selinux: reduce the object class calculations at inode init time

We only need to call inode_mode_to_security_class() once in
selinux_inode_init_security().
Reviewed-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>

security/selinux/hooks.c

@@ -2920,23 +2920,22 @@ static int selinux_inode_init_security(struct inode *inode, struct inode *dir,
 	struct superblock_security_struct *sbsec;
 	struct xattr *xattr = lsm_get_xattr_slot(xattrs, xattr_count);
 	u32 newsid, clen;
+	u16 newsclass;
 	int rc;
 	char *context;
 
 	sbsec = selinux_superblock(dir->i_sb);
 
 	newsid = tsec->create_sid;
-
-	rc = selinux_determine_inode_label(tsec, dir, qstr,
-		inode_mode_to_security_class(inode->i_mode),
-		&newsid);
+	newsclass = inode_mode_to_security_class(inode->i_mode);
+	rc = selinux_determine_inode_label(tsec, dir, qstr, newsclass, &newsid);
 	if (rc)
 		return rc;
 
 	/* Possibly defer initialization to selinux_complete_init. */
 	if (sbsec->flags & SE_SBINITIALIZED) {
 		struct inode_security_struct *isec = selinux_inode(inode);
-		isec->sclass = inode_mode_to_security_class(inode->i_mode);
+		isec->sclass = newsclass;
 		isec->sid = newsid;
 		isec->initialized = LABEL_INITIALIZED;
 	}