linux-kernel - Re: [PATCH 3/9] drbd: Drop unnecessary static

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Message-ID: <a7dbb81a-fef3-fa6f-c92e-c6b0f65a94a1@kernel.dk>
Date:   Tue, 27 Jun 2017 17:58:16 -0600
From:   Jens Axboe <axboe@...nel.dk>
To:     Kees Cook <keescook@...omium.org>,
        Roland Kammerer <roland.kammerer@...bit.com>
Cc:     Julia Lawall <Julia.Lawall@...6.fr>,
        Philipp Reisner <philipp.reisner@...bit.com>,
        kernel-janitors@...r.kernel.org,
        Lars Ellenberg <lars.ellenberg@...bit.com>,
        drbd-dev@...ts.linbit.com, LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 3/9] drbd: Drop unnecessary static

On 06/27/2017 05:49 PM, Kees Cook wrote:
> On Fri, May 5, 2017 at 12:19 AM, Roland Kammerer
> <roland.kammerer@...bit.com> wrote:
>> On Thu, May 04, 2017 at 10:10:48PM +0200, Julia Lawall wrote:
>>> Drop static on a local variable, when the variable is initialized before
>>> any use, on every possible execution path through the function.  The static
>>> has no benefit, and dropping it reduces the code size.
>>>
>>> The semantic patch that fixes this problem is as follows:
>>> (http://coccinelle.lip6.fr/)
>>>
>>> // <smpl>
>>> @bad exists@
>>> position p;
>>> identifier x;
>>> type T;
>>> @@
>>>
>>> static T x@p;
>>> ...
>>> x = <+...x...+>
>>>
>>> @@
>>> identifier x;
>>> expression e;
>>> type T;
>>> position p != bad.p;
>>> @@
>>>
>>> -static
>>>  T x@p;
>>>  ... when != x
>>>      when strict
>>> ?x = e;
>>> // </smpl>
>>>
>>> The change in code size is indicates by the following output from the size
>>> command.
>>>
>>> before:
>>>    text    data     bss     dec     hex filename
>>>   67299    2291    1056   70646   113f6 drivers/block/drbd/drbd_nl.o
>>>
>>> after:
>>>    text    data     bss     dec     hex filename
>>>   67283    2291    1056   70630   113e6 drivers/block/drbd/drbd_nl.o
>>>
>>> Signed-off-by: Julia Lawall <Julia.Lawall@...6.fr>
>>>
>>> ---
>>>  drivers/block/drbd/drbd_nl.c |    2 +-
>>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c
>>> index 02255a0..ad0fcb4 100644
>>> --- a/drivers/block/drbd/drbd_nl.c
>>> +++ b/drivers/block/drbd/drbd_nl.c
>>> @@ -2294,7 +2294,7 @@ static bool conn_ov_running(struct drbd_connection *connection)
>>>  static enum drbd_ret_code
>>>  check_net_options(struct drbd_connection *connection, struct net_conf *new_net_conf)
>>>  {
>>> -     static enum drbd_ret_code rv;
>>> +     enum drbd_ret_code rv;
>>>       struct drbd_peer_device *peer_device;
>>>       int i;
>>
>> Yes, that already got dropped for drbd9 and is obviously correct for
>> in-tree drbd8.
>>
>> Signed-off-by: Roland Kammerer <roland.kammerer@...bit.com>
>>
>> Regards, rck
> 
> Which tree should this go through? Jens, I think yours?

Yes, I'll queue it up for 4.13. Thanks Julia.

-- 
Jens Axboe