fs: dcache reduce branches in lookup path
Reduce some branches and memory accesses in dcache lookup by adding dentry
flags to indicate common d_ops are set, rather than having to check them.
This saves a pointer memory access (dentry->d_op) in common path lookup
situations, and saves another pointer load and branch in cases where we
have d_op but not the particular operation.
Patched with:
git grep -E '[.>]([[:space:]])*d_op([[:space:]])*=' | xargs sed -e 's/\([^\t ]*\)->d_op = \(.*\);/d_set_d_op(\1, \2);/' -e 's/\([^\t ]*\)\.d_op = \(.*\);/d_set_d_op(\&\1, \2);/' -i
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
diff --git a/include/linux/dcache.h b/include/linux/dcache.h
index e441469..f4b40a7 100644
--- a/include/linux/dcache.h
+++ b/include/linux/dcache.h
@@ -183,6 +183,11 @@
#define DCACHE_GENOCIDE 0x0200
#define DCACHE_MOUNTED 0x0400 /* is a mountpoint */
+#define DCACHE_OP_HASH 0x1000
+#define DCACHE_OP_COMPARE 0x2000
+#define DCACHE_OP_REVALIDATE 0x4000
+#define DCACHE_OP_DELETE 0x8000
+
extern spinlock_t dcache_inode_lock;
extern seqlock_t rename_lock;
@@ -201,6 +206,7 @@
extern void __d_drop(struct dentry *dentry);
extern void d_drop(struct dentry *dentry);
extern void d_delete(struct dentry *);
+extern void d_set_d_op(struct dentry *dentry, const struct dentry_operations *op);
/* allocate/de-allocate */
extern struct dentry * d_alloc(struct dentry *, const struct qstr *);