fs: dcache reduce branches in lookup path

[firefly-linux-kernel-4.4.55.git] / fs / dcache.c

diff --git a/fs/dcache.c b/fs/dcache.c
index 1d5cf511e1c7a4b379d179872ed0acd3c23eb0f7..f9693da3efbd73c36224bb14b982642425ae4a17 100644 (file)
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -398,7 +398,7 @@ repeat:
                return;
        }
 
-       if (dentry->d_op && dentry->d_op->d_delete) {
+       if (dentry->d_flags & DCACHE_OP_DELETE) {
                if (dentry->d_op->d_delete(dentry))
                        goto kill_it;
        }
@@ -1301,6 +1301,28 @@ struct dentry *d_alloc_name(struct dentry *parent, const char *name)
 }
 EXPORT_SYMBOL(d_alloc_name);
 
+void d_set_d_op(struct dentry *dentry, const struct dentry_operations *op)
+{
+       BUG_ON(dentry->d_op);
+       BUG_ON(dentry->d_flags & (DCACHE_OP_HASH        |
+                               DCACHE_OP_COMPARE       |
+                               DCACHE_OP_REVALIDATE    |
+                               DCACHE_OP_DELETE ));
+       dentry->d_op = op;
+       if (!op)
+               return;
+       if (op->d_hash)
+               dentry->d_flags |= DCACHE_OP_HASH;
+       if (op->d_compare)
+               dentry->d_flags |= DCACHE_OP_COMPARE;
+       if (op->d_revalidate)
+               dentry->d_flags |= DCACHE_OP_REVALIDATE;
+       if (op->d_delete)
+               dentry->d_flags |= DCACHE_OP_DELETE;
+
+}
+EXPORT_SYMBOL(d_set_d_op);
+
 static void __d_instantiate(struct dentry *dentry, struct inode *inode)
 {
        spin_lock(&dentry->d_lock);
@@ -1731,7 +1753,7 @@ seqretry:
                 */
                if (read_seqcount_retry(&dentry->d_seq, *seq))
                        goto seqretry;
-               if (parent->d_op && parent->d_op->d_compare) {
+               if (parent->d_flags & DCACHE_OP_COMPARE) {
                        if (parent->d_op->d_compare(parent, *inode,
                                                dentry, i,
                                                tlen, tname, name))
@@ -1846,7 +1868,7 @@ struct dentry *__d_lookup(struct dentry *parent, struct qstr *name)
                 */
                tlen = dentry->d_name.len;
                tname = dentry->d_name.name;
-               if (parent->d_op && parent->d_op->d_compare) {
+               if (parent->d_flags & DCACHE_OP_COMPARE) {
                        if (parent->d_op->d_compare(parent, parent->d_inode,
                                                dentry, dentry->d_inode,
                                                tlen, tname, name))
@@ -1887,7 +1909,7 @@ struct dentry *d_hash_and_lookup(struct dentry *dir, struct qstr *name)
         * routine may choose to leave the hash value unchanged.
         */
        name->hash = full_name_hash(name->name, name->len);
-       if (dir->d_op && dir->d_op->d_hash) {
+       if (dir->d_flags & DCACHE_OP_HASH) {
                if (dir->d_op->d_hash(dir, dir->d_inode, name) < 0)
                        goto out;
        }