[PATCH] nvme: host: hwmon: constify pointers to hwmon_channel_info

[PATCH] nvme: host: hwmon: constify pointers to hwmon_channel_info

[Krzysztof Kozlowski]

Statically allocated array of pointed to hwmon_channel_info can be made
const for safety.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

---

This depends on hwmon core patch:
https://lore.kernel.org/all/20230406203103.3011503-2-krzysztof.kozlowski@linaro.org/

Therefore I propose this should also go via hwmon tree.

Cc: Jean Delvare <jdelvare@suse.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: linux-hwmon@vger.kernel.org
---
 drivers/nvme/host/hwmon.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/nvme/host/hwmon.c b/drivers/nvme/host/hwmon.c
index 9e6e56c20ec9..c0181d6abd6e 100644
--- a/drivers/nvme/host/hwmon.c
+++ b/drivers/nvme/host/hwmon.c
@@ -185,7 +185,7 @@ static umode_t nvme_hwmon_is_visible(const void *_data,
 	return 0;
 }
 
-static const struct hwmon_channel_info *nvme_hwmon_info[] = {
+static const struct hwmon_channel_info * const nvme_hwmon_info[] = {
 	HWMON_CHANNEL_INFO(chip, HWMON_C_REGISTER_TZ),
 	HWMON_CHANNEL_INFO(temp,
 			   HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_MIN |
-- 
2.34.1

Re: [PATCH] nvme: host: hwmon: constify pointers to hwmon_channel_info

[kernel test robot]

Hi Krzysztof,

kernel test robot noticed the following build warnings:

[auto build test WARNING on groeck-staging/hwmon-next]
[also build test WARNING on axboe-block/for-next linus/master v6.3-rc5 next-20230406]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Krzysztof-Kozlowski/nvme-host-hwmon-constify-pointers-to-hwmon_channel_info/20230407-230001
base:   https://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging.git hwmon-next
patch link:    https://lore.kernel.org/r/20230407145845.79557-1-krzysztof.kozlowski%40linaro.org
patch subject: [PATCH] nvme: host: hwmon: constify pointers to hwmon_channel_info
config: m68k-allyesconfig (https://download.01.org/0day-ci/archive/20230408/202304080031.JzoLJ7pI-lkp@intel.com/config)
compiler: m68k-linux-gcc (GCC) 12.1.0
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/intel-lab-lkp/linux/commit/a92019809fb469cc9c9f751cee4cfaad054ddb48
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Krzysztof-Kozlowski/nvme-host-hwmon-constify-pointers-to-hwmon_channel_info/20230407-230001
        git checkout a92019809fb469cc9c9f751cee4cfaad054ddb48
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=m68k olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=m68k SHELL=/bin/bash drivers/nvme/

If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@intel.com>
| Link: https://lore.kernel.org/oe-kbuild-all/202304080031.JzoLJ7pI-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> drivers/nvme/host/hwmon.c:221:19: warning: initialization discards 'const' qualifier from pointer target type [-Wdiscarded-qualifiers]
     221 |         .info   = nvme_hwmon_info,
         |                   ^~~~~~~~~~~~~~~


vim +/const +221 drivers/nvme/host/hwmon.c

400b6a7b13a3fd Guenter Roeck 2019-11-06  218  
400b6a7b13a3fd Guenter Roeck 2019-11-06  219  static const struct hwmon_chip_info nvme_hwmon_chip_info = {
400b6a7b13a3fd Guenter Roeck 2019-11-06  220  	.ops	= &nvme_hwmon_ops,
400b6a7b13a3fd Guenter Roeck 2019-11-06 @221  	.info	= nvme_hwmon_info,
400b6a7b13a3fd Guenter Roeck 2019-11-06  222  };
400b6a7b13a3fd Guenter Roeck 2019-11-06  223  

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests

Re: [PATCH] nvme: host: hwmon: constify pointers to hwmon_channel_info

[kernel test robot]

Hi Krzysztof,

kernel test robot noticed the following build errors:

[auto build test ERROR on groeck-staging/hwmon-next]
[also build test ERROR on axboe-block/for-next linus/master v6.3-rc5 next-20230406]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Krzysztof-Kozlowski/nvme-host-hwmon-constify-pointers-to-hwmon_channel_info/20230407-230001
base:   https://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging.git hwmon-next
patch link:    https://lore.kernel.org/r/20230407145845.79557-1-krzysztof.kozlowski%40linaro.org
patch subject: [PATCH] nvme: host: hwmon: constify pointers to hwmon_channel_info
config: i386-randconfig-a001-20230403 (https://download.01.org/0day-ci/archive/20230408/202304080224.0YKfRdwi-lkp@intel.com/config)
compiler: clang version 14.0.6 (https://github.com/llvm/llvm-project f28c006a5895fc0e329fe15fead81e37457cb1d1)
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/intel-lab-lkp/linux/commit/a92019809fb469cc9c9f751cee4cfaad054ddb48
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Krzysztof-Kozlowski/nvme-host-hwmon-constify-pointers-to-hwmon_channel_info/20230407-230001
        git checkout a92019809fb469cc9c9f751cee4cfaad054ddb48
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=i386 olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=i386 SHELL=/bin/bash drivers/nvme/host/

If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@intel.com>
| Link: https://lore.kernel.org/oe-kbuild-all/202304080224.0YKfRdwi-lkp@intel.com/

All errors (new ones prefixed by >>):

>> drivers/nvme/host/hwmon.c:221:10: error: initializing 'const struct hwmon_channel_info **' with an expression of type 'const struct hwmon_channel_info *const[3]' discards qualifiers [-Werror,-Wincompatible-pointer-types-discards-qualifiers]
           .info   = nvme_hwmon_info,
                     ^~~~~~~~~~~~~~~
   1 error generated.


vim +221 drivers/nvme/host/hwmon.c

400b6a7b13a3fd Guenter Roeck 2019-11-06  218  
400b6a7b13a3fd Guenter Roeck 2019-11-06  219  static const struct hwmon_chip_info nvme_hwmon_chip_info = {
400b6a7b13a3fd Guenter Roeck 2019-11-06  220  	.ops	= &nvme_hwmon_ops,
400b6a7b13a3fd Guenter Roeck 2019-11-06 @221  	.info	= nvme_hwmon_info,
400b6a7b13a3fd Guenter Roeck 2019-11-06  222  };
400b6a7b13a3fd Guenter Roeck 2019-11-06  223  

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests

Re: [PATCH] nvme: host: hwmon: constify pointers to hwmon_channel_info

[Christoph Hellwig]

Thanks,

applied to nvme-6.4 with a trivial whitespace fix.

Re: [PATCH] nvme: host: hwmon: constify pointers to hwmon_channel_info

[Christoph Hellwig]

On Tue, Apr 11, 2023 at 08:09:00AM +0200, Christoph Hellwig wrote:
> Thanks,
> 
> applied to nvme-6.4 with a trivial whitespace fix.

Actually, I've dropped this again as it causes this warning:

drivers/nvme/host/hwmon.c:221:19: warning: initialization discards ‘const’
qualifier from pointer target type [-Wdiscarded-qualifiers]

This looks like we might need a core hwmon change first.

Re: [PATCH] nvme: host: hwmon: constify pointers to hwmon_channel_info

[Krzysztof Kozlowski]

On 11/04/2023 08:10, Christoph Hellwig wrote:
> On Tue, Apr 11, 2023 at 08:09:00AM +0200, Christoph Hellwig wrote:
>> Thanks,
>>
>> applied to nvme-6.4 with a trivial whitespace fix.
> 
> Actually, I've dropped this again as it causes this warning:
> 
> drivers/nvme/host/hwmon.c:221:19: warning: initialization discards ‘const’
> qualifier from pointer target type [-Wdiscarded-qualifiers]
> 
> This looks like we might need a core hwmon change first.

The dependency was described in the patch. Guenter also provided
a stable branch with the dependency:

git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging.git hwmon-const

Best regards,
Krzysztof

Re: [PATCH] nvme: host: hwmon: constify pointers to hwmon_channel_info

[Christoph Hellwig]

On Tue, Apr 11, 2023 at 08:11:41AM +0200, Krzysztof Kozlowski wrote:
> The dependency was described in the patch. Guenter also provided
> a stable branch with the dependency:

Ok.  See below for the version with the whitespace and Subject fix I'd like
to see.  With that:

Acked-by: Christoph Hellwig <hch@lst.de>

---
From 882410442b1bb5730f3eec29d8dc9ccda5e92cdb Mon Sep 17 00:00:00 2001
From: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Date: Fri, 7 Apr 2023 16:58:45 +0200
Subject: nvme-hwmon: constify pointers to hwmon_channel_info

Statically allocated array of pointed to hwmon_channel_info can be made
const for safety.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
---
 drivers/nvme/host/hwmon.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/nvme/host/hwmon.c b/drivers/nvme/host/hwmon.c
index 9e6e56c20ec993..6aa153f3178a60 100644
--- a/drivers/nvme/host/hwmon.c
+++ b/drivers/nvme/host/hwmon.c
@@ -185,7 +185,7 @@ static umode_t nvme_hwmon_is_visible(const void *_data,
 	return 0;
 }
 
-static const struct hwmon_channel_info *nvme_hwmon_info[] = {
+static const struct hwmon_channel_info *const nvme_hwmon_info[] = {
 	HWMON_CHANNEL_INFO(chip, HWMON_C_REGISTER_TZ),
 	HWMON_CHANNEL_INFO(temp,
 			   HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_MIN |
-- 
2.39.2