Re: [PATCH 08/14] zram: check that backends array has at least one backend

[kernel test robot <lkp@intel.com>]

Hi Sergey,

kernel test robot noticed the following build errors:

[auto build test ERROR on axboe-block/for-next]
[also build test ERROR on akpm-mm/mm-everything linus/master v6.9-rc6 next-20240503]
[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/Sergey-Senozhatsky/zram-move-from-crypto-API-to-custom-comp-backends-API/20240503-172335
base:   https://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block.git for-next
patch link:    https://lore.kernel.org/r/20240503091823.3616962-9-senozhatsky%40chromium.org
patch subject: [PATCH 08/14] zram: check that backends array has at least one backend
config: x86_64-rhel-8.3 (https://download.01.org/0day-ci/archive/20240504/202405041458.j3L25KZg-lkp@intel.com/config)
compiler: gcc-13 (Ubuntu 13.2.0-4ubuntu3) 13.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240504/202405041458.j3L25KZg-lkp@intel.com/reproduce)

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@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202405041458.j3L25KZg-lkp@intel.com/

All errors (new ones prefixed by >>):

   In file included from <command-line>:
   drivers/block/zram/zcomp.c: In function 'zcomp_create':
>> include/linux/compiler_types.h:449:45: error: call to '__compiletime_assert_419' declared with attribute error: BUILD_BUG_ON failed: ARRAY_SIZE(backends) <= 1
     449 |         _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
         |                                             ^
   include/linux/compiler_types.h:430:25: note: in definition of macro '__compiletime_assert'
     430 |                         prefix ## suffix();                             \
         |                         ^~~~~~
   include/linux/compiler_types.h:449:9: note: in expansion of macro '_compiletime_assert'
     449 |         _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
         |         ^~~~~~~~~~~~~~~~~~~
   include/linux/build_bug.h:39:37: note: in expansion of macro 'compiletime_assert'
      39 | #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
         |                                     ^~~~~~~~~~~~~~~~~~
   include/linux/build_bug.h:50:9: note: in expansion of macro 'BUILD_BUG_ON_MSG'
      50 |         BUILD_BUG_ON_MSG(condition, "BUILD_BUG_ON failed: " #condition)
         |         ^~~~~~~~~~~~~~~~
   drivers/block/zram/zcomp.c:214:9: note: in expansion of macro 'BUILD_BUG_ON'
     214 |         BUILD_BUG_ON(ARRAY_SIZE(backends) <= 1);
         |         ^~~~~~~~~~~~


vim +/__compiletime_assert_419 +449 include/linux/compiler_types.h

eb5c2d4b45e3d2 Will Deacon 2020-07-21  435  
eb5c2d4b45e3d2 Will Deacon 2020-07-21  436  #define _compiletime_assert(condition, msg, prefix, suffix) \
eb5c2d4b45e3d2 Will Deacon 2020-07-21  437  	__compiletime_assert(condition, msg, prefix, suffix)
eb5c2d4b45e3d2 Will Deacon 2020-07-21  438  
eb5c2d4b45e3d2 Will Deacon 2020-07-21  439  /**
eb5c2d4b45e3d2 Will Deacon 2020-07-21  440   * compiletime_assert - break build and emit msg if condition is false
eb5c2d4b45e3d2 Will Deacon 2020-07-21  441   * @condition: a compile-time constant condition to check
eb5c2d4b45e3d2 Will Deacon 2020-07-21  442   * @msg:       a message to emit if condition is false
eb5c2d4b45e3d2 Will Deacon 2020-07-21  443   *
eb5c2d4b45e3d2 Will Deacon 2020-07-21  444   * In tradition of POSIX assert, this macro will break the build if the
eb5c2d4b45e3d2 Will Deacon 2020-07-21  445   * supplied condition is *false*, emitting the supplied error message if the
eb5c2d4b45e3d2 Will Deacon 2020-07-21  446   * compiler has support to do so.
eb5c2d4b45e3d2 Will Deacon 2020-07-21  447   */
eb5c2d4b45e3d2 Will Deacon 2020-07-21  448  #define compiletime_assert(condition, msg) \
eb5c2d4b45e3d2 Will Deacon 2020-07-21 @449  	_compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
eb5c2d4b45e3d2 Will Deacon 2020-07-21  450  

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