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authorLinus Torvalds <torvalds@linux-foundation.org>2016-06-10 07:51:30 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2016-06-10 20:21:46 -0700
commit8387ff2577eb9ed245df9a39947f66976c6bcd02 (patch)
tree79fafcb5777f16e520d1c39e9389039f866b4c6d /fs/kernfs
parent147d9e7bcad3b8d5465f6eea6292731e7f35dee8 (diff)
downloadlwn-8387ff2577eb9ed245df9a39947f66976c6bcd02.tar.gz
lwn-8387ff2577eb9ed245df9a39947f66976c6bcd02.zip
vfs: make the string hashes salt the hash
We always mixed in the parent pointer into the dentry name hash, but we did it late at lookup time. It turns out that we can simplify that lookup-time action by salting the hash with the parent pointer early instead of late. A few other users of our string hashes also wanted to mix in their own pointers into the hash, and those are updated to use the same mechanism. Hash users that don't have any particular initial salt can just use the NULL pointer as a no-salt. Cc: Vegard Nossum <vegard.nossum@oracle.com> Cc: George Spelvin <linux@sciencehorizons.net> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/kernfs')
-rw-r--r--fs/kernfs/dir.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c
index 8a652404eef6..e57174d43683 100644
--- a/fs/kernfs/dir.c
+++ b/fs/kernfs/dir.c
@@ -336,11 +336,11 @@ struct kernfs_node *kernfs_get_parent(struct kernfs_node *kn)
*/
static unsigned int kernfs_name_hash(const char *name, const void *ns)
{
- unsigned long hash = init_name_hash();
+ unsigned long hash = init_name_hash(ns);
unsigned int len = strlen(name);
while (len--)
hash = partial_name_hash(*name++, hash);
- hash = (end_name_hash(hash) ^ hash_ptr((void *)ns, 31));
+ hash = end_name_hash(hash);
hash &= 0x7fffffffU;
/* Reserve hash numbers 0, 1 and INT_MAX for magic directory entries */
if (hash < 2)