Commit b064904c authored by Heiko Carstens's avatar Heiko Carstens Committed by Vasily Gorbik
Browse files

s390/checksum: provide csum_ipv6_magic() 



This implementation needs only ~30% of the time to calculate the
checksum compared to the generic variant. In addition the compiler
also generates only ~30% of the instructions compared to the generic
variant (on z14, compiled with march=z196).

Signed-off-by: default avatarHeiko Carstens <hca@linux.ibm.com>
Signed-off-by: default avatarVasily Gorbik <gor@linux.ibm.com>
parent d012a719

arch/s390/include/asm/checksum.h

+22 −2
Original line number Diff line number Diff line
@@ -13,6 +13,7 @@ 
#define _S390_CHECKSUM_H



#include <linux/uaccess.h>

#include <linux/in6.h>



/*

 * computes the checksum of a memory block at buff, length len,
@@ -115,6 +116,25 @@ static inline __sum16 ip_compute_csum(const void *buff, int len) 
	return csum_fold(csum_partial(buff, len, 0));

}



#endif /* _S390_CHECKSUM_H */



#define _HAVE_ARCH_IPV6_CSUM

static inline __sum16 csum_ipv6_magic(const struct in6_addr *saddr,

				      const struct in6_addr *daddr,

				      __u32 len, __u8 proto, __wsum csum)

{

	__u64 sum = (__force __u64)csum;



	sum += (__force __u32)saddr->s6_addr32[0];

	sum += (__force __u32)saddr->s6_addr32[1];

	sum += (__force __u32)saddr->s6_addr32[2];

	sum += (__force __u32)saddr->s6_addr32[3];

	sum += (__force __u32)daddr->s6_addr32[0];

	sum += (__force __u32)daddr->s6_addr32[1];

	sum += (__force __u32)daddr->s6_addr32[2];

	sum += (__force __u32)daddr->s6_addr32[3];

	sum += len;

	sum += proto;

	sum += (sum >> 32) | (sum << 32);

	return csum_fold((__force __wsum)(sum >> 32));

}



#endif /* _S390_CHECKSUM_H */

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