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

[Julia Lawall]

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@xxxxxxxxxxxxxxxxxxxxx>
> ---
>  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
> 
> 
> _______________________________________________
> Cocci mailing list
> Cocci@xxxxxxxxxxxxxxx
> https://systeme.lip6.fr/mailman/listinfo/cocci
> 
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/