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authorLinus Torvalds <torvalds@linux-foundation.org>2016-07-28 12:26:31 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2016-07-28 12:26:31 -0700
commit554828ee0db41618d101d9549db8808af9fd9d65 (patch)
tree8a3e3022c084f7c7c1eebc494a1b94f0ee0d5cae /fs/fat
parent194dc870a5890e855ecffb30f3b80ba7c88f96d6 (diff)
parent703b5faf22fbddf984a361e6555f3a03fdba63d9 (diff)
downloadop-kernel-dev-554828ee0db41618d101d9549db8808af9fd9d65.zip
op-kernel-dev-554828ee0db41618d101d9549db8808af9fd9d65.tar.gz
Merge branch 'salted-string-hash'
This changes the vfs dentry hashing to mix in the parent pointer at the _beginning_ of the hash, rather than at the end. That actually improves both the hash and the code generation, because we can move more of the computation to the "static" part of the dcache setup, and do less at lookup runtime. It turns out that a lot of other hash users also really wanted to mix in a base pointer as a 'salt' for the hash, and so the slightly extended interface ends up working well for other cases too. Users that want a string hash that is purely about the string pass in a 'salt' pointer of NULL. * merge branch 'salted-string-hash': fs/dcache.c: Save one 32-bit multiply in dcache lookup vfs: make the string hashes salt the hash
Diffstat (limited to 'fs/fat')
-rw-r--r--fs/fat/namei_msdos.c2
-rw-r--r--fs/fat/namei_vfat.c4
2 files changed, 3 insertions, 3 deletions
diff --git a/fs/fat/namei_msdos.c b/fs/fat/namei_msdos.c
index b7e2b33..1337c0c 100644
--- a/fs/fat/namei_msdos.c
+++ b/fs/fat/namei_msdos.c
@@ -154,7 +154,7 @@ static int msdos_hash(const struct dentry *dentry, struct qstr *qstr)
error = msdos_format_name(qstr->name, qstr->len, msdos_name, options);
if (!error)
- qstr->hash = full_name_hash(msdos_name, MSDOS_NAME);
+ qstr->hash = full_name_hash(dentry, msdos_name, MSDOS_NAME);
return 0;
}
diff --git a/fs/fat/namei_vfat.c b/fs/fat/namei_vfat.c
index 7092584..6ccdf3f 100644
--- a/fs/fat/namei_vfat.c
+++ b/fs/fat/namei_vfat.c
@@ -107,7 +107,7 @@ static unsigned int vfat_striptail_len(const struct qstr *qstr)
*/
static int vfat_hash(const struct dentry *dentry, struct qstr *qstr)
{
- qstr->hash = full_name_hash(qstr->name, vfat_striptail_len(qstr));
+ qstr->hash = full_name_hash(dentry, qstr->name, vfat_striptail_len(qstr));
return 0;
}
@@ -127,7 +127,7 @@ static int vfat_hashi(const struct dentry *dentry, struct qstr *qstr)
name = qstr->name;
len = vfat_striptail_len(qstr);
- hash = init_name_hash();
+ hash = init_name_hash(dentry);
while (len--)
hash = partial_name_hash(nls_tolower(t, *name++), hash);
qstr->hash = end_name_hash(hash);
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