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authorGeorge Spelvin <linux@sciencehorizons.net>2016-05-20 08:41:37 -0400
committerGeorge Spelvin <linux@sciencehorizons.net>2016-05-28 15:42:50 -0400
commitfcfd2fbf22d2587196890103d41e3d554c47da0e (patch)
treed8e67346881f72e06782c08305b88c8ce167b698 /include/linux/stringhash.h
parentf4bcbe792b8f434e32487cff9d9e30ab45a3ce02 (diff)
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 <linux@sciencehorizons.net>
Diffstat (limited to 'include/linux/stringhash.h')
-rw-r--r--include/linux/stringhash.h8
1 files changed, 6 insertions, 2 deletions
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 <linux/types.h>
+#include <linux/compiler.h> /* For __pure */
+#include <linux/types.h> /* 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 */