Re: [Cocci] [PATCH 1/1] btrfs: Deletion of unnecessary checks before six function calls

Julia Lawall
2014-10-31T21:59:23Z

On Fri, 31 Oct 2014, SF Markus Elfring wrote:

> The following functions test whether their argument is NULL and then
> return immediately.
> * btrfs_free_path()
> * free_extent_buffer()
> * free_extent_map()
> * free_extent_state()
> * iput()
> * kfree()
>
> Thus the test around the call is not needed.
>
> This issue was detected by using the Coccinelle software.
>
> Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
> ---
> fs/btrfs/dev-replace.c | 3 +--
> fs/btrfs/extent_io.c | 12 ++++--------
> fs/btrfs/file.c | 6 ++----
> fs/btrfs/free-space-cache.c | 7 +++----
> fs/btrfs/inode.c | 6 ++----
> fs/btrfs/reada.c | 3 +--
> fs/btrfs/relocation.c | 3 +--
> fs/btrfs/tests/btrfs-tests.c | 3 +--
> fs/btrfs/tree-defrag.c | 3 +--
> fs/btrfs/tree-log.c | 6 ++----
> 10 files changed, 18 insertions(+), 34 deletions(-)
>
> diff --git a/fs/btrfs/dev-replace.c b/fs/btrfs/dev-replace.c
> index 6f662b3..3465029 100644
> --- a/fs/btrfs/dev-replace.c
> +++ b/fs/btrfs/dev-replace.c
> @@ -183,8 +183,7 @@ no_valid_dev_replace_entry_found:
> }
>
> out:
> - if (path)
> - btrfs_free_path(path);
> + btrfs_free_path(path);

It appears to be statically apparent whether btrfs_free_path is needed or
not. The code could be changed both not to have the test and not to have
the jump and call to btrfs_free_path.

This is probably the case for the other occurrences next to labels.

julia

> return ret;
> }
>
> diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
> index bf3f424..cfbf00a 100644
> --- a/fs/btrfs/extent_io.c
> +++ b/fs/btrfs/extent_io.c
> @@ -704,8 +704,7 @@ next:
>
> out:
> spin_unlock(&tree->lock);
> - if (prealloc)
> - free_extent_state(prealloc);
> + free_extent_state(prealloc);
>
> return 0;
>
> @@ -1006,8 +1005,7 @@ hit_next:
>
> out:
> spin_unlock(&tree->lock);
> - if (prealloc)
> - free_extent_state(prealloc);
> + free_extent_state(prealloc);
>
> return err;
>
> @@ -1223,8 +1221,7 @@ hit_next:
>
> out:
> spin_unlock(&tree->lock);
> - if (prealloc)
> - free_extent_state(prealloc);
> + free_extent_state(prealloc);
>
> return err;
>
> @@ -4146,8 +4143,7 @@ int extent_readpages(struct extent_io_tree *tree,
> __extent_readpages(tree, pagepool, nr, get_extent, &em_cached,
> &bio, 0, &bio_flags, READ);
>
> - if (em_cached)
> - free_extent_map(em_cached);
> + free_extent_map(em_cached);
>
> BUG_ON(!list_empty(pages));
> if (bio)
> diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
> index a18ceab..add07ce8 100644
> --- a/fs/btrfs/file.c
> +++ b/fs/btrfs/file.c
> @@ -677,10 +677,8 @@ next:
> /* once for the tree*/
> free_extent_map(em);
> }
> - if (split)
> - free_extent_map(split);
> - if (split2)
> - free_extent_map(split2);
> + free_extent_map(split);
> + free_extent_map(split2);
> }
>
> /*
> diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c
> index 3384819..11883e2 100644
> --- a/fs/btrfs/free-space-cache.c
> +++ b/fs/btrfs/free-space-cache.c
> @@ -1943,8 +1943,7 @@ new_bitmap:
>
> out:
> if (info) {
> - if (info->bitmap)
> - kfree(info->bitmap);
> + kfree(info->bitmap);
> kmem_cache_free(btrfs_free_space_cachep, info);
> }
>
> @@ -3322,8 +3321,8 @@ again:
>
> if (info)
> kmem_cache_free(btrfs_free_space_cachep, info);
> - if (map)
> - kfree(map);
> +
> + kfree(map);
> return 0;
> }
>
> diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
> index d23362f..7301b99 100644
> --- a/fs/btrfs/inode.c
> +++ b/fs/btrfs/inode.c
> @@ -857,8 +857,7 @@ static u64 get_extent_allocation_hint(struct inode *inode,
> u64 start,
> em = search_extent_mapping(em_tree, 0, 0);
> if (em && em->block_start < EXTENT_MAP_LAST_BYTE)
> alloc_hint = em->block_start;
> - if (em)
> - free_extent_map(em);
> + free_extent_map(em);
> } else {
> alloc_hint = em->block_start;
> free_extent_map(em);
> @@ -6573,8 +6572,7 @@ out:
>
> trace_btrfs_get_extent(root, em);
>
> - if (path)
> - btrfs_free_path(path);
> + btrfs_free_path(path);
> if (trans) {
> ret = btrfs_end_transaction(trans, root);
> if (!err)
> diff --git a/fs/btrfs/reada.c b/fs/btrfs/reada.c
> index b63ae20..ec8eb49 100644
> --- a/fs/btrfs/reada.c
> +++ b/fs/btrfs/reada.c
> @@ -731,8 +731,7 @@ static int reada_start_machine_dev(struct btrfs_fs_info
> *fs_info,
> else if (eb)
> __readahead_hook(fs_info->extent_root, eb, eb->start, ret);
>
> - if (eb)
> - free_extent_buffer(eb);
> + free_extent_buffer(eb);
>
> return 1;
>
> diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
> index 74257d6..f87a5ee 100644
> --- a/fs/btrfs/relocation.c
> +++ b/fs/btrfs/relocation.c
> @@ -4158,8 +4158,7 @@ out:
> btrfs_end_transaction(trans, root);
> btrfs_btree_balance_dirty(root);
> if (err) {
> - if (inode)
> - iput(inode);
> + iput(inode);
> inode = ERR_PTR(err);
> }
> return inode;
> diff --git a/fs/btrfs/tests/btrfs-tests.c b/fs/btrfs/tests/btrfs-tests.c
> index 9626252..7fb123f 100644
> --- a/fs/btrfs/tests/btrfs-tests.c
> +++ b/fs/btrfs/tests/btrfs-tests.c
> @@ -162,8 +162,7 @@ void btrfs_free_dummy_root(struct btrfs_root *root)
> {
> if (!root)
> return;
> - if (root->node)
> - free_extent_buffer(root->node);
> + free_extent_buffer(root->node);
> if (root->fs_info)
> btrfs_free_dummy_fs_info(root->fs_info);
> kfree(root);
> diff --git a/fs/btrfs/tree-defrag.c b/fs/btrfs/tree-defrag.c
> index a63719c..c74f106 100644
> --- a/fs/btrfs/tree-defrag.c
> +++ b/fs/btrfs/tree-defrag.c
> @@ -118,8 +118,7 @@ int btrfs_defrag_leaves(struct btrfs_trans_handle *trans,
> ret = -EAGAIN;
> }
> out:
> - if (path)
> - btrfs_free_path(path);
> + btrfs_free_path(path);
> if (ret == -EAGAIN) {
> if (root->defrag_max.objectid > root->defrag_progress.objectid)
> goto done;
> diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
> index 1475979..70926a9 100644
> --- a/fs/btrfs/tree-log.c
> +++ b/fs/btrfs/tree-log.c
> @@ -736,8 +736,7 @@ static noinline int replay_one_extent(struct
> btrfs_trans_handle *trans,
> inode_add_bytes(inode, nbytes);
> ret = btrfs_update_inode(trans, root, inode);
> out:
> - if (inode)
> - iput(inode);
> + iput(inode);
> return ret;
> }
>
> @@ -2210,8 +2209,7 @@ static noinline int walk_down_log_tree(struct
> btrfs_trans_handle *trans,
> }
>
> WARN_ON(*level <= 0);
> - if (path->nodes[*level-1])
> - free_extent_buffer(path->nodes[*level-1]);
> + free_extent_buffer(path->nodes[*level-1]);
> path->nodes[*level-1] = next;
> *level = btrfs_header_level(next);
> path->slots[*level] = 0;
> --
> 2.1.3
>
>
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