On Fri, May 5, 2017 at 12:19 AM, Roland Kammerer
<[email protected]> 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 <[email protected]>
>>
>> ---
>> 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 <[email protected]>
>
> Regards, rck
Which tree should this go through? Jens, I think yours?
Thanks!
-Kees
--
Kees Cook
Pixel Security
On 06/27/2017 05:49 PM, Kees Cook wrote:
> On Fri, May 5, 2017 at 12:19 AM, Roland Kammerer
> <[email protected]> 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 <[email protected]>
>>>
>>> ---
>>> 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 <[email protected]>
>>
>> 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