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>
diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c
index 998e3a7..35efd85 100644
--- a/fs/proc/proc_sysctl.c
+++ b/fs/proc/proc_sysctl.c
@@ -120,7 +120,7 @@
 		goto out;
 
 	err = NULL;
-	dentry->d_op = &proc_sys_dentry_operations;
+	d_set_d_op(dentry, &proc_sys_dentry_operations);
 	d_add(dentry, inode);
 
 out:
@@ -201,7 +201,7 @@
 				dput(child);
 				return -ENOMEM;
 			} else {
-				child->d_op = &proc_sys_dentry_operations;
+				d_set_d_op(child, &proc_sys_dentry_operations);
 				d_add(child, inode);
 			}
 		} else {