commit fb045adb99d9b7c562dc7fef834857f78249daa1
author Nick Piggin <npiggin@kernel.dk> Fri Jan 07 17:49:55 2011 +1100
committer Nick Piggin <npiggin@kernel.dk> Fri Jan 07 17:50:28 2011 +1100
tree 1fd6a4024fffeec568abe100d730589bfdb81c38
parent 5f57cbcc02cf18f6b22ef4066bb10afeb8f930ff

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>

fs/fat/inode.c

diff --git a/fs/fat/inode.c b/fs/fat/inode.c
index 8cccfeb..206351a 100644
--- a/fs/fat/inode.c
+++ b/fs/fat/inode.c
@@ -750,7 +750,7 @@
 	 */
 	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 @@
 
 	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);
 

fs/fat/namei_msdos.c

diff --git a/fs/fat/namei_msdos.c b/fs/fat/namei_msdos.c
index 3b3e072..35ffe43 100644
--- a/fs/fat/namei_msdos.c
+++ b/fs/fat/namei_msdos.c
@@ -227,10 +227,10 @@
 	}
 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 @@
 	}
 
 	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;
 }

fs/fat/namei_vfat.c

diff --git a/fs/fat/namei_vfat.c b/fs/fat/namei_vfat.c
index 4fc0627..3be5ed7 100644
--- a/fs/fat/namei_vfat.c
+++ b/fs/fat/namei_vfat.c
@@ -766,11 +766,11 @@
 
 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 @@
 	}
 
 	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;