btrfs: simplify list initialization in btrfs_compr_pool_scan()

In btrfs_compr_pool_scan(), use LIST_HEAD() to declare and initialize
the 'remove' list_head in one step instead of using INIT_LIST_HEAD()
separately.

Signed-off-by: Baolin Liu <liubaolin@kylinos.cn>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

Author: murphy12138

fs/btrfs/compression.c

@@ -192,15 +192,13 @@ static unsigned long btrfs_compr_pool_count(struct shrinker *sh, struct shrink_c
 
 static unsigned long btrfs_compr_pool_scan(struct shrinker *sh, struct shrink_control *sc)
 {
-	struct list_head remove;
+	LIST_HEAD(remove);
 	struct list_head *tmp, *next;
 	int freed;
 
 	if (compr_pool.count == 0)
 		return SHRINK_STOP;
 
-	INIT_LIST_HEAD(&remove);
-
 	/* For now, just simply drain the whole list. */
 	spin_lock(&compr_pool.lock);
 	list_splice_init(&compr_pool.list, &remove);