linux-kernel - Re: [PATCH] misc: misc_minor_alloc to allocate ids for all dynamic/misc dynamic minors

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Message-ID: <CALkUMdSzeH-7=jXsGV1+ubzfqHVOC3z0RbN9BG08HTKwFoAWeg@mail.gmail.com>
Date: Thu, 17 Oct 2024 16:38:58 +0530
From: Vimal Agrawal <avimalin@...il.com>
To: Dan Carpenter <dan.carpenter@...aro.org>
Cc: oe-kbuild@...ts.linux.dev, linux-kernel@...r.kernel.org, 
	gregkh@...uxfoundation.org, arnd@...db.de, lkp@...el.com, 
	oe-kbuild-all@...ts.linux.dev, vimal.agrawal@...hos.com
Subject: Re: [PATCH] misc: misc_minor_alloc to allocate ids for all
 dynamic/misc dynamic minors

Hi Dan,

Both warning and missed case for return from this function for static
minor are already fixed in the v2 version of the patch. I will be
sending out the v3 version shortly ( after splitting it from kunit
changes).
Thanks for pointing this out.

Vimal

On Wed, Oct 16, 2024 at 7:52 PM Dan Carpenter <dan.carpenter@...aro.org> wrote:
>
> Hi Vimal,
>
> kernel test robot noticed the following build warnings:
>
> https://git-scm.com/docs/git-format-patch#_base_tree_information]
>
> url:    https://github.com/intel-lab-lkp/linux/commits/Vimal-Agrawal/misc-misc_minor_alloc-to-allocate-ids-for-all-dynamic-misc-dynamic-minors/20241014-211915
> base:   char-misc/char-misc-testing
> patch link:    https://lore.kernel.org/r/20241014131416.27324-1-vimal.agrawal%40sophos.com
> patch subject: [PATCH] misc: misc_minor_alloc to allocate ids for all dynamic/misc dynamic minors
> config: sparc64-randconfig-r072-20241015 (https://download.01.org/0day-ci/archive/20241016/202410161811.aIPEJHOt-lkp@intel.com/config)
> compiler: sparc64-linux-gcc (GCC) 14.1.0
>
> If you fix the issue in a separate patch/commit (i.e. not just a new version of
> the same patch/commit), kindly add following tags
> | Reported-by: kernel test robot <lkp@...el.com>
> | Reported-by: Dan Carpenter <dan.carpenter@...aro.org>
> | Closes: https://lore.kernel.org/r/202410161811.aIPEJHOt-lkp@intel.com/
>
> smatch warnings:
> drivers/char/misc.c:89 misc_minor_alloc() error: uninitialized symbol 'ret'.
>
> vim +/ret +89 drivers/char/misc.c
>
> d52c84545e305b Vimal Agrawal    2024-10-14  66  static int misc_minor_alloc(int minor)
> ab760791c0cfbb D Scott Phillips 2022-11-14  67  {
> ab760791c0cfbb D Scott Phillips 2022-11-14  68          int ret;
> ab760791c0cfbb D Scott Phillips 2022-11-14  69
> d52c84545e305b Vimal Agrawal    2024-10-14  70          if (minor == MISC_DYNAMIC_MINOR) {
> d52c84545e305b Vimal Agrawal    2024-10-14  71                  /* allocate free id */
> ab760791c0cfbb D Scott Phillips 2022-11-14  72                  ret = ida_alloc_max(&misc_minors_ida, DYNAMIC_MINORS - 1, GFP_KERNEL);
> ab760791c0cfbb D Scott Phillips 2022-11-14  73                  if (ret >= 0) {
> ab760791c0cfbb D Scott Phillips 2022-11-14  74                          ret = DYNAMIC_MINORS - ret - 1;
> ab760791c0cfbb D Scott Phillips 2022-11-14  75                  } else {
> ab760791c0cfbb D Scott Phillips 2022-11-14  76                          ret = ida_alloc_range(&misc_minors_ida, MISC_DYNAMIC_MINOR + 1,
> ab760791c0cfbb D Scott Phillips 2022-11-14  77                                        MINORMASK, GFP_KERNEL);
> ab760791c0cfbb D Scott Phillips 2022-11-14  78                  }
> d52c84545e305b Vimal Agrawal    2024-10-14  79          } else {
> d52c84545e305b Vimal Agrawal    2024-10-14  80                  /* specific minor, check if it is in dynamic or misc dynamic range  */
> d52c84545e305b Vimal Agrawal    2024-10-14  81                  if (minor < DYNAMIC_MINORS) {
> d52c84545e305b Vimal Agrawal    2024-10-14  82                          minor = DYNAMIC_MINORS - minor - 1;
> d52c84545e305b Vimal Agrawal    2024-10-14  83                          ret = ida_alloc_range(&misc_minors_ida, minor, minor, GFP_KERNEL);
> d52c84545e305b Vimal Agrawal    2024-10-14  84                  }
> d52c84545e305b Vimal Agrawal    2024-10-14  85
> d52c84545e305b Vimal Agrawal    2024-10-14  86                  if (minor > MISC_DYNAMIC_MINOR)
> d52c84545e305b Vimal Agrawal    2024-10-14  87                          ret = ida_alloc_range(&misc_minors_ida, minor, minor, GFP_KERNEL);
>
> What about if minor is >= DYNAMIC_MINORS (128) but <= MISC_DYNAMIC_MINOR (255)?
>
> d52c84545e305b Vimal Agrawal    2024-10-14  88          }
> ab760791c0cfbb D Scott Phillips 2022-11-14 @89          return ret;
> ab760791c0cfbb D Scott Phillips 2022-11-14  90  }
>
> --
> 0-DAY CI Kernel Test Service
> https://github.com/intel/lkp-tests/wiki
>