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authorWill Deacon <will.deacon@arm.com>2013-12-12 17:40:21 +0000
committerLinus Torvalds <torvalds@linux-foundation.org>2013-12-12 10:39:01 -0800
commita5c21dcefa1c3d759457a604b3cfc4af29c8713f (patch)
tree6832dfcb836f8d5043ba70f17a0ea9c2c428bc4d /include
parent319720f534d88039615bceb88d4bc094a7cd4ce9 (diff)
dcache: allow word-at-a-time name hashing with big-endian CPUs
When explicitly hashing the end of a string with the word-at-a-time interface, we have to be careful which end of the word we pick up. On big-endian CPUs, the upper-bits will contain the data we're after, so ensure we generate our masks accordingly (and avoid hashing whatever random junk may have been sitting after the string). This patch adds a new dcache helper, bytemask_from_count, which creates a mask appropriate for the CPU endianness. Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include')
-rw-r--r--include/linux/dcache.h2
1 files changed, 2 insertions, 0 deletions
diff --git a/include/linux/dcache.h b/include/linux/dcache.h
index 57e87e749a48..bf72e9ac6de0 100644
--- a/include/linux/dcache.h
+++ b/include/linux/dcache.h
@@ -29,8 +29,10 @@ struct vfsmount;
/* The hash is always the low bits of hash_len */
#ifdef __LITTLE_ENDIAN
#define HASH_LEN_DECLARE u32 hash; u32 len;
+ #define bytemask_from_count(cnt) (~(~0ul << (cnt)*8))
#else
#define HASH_LEN_DECLARE u32 len; u32 hash;
+ #define bytemask_from_count(cnt) (~(~0ul >> (cnt)*8))
#endif
/*