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, 2 insertions, 2 deletions

diff --git a/fs/sysv/namei.c b/fs/sysv/namei.c
index 7507aeb4c90e..b5e68da2db32 100644
--- a/fs/sysv/namei.c
+++ b/fs/sysv/namei.c
@@ -48,7 +48,7 @@ static struct dentry *sysv_lookup(struct inode * dir, struct dentry * dentry, st
         struct inode * inode = NULL;
         ino_t ino;
 
-        dentry->d_op = dir->i_sb->s_root->d_op;
+        d_set_d_op(dentry, dir->i_sb->s_root->d_op);
         if (dentry->d_name.len > SYSV_NAMELEN)
                 return ERR_PTR(-ENAMETOOLONG);
         ino = sysv_inode_by_name(dentry);
diff --git a/fs/sysv/super.c b/fs/sysv/super.c
index 3d9c62be0c10..76712aefc4ab 100644
--- a/fs/sysv/super.c
+++ b/fs/sysv/super.c
@@ -346,7 +346,7 @@ static int complete_read_super(struct super_block *sb, int silent, int size)
         if (sbi->s_forced_ro)
                 sb->s_flags |= MS_RDONLY;
         if (sbi->s_truncate)
-                sb->s_root->d_op = &sysv_dentry_operations;
+                d_set_d_op(sb->s_root, &sysv_dentry_operations);
         return 1;
 }