warning: restricted __be32 degrades to integer

> diff --git a/drivers/net/ethernet/chelsio/cxgb4/cxgb4_filter.c b/drivers/net/ethernet/chelsio/cxgb4/cxgb4_filter.c
> index 7dddb9e748b81..86745f33a252d 100644
> --- a/drivers/net/ethernet/chelsio/cxgb4/cxgb4_filter.c
> +++ b/drivers/net/ethernet/chelsio/cxgb4/cxgb4_filter.c
> @@ -810,16 +810,16 @@ static bool is_addr_all_mask(u8 *ipmask, int family)
>  		struct in_addr *addr;
>  
>  		addr = (struct in_addr *)ipmask;
> -		if (addr->s_addr == 0xffffffff)
> +		if (ntohl(addr->s_addr) == 0xffffffff)

Endianity does not really matter for ~0, but can compiler figure it
out?

would it be better to do these tests as 

      if (foo == htonl(0xffffffff))

to make it clear to the compiler?

Thanks,
								Pavel

>  	} else if (family == AF_INET6) {
>  		struct in6_addr *addr6;
>  
>  		addr6 = (struct in6_addr *)ipmask;
> -		if (addr6->s6_addr32[0] == 0xffffffff &&
> -		    addr6->s6_addr32[1] == 0xffffffff &&
> -		    addr6->s6_addr32[2] == 0xffffffff &&
> -		    addr6->s6_addr32[3] == 0xffffffff)
> +		if (ntohl(addr6->s6_addr32[0]) == 0xffffffff &&
> +		    ntohl(addr6->s6_addr32[1]) == 0xffffffff &&
> +		    ntohl(addr6->s6_addr32[2]) == 0xffffffff &&
> +		    ntohl(addr6->s6_addr32[3]) == 0xffffffff)
>  			return true;
>  	}
>  	return false;

-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

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