Merge branch 'dentry-cleanups' (dcache access cleanups and optimizations)

This branch simplifies and clarifies the dcache lookup, and allows us to
do certain nice optimizations when comparing dentries.  It also cleans
up the interface to __d_lookup_rcu(), especially around passing the
inode information around.

* dentry-cleanups:
  vfs: make it possible to access the dentry hash/len as one 64-bit entry
  vfs: move dentry name length comparison from dentry_cmp() into callers
  vfs: do the careful dentry name access for all dentry_cmp cases
  vfs: remove unnecessary d_unhashed() check from __d_lookup_rcu
  vfs: clean up __d_lookup_rcu() and dentry_cmp() interfaces

1 files changed, 18 insertions, 3 deletions

diff --git a/include/linux/dcache.h b/include/linux/dcache.h
index 7e11f1418203..094789ff3e9f 100644
--- a/include/linux/dcache.h
+++ b/include/linux/dcache.h
@@ -25,6 +25,13 @@ struct vfsmount;
 
 #define IS_ROOT(x) ((x) == (x)->d_parent)
 
+/* The hash is always the low bits of hash_len */
+#ifdef __LITTLE_ENDIAN
+ #define HASH_LEN_DECLARE u32 hash; u32 len;
+#else
+ #define HASH_LEN_DECLARE u32 len; u32 hash;
+#endif
+
 /*
  * "quick string" -- eases parameter passing, but more importantly
  * saves "metadata" about the string (ie length and the hash).
@@ -33,11 +40,19 @@ struct vfsmount;
  * dentry.
  */
 struct qstr {
-	unsigned int hash;
-	unsigned int len;
+	union {
+		struct {
+			HASH_LEN_DECLARE;
+		};
+		u64 hash_len;
+	};
 	const unsigned char *name;
 };
 
+#define QSTR_INIT(n,l) { { { .len = l } }, .name = n }
+#define hashlen_hash(hashlen) ((u32) (hashlen))
+#define hashlen_len(hashlen)  ((u32)((hashlen) >> 32))
+
 struct dentry_stat_t {
 	int nr_dentry;
 	int nr_unused;
@@ -282,7 +297,7 @@ extern struct dentry *d_hash_and_lookup(struct dentry *, struct qstr *);
 extern struct dentry *__d_lookup(struct dentry *, struct qstr *);
 extern struct dentry *__d_lookup_rcu(const struct dentry *parent,
 				const struct qstr *name,
-				unsigned *seq, struct inode **inode);
+				unsigned *seq, struct inode *inode);
 
 /**
  * __d_rcu_to_refcount - take a refcount on dentry if sequence check is ok