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>

3 files changed, 9 insertions, 9 deletions

diff --git a/fs/fat/inode.c b/fs/fat/inode.c
index 8cccfebee180..206351af7c58 100644
--- a/fs/fat/inode.c
+++ b/fs/fat/inode.c
@@ -750,7 +750,7 @@ static struct dentry *fat_fh_to_dentry(struct super_block *sb,
          */
         result = d_obtain_alias(inode);
         if (!IS_ERR(result))
-                result->d_op = sb->s_root->d_op;
+                d_set_d_op(result, sb->s_root->d_op);
         return result;
 }
 
@@ -800,7 +800,7 @@ static struct dentry *fat_get_parent(struct dentry *child)
 
         parent = d_obtain_alias(inode);
         if (!IS_ERR(parent))
-                parent->d_op = sb->s_root->d_op;
+                d_set_d_op(parent, sb->s_root->d_op);
 out:
         unlock_super(sb);
 
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;
 }
diff --git a/fs/fat/namei_vfat.c b/fs/fat/namei_vfat.c
index 4fc06278db48..3be5ed7d859f 100644
--- a/fs/fat/namei_vfat.c
+++ b/fs/fat/namei_vfat.c
@@ -766,11 +766,11 @@ static struct dentry *vfat_lookup(struct inode *dir, struct dentry *dentry,
 
 out:
         unlock_super(sb);
-        dentry->d_op = sb->s_root->d_op;
+        d_set_d_op(dentry, sb->s_root->d_op);
         dentry->d_time = dentry->d_parent->d_inode->i_version;
         dentry = d_splice_alias(inode, dentry);
         if (dentry) {
-                dentry->d_op = sb->s_root->d_op;
+                d_set_d_op(dentry, sb->s_root->d_op);
                 dentry->d_time = dentry->d_parent->d_inode->i_version;
         }
         return dentry;
@@ -1072,9 +1072,9 @@ static int vfat_fill_super(struct super_block *sb, void *data, int silent)
         }
 
         if (MSDOS_SB(sb)->options.name_check != 's')
-                sb->s_root->d_op = &vfat_ci_dentry_ops;
+                d_set_d_op(sb->s_root, &vfat_ci_dentry_ops);
         else
-                sb->s_root->d_op = &vfat_dentry_ops;
+                d_set_d_op(sb->s_root, &vfat_dentry_ops);
 
         unlock_super(sb);
         return 0;