[PATCH v2] net: clean up some sparse endianness warnings in ipv6.h

Jeff Layton
2014-07-16T10:55:56Z

sparse is throwing warnings when building sunrpc modules due to some
endianness shenanigans in ipv6.h. Specifically:

CHECK net/sunrpc/addr.c
include/net/ipv6.h:573:17: warning: restricted __be64 degrades to integer
include/net/ipv6.h:577:34: warning: restricted __be32 degrades to integer
include/net/ipv6.h:573:17: warning: restricted __be64 degrades to integer
include/net/ipv6.h:577:34: warning: restricted __be32 degrades to integer

Sprinkle some endianness fixups to silence them. These should all get
fixed up at compile time, so I don't think this will add any extra work
to be done at runtime.

Signed-off-by: Jeff Layton <jlayton@primarydata.com>
---
include/net/ipv6.h | 17 +++++++++++------
1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/include/net/ipv6.h b/include/net/ipv6.h
index 574337fe72dd..0535da61fe0b 100644
--- a/include/net/ipv6.h
+++ b/include/net/ipv6.h
@@ -557,24 +557,29 @@ static inline u32 __ipv6_addr_jhash(const struct in6_addr *a, const u32 initval)
static inline bool ipv6_addr_loopback(const struct in6_addr *a)
{
#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && BITS_PER_LONG == 64
- const unsigned long *ul = (const unsigned long *)a;
+ const __be64 *be = (const __be64 *)a;

- return (ul[0] | (ul[1] ^ cpu_to_be64(1))) == 0UL;
+ return (be[0] | (be[1] ^ cpu_to_be64(1))) == 0UL;
#else
return (a->s6_addr32[0] | a->s6_addr32[1] |
- a->s6_addr32[2] | (a->s6_addr32[3] ^ htonl(1))) == 0;
+ a->s6_addr32[2] | (a->s6_addr32[3] ^ cpu_to_be32(1))) == 0;
#endif
}

+/*
+ * Note that we must __force cast these to unsigned long to make sparse happy,
+ * since all of the endian-annotated types are fixed size regardless of arch.
+ */
static inline bool ipv6_addr_v4mapped(const struct in6_addr *a)
{
return (
#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && BITS_PER_LONG == 64
- *(__be64 *)a |
+ *(unsigned long *)a |
#else
- (a->s6_addr32[0] | a->s6_addr32[1]) |
+ (__force unsigned long)(a->s6_addr32[0] | a->s6_addr32[1]) |
#endif
- (a->s6_addr32[2] ^ htonl(0x0000ffff))) == 0UL;
+ (__force unsigned long)(a->s6_addr32[2] ^
+ cpu_to_be32(0x0000ffff))) == 0UL;
}

/*
--
1.9.3