btrfs: use list_first_entry() everywhere

Using the helper makes it a bit more clear that we're accessing the
first list entry.

Reviewed-by: Qu Wenruo <[e-mail]>
Signed-off-by: David Sterba <[e-mail]>

fs/btrfs/async-thread.c

···
 		spin_lock_irqsave(lock, flags);
 		if (list_empty(list))
 			break;
-		work = list_entry(list->next, struct btrfs_work,
-				  ordered_list);
+		work = list_first_entry(list, struct btrfs_work, ordered_list);
 		if (!test_bit(WORK_DONE_BIT, &work->flags))
 			break;
 		/*

fs/btrfs/backref.c

···
 		return;
 
 	while (!list_empty(&node->upper)) {
-		edge = list_entry(node->upper.next, struct btrfs_backref_edge,
-				  list[LOWER]);
+		edge = list_first_entry(&node->upper, struct btrfs_backref_edge,
+					list[LOWER]);
 		list_del(&edge->list[LOWER]);
 		list_del(&edge->list[UPPER]);
 		btrfs_backref_free_edge(cache, edge);
···
 		 * type BTRFS_TREE_BLOCK_REF_KEY
 		 */
 		ASSERT(list_is_singular(&cur->upper));
-		edge = list_entry(cur->upper.next, struct btrfs_backref_edge,
-				  list[LOWER]);
+		edge = list_first_entry(&cur->upper, struct btrfs_backref_edge,
+					list[LOWER]);
 		ASSERT(list_empty(&edge->list[UPPER]));
 		exist = edge->node[UPPER];
 		/*

fs/btrfs/block-group.c

···
 
 	write_lock(&info->block_group_cache_lock);
 	while (!list_empty(&info->caching_block_groups)) {
-		caching_ctl = list_entry(info->caching_block_groups.next,
-					 struct btrfs_caching_control, list);
+		caching_ctl = list_first_entry(&info->caching_block_groups,
+					       struct btrfs_caching_control, list);
 		list_del(&caching_ctl->list);
 		btrfs_put_caching_control(caching_ctl);
 	}
···
 	btrfs_release_global_block_rsv(info);
 
 	while (!list_empty(&info->space_info)) {
-		space_info = list_entry(info->space_info.next,
-					struct btrfs_space_info,
-					list);
+		space_info = list_first_entry(&info->space_info,
+					      struct btrfs_space_info, list);
 
 		/*
 		 * Do not hide this behind enospc_debug, this is actually

fs/btrfs/disk-io.c

···
 	int i;
 
 	while (!list_empty(&fs_info->dead_roots)) {
-		gang[0] = list_entry(fs_info->dead_roots.next,
-				     struct btrfs_root, root_list);
+		gang[0] = list_first_entry(&fs_info->dead_roots,
+					   struct btrfs_root, root_list);
 		list_del(&gang[0]->root_list);
 
 		if (test_bit(BTRFS_ROOT_IN_RADIX, &gang[0]->state))

fs/btrfs/extent-io-tree.c

···
 	struct extent_state *state;
 
 	while (!list_empty(&states)) {
-		state = list_entry(states.next, struct extent_state, leak_list);
+		state = list_first_entry(&states, struct extent_state, leak_list);
 		pr_err("BTRFS: state leak: start %llu end %llu state %u in tree %d refs %d\n",
 		       state->start, state->end, state->state,
 		       extent_state_in_tree(state),

fs/btrfs/free-space-cache.c

···
 
 	/* Get the cluster for this block_group if it exists */
 	if (block_group && !list_empty(&block_group->cluster_list)) {
-		cluster = list_entry(block_group->cluster_list.next,
-				     struct btrfs_free_cluster,
-				     block_group_list);
+		cluster = list_first_entry(&block_group->cluster_list,
+					   struct btrfs_free_cluster, block_group_list);
 	}
 
 	if (!node && cluster) {
···
 		struct rb_node *node;
 		struct btrfs_free_space *entry;
 
-		cluster = list_entry(block_group->cluster_list.next,
-				     struct btrfs_free_cluster,
-				     block_group_list);
+		cluster = list_first_entry(&block_group->cluster_list,
+					   struct btrfs_free_cluster, block_group_list);
 		spin_lock(&cluster->lock);
 		node = rb_first(&cluster->root);
 		if (!node) {

fs/btrfs/inode.c

···
 		PAGE_SHIFT;
 
 	while (!list_empty(&async_chunk->extents)) {
-		async_extent = list_entry(async_chunk->extents.next,
-					  struct async_extent, list);
+		async_extent = list_first_entry(&async_chunk->extents,
+						struct async_extent, list);
 		list_del(&async_extent->list);
 		submit_one_async_extent(async_chunk, async_extent, &alloc_hint);
 	}
···
 		struct btrfs_inode *inode;
 		struct inode *tmp_inode;
 
-		inode = list_entry(splice.next, struct btrfs_inode, delalloc_inodes);
+		inode = list_first_entry(&splice, struct btrfs_inode, delalloc_inodes);
 
 		list_move_tail(&inode->delalloc_inodes, &root->delalloc_inodes);
 

fs/btrfs/raid56.c

···
 
 	spin_lock(&table->cache_lock);
 	while (!list_empty(&table->stripe_cache)) {
-		rbio = list_entry(table->stripe_cache.next,
-				  struct btrfs_raid_bio,
-				  stripe_cache);
+		rbio = list_first_entry(&table->stripe_cache,
+					struct btrfs_raid_bio, stripe_cache);
 		__remove_rbio_from_cache(rbio);
 	}
 	spin_unlock(&table->cache_lock);
···
 	list_sort(NULL, &plug->rbio_list, plug_cmp);
 
 	while (!list_empty(&plug->rbio_list)) {
-		cur = list_entry(plug->rbio_list.next,
-				 struct btrfs_raid_bio, plug_list);
+		cur = list_first_entry(&plug->rbio_list,
+				       struct btrfs_raid_bio, plug_list);
 		list_del_init(&cur->plug_list);
 
 		if (rbio_is_full(cur)) {

fs/btrfs/relocation.c

···
 	int idx = *index;
 
 	while (!list_empty(&node->upper)) {
-		edge = list_entry(node->upper.next,
-				  struct btrfs_backref_edge, list[LOWER]);
+		edge = list_first_entry(&node->upper, struct btrfs_backref_edge,
+					list[LOWER]);
 		edges[idx++] = edge;
 		node = edge->node[UPPER];
 	}
···
 			idx--;
 			continue;
 		}
-		edge = list_entry(edge->list[LOWER].next,
-				  struct btrfs_backref_edge, list[LOWER]);
+		edge = list_first_entry(&edge->list[LOWER], struct btrfs_backref_edge,
+					list[LOWER]);
 		edges[idx - 1] = edge;
 		*index = idx;
 		return edge->node[UPPER];
···
 			struct btrfs_backref_edge *edge;
 			struct btrfs_backref_node *lower;
 
-			edge = list_entry(cur->lower.next,
-					struct btrfs_backref_edge, list[UPPER]);
+			edge = list_first_entry(&cur->lower, struct btrfs_backref_edge,
+						list[UPPER]);
 			list_del(&edge->list[UPPER]);
 			list_del(&edge->list[LOWER]);
 			lower = edge->node[LOWER];
···
 	rc->merge_reloc_tree = true;
 
 	while (!list_empty(&rc->reloc_roots)) {
-		reloc_root = list_entry(rc->reloc_roots.next,
-					struct btrfs_root, root_list);
+		reloc_root = list_first_entry(&rc->reloc_roots,
+					      struct btrfs_root, root_list);
 		list_del_init(&reloc_root->root_list);
 
 		root = btrfs_get_fs_root(fs_info, reloc_root->root_key.offset,
···
 
 	while (!list_empty(&reloc_roots)) {
 		found = 1;
-		reloc_root = list_entry(reloc_roots.next,
-					struct btrfs_root, root_list);
+		reloc_root = list_first_entry(&reloc_roots, struct btrfs_root, root_list);
 
 		root = btrfs_get_fs_root(fs_info, reloc_root->root_key.offset,
 					 false);
···
 			if (list_empty(&next->upper))
 				break;
 
-			edge = list_entry(next->upper.next,
-					struct btrfs_backref_edge, list[LOWER]);
+			edge = list_first_entry(&next->upper, struct btrfs_backref_edge,
+						list[LOWER]);
 			edges[index++] = edge;
 			next = edge->node[UPPER];
 		}
···
 
 	for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
 		while (!list_empty(&cache->pending[level])) {
-			node = list_entry(cache->pending[level].next,
-					  struct btrfs_backref_node, list);
+			node = list_first_entry(&cache->pending[level],
+						struct btrfs_backref_node, list);
 			list_move_tail(&node->list, &list);
 			BUG_ON(!node->pending);
 
···
 			if (list_empty(&next->upper))
 				break;
 
-			edge = list_entry(next->upper.next,
-					struct btrfs_backref_edge, list[LOWER]);
+			edge = list_first_entry(&next->upper, struct btrfs_backref_edge,
+						list[LOWER]);
 			edges[index++] = edge;
 			next = edge->node[UPPER];
 		}
···
 	rc->merge_reloc_tree = true;
 
 	while (!list_empty(&reloc_roots)) {
-		reloc_root = list_entry(reloc_roots.next,
-					struct btrfs_root, root_list);
+		reloc_root = list_first_entry(&reloc_roots, struct btrfs_root, root_list);
 		list_del(&reloc_root->root_list);
 
 		if (btrfs_root_refs(&reloc_root->root_item) == 0) {
···
 
 	while (!list_empty(&list)) {
 		struct btrfs_ordered_sum *sums =
-			list_entry(list.next, struct btrfs_ordered_sum, list);
+			list_first_entry(&list, struct btrfs_ordered_sum, list);
 
 		list_del_init(&sums->list);
 

fs/btrfs/send.c

···
 	struct recorded_ref *cur;
 
 	while (!list_empty(head)) {
-		cur = list_entry(head->next, struct recorded_ref, list);
+		cur = list_first_entry(head, struct recorded_ref, list);
 		recorded_ref_free(cur);
 	}
 }
···
 		/*
 		 * We have a moved dir. Add the old parent to check_dirs
 		 */
-		cur = list_entry(sctx->deleted_refs.next, struct recorded_ref,
-				list);
+		cur = list_first_entry(&sctx->deleted_refs, struct recorded_ref, list);
 		ret = dup_ref(cur, &check_dirs);
 		if (ret < 0)
 			goto out;

fs/btrfs/tree-log.c

···
 				struct btrfs_ordered_sum *sums;
 				struct btrfs_root *csum_root;
 
-				sums = list_entry(ordered_sums.next,
-						struct btrfs_ordered_sum,
-						list);
+				sums = list_first_entry(&ordered_sums,
+							struct btrfs_ordered_sum,
+							list);
 				csum_root = btrfs_csum_root(fs_info,
 							    sums->logical);
 				if (!ret)
···
 	ret = 0;
 
 	while (!list_empty(&ordered_sums)) {
-		struct btrfs_ordered_sum *sums = list_entry(ordered_sums.next,
-						   struct btrfs_ordered_sum,
-						   list);
+		struct btrfs_ordered_sum *sums = list_first_entry(&ordered_sums,
+								  struct btrfs_ordered_sum,
+								  list);
 		if (!ret)
 			ret = log_csums(trans, inode, log_root, sums);
 		list_del(&sums->list);
···
 	list_sort(NULL, &extents, extent_cmp);
 process:
 	while (!list_empty(&extents)) {
-		em = list_entry(extents.next, struct extent_map, list);
+		em = list_first_entry(&extents, struct extent_map, list);
 
 		list_del_init(&em->list);
 

fs/btrfs/volumes.c

···
 
 	WARN_ON(fs_devices->opened);
 	while (!list_empty(&fs_devices->devices)) {
-		device = list_entry(fs_devices->devices.next,
-				    struct btrfs_device, dev_list);
+		device = list_first_entry(&fs_devices->devices,
+					  struct btrfs_device, dev_list);
 		list_del(&device->dev_list);
 		btrfs_free_device(device);
 	}
···
 	struct btrfs_fs_devices *fs_devices;
 
 	while (!list_empty(&fs_uuids)) {
-		fs_devices = list_entry(fs_uuids.next,
-					struct btrfs_fs_devices, fs_list);
+		fs_devices = list_first_entry(&fs_uuids, struct btrfs_fs_devices,
+					      fs_list);
 		list_del(&fs_devices->fs_list);
 		free_fs_devices(fs_devices);
 	}