lib/checksum.c: make do_csum optional

Mike Frysinger suggested that do_csum should be optional
so that an architecture can use the generic checksum code
but still provide an optimized fast-path for the most
critical function.

This can mean an implementation using inline assembly,
or in case of Alpha one using 64-bit arithmetic in C.

Cc: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
This commit is contained in:
Arnd Bergmann 2009-06-23 21:37:26 +02:00
parent c44ba9f668
commit 20c1f641bb
1 changed files with 2 additions and 0 deletions

View File

@ -37,6 +37,7 @@
#include <asm/byteorder.h>
#ifndef do_csum
static inline unsigned short from32to16(unsigned int x)
{
/* add up 16-bit and 16-bit for 16+c bit */
@ -102,6 +103,7 @@ static unsigned int do_csum(const unsigned char *buff, int len)
out:
return result;
}
#endif
/*
* This is a version of ip_compute_csum() optimized for IP headers,