fs: load the ->i_sb pointer once in inode_sb_list_{add,del}

While this may sound like a pedantic clean up, it does in fact impact
code generation -- the patched add routine is slightly smaller.

Signed-off-by: Mateusz Guzik <mjguzik@gmail.com>
Link: https://lore.kernel.org/r/20250319004635.1820589-1-mjguzik@gmail.com
Signed-off-by: Christian Brauner <brauner@kernel.org>

Author: mjguzik

fs/inode.c

@@ -623,18 +623,22 @@ static void inode_wait_for_lru_isolating(struct inode *inode)
  */
 void inode_sb_list_add(struct inode *inode)
 {
-	spin_lock(&inode->i_sb->s_inode_list_lock);
-	list_add(&inode->i_sb_list, &inode->i_sb->s_inodes);
-	spin_unlock(&inode->i_sb->s_inode_list_lock);
+	struct super_block *sb = inode->i_sb;
+
+	spin_lock(&sb->s_inode_list_lock);
+	list_add(&inode->i_sb_list, &sb->s_inodes);
+	spin_unlock(&sb->s_inode_list_lock);
 }
 EXPORT_SYMBOL_GPL(inode_sb_list_add);
 
 static inline void inode_sb_list_del(struct inode *inode)
 {
+	struct super_block *sb = inode->i_sb;
+
 	if (!list_empty(&inode->i_sb_list)) {
-		spin_lock(&inode->i_sb->s_inode_list_lock);
+		spin_lock(&sb->s_inode_list_lock);
 		list_del_init(&inode->i_sb_list);
-		spin_unlock(&inode->i_sb->s_inode_list_lock);
+		spin_unlock(&sb->s_inode_list_lock);
 	}
 }