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

39 files changed, 107 insertions, 95 deletions

diff --git a/drivers/staging/lustre/lustre/llite/statahead.c b/drivers/staging/lustre/lustre/llite/statahead.c
index f77524294c27..8e52722266fe 100644
--- a/drivers/staging/lustre/lustre/llite/statahead.c
+++ b/drivers/staging/lustre/lustre/llite/statahead.c
@@ -170,7 +170,8 @@ static inline int is_omitted_entry(struct ll_statahead_info *sai, __u64 index)
  * Insert it into sai_entries tail when init.
  */
 static struct ll_sa_entry *
-ll_sa_entry_alloc(struct ll_statahead_info *sai, __u64 index,
+ll_sa_entry_alloc(struct dentry *parent,
+                  struct ll_statahead_info *sai, __u64 index,
                   const char *name, int len)
 {
         struct ll_inode_info *lli;
@@ -217,7 +218,8 @@ ll_sa_entry_alloc(struct ll_statahead_info *sai, __u64 index,
         dname = (char *)entry + sizeof(struct ll_sa_entry);
         memcpy(dname, name, len);
         dname[len] = 0;
-        entry->se_qstr.hash = full_name_hash(name, len);
+
+        entry->se_qstr.hash = full_name_hash(parent, name, len);
         entry->se_qstr.len = len;
         entry->se_qstr.name = dname;
 
@@ -898,7 +900,7 @@ static void ll_statahead_one(struct dentry *parent, const char *entry_name,
         int                    rc;
         int                    rc1;
 
-        entry = ll_sa_entry_alloc(sai, sai->sai_index, entry_name,
+        entry = ll_sa_entry_alloc(parent, sai, sai->sai_index, entry_name,
                                   entry_name_len);
         if (IS_ERR(entry))
                 return;
diff --git a/fs/adfs/dir.c b/fs/adfs/dir.c
index fd4cf2c48e48..bec25f7017c0 100644
--- a/fs/adfs/dir.c
+++ b/fs/adfs/dir.c
@@ -207,7 +207,7 @@ adfs_hash(const struct dentry *parent, struct qstr *qstr)
          */
         qstr->len = i = name_len;
         name = qstr->name;
-        hash = init_name_hash();
+        hash = init_name_hash(parent);
         while (i--) {
                 char c;
 
diff --git a/fs/affs/namei.c b/fs/affs/namei.c
index 00d3002a6780..eb32029bc776 100644
--- a/fs/affs/namei.c
+++ b/fs/affs/namei.c
@@ -61,7 +61,7 @@ affs_get_toupper(struct super_block *sb)
  * Note: the dentry argument is the parent dentry.
  */
 static inline int
-__affs_hash_dentry(struct qstr *qstr, toupper_t toupper, bool notruncate)
+__affs_hash_dentry(const struct dentry *dentry, struct qstr *qstr, toupper_t toupper, bool notruncate)
 {
         const u8 *name = qstr->name;
         unsigned long hash;
@@ -72,7 +72,7 @@ __affs_hash_dentry(struct qstr *qstr, toupper_t toupper, bool notruncate)
         if (retval)
                 return retval;
 
-        hash = init_name_hash();
+        hash = init_name_hash(dentry);
         len = min(qstr->len, AFFSNAMEMAX);
         for (; len > 0; name++, len--)
                 hash = partial_name_hash(toupper(*name), hash);
@@ -84,7 +84,7 @@ __affs_hash_dentry(struct qstr *qstr, toupper_t toupper, bool notruncate)
 static int
 affs_hash_dentry(const struct dentry *dentry, struct qstr *qstr)
 {
-        return __affs_hash_dentry(qstr, affs_toupper,
+        return __affs_hash_dentry(dentry, qstr, affs_toupper,
                                   affs_nofilenametruncate(dentry));
 
 }
@@ -92,7 +92,7 @@ affs_hash_dentry(const struct dentry *dentry, struct qstr *qstr)
 static int
 affs_intl_hash_dentry(const struct dentry *dentry, struct qstr *qstr)
 {
-        return __affs_hash_dentry(qstr, affs_intl_toupper,
+        return __affs_hash_dentry(dentry, qstr, affs_intl_toupper,
                                   affs_nofilenametruncate(dentry));
 
 }
diff --git a/fs/autofs4/waitq.c b/fs/autofs4/waitq.c
index 631f1554c87b..708214457d16 100644
--- a/fs/autofs4/waitq.c
+++ b/fs/autofs4/waitq.c
@@ -398,7 +398,7 @@ int autofs4_wait(struct autofs_sb_info *sbi,
                 }
         }
         qstr.name = name;
-        qstr.hash = full_name_hash(name, qstr.len);
+        qstr.hash = full_name_hash(dentry, name, qstr.len);
 
         if (mutex_lock_interruptible(&sbi->wq_mutex)) {
                 kfree(qstr.name);
diff --git a/fs/ceph/inode.c b/fs/ceph/inode.c
index f059b5997072..99bdef66213a 100644
--- a/fs/ceph/inode.c
+++ b/fs/ceph/inode.c
@@ -1164,7 +1164,7 @@ int ceph_fill_trace(struct super_block *sb, struct ceph_mds_request *req,
 
                         dname.name = rinfo->dname;
                         dname.len = rinfo->dname_len;
-                        dname.hash = full_name_hash(dname.name, dname.len);
+                        dname.hash = full_name_hash(parent, dname.name, dname.len);
                         vino.ino = le64_to_cpu(rinfo->targeti.in->ino);
                         vino.snap = le64_to_cpu(rinfo->targeti.in->snapid);
 retry_lookup:
@@ -1508,7 +1508,7 @@ int ceph_readdir_prepopulate(struct ceph_mds_request *req,
 
                 dname.name = rde->name;
                 dname.len = rde->name_len;
-                dname.hash = full_name_hash(dname.name, dname.len);
+                dname.hash = full_name_hash(parent, dname.name, dname.len);
 
                 vino.ino = le64_to_cpu(rde->inode.in->ino);
                 vino.snap = le64_to_cpu(rde->inode.in->snapid);
diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index 2103b823bec0..4e8678a612b6 100644
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -3204,7 +3204,7 @@ static void handle_lease(struct ceph_mds_client *mdsc,
                 WARN_ON(1);
                 goto release;  /* hrm... */
         }
-        dname.hash = full_name_hash(dname.name, dname.len);
+        dname.hash = full_name_hash(parent, dname.name, dname.len);
         dentry = d_lookup(parent, &dname);
         dput(parent);
         if (!dentry)
diff --git a/fs/cifs/dir.c b/fs/cifs/dir.c
index fb0903fffc22..5efd6f1fb8a5 100644
--- a/fs/cifs/dir.c
+++ b/fs/cifs/dir.c
@@ -856,7 +856,7 @@ static int cifs_ci_hash(const struct dentry *dentry, struct qstr *q)
         wchar_t c;
         int i, charlen;
 
-        hash = init_name_hash();
+        hash = init_name_hash(dentry);
         for (i = 0; i < q->len; i += charlen) {
                 charlen = codepage->char2uni(&q->name[i], q->len - i, &c);
                 /* error out if we can't convert the character */
diff --git a/fs/dcache.c b/fs/dcache.c
index d6847d7b123d..24bf27d66f6e 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -104,11 +104,9 @@ static unsigned int d_hash_shift __read_mostly;
 
 static struct hlist_bl_head *dentry_hashtable __read_mostly;
 
-static inline struct hlist_bl_head *d_hash(const struct dentry *parent,
-                                        unsigned int hash)
+static inline struct hlist_bl_head *d_hash(unsigned int hash)
 {
-        hash += (unsigned long) parent / L1_CACHE_BYTES;
-        return dentry_hashtable + hash_32(hash, d_hash_shift);
+        return dentry_hashtable + (hash >> (32 - d_hash_shift));
 }
 
 #define IN_LOOKUP_SHIFT 10
@@ -488,7 +486,7 @@ void __d_drop(struct dentry *dentry)
                 if (unlikely(IS_ROOT(dentry)))
                         b = &dentry->d_sb->s_anon;
                 else
-                        b = d_hash(dentry->d_parent, dentry->d_name.hash);
+                        b = d_hash(dentry->d_name.hash);
 
                 hlist_bl_lock(b);
                 __hlist_bl_del(&dentry->d_hash);
@@ -1716,7 +1714,7 @@ struct dentry *d_alloc_name(struct dentry *parent, const char *name)
         struct qstr q;
 
         q.name = name;
-        q.hash_len = hashlen_string(name);
+        q.hash_len = hashlen_string(parent, name);
         return d_alloc(parent, &q);
 }
 EXPORT_SYMBOL(d_alloc_name);
@@ -2140,7 +2138,7 @@ struct dentry *__d_lookup_rcu(const struct dentry *parent,
 {
         u64 hashlen = name->hash_len;
         const unsigned char *str = name->name;
-        struct hlist_bl_head *b = d_hash(parent, hashlen_hash(hashlen));
+        struct hlist_bl_head *b = d_hash(hashlen_hash(hashlen));
         struct hlist_bl_node *node;
         struct dentry *dentry;
 
@@ -2257,7 +2255,7 @@ struct dentry *__d_lookup(const struct dentry *parent, const struct qstr *name)
         unsigned int len = name->len;
         unsigned int hash = name->hash;
         const unsigned char *str = name->name;
-        struct hlist_bl_head *b = d_hash(parent, hash);
+        struct hlist_bl_head *b = d_hash(hash);
         struct hlist_bl_node *node;
         struct dentry *found = NULL;
         struct dentry *dentry;
@@ -2337,7 +2335,7 @@ struct dentry *d_hash_and_lookup(struct dentry *dir, struct qstr *name)
          * calculate the standard hash first, as the d_op->d_hash()
          * routine may choose to leave the hash value unchanged.
          */
-        name->hash = full_name_hash(name->name, name->len);
+        name->hash = full_name_hash(dir, name->name, name->len);
         if (dir->d_flags & DCACHE_OP_HASH) {
                 int err = dir->d_op->d_hash(dir, name);
                 if (unlikely(err < 0))
@@ -2410,7 +2408,7 @@ static void __d_rehash(struct dentry * entry, struct hlist_bl_head *b)
 
 static void _d_rehash(struct dentry * entry)
 {
-        __d_rehash(entry, d_hash(entry->d_parent, entry->d_name.hash));
+        __d_rehash(entry, d_hash(entry->d_name.hash));
 }
 
 /**
@@ -2874,7 +2872,7 @@ static void __d_move(struct dentry *dentry, struct dentry *target,
          * for the same hash queue because of how unlikely it is.
          */
         __d_drop(dentry);
-        __d_rehash(dentry, d_hash(target->d_parent, target->d_name.hash));
+        __d_rehash(dentry, d_hash(target->d_name.hash));
 
         /*
          * Unhash the target (d_delete() is not usable here).  If exchanging
@@ -2882,8 +2880,7 @@ static void __d_move(struct dentry *dentry, struct dentry *target,
          */
         __d_drop(target);
         if (exchange) {
-                __d_rehash(target,
-                           d_hash(dentry->d_parent, dentry->d_name.hash));
+                __d_rehash(target, d_hash(dentry->d_name.hash));
         }
 
         /* Switch the names.. */
diff --git a/fs/efivarfs/super.c b/fs/efivarfs/super.c
index 9cb54a38832d..a5e607e8f056 100644
--- a/fs/efivarfs/super.c
+++ b/fs/efivarfs/super.c
@@ -65,7 +65,7 @@ static int efivarfs_d_compare(const struct dentry *parent,
 
 static int efivarfs_d_hash(const struct dentry *dentry, struct qstr *qstr)
 {
-        unsigned long hash = init_name_hash();
+        unsigned long hash = init_name_hash(dentry);
         const unsigned char *s = qstr->name;
         unsigned int len = qstr->len;
 
@@ -98,7 +98,7 @@ static struct dentry *efivarfs_alloc_dentry(struct dentry *parent, char *name)
         q.name = name;
         q.len = strlen(name);
 
-        err = efivarfs_d_hash(NULL, &q);
+        err = efivarfs_d_hash(parent, &q);
         if (err)
                 return ERR_PTR(err);
 
diff --git a/fs/fat/namei_msdos.c b/fs/fat/namei_msdos.c
index b7e2b33aa793..1337c0c7527d 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 7092584f424a..6ccdf3f34f90 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);
diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
index cbece1221417..203adf3b75db 100644
--- a/fs/fuse/dev.c
+++ b/fs/fuse/dev.c
@@ -1525,7 +1525,6 @@ static int fuse_notify_inval_entry(struct fuse_conn *fc, unsigned int size,
                 goto err;
         fuse_copy_finish(cs);
         buf[outarg.namelen] = 0;
-        name.hash = full_name_hash(name.name, name.len);
 
         down_read(&fc->killsb);
         err = -ENOENT;
@@ -1576,7 +1575,6 @@ static int fuse_notify_delete(struct fuse_conn *fc, unsigned int size,
                 goto err;
         fuse_copy_finish(cs);
         buf[outarg.namelen] = 0;
-        name.hash = full_name_hash(name.name, name.len);
 
         down_read(&fc->killsb);
         err = -ENOENT;
diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
index cca7b048c07b..5f1627725791 100644
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -955,6 +955,7 @@ int fuse_reverse_inval_entry(struct super_block *sb, u64 parent_nodeid,
         if (!dir)
                 goto unlock;
 
+        name->hash = full_name_hash(dir, name->name, name->len);
         entry = d_lookup(dir, name);
         dput(dir);
         if (!entry)
@@ -1204,7 +1205,7 @@ static int fuse_direntplus_link(struct file *file,
 
         fc = get_fuse_conn(dir);
 
-        name.hash = full_name_hash(name.name, name.len);
+        name.hash = full_name_hash(parent, name.name, name.len);
         dentry = d_lookup(parent, &name);
         if (!dentry) {
 retry:
diff --git a/fs/hfs/string.c b/fs/hfs/string.c
index 85b610c3909f..ec9f164c35a5 100644
--- a/fs/hfs/string.c
+++ b/fs/hfs/string.c
@@ -59,7 +59,7 @@ int hfs_hash_dentry(const struct dentry *dentry, struct qstr *this)
         if (len > HFS_NAMELEN)
                 len = HFS_NAMELEN;
 
-        hash = init_name_hash();
+        hash = init_name_hash(dentry);
         for (; len; len--)
                 hash = partial_name_hash(caseorder[*name++], hash);
         this->hash = end_name_hash(hash);
diff --git a/fs/hfsplus/unicode.c b/fs/hfsplus/unicode.c
index e8ef121a4d8b..c13c8a240be3 100644
--- a/fs/hfsplus/unicode.c
+++ b/fs/hfsplus/unicode.c
@@ -346,7 +346,7 @@ int hfsplus_hash_dentry(const struct dentry *dentry, struct qstr *str)
 
         casefold = test_bit(HFSPLUS_SB_CASEFOLD, &HFSPLUS_SB(sb)->flags);
         decompose = !test_bit(HFSPLUS_SB_NODECOMPOSE, &HFSPLUS_SB(sb)->flags);
-        hash = init_name_hash();
+        hash = init_name_hash(dentry);
         astr = str->name;
         len = str->len;
         while (len > 0) {
diff --git a/fs/hpfs/dentry.c b/fs/hpfs/dentry.c
index fa27980f2229..60e6d334d79a 100644
--- a/fs/hpfs/dentry.c
+++ b/fs/hpfs/dentry.c
@@ -26,7 +26,7 @@ static int hpfs_hash_dentry(const struct dentry *dentry, struct qstr *qstr)
                 /*return -ENOENT;*/
         x:
 
-        hash = init_name_hash();
+        hash = init_name_hash(dentry);
         for (i = 0; i < l; i++)
                 hash = partial_name_hash(hpfs_upcase(hpfs_sb(dentry->d_sb)->sb_cp_table,qstr->name[i]), hash);
         qstr->hash = end_name_hash(hash);
diff --git a/fs/isofs/inode.c b/fs/isofs/inode.c
index 131dedc920d8..761fade7680f 100644
--- a/fs/isofs/inode.c
+++ b/fs/isofs/inode.c
@@ -174,7 +174,7 @@ struct iso9660_options{
  * Compute the hash for the isofs name corresponding to the dentry.
  */
 static int
-isofs_hashi_common(struct qstr *qstr, int ms)
+isofs_hashi_common(const struct dentry *dentry, struct qstr *qstr, int ms)
 {
         const char *name;
         int len;
@@ -188,7 +188,7 @@ isofs_hashi_common(struct qstr *qstr, int ms)
                         len--;
         }
 
-        hash = init_name_hash();
+        hash = init_name_hash(dentry);
         while (len--) {
                 c = tolower(*name++);
                 hash = partial_name_hash(c, hash);
@@ -231,7 +231,7 @@ static int isofs_dentry_cmp_common(
 static int
 isofs_hashi(const struct dentry *dentry, struct qstr *qstr)
 {
-        return isofs_hashi_common(qstr, 0);
+        return isofs_hashi_common(dentry, qstr, 0);
 }
 
 static int
@@ -246,7 +246,7 @@ isofs_dentry_cmpi(const struct dentry *parent, const struct dentry *dentry,
  * Compute the hash for the isofs name corresponding to the dentry.
  */
 static int
-isofs_hash_common(struct qstr *qstr, int ms)
+isofs_hash_common(const struct dentry *dentry, struct qstr *qstr, int ms)
 {
         const char *name;
         int len;
@@ -258,7 +258,7 @@ isofs_hash_common(struct qstr *qstr, int ms)
                         len--;
         }
 
-        qstr->hash = full_name_hash(name, len);
+        qstr->hash = full_name_hash(dentry, name, len);
 
         return 0;
 }
@@ -266,13 +266,13 @@ isofs_hash_common(struct qstr *qstr, int ms)
 static int
 isofs_hash_ms(const struct dentry *dentry, struct qstr *qstr)
 {
-        return isofs_hash_common(qstr, 1);
+        return isofs_hash_common(dentry, qstr, 1);
 }
 
 static int
 isofs_hashi_ms(const struct dentry *dentry, struct qstr *qstr)
 {
-        return isofs_hashi_common(qstr, 1);
+        return isofs_hashi_common(dentry, qstr, 1);
 }
 
 static int
diff --git a/fs/jffs2/dir.c b/fs/jffs2/dir.c
index 84c4bf3631a2..30eb33ff8189 100644
--- a/fs/jffs2/dir.c
+++ b/fs/jffs2/dir.c
@@ -81,6 +81,7 @@ static struct dentry *jffs2_lookup(struct inode *dir_i, struct dentry *target,
         struct jffs2_full_dirent *fd = NULL, *fd_list;
         uint32_t ino = 0;
         struct inode *inode = NULL;
+        unsigned int nhash;
 
         jffs2_dbg(1, "jffs2_lookup()\n");
 
@@ -89,11 +90,14 @@ static struct dentry *jffs2_lookup(struct inode *dir_i, struct dentry *target,
 
         dir_f = JFFS2_INODE_INFO(dir_i);
 
+        /* The 'nhash' on the fd_list is not the same as the dentry hash */
+        nhash = full_name_hash(NULL, target->d_name.name, target->d_name.len);
+
         mutex_lock(&dir_f->sem);
 
         /* NB: The 2.2 backport will need to explicitly check for '.' and '..' here */
-        for (fd_list = dir_f->dents; fd_list && fd_list->nhash <= target->d_name.hash; fd_list = fd_list->next) {
-                if (fd_list->nhash == target->d_name.hash &&
+        for (fd_list = dir_f->dents; fd_list && fd_list->nhash <= nhash; fd_list = fd_list->next) {
+                if (fd_list->nhash == nhash &&
                     (!fd || fd_list->version > fd->version) &&
                     strlen(fd_list->name) == target->d_name.len &&
                     !strncmp(fd_list->name, target->d_name.name, target->d_name.len)) {
diff --git a/fs/jffs2/readinode.c b/fs/jffs2/readinode.c
index bfebbf13698c..06a71dbd4833 100644
--- a/fs/jffs2/readinode.c
+++ b/fs/jffs2/readinode.c
@@ -674,7 +674,7 @@ static inline int read_direntry(struct jffs2_sb_info *c, struct jffs2_raw_node_r
                 }
         }
 
-        fd->nhash = full_name_hash(fd->name, rd->nsize);
+        fd->nhash = full_name_hash(NULL, fd->name, rd->nsize);
         fd->next = NULL;
         fd->name[rd->nsize] = '\0';
 
diff --git a/fs/jffs2/scan.c b/fs/jffs2/scan.c
index 9ad5ba4b299b..90431dd613b8 100644
--- a/fs/jffs2/scan.c
+++ b/fs/jffs2/scan.c
@@ -1100,7 +1100,7 @@ static int jffs2_scan_dirent_node(struct jffs2_sb_info *c, struct jffs2_eraseblo
         fd->next = NULL;
         fd->version = je32_to_cpu(rd->version);
         fd->ino = je32_to_cpu(rd->ino);
-        fd->nhash = full_name_hash(fd->name, checkedlen);
+        fd->nhash = full_name_hash(NULL, fd->name, checkedlen);
         fd->type = rd->type;
         jffs2_add_fd_to_list(c, fd, &ic->scan_dents);
 
diff --git a/fs/jffs2/summary.c b/fs/jffs2/summary.c
index bc5385471a6e..be7c8a6a5748 100644
--- a/fs/jffs2/summary.c
+++ b/fs/jffs2/summary.c
@@ -476,7 +476,7 @@ static int jffs2_sum_process_sum_data(struct jffs2_sb_info *c, struct jffs2_eras
                                 fd->next = NULL;
                                 fd->version = je32_to_cpu(spd->version);
                                 fd->ino = je32_to_cpu(spd->ino);
-                                fd->nhash = full_name_hash(fd->name, checkedlen);
+                                fd->nhash = full_name_hash(NULL, fd->name, checkedlen);
                                 fd->type = spd->type;
 
                                 jffs2_add_fd_to_list(c, fd, &ic->scan_dents);
diff --git a/fs/jffs2/write.c b/fs/jffs2/write.c
index 7fb187ab2682..cda9a361368e 100644
--- a/fs/jffs2/write.c
+++ b/fs/jffs2/write.c
@@ -245,7 +245,7 @@ struct jffs2_full_dirent *jffs2_write_dirent(struct jffs2_sb_info *c, struct jff
 
         fd->version = je32_to_cpu(rd->version);
         fd->ino = je32_to_cpu(rd->ino);
-        fd->nhash = full_name_hash(name, namelen);
+        fd->nhash = full_name_hash(NULL, name, namelen);
         fd->type = rd->type;
         memcpy(fd->name, name, namelen);
         fd->name[namelen]=0;
@@ -598,7 +598,7 @@ int jffs2_do_unlink(struct jffs2_sb_info *c, struct jffs2_inode_info *dir_f,
                 jffs2_add_fd_to_list(c, fd, &dir_f->dents);
                 mutex_unlock(&dir_f->sem);
         } else {
-                uint32_t nhash = full_name_hash(name, namelen);
+                uint32_t nhash = full_name_hash(NULL, name, namelen);
 
                 fd = dir_f->dents;
                 /* We don't actually want to reserve any space, but we do
diff --git a/fs/jfs/namei.c b/fs/jfs/namei.c
index 539deddecbb0..04baf0dfc40c 100644
--- a/fs/jfs/namei.c
+++ b/fs/jfs/namei.c
@@ -1564,7 +1564,7 @@ static int jfs_ci_hash(const struct dentry *dir, struct qstr *this)
         unsigned long hash;
         int i;
 
-        hash = init_name_hash();
+        hash = init_name_hash(dir);
         for (i=0; i < this->len; i++)
                 hash = partial_name_hash(tolower(this->name[i]), hash);
         this->hash = end_name_hash(hash);
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)
diff --git a/fs/logfs/dir.c b/fs/logfs/dir.c
index 2d5336bd4efd..bcd754d216bd 100644
--- a/fs/logfs/dir.c
+++ b/fs/logfs/dir.c
@@ -95,7 +95,7 @@ static int beyond_eof(struct inode *inode, loff_t bix)
  * of each character and pick a prime nearby, preferably a bit-sparse
  * one.
  */
-static u32 hash_32(const char *s, int len, u32 seed)
+static u32 logfs_hash_32(const char *s, int len, u32 seed)
 {
         u32 hash = seed;
         int i;
@@ -159,7 +159,7 @@ static struct page *logfs_get_dd_page(struct inode *dir, struct dentry *dentry)
         struct qstr *name = &dentry->d_name;
         struct page *page;
         struct logfs_disk_dentry *dd;
-        u32 hash = hash_32(name->name, name->len, 0);
+        u32 hash = logfs_hash_32(name->name, name->len, 0);
         pgoff_t index;
         int round;
 
@@ -370,7 +370,7 @@ static int logfs_write_dir(struct inode *dir, struct dentry *dentry,
 {
         struct page *page;
         struct logfs_disk_dentry *dd;
-        u32 hash = hash_32(dentry->d_name.name, dentry->d_name.len, 0);
+        u32 hash = logfs_hash_32(dentry->d_name.name, dentry->d_name.len, 0);
         pgoff_t index;
         int round, err;
 
diff --git a/fs/namei.c b/fs/namei.c
index 70580ab1445c..7cb9be3e200a 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1890,9 +1890,9 @@ static inline unsigned int fold_hash(unsigned long x, unsigned long y)
  * payload bytes, to match the way that hash_name() iterates until it
  * finds the delimiter after the name.
  */
-unsigned int full_name_hash(const char *name, unsigned int len)
+unsigned int full_name_hash(const void *salt, const char *name, unsigned int len)
 {
-        unsigned long a, x = 0, y = 0;
+        unsigned long a, x = 0, y = (unsigned long)salt;
 
         for (;;) {
                 if (!len)
@@ -1911,15 +1911,19 @@ done:
 EXPORT_SYMBOL(full_name_hash);
 
 /* Return the "hash_len" (hash and length) of a null-terminated string */
-u64 hashlen_string(const char *name)
+u64 hashlen_string(const void *salt, const char *name)
 {
-        unsigned long a = 0, x = 0, y = 0, adata, mask, len;
+        unsigned long a = 0, x = 0, y = (unsigned long)salt;
+        unsigned long adata, mask, len;
         const struct word_at_a_time constants = WORD_AT_A_TIME_CONSTANTS;
 
-        len = -sizeof(unsigned long);
+        len = 0;
+        goto inside;
+
         do {
                 HASH_MIX(x, y, a);
                 len += sizeof(unsigned long);
+inside:
                 a = load_unaligned_zeropad(name+len);
         } while (!has_zero(a, &adata, &constants));
 
@@ -1935,15 +1939,19 @@ EXPORT_SYMBOL(hashlen_string);
  * Calculate the length and hash of the path component, and
  * return the "hash_len" as the result.
  */
-static inline u64 hash_name(const char *name)
+static inline u64 hash_name(const void *salt, const char *name)
 {
-        unsigned long a = 0, b, x = 0, y = 0, adata, bdata, mask, len;
+        unsigned long a = 0, b, x = 0, y = (unsigned long)salt;
+        unsigned long adata, bdata, mask, len;
         const struct word_at_a_time constants = WORD_AT_A_TIME_CONSTANTS;
 
-        len = -sizeof(unsigned long);
+        len = 0;
+        goto inside;
+
         do {
                 HASH_MIX(x, y, a);
                 len += sizeof(unsigned long);
+inside:
                 a = load_unaligned_zeropad(name+len);
                 b = a ^ REPEAT_BYTE('/');
         } while (!(has_zero(a, &adata, &constants) | has_zero(b, &bdata, &constants)));
@@ -1959,9 +1967,9 @@ static inline u64 hash_name(const char *name)
 #else   /* !CONFIG_DCACHE_WORD_ACCESS: Slow, byte-at-a-time version */
 
 /* Return the hash of a string of known length */
-unsigned int full_name_hash(const char *name, unsigned int len)
+unsigned int full_name_hash(const void *salt, const char *name, unsigned int len)
 {
-        unsigned long hash = init_name_hash();
+        unsigned long hash = init_name_hash(salt);
         while (len--)
                 hash = partial_name_hash((unsigned char)*name++, hash);
         return end_name_hash(hash);
@@ -1969,9 +1977,9 @@ unsigned int full_name_hash(const char *name, unsigned int len)
 EXPORT_SYMBOL(full_name_hash);
 
 /* Return the "hash_len" (hash and length) of a null-terminated string */
-u64 hashlen_string(const char *name)
+u64 hashlen_string(const void *salt, const char *name)
 {
-        unsigned long hash = init_name_hash();
+        unsigned long hash = init_name_hash(salt);
         unsigned long len = 0, c;
 
         c = (unsigned char)*name;
@@ -1988,9 +1996,9 @@ EXPORT_SYMBOL(hashlen_string);
  * We know there's a real path component here of at least
  * one character.
  */
-static inline u64 hash_name(const char *name)
+static inline u64 hash_name(const void *salt, const char *name)
 {
-        unsigned long hash = init_name_hash();
+        unsigned long hash = init_name_hash(salt);
         unsigned long len = 0, c;
 
         c = (unsigned char)*name;
@@ -2030,7 +2038,7 @@ static int link_path_walk(const char *name, struct nameidata *nd)
                 if (err)
                         return err;
 
-                hash_len = hash_name(name);
+                hash_len = hash_name(nd->path.dentry, name);
 
                 type = LAST_NORM;
                 if (name[0] == '.') switch (hashlen_len(hash_len)) {
@@ -2436,7 +2444,7 @@ struct dentry *lookup_one_len(const char *name, struct dentry *base, int len)
 
         this.name = name;
         this.len = len;
-        this.hash = full_name_hash(name, len);
+        this.hash = full_name_hash(base, name, len);
         if (!len)
                 return ERR_PTR(-EACCES);
 
@@ -2489,7 +2497,7 @@ struct dentry *lookup_one_len_unlocked(const char *name,
 
         this.name = name;
         this.len = len;
-        this.hash = full_name_hash(name, len);
+        this.hash = full_name_hash(base, name, len);
         if (!len)
                 return ERR_PTR(-EACCES);
 
diff --git a/fs/ncpfs/dir.c b/fs/ncpfs/dir.c
index bfdad003ee56..9add7ab747a5 100644
--- a/fs/ncpfs/dir.c
+++ b/fs/ncpfs/dir.c
@@ -139,7 +139,7 @@ ncp_hash_dentry(const struct dentry *dentry, struct qstr *this)
                 int i;
 
                 t = NCP_IO_TABLE(sb);
-                hash = init_name_hash();
+                hash = init_name_hash(dentry);
                 for (i=0; i<this->len ; i++)
                         hash = partial_name_hash(ncp_tolower(t, this->name[i]),
                                                                         hash);
diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index 19d93d0cd400..411375f3c585 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -232,7 +232,7 @@ int nfs_readdir_make_qstr(struct qstr *string, const char *name, unsigned int le
          * in a page cache page which kmemleak does not scan.
          */
         kmemleak_not_leak(string->name);
-        string->hash = full_name_hash(name, len);
+        string->hash = full_name_hash(NULL, name, len);
         return 0;
 }
 
@@ -502,7 +502,7 @@ void nfs_prime_dcache(struct dentry *parent, struct nfs_entry *entry)
                 if (filename.len == 2 && filename.name[1] == '.')
                         return;
         }
-        filename.hash = full_name_hash(filename.name, filename.len);
+        filename.hash = full_name_hash(parent, filename.name, filename.len);
 
         dentry = d_lookup(parent, &filename);
 again:
diff --git a/fs/ntfs/namei.c b/fs/ntfs/namei.c
index 443abecf01b7..358258364616 100644
--- a/fs/ntfs/namei.c
+++ b/fs/ntfs/namei.c
@@ -253,7 +253,7 @@ handle_name:
                 err = (signed)nls_name.len;
                 goto err_out;
         }
-        nls_name.hash = full_name_hash(nls_name.name, nls_name.len);
+        nls_name.hash = full_name_hash(dent, nls_name.name, nls_name.len);
 
         dent = d_add_ci(dent, dent_inode, &nls_name);
         kfree(nls_name.name);
diff --git a/fs/ocfs2/dlm/dlmcommon.h b/fs/ocfs2/dlm/dlmcommon.h
index 004f2cbe8f71..8107d0d0c3f6 100644
--- a/fs/ocfs2/dlm/dlmcommon.h
+++ b/fs/ocfs2/dlm/dlmcommon.h
@@ -47,7 +47,7 @@
 #define DLM_HASH_BUCKETS        (DLM_HASH_PAGES * DLM_BUCKETS_PER_PAGE)
 
 /* Intended to make it easier for us to switch out hash functions */
-#define dlm_lockid_hash(_n, _l) full_name_hash(_n, _l)
+#define dlm_lockid_hash(_n, _l) full_name_hash(NULL, _n, _l)
 
 enum dlm_mle_type {
         DLM_MLE_BLOCK = 0,
diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c
index 5e57c3e46e1d..b59db94d2ff4 100644
--- a/fs/proc/proc_sysctl.c
+++ b/fs/proc/proc_sysctl.c
@@ -623,7 +623,7 @@ static bool proc_sys_fill_cache(struct file *file,
 
         qname.name = table->procname;
         qname.len  = strlen(table->procname);
-        qname.hash = full_name_hash(qname.name, qname.len);
+        qname.hash = full_name_hash(dir, qname.name, qname.len);
 
         child = d_lookup(dir, &qname);
         if (!child) {
diff --git a/fs/sysv/namei.c b/fs/sysv/namei.c
index 90b60c03b588..a42de45ce40d 100644
--- a/fs/sysv/namei.c
+++ b/fs/sysv/namei.c
@@ -33,7 +33,7 @@ static int sysv_hash(const struct dentry *dentry, struct qstr *qstr)
            function. */
         if (qstr->len > SYSV_NAMELEN) {
                 qstr->len = SYSV_NAMELEN;
-                qstr->hash = full_name_hash(qstr->name, qstr->len);
+                qstr->hash = full_name_hash(dentry, qstr->name, qstr->len);
         }
         return 0;
 }
diff --git a/include/linux/stringhash.h b/include/linux/stringhash.h
index 451771d9b9c0..7c2d95170d01 100644
--- a/include/linux/stringhash.h
+++ b/include/linux/stringhash.h
@@ -3,6 +3,7 @@
 
 #include <linux/compiler.h>     /* For __pure */
 #include <linux/types.h>        /* For u32, u64 */
+#include <linux/hash.h>
 
 /*
  * Routines for hashing strings of bytes to a 32-bit hash value.
@@ -34,7 +35,7 @@
  */
 
 /* Hash courtesy of the R5 hash in reiserfs modulo sign bits */
-#define init_name_hash()                0
+#define init_name_hash(salt)            (unsigned long)(salt)
 
 /* partial hash update function. Assume roughly 4 bits per character */
 static inline unsigned long
@@ -45,11 +46,12 @@ partial_name_hash(unsigned long c, unsigned long prevhash)
 
 /*
  * Finally: cut down the number of bits to a int value (and try to avoid
- * losing bits)
+ * losing bits).  This also has the property (wanted by the dcache)
+ * that the msbits make a good hash table index.
  */
 static inline unsigned long end_name_hash(unsigned long hash)
 {
-        return (unsigned int)hash;
+        return __hash_32((unsigned int)hash);
 }
 
 /*
@@ -60,7 +62,7 @@ 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 __pure full_name_hash(const char *, unsigned int);
+extern unsigned int __pure full_name_hash(const void *salt, const char *, unsigned int);
 
 /*
  * A hash_len is a u64 with the hash of a string in the low
@@ -71,6 +73,6 @@ extern unsigned int __pure full_name_hash(const char *, unsigned int);
 #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);
+extern u64 __pure hashlen_string(const void *salt, const char *name);
 
 #endif  /* __LINUX_STRINGHASH_H */
diff --git a/include/linux/sunrpc/svcauth.h b/include/linux/sunrpc/svcauth.h
index 91d5a5d6f52b..d03932055328 100644
--- a/include/linux/sunrpc/svcauth.h
+++ b/include/linux/sunrpc/svcauth.h
@@ -172,12 +172,12 @@ extern void unix_gid_cache_destroy(struct net *net);
  */
 static inline unsigned long hash_str(char const *name, int bits)
 {
-        return hashlen_hash(hashlen_string(name)) >> (32 - bits);
+        return hashlen_hash(hashlen_string(NULL, name)) >> (32 - bits);
 }
 
 static inline unsigned long hash_mem(char const *buf, int length, int bits)
 {
-        return full_name_hash(buf, length) >> (32 - bits);
+        return full_name_hash(NULL, buf, length) >> (32 - bits);
 }
 
 #endif /* __KERNEL__ */
diff --git a/lib/test_hash.c b/lib/test_hash.c
index c9549c8b4909..66c5fc8351e8 100644
--- a/lib/test_hash.c
+++ b/lib/test_hash.c
@@ -155,8 +155,8 @@ test_hash_init(void)
                 buf[j] = '\0';
 
                 for (i = 0; i <= j; i++) {
-                        u64 hashlen = hashlen_string(buf+i);
-                        u32 h0 = full_name_hash(buf+i, j-i);
+                        u64 hashlen = hashlen_string(buf+i, buf+i);
+                        u32 h0 = full_name_hash(buf+i, buf+i, j-i);
 
                         /* Check that hashlen_string gets the length right */
                         if (hashlen_len(hashlen) != j-i) {
diff --git a/net/core/dev.c b/net/core/dev.c
index 2a9c39f8824e..4ce07dc25573 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -198,7 +198,7 @@ static inline void dev_base_seq_inc(struct net *net)
 
 static inline struct hlist_head *dev_name_hash(struct net *net, const char *name)
 {
-        unsigned int hash = full_name_hash(name, strnlen(name, IFNAMSIZ));
+        unsigned int hash = full_name_hash(net, name, strnlen(name, IFNAMSIZ));
 
         return &net->dev_name_head[hash_32(hash, NETDEV_HASHBITS)];
 }
diff --git a/security/smack/smack_access.c b/security/smack/smack_access.c
index a283f9e796c1..23e5808a0970 100644
--- a/security/smack/smack_access.c
+++ b/security/smack/smack_access.c
@@ -413,7 +413,7 @@ void smk_insert_entry(struct smack_known *skp)
         unsigned int hash;
         struct hlist_head *head;
 
-        hash = full_name_hash(skp->smk_known, strlen(skp->smk_known));
+        hash = full_name_hash(NULL, skp->smk_known, strlen(skp->smk_known));
         head = &smack_known_hash[hash & (SMACK_HASH_SLOTS - 1)];
 
         hlist_add_head_rcu(&skp->smk_hashed, head);
@@ -433,7 +433,7 @@ struct smack_known *smk_find_entry(const char *string)
         struct hlist_head *head;
         struct smack_known *skp;
 
-        hash = full_name_hash(string, strlen(string));
+        hash = full_name_hash(NULL, string, strlen(string));
         head = &smack_known_hash[hash & (SMACK_HASH_SLOTS - 1)];
 
         hlist_for_each_entry_rcu(skp, head, smk_hashed)
diff --git a/security/tomoyo/memory.c b/security/tomoyo/memory.c
index 0e995716cc25..1598b559ac42 100644
--- a/security/tomoyo/memory.c
+++ b/security/tomoyo/memory.c
@@ -154,7 +154,7 @@ const struct tomoyo_path_info *tomoyo_get_name(const char *name)
         if (!name)
                 return NULL;
         len = strlen(name) + 1;
-        hash = full_name_hash((const unsigned char *) name, len - 1);
+        hash = full_name_hash(NULL, (const unsigned char *) name, len - 1);
         head = &tomoyo_name_list[hash_long(hash, TOMOYO_HASH_BITS)];
         if (mutex_lock_interruptible(&tomoyo_policy_lock))
                 return NULL;
diff --git a/security/tomoyo/util.c b/security/tomoyo/util.c
index b974a6997d7f..5fe3679137ae 100644
--- a/security/tomoyo/util.c
+++ b/security/tomoyo/util.c
@@ -666,7 +666,7 @@ void tomoyo_fill_path_info(struct tomoyo_path_info *ptr)
         ptr->const_len = tomoyo_const_part_length(name);
         ptr->is_dir = len && (name[len - 1] == '/');
         ptr->is_patterned = (ptr->const_len < len);
-        ptr->hash = full_name_hash(name, len);
+        ptr->hash = full_name_hash(NULL, name, len);
 }
 
 /**