Re: [PATCH] befs/btree: remove unneeded initializations
From: Luis de Bethencourt
Date: Wed Jun 01 2016 - 19:43:28 EST
On 01/06/16 23:42, Andrew Morton wrote:
> On Mon, 30 May 2016 01:39:59 +0100 Luis de Bethencourt <luisbg@xxxxxxxxxxxxxxx> wrote:
>> off in befs_bt_read_node() will be written by befs_read_datastream(), with
>> the value that node->od_node needs.
>> node_off in befs_btree_read() isn't read before set to root_node_ptr.
>> Removing these two unneeded initializations.
>> --- a/fs/befs/btree.c
>> +++ b/fs/befs/btree.c
>> @@ -196,7 +196,7 @@ static int
>> befs_bt_read_node(struct super_block *sb, const befs_data_stream *ds,
>> struct befs_btree_node *node, befs_off_t node_off)
>> - uint off = 0;
>> + uint off;
>> befs_debug(sb, "---> %s", __func__);
> With this code:
> int foo;
> whatever = foo;
> some versions of gcc will warn that foo might be used uninitialized.
> Other versions of gcc don't do this. That's why the seemingly-unneeded
> initializations are there.
> Neither of the versions of gcc which I tested with actually do warn,
> but I'm inclined to leave things as-is: some people will get warnings
> and that's probably worse than a couple of bytes bloat in befs.
> It shouldn't cause any bloat, really. We have the "uninitialized_var"
> macro which avoids any bloat and is self-documenting. And the nice
> thing about self-documenting code is that it prevents Andrew from
> having to explain strange code to Luis ;) But unintialized_var in
> unpopular for reasons which I personally find unpersuasive, given
> the advantages...
I understand. Let's keep the code as it is.
Not worth adding uninitialized_var() for that declaration. Even though they
are self-documenting indeed.
Is this also the case with the node_off declaration?
Before being passed by reference to befs_btree_seekleaf() the initial value
is overwritten with node_off = bt_super.root_node_ptr;
Thanks for reviewing this,