[PATCH] btrfs: Remove unneeded return variable

[Yang Li <yang.lee@linux.alibaba.com>]

This patch removes unneeded return variables, using only
'0' instead.
It fixes the following warning detected by coccinelle:
./fs/btrfs/extent_map.c:299:5-8: Unneeded variable: "ret". Return "0" on
line 331
./fs/btrfs/disk-io.c:4402:5-8: Unneeded variable: "ret". Return "0" on
line 4410

Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Yang Li <yang.lee@linux.alibaba.com>
---
 fs/btrfs/disk-io.c    | 5 ++---
 fs/btrfs/extent_map.c | 3 +--
 2 files changed, 3 insertions(+), 5 deletions(-)

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 6b35b7e..e951da7 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -4399,7 +4399,6 @@ static int btrfs_destroy_delayed_refs(struct btrfs_transaction *trans,
 	struct rb_node *node;
 	struct btrfs_delayed_ref_root *delayed_refs;
 	struct btrfs_delayed_ref_node *ref;
-	int ret = 0;
 
 	delayed_refs = &trans->delayed_refs;
 
@@ -4407,7 +4406,7 @@ static int btrfs_destroy_delayed_refs(struct btrfs_transaction *trans,
 	if (atomic_read(&delayed_refs->num_entries) == 0) {
 		spin_unlock(&delayed_refs->lock);
 		btrfs_debug(fs_info, "delayed_refs has NO entry");
-		return ret;
+		return 0;
 	}
 
 	while ((node = rb_first_cached(&delayed_refs->href_root)) != NULL) {
@@ -4473,7 +4472,7 @@ static int btrfs_destroy_delayed_refs(struct btrfs_transaction *trans,
 
 	spin_unlock(&delayed_refs->lock);
 
-	return ret;
+	return 0;
 }
 
 static void btrfs_destroy_delalloc_inodes(struct btrfs_root *root)
diff --git a/fs/btrfs/extent_map.c b/fs/btrfs/extent_map.c
index bd6229f..bac7eba 100644
--- a/fs/btrfs/extent_map.c
+++ b/fs/btrfs/extent_map.c
@@ -296,7 +296,6 @@ static void try_merge_map(struct extent_map_tree *tree, struct extent_map *em)
 int unpin_extent_cache(struct extent_map_tree *tree, u64 start, u64 len,
 		       u64 gen)
 {
-	int ret = 0;
 	struct extent_map *em;
 	bool prealloc = false;
 
@@ -328,7 +327,7 @@ int unpin_extent_cache(struct extent_map_tree *tree, u64 start, u64 len,
 	free_extent_map(em);
 out:
 	write_unlock(&tree->lock);
-	return ret;
+	return 0;
 
 }
 
-- 
1.8.3.1