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


    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
    >
    >
    > _______________________________________________
    > Cocci mailing list
    > Cocci@systeme.lip6.fr
    > https://systeme.lip6.fr/mailman/listinfo/cocci
    >


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