btrfs: reada: Fix returned errno code

reada is using -1 instead of the -ENOMEM defined macro to specify that
a buffer allocation failed. Since the error number is propagated, the
caller will get a -EPERM which is the wrong error condition.

Also, updating the caller to return the exact value from
reada_add_block.

Smatch tool warning:
reada_add_block() warn: returning -1 instead of -ENOMEM is sloppy

Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: Luis de Bethencourt <luisbg@osg.samsung.com>
Signed-off-by: David Sterba <dsterba@suse.com>

1 files changed, 5 insertions, 3 deletions

diff --git a/fs/btrfs/reada.c b/fs/btrfs/reada.c
index 4645cd16d5ba..619f92963e27 100644
--- a/fs/btrfs/reada.c
+++ b/fs/btrfs/reada.c
@@ -569,7 +569,7 @@ static int reada_add_block(struct reada_control *rc, u64 logical,
         rec = kzalloc(sizeof(*rec), GFP_NOFS);
         if (!rec) {
                 reada_extent_put(root->fs_info, re);
-                return -1;
+                return -ENOMEM;
         }
 
         rec->rc = rc;
@@ -918,6 +918,7 @@ struct reada_control *btrfs_reada_add(struct btrfs_root *root,
         u64 start;
         u64 generation;
         int level;
+        int ret;
         struct extent_buffer *node;
         static struct btrfs_key max_key = {
                 .objectid = (u64)-1,
@@ -943,9 +944,10 @@ struct reada_control *btrfs_reada_add(struct btrfs_root *root,
         generation = btrfs_header_generation(node);
         free_extent_buffer(node);
 
-        if (reada_add_block(rc, start, &max_key, level, generation)) {
+        ret = reada_add_block(rc, start, &max_key, level, generation);
+        if (ret) {
                 kfree(rc);
-                return ERR_PTR(-ENOMEM);
+                return ERR_PTR(ret);
         }
 
         reada_start_machine(root->fs_info);