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>

1 files changed, 3 insertions, 3 deletions

diff --git a/fs/fat/namei_msdos.c b/fs/fat/namei_msdos.c
index 3b3e072d8982..35ffe43afa4b 100644
--- a/fs/fat/namei_msdos.c
+++ b/fs/fat/namei_msdos.c
@@ -227,10 +227,10 @@ static struct dentry *msdos_lookup(struct inode *dir, struct dentry *dentry,
         }
 out:
         unlock_super(sb);
-        dentry->d_op = &msdos_dentry_operations;
+        d_set_d_op(dentry, &msdos_dentry_operations);
         dentry = d_splice_alias(inode, dentry);
         if (dentry)
-                dentry->d_op = &msdos_dentry_operations;
+                d_set_d_op(dentry, &msdos_dentry_operations);
         return dentry;
 
 error:
@@ -673,7 +673,7 @@ static int msdos_fill_super(struct super_block *sb, void *data, int silent)
         }
 
         sb->s_flags |= MS_NOATIME;
-        sb->s_root->d_op = &msdos_dentry_operations;
+        d_set_d_op(sb->s_root, &msdos_dentry_operations);
         unlock_super(sb);
         return 0;
 }