Re: [PATCH] hwtracing: coresight: constify attribute_group structures.

[Arvind Yadav]

Hi Mathieu,


On Friday 07 July 2017 08:58 PM, Mathieu Poirier wrote:

On 4 July 2017 at 23:49, Arvind Yadav <arvind.yadav...@gmail.com> wrote:

attribute_groups are not supposed to change at runtime. All functions
working with attribute_groups provided by <linux/sysfs.h> work with const
attribute_group. So mark the non-const structs as const.

File size before:
   text     data     bss     dec     hex filename
    2573     288     296    3157     c55 coresight-etm-perf.o

File size After adding 'const':
    text    data     bss     dec     hex filename
    2613     224     296    3133     c3d coresight-etm-perf.o

Hi Arvind,

Did you find this using an automated tool or simply stumbled on it
while reviewing the code?  In case of the former it is usually a good
idea to specify which tool was used in the change log.

      Automated tools are not able to caught this kind of error.
      I have fixed same changes in zram ( commit - dfc8ed8d6a).
      Minchan Kim suggested me to change all the places where have not
      used const. It's good idea have a tool which can able to detect these
      kind of error. I will try to create a tool.

Thanks,
Mathieu

Signed-off-by: Arvind Yadav <arvind.yadav...@gmail.com>
---
  drivers/hwtracing/coresight/coresight-etm-perf.c | 2 +-
  1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/hwtracing/coresight/coresight-etm-perf.c 
b/drivers/hwtracing/coresight/coresight-etm-perf.c
index 288a423..e97775d 100644
--- a/drivers/hwtracing/coresight/coresight-etm-perf.c
+++ b/drivers/hwtracing/coresight/coresight-etm-perf.c
@@ -60,7 +60,7 @@ struct etm_event_data {
         NULL,
  };

-static struct attribute_group etm_pmu_format_group = {
+static const struct attribute_group etm_pmu_format_group = {
         .name   = "format",
         .attrs  = etm_config_formats_attr,
  };
--
1.9.1

Thanks,
~arvind