btrfs: clean up NULL checks in qgroup_unreserve_range()

Smatch complains that this code dereferences "entry" before checking
whether it's NULL on the next line.  Fortunately, rb_entry() will never
return NULL so it doesn't cause a problem.  We can clean up the NULL
checking a bit to silence the warning and make the code more clear.

Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
index c54ea65..77c5474 100644 (file)
--- a/fs/btrfs/qgroup.c
+++ b/fs/btrfs/qgroup.c
@@ -3435,24 +3435,20 @@ static int qgroup_unreserve_range(struct btrfs_inode *inode,
 {
        struct rb_node *node;
        struct rb_node *next;
-       struct ulist_node *entry = NULL;
+       struct ulist_node *entry;
        int ret = 0;
 
        node = reserved->range_changed.root.rb_node;
+       if (!node)
+               return 0;
        while (node) {
                entry = rb_entry(node, struct ulist_node, rb_node);
                if (entry->val < start)
                        node = node->rb_right;
-               else if (entry)
-                       node = node->rb_left;
                else
-                       break;
+                       node = node->rb_left;
        }
 
-       /* Empty changeset */
-       if (!entry)
-               return 0;
-
        if (entry->val > start && rb_prev(&entry->rb_node))
                entry = rb_entry(rb_prev(&entry->rb_node), struct ulist_node,
                                 rb_node);