From fcfd2fbf22d2587196890103d41e3d554c47da0e Mon Sep 17 00:00:00 2001 From: George Spelvin Date: Fri, 20 May 2016 08:41:37 -0400 Subject: fs/namei.c: Add hashlen_string() function We'd like to make more use of the highly-optimized dcache hash functions throughout the kernel, rather than have every subsystem create its own, and a function that hashes basic null-terminated strings is required for that. (The name is to emphasize that it returns both hash and length.) It's actually useful in the dcache itself, specifically d_alloc_name(). Other uses in the next patch. full_name_hash() is also tweaked to make it more generally useful: 1) Take a "char *" rather than "unsigned char *" argument, to be consistent with hash_name(). 2) Handle zero-length inputs. If we want more callers, we don't want to make them worry about corner cases. Signed-off-by: George Spelvin --- include/linux/stringhash.h | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) (limited to 'include') diff --git a/include/linux/stringhash.h b/include/linux/stringhash.h index 2eaaaf6d2776..451771d9b9c0 100644 --- a/include/linux/stringhash.h +++ b/include/linux/stringhash.h @@ -1,7 +1,8 @@ #ifndef __LINUX_STRINGHASH_H #define __LINUX_STRINGHASH_H -#include +#include /* For __pure */ +#include /* For u32, u64 */ /* * Routines for hashing strings of bytes to a 32-bit hash value. @@ -59,7 +60,7 @@ static inline unsigned long end_name_hash(unsigned long hash) * * If not set, this falls back to a wrapper around the preceding. */ -extern unsigned int full_name_hash(const unsigned char *, unsigned int); +extern unsigned int __pure full_name_hash(const char *, unsigned int); /* * A hash_len is a u64 with the hash of a string in the low @@ -69,4 +70,7 @@ extern unsigned int full_name_hash(const unsigned char *, unsigned int); #define hashlen_len(hashlen) ((u32)((hashlen) >> 32)) #define hashlen_create(hash, len) ((u64)(len)<<32 | (u32)(hash)) +/* Return the "hash_len" (hash and length) of a null-terminated string */ +extern u64 __pure hashlen_string(const char *name); + #endif /* __LINUX_STRINGHASH_H */ -- cgit v1.2.3