static struct hlist_bl_head *dentry_hashtable __read_mostly;
-static inline struct hlist_bl_head *d_hash(struct dentry *parent,
- unsigned long hash)
+static inline struct hlist_bl_head *d_hash(const struct dentry *parent,
+ unsigned int hash)
{
- hash += ((unsigned long) parent ^ GOLDEN_RATIO_PRIME) / L1_CACHE_BYTES;
- hash = hash ^ ((hash ^ GOLDEN_RATIO_PRIME) >> D_HASHBITS);
+ hash += (unsigned long) parent / L1_CACHE_BYTES;
+ hash = hash + (hash >> D_HASHBITS);
return dentry_hashtable + (hash & D_HASHMASK);
}
}
#endif
+/*
+ * Compare 2 name strings, return 0 if they match, otherwise non-zero.
+ * The strings are both count bytes long, and count is non-zero.
+ */
+static inline int dentry_cmp(const unsigned char *cs, size_t scount,
+ const unsigned char *ct, size_t tcount)
+{
+#ifdef CONFIG_DCACHE_WORD_ACCESS
+ unsigned long a,b,mask;
+
+ if (unlikely(scount != tcount))
+ return 1;
+
+ for (;;) {
+ a = *(unsigned long *)cs;
+ b = *(unsigned long *)ct;
+ if (tcount < sizeof(unsigned long))
+ break;
+ if (unlikely(a != b))
+ return 1;
+ cs += sizeof(unsigned long);
+ ct += sizeof(unsigned long);
+ tcount -= sizeof(unsigned long);
+ if (!tcount)
+ return 0;
+ }
+ mask = ~(~0ul << tcount*8);
+ return unlikely(!!((a ^ b) & mask));
+#else
+ if (scount != tcount)
+ return 1;
+
+ do {
+ if (*cs != *ct)
+ return 1;
+ cs++;
+ ct++;
+ tcount--;
+ } while (tcount);
+ return 0;
+#endif
+}
+
static void __d_free(struct rcu_head *head)
{
struct dentry *dentry = container_of(head, struct dentry, d_u.d_rcu);
* child is looked up. Thus, an interlocking stepping of sequence lock checks
* is formed, giving integrity down the path walk.
*/
-struct dentry *__d_lookup_rcu(struct dentry *parent, struct qstr *name,
- unsigned *seq, struct inode **inode)
+struct dentry *__d_lookup_rcu(const struct dentry *parent,
+ const struct qstr *name,
+ unsigned *seqp, struct inode **inode)
{
unsigned int len = name->len;
unsigned int hash = name->hash;
* See Documentation/filesystems/path-lookup.txt for more details.
*/
hlist_bl_for_each_entry_rcu(dentry, node, b, d_hash) {
+ unsigned seq;
struct inode *i;
const char *tname;
int tlen;
continue;
seqretry:
- *seq = read_seqcount_begin(&dentry->d_seq);
+ seq = read_seqcount_begin(&dentry->d_seq);
if (dentry->d_parent != parent)
continue;
if (d_unhashed(dentry))
* edge of memory when walking. If we could load this
* atomically some other way, we could drop this check.
*/
- if (read_seqcount_retry(&dentry->d_seq, *seq))
+ if (read_seqcount_retry(&dentry->d_seq, seq))
goto seqretry;
if (unlikely(parent->d_flags & DCACHE_OP_COMPARE)) {
if (parent->d_op->d_compare(parent, *inode,
* order to do anything useful with the returned dentry
* anyway.
*/
+ *seqp = seq;
*inode = i;
return dentry;
}