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>

2 files changed, 3 insertions, 3 deletions

diff --git a/fs/btrfs/export.c b/fs/btrfs/export.c
index 659f532d26a0..0ccf9a8afcdf 100644
--- a/fs/btrfs/export.c
+++ b/fs/btrfs/export.c
@@ -110,7 +110,7 @@ static struct dentry *btrfs_get_dentry(struct super_block *sb, u64 objectid,
 
         dentry = d_obtain_alias(inode);
         if (!IS_ERR(dentry))
-                dentry->d_op = &btrfs_dentry_operations;
+                d_set_d_op(dentry, &btrfs_dentry_operations);
         return dentry;
 fail:
         srcu_read_unlock(&fs_info->subvol_srcu, index);
@@ -225,7 +225,7 @@ static struct dentry *btrfs_get_parent(struct dentry *child)
         key.offset = 0;
         dentry = d_obtain_alias(btrfs_iget(root->fs_info->sb, &key, root, NULL));
         if (!IS_ERR(dentry))
-                dentry->d_op = &btrfs_dentry_operations;
+                d_set_d_op(dentry, &btrfs_dentry_operations);
         return dentry;
 fail:
         btrfs_free_path(path);
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index f9d2994a42a2..63e4546b478a 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -4084,7 +4084,7 @@ struct inode *btrfs_lookup_dentry(struct inode *dir, struct dentry *dentry)
         int index;
         int ret;
 
-        dentry->d_op = &btrfs_dentry_operations;
+        d_set_d_op(dentry, &btrfs_dentry_operations);
 
         if (dentry->d_name.len > BTRFS_NAME_LEN)
                 return ERR_PTR(-ENAMETOOLONG);