f2fs: introduce release_discard_addr() for cleanup

Introduce release_discard_addr() to include common codes for cleanup.
Signed-off-by: Chao Yu <yuchao0@huawei.com>
[Fengguang Wu: declare static function, reported by kbuild test robot]
Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/segment.c

@@ -1581,16 +1581,20 @@ static bool add_discard_addrs(struct f2fs_sb_info *sbi, struct cp_control *cpc,
 	return false;
 }
 
+static void release_discard_addr(struct discard_entry *entry)
+{
+	list_del(&entry->list);
+	kmem_cache_free(discard_entry_slab, entry);
+}
+
 void release_discard_addrs(struct f2fs_sb_info *sbi)
 {
 	struct list_head *head = &(SM_I(sbi)->dcc_info->entry_list);
 	struct discard_entry *entry, *this;
 
 	/* drop caches */
-	list_for_each_entry_safe(entry, this, head, list) {
-		list_del(&entry->list);
-		kmem_cache_free(discard_entry_slab, entry);
-	}
+	list_for_each_entry_safe(entry, this, head, list)
+		release_discard_addr(entry);
 }
 
 /*
@@ -1690,9 +1694,8 @@ void clear_prefree_segments(struct f2fs_sb_info *sbi, struct cp_control *cpc)
 		if (cur_pos < sbi->blocks_per_seg)
 			goto find_next;
 
-		list_del(&entry->list);
+		release_discard_addr(entry);
 		dcc->nr_discards -= total_len;
-		kmem_cache_free(discard_entry_slab, entry);
 	}
 
 	wake_up_discard_thread(sbi, false);