staging: fbtft: Use ARRAY_SIZE() to get argument count

Message ID Y1vZXUi0Bjiub8HZ@ubunlion
State New
Headers
Series staging: fbtft: Use ARRAY_SIZE() to get argument count |

Commit Message

Deepak R Varma Oct. 28, 2022, 1:30 p.m. UTC
  The ARRAY_SIZE(foo) macro should be preferred over sizeof operator
based computation such as sizeof(foo)/sizeof(foo[0]) for finding
number of elements in an array. Issue identified using coccicheck.

Signed-off-by: Deepak R Varma <drv@mailo.com>
---
 drivers/staging/fbtft/fbtft.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--
2.34.1
  

Comments

kernel test robot Oct. 28, 2022, 11:56 p.m. UTC | #1
Hi Deepak,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on staging/staging-testing]

url:    https://github.com/intel-lab-lkp/linux/commits/Deepak-R-Varma/staging-fbtft-Use-ARRAY_SIZE-to-get-argument-count/20221028-213204
patch link:    https://lore.kernel.org/r/Y1vZXUi0Bjiub8HZ%40ubunlion
patch subject: [PATCH] staging: fbtft: Use ARRAY_SIZE() to get argument count
config: arm-randconfig-r004-20221029
compiler: clang version 16.0.0 (https://github.com/llvm/llvm-project 791a7ae1ba3efd6bca96338e10ffde557ba83920)
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
        # install arm cross compiling tool for clang build
        # apt-get install binutils-arm-linux-gnueabi
        # https://github.com/intel-lab-lkp/linux/commit/74374d9d2a2d6066b94d64aa44e9a1b24c854c4e
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Deepak-R-Varma/staging-fbtft-Use-ARRAY_SIZE-to-get-argument-count/20221028-213204
        git checkout 74374d9d2a2d6066b94d64aa44e9a1b24c854c4e
        # 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=arm SHELL=/bin/bash drivers/staging/fbtft/

If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

>> drivers/staging/fbtft/fbtft-core.c:206:15: error: initializer element is not a compile-time constant
                     (xs >> 8) & 0xFF, xs & 0xFF, (xe >> 8) & 0xFF, xe & 0xFF);
                     ~~~~~~~~~~^~~~~~
   drivers/staging/fbtft/fbtft.h:237:47: note: expanded from macro 'write_reg'
           ((par)->fbtftops.write_register(par, NUMARGS(__VA_ARGS__), __VA_ARGS__))
                                                        ^~~~~~~~~~~
   drivers/staging/fbtft/fbtft.h:234:44: note: expanded from macro 'NUMARGS'
   #define NUMARGS(...)  ARRAY_SIZE(((int[]){ __VA_ARGS__ }))
                                              ^~~~~~~~~~~
   include/linux/kernel.h:55:75: note: expanded from macro 'ARRAY_SIZE'
   #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]) + __must_be_array(arr))
                                                                             ^~~
   include/linux/compiler.h:232:59: note: expanded from macro '__must_be_array'
   #define __must_be_array(a)      BUILD_BUG_ON_ZERO(__same_type((a), &(a)[0]))
                                                                  ^
   include/linux/compiler_types.h:298:63: note: expanded from macro '__same_type'
   #define __same_type(a, b) __builtin_types_compatible_p(typeof(a), typeof(b))
                                                                 ^
   include/linux/build_bug.h:16:62: note: expanded from macro 'BUILD_BUG_ON_ZERO'
   #define BUILD_BUG_ON_ZERO(e) ((int)(sizeof(struct { int:(-!!(e)); })))
                                                                ^
   drivers/staging/fbtft/fbtft-core.c:209:15: error: initializer element is not a compile-time constant
                     (ys >> 8) & 0xFF, ys & 0xFF, (ye >> 8) & 0xFF, ye & 0xFF);
                     ~~~~~~~~~~^~~~~~
   drivers/staging/fbtft/fbtft.h:237:47: note: expanded from macro 'write_reg'
           ((par)->fbtftops.write_register(par, NUMARGS(__VA_ARGS__), __VA_ARGS__))
                                                        ^~~~~~~~~~~
   drivers/staging/fbtft/fbtft.h:234:44: note: expanded from macro 'NUMARGS'
   #define NUMARGS(...)  ARRAY_SIZE(((int[]){ __VA_ARGS__ }))
                                              ^~~~~~~~~~~
   include/linux/kernel.h:55:75: note: expanded from macro 'ARRAY_SIZE'
   #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]) + __must_be_array(arr))
                                                                             ^~~
   include/linux/compiler.h:232:59: note: expanded from macro '__must_be_array'
   #define __must_be_array(a)      BUILD_BUG_ON_ZERO(__same_type((a), &(a)[0]))
                                                                  ^
   include/linux/compiler_types.h:298:63: note: expanded from macro '__same_type'
   #define __same_type(a, b) __builtin_types_compatible_p(typeof(a), typeof(b))
                                                                 ^
   include/linux/build_bug.h:16:62: note: expanded from macro 'BUILD_BUG_ON_ZERO'
   #define BUILD_BUG_ON_ZERO(e) ((int)(sizeof(struct { int:(-!!(e)); })))
                                                                ^
   drivers/staging/fbtft/fbtft-core.c:330:6: warning: variable 'count' set but not used [-Wunused-but-set-variable]
           int count = 0;
               ^
   1 warning and 2 errors generated.
--
>> drivers/staging/fbtft/fb_bd663474.c:110:26: error: initializer element is not a compile-time constant
                   write_reg(par, 0x0200, xs);
                                          ^~
   drivers/staging/fbtft/fbtft.h:237:47: note: expanded from macro 'write_reg'
           ((par)->fbtftops.write_register(par, NUMARGS(__VA_ARGS__), __VA_ARGS__))
                                                        ^~~~~~~~~~~
   drivers/staging/fbtft/fbtft.h:234:44: note: expanded from macro 'NUMARGS'
   #define NUMARGS(...)  ARRAY_SIZE(((int[]){ __VA_ARGS__ }))
                                              ^~~~~~~~~~~
   include/linux/kernel.h:55:75: note: expanded from macro 'ARRAY_SIZE'
   #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]) + __must_be_array(arr))
                                                                             ^~~
   include/linux/compiler.h:232:59: note: expanded from macro '__must_be_array'
   #define __must_be_array(a)      BUILD_BUG_ON_ZERO(__same_type((a), &(a)[0]))
                                                                  ^
   include/linux/compiler_types.h:298:63: note: expanded from macro '__same_type'
   #define __same_type(a, b) __builtin_types_compatible_p(typeof(a), typeof(b))
                                                                 ^
   include/linux/build_bug.h:16:62: note: expanded from macro 'BUILD_BUG_ON_ZERO'
   #define BUILD_BUG_ON_ZERO(e) ((int)(sizeof(struct { int:(-!!(e)); })))
                                                                ^
   drivers/staging/fbtft/fb_bd663474.c:111:26: error: initializer element is not a compile-time constant
                   write_reg(par, 0x0201, ys);
                                          ^~
   drivers/staging/fbtft/fbtft.h:237:47: note: expanded from macro 'write_reg'
           ((par)->fbtftops.write_register(par, NUMARGS(__VA_ARGS__), __VA_ARGS__))
                                                        ^~~~~~~~~~~
   drivers/staging/fbtft/fbtft.h:234:44: note: expanded from macro 'NUMARGS'
   #define NUMARGS(...)  ARRAY_SIZE(((int[]){ __VA_ARGS__ }))
                                              ^~~~~~~~~~~
   include/linux/kernel.h:55:75: note: expanded from macro 'ARRAY_SIZE'
   #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]) + __must_be_array(arr))
                                                                             ^~~
   include/linux/compiler.h:232:59: note: expanded from macro '__must_be_array'
   #define __must_be_array(a)      BUILD_BUG_ON_ZERO(__same_type((a), &(a)[0]))
                                                                  ^
   include/linux/compiler_types.h:298:63: note: expanded from macro '__same_type'
   #define __same_type(a, b) __builtin_types_compatible_p(typeof(a), typeof(b))
                                                                 ^
   include/linux/build_bug.h:16:62: note: expanded from macro 'BUILD_BUG_ON_ZERO'
   #define BUILD_BUG_ON_ZERO(e) ((int)(sizeof(struct { int:(-!!(e)); })))
                                                                ^
   drivers/staging/fbtft/fb_bd663474.c:114:36: error: initializer element is not a compile-time constant
                   write_reg(par, 0x0200, WIDTH - 1 - xs);
                   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~
   drivers/staging/fbtft/fbtft.h:237:47: note: expanded from macro 'write_reg'
           ((par)->fbtftops.write_register(par, NUMARGS(__VA_ARGS__), __VA_ARGS__))
                                                ~~~~~~~~^~~~~~~~~~~~
   drivers/staging/fbtft/fbtft.h:234:44: note: expanded from macro 'NUMARGS'
   #define NUMARGS(...)  ARRAY_SIZE(((int[]){ __VA_ARGS__ }))
                         ~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~
   include/linux/kernel.h:55:75: note: expanded from macro 'ARRAY_SIZE'
   #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]) + __must_be_array(arr))
                                                             ~~~~~~~~~~~~~~~~^~~~
   include/linux/compiler.h:232:59: note: expanded from macro '__must_be_array'
   #define __must_be_array(a)      BUILD_BUG_ON_ZERO(__same_type((a), &(a)[0]))
                                   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~
   include/linux/compiler_types.h:298:63: note: expanded from macro '__same_type'
   #define __same_type(a, b) __builtin_types_compatible_p(typeof(a), typeof(b))
                                                                 ^
   include/linux/build_bug.h:16:62: note: expanded from macro 'BUILD_BUG_ON_ZERO'
   #define BUILD_BUG_ON_ZERO(e) ((int)(sizeof(struct { int:(-!!(e)); })))
                                                                ^
   drivers/staging/fbtft/fb_bd663474.c:115:37: error: initializer element is not a compile-time constant
                   write_reg(par, 0x0201, HEIGHT - 1 - ys);
                   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~
   drivers/staging/fbtft/fbtft.h:237:47: note: expanded from macro 'write_reg'
           ((par)->fbtftops.write_register(par, NUMARGS(__VA_ARGS__), __VA_ARGS__))
                                                ~~~~~~~~^~~~~~~~~~~~
   drivers/staging/fbtft/fbtft.h:234:44: note: expanded from macro 'NUMARGS'
   #define NUMARGS(...)  ARRAY_SIZE(((int[]){ __VA_ARGS__ }))
                         ~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~
   include/linux/kernel.h:55:75: note: expanded from macro 'ARRAY_SIZE'
   #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]) + __must_be_array(arr))
                                                             ~~~~~~~~~~~~~~~~^~~~
   include/linux/compiler.h:232:59: note: expanded from macro '__must_be_array'
   #define __must_be_array(a)      BUILD_BUG_ON_ZERO(__same_type((a), &(a)[0]))
                                   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~
   include/linux/compiler_types.h:298:63: note: expanded from macro '__same_type'
   #define __same_type(a, b) __builtin_types_compatible_p(typeof(a), typeof(b))
                                                                 ^
   include/linux/build_bug.h:16:62: note: expanded from macro 'BUILD_BUG_ON_ZERO'
   #define BUILD_BUG_ON_ZERO(e) ((int)(sizeof(struct { int:(-!!(e)); })))
                                                                ^
   drivers/staging/fbtft/fb_bd663474.c:118:36: error: initializer element is not a compile-time constant
                   write_reg(par, 0x0200, WIDTH - 1 - ys);
                   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~
   drivers/staging/fbtft/fbtft.h:237:47: note: expanded from macro 'write_reg'
           ((par)->fbtftops.write_register(par, NUMARGS(__VA_ARGS__), __VA_ARGS__))
                                                ~~~~~~~~^~~~~~~~~~~~
   drivers/staging/fbtft/fbtft.h:234:44: note: expanded from macro 'NUMARGS'
   #define NUMARGS(...)  ARRAY_SIZE(((int[]){ __VA_ARGS__ }))
                         ~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~
   include/linux/kernel.h:55:75: note: expanded from macro 'ARRAY_SIZE'
   #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]) + __must_be_array(arr))
                                                             ~~~~~~~~~~~~~~~~^~~~
   include/linux/compiler.h:232:59: note: expanded from macro '__must_be_array'
   #define __must_be_array(a)      BUILD_BUG_ON_ZERO(__same_type((a), &(a)[0]))
                                   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~
   include/linux/compiler_types.h:298:63: note: expanded from macro '__same_type'
   #define __same_type(a, b) __builtin_types_compatible_p(typeof(a), typeof(b))
--
>> drivers/staging/fbtft/fb_hx8353d.c:67:26: error: initializer element is not a compile-time constant
           write_reg(par, 0x2a, xs >> 8, xs & 0xff, xe >> 8, xe & 0xff);
                                ~~~^~~~
   drivers/staging/fbtft/fbtft.h:237:47: note: expanded from macro 'write_reg'
           ((par)->fbtftops.write_register(par, NUMARGS(__VA_ARGS__), __VA_ARGS__))
                                                        ^~~~~~~~~~~
   drivers/staging/fbtft/fbtft.h:234:44: note: expanded from macro 'NUMARGS'
   #define NUMARGS(...)  ARRAY_SIZE(((int[]){ __VA_ARGS__ }))
                                              ^~~~~~~~~~~
   include/linux/kernel.h:55:75: note: expanded from macro 'ARRAY_SIZE'
   #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]) + __must_be_array(arr))
                                                                             ^~~
   include/linux/compiler.h:232:59: note: expanded from macro '__must_be_array'
   #define __must_be_array(a)      BUILD_BUG_ON_ZERO(__same_type((a), &(a)[0]))
                                                                  ^
   include/linux/compiler_types.h:298:63: note: expanded from macro '__same_type'
   #define __same_type(a, b) __builtin_types_compatible_p(typeof(a), typeof(b))
                                                                 ^
   include/linux/build_bug.h:16:62: note: expanded from macro 'BUILD_BUG_ON_ZERO'
   #define BUILD_BUG_ON_ZERO(e) ((int)(sizeof(struct { int:(-!!(e)); })))
                                                                ^
   drivers/staging/fbtft/fb_hx8353d.c:70:26: error: initializer element is not a compile-time constant
           write_reg(par, 0x2b, ys >> 8, ys & 0xff, ye >> 8, ye & 0xff);
                                ~~~^~~~
   drivers/staging/fbtft/fbtft.h:237:47: note: expanded from macro 'write_reg'
           ((par)->fbtftops.write_register(par, NUMARGS(__VA_ARGS__), __VA_ARGS__))
                                                        ^~~~~~~~~~~
   drivers/staging/fbtft/fbtft.h:234:44: note: expanded from macro 'NUMARGS'
   #define NUMARGS(...)  ARRAY_SIZE(((int[]){ __VA_ARGS__ }))
                                              ^~~~~~~~~~~
   include/linux/kernel.h:55:75: note: expanded from macro 'ARRAY_SIZE'
   #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]) + __must_be_array(arr))
                                                                             ^~~
   include/linux/compiler.h:232:59: note: expanded from macro '__must_be_array'
   #define __must_be_array(a)      BUILD_BUG_ON_ZERO(__same_type((a), &(a)[0]))
                                                                  ^
   include/linux/compiler_types.h:298:63: note: expanded from macro '__same_type'
   #define __same_type(a, b) __builtin_types_compatible_p(typeof(a), typeof(b))
                                                                 ^
   include/linux/build_bug.h:16:62: note: expanded from macro 'BUILD_BUG_ON_ZERO'
   #define BUILD_BUG_ON_ZERO(e) ((int)(sizeof(struct { int:(-!!(e)); })))
                                                                ^
   drivers/staging/fbtft/fb_hx8353d.c:92:6: error: initializer element is not a compile-time constant
                             mx | my | (par->bgr << 3));
                             ^~~~~~~~~~~~~~~~~~~~~~~~~~
   drivers/staging/fbtft/fb_hx8353d.c:77:12: note: expanded from macro 'mx'
   #define mx BIT(6)
              ^
   include/vdso/bits.h:7:19: note: expanded from macro 'BIT'
   #define BIT(nr)                 (UL(1) << (nr))
                                   ^
   drivers/staging/fbtft/fbtft.h:237:47: note: expanded from macro 'write_reg'
           ((par)->fbtftops.write_register(par, NUMARGS(__VA_ARGS__), __VA_ARGS__))
                                                ~~~~~~~~^~~~~~~~~~~~
   note: (skipping 2 expansions in backtrace; use -fmacro-backtrace-limit=0 to see all)
   include/linux/compiler.h:232:59: note: expanded from macro '__must_be_array'
   #define __must_be_array(a)      BUILD_BUG_ON_ZERO(__same_type((a), &(a)[0]))
                                   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~
   include/linux/compiler_types.h:298:63: note: expanded from macro '__same_type'
   #define __same_type(a, b) __builtin_types_compatible_p(typeof(a), typeof(b))
                                                                 ^
   include/linux/build_bug.h:16:62: note: expanded from macro 'BUILD_BUG_ON_ZERO'
   #define BUILD_BUG_ON_ZERO(e) ((int)(sizeof(struct { int:(-!!(e)); })))
                                                                ^
   drivers/staging/fbtft/fb_hx8353d.c:96:6: error: initializer element is not a compile-time constant
                             my | mv | (par->bgr << 3));
                             ^~~~~~~~~~~~~~~~~~~~~~~~~~
   drivers/staging/fbtft/fb_hx8353d.c:76:12: note: expanded from macro 'my'
   #define my BIT(7)
              ^
   include/vdso/bits.h:7:19: note: expanded from macro 'BIT'
   #define BIT(nr)                 (UL(1) << (nr))
                                   ^
   drivers/staging/fbtft/fbtft.h:237:47: note: expanded from macro 'write_reg'
           ((par)->fbtftops.write_register(par, NUMARGS(__VA_ARGS__), __VA_ARGS__))
                                                ~~~~~~~~^~~~~~~~~~~~
   note: (skipping 2 expansions in backtrace; use -fmacro-backtrace-limit=0 to see all)
   include/linux/compiler.h:232:59: note: expanded from macro '__must_be_array'
   #define __must_be_array(a)      BUILD_BUG_ON_ZERO(__same_type((a), &(a)[0]))
                                   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~
   include/linux/compiler_types.h:298:63: note: expanded from macro '__same_type'
   #define __same_type(a, b) __builtin_types_compatible_p(typeof(a), typeof(b))
                                                                 ^
   include/linux/build_bug.h:16:62: note: expanded from macro 'BUILD_BUG_ON_ZERO'
   #define BUILD_BUG_ON_ZERO(e) ((int)(sizeof(struct { int:(-!!(e)); })))
                                                                ^
   drivers/staging/fbtft/fb_hx8353d.c:100:15: error: initializer element is not a compile-time constant
                             par->bgr << 3);
                             ~~~~~~~~~^~~~
   drivers/staging/fbtft/fbtft.h:237:47: note: expanded from macro 'write_reg'
           ((par)->fbtftops.write_register(par, NUMARGS(__VA_ARGS__), __VA_ARGS__))
                                                        ^~~~~~~~~~~
   drivers/staging/fbtft/fbtft.h:234:44: note: expanded from macro 'NUMARGS'
   #define NUMARGS(...)  ARRAY_SIZE(((int[]){ __VA_ARGS__ }))
                                              ^~~~~~~~~~~
   include/linux/kernel.h:55:75: note: expanded from macro 'ARRAY_SIZE'
   #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]) + __must_be_array(arr))
                                                                             ^~~
   include/linux/compiler.h:232:59: note: expanded from macro '__must_be_array'
   #define __must_be_array(a)      BUILD_BUG_ON_ZERO(__same_type((a), &(a)[0]))
                                                                  ^
--
>> drivers/staging/fbtft/fb_hx8357d.c:135:8: error: initializer element is not a compile-time constant
                     xs >> 8, xs & 0xff,  /* XSTART */
                     ~~~^~~~
   drivers/staging/fbtft/fbtft.h:237:47: note: expanded from macro 'write_reg'
           ((par)->fbtftops.write_register(par, NUMARGS(__VA_ARGS__), __VA_ARGS__))
                                                        ^~~~~~~~~~~
   drivers/staging/fbtft/fbtft.h:234:44: note: expanded from macro 'NUMARGS'
   #define NUMARGS(...)  ARRAY_SIZE(((int[]){ __VA_ARGS__ }))
                                              ^~~~~~~~~~~
   include/linux/kernel.h:55:75: note: expanded from macro 'ARRAY_SIZE'
   #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]) + __must_be_array(arr))
                                                                             ^~~
   include/linux/compiler.h:232:59: note: expanded from macro '__must_be_array'
   #define __must_be_array(a)      BUILD_BUG_ON_ZERO(__same_type((a), &(a)[0]))
                                                                  ^
   include/linux/compiler_types.h:298:63: note: expanded from macro '__same_type'
   #define __same_type(a, b) __builtin_types_compatible_p(typeof(a), typeof(b))
                                                                 ^
   include/linux/build_bug.h:16:62: note: expanded from macro 'BUILD_BUG_ON_ZERO'
   #define BUILD_BUG_ON_ZERO(e) ((int)(sizeof(struct { int:(-!!(e)); })))
                                                                ^
   drivers/staging/fbtft/fb_hx8357d.c:139:8: error: initializer element is not a compile-time constant
                     ys >> 8, ys & 0xff,  /* YSTART */
                     ~~~^~~~
   drivers/staging/fbtft/fbtft.h:237:47: note: expanded from macro 'write_reg'
           ((par)->fbtftops.write_register(par, NUMARGS(__VA_ARGS__), __VA_ARGS__))
                                                        ^~~~~~~~~~~
   drivers/staging/fbtft/fbtft.h:234:44: note: expanded from macro 'NUMARGS'
   #define NUMARGS(...)  ARRAY_SIZE(((int[]){ __VA_ARGS__ }))
                                              ^~~~~~~~~~~
   include/linux/kernel.h:55:75: note: expanded from macro 'ARRAY_SIZE'
   #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]) + __must_be_array(arr))
                                                                             ^~~
   include/linux/compiler.h:232:59: note: expanded from macro '__must_be_array'
   #define __must_be_array(a)      BUILD_BUG_ON_ZERO(__same_type((a), &(a)[0]))
                                                                  ^
   include/linux/compiler_types.h:298:63: note: expanded from macro '__same_type'
   #define __same_type(a, b) __builtin_types_compatible_p(typeof(a), typeof(b))
                                                                 ^
   include/linux/build_bug.h:16:62: note: expanded from macro 'BUILD_BUG_ON_ZERO'
   #define BUILD_BUG_ON_ZERO(e) ((int)(sizeof(struct { int:(-!!(e)); })))
                                                                ^
   drivers/staging/fbtft/fb_hx8357d.c:174:44: error: initializer element is not a compile-time constant
           write_reg(par, MIPI_DCS_SET_ADDRESS_MODE, val);
                                                     ^~~
   drivers/staging/fbtft/fbtft.h:237:47: note: expanded from macro 'write_reg'
           ((par)->fbtftops.write_register(par, NUMARGS(__VA_ARGS__), __VA_ARGS__))
                                                        ^~~~~~~~~~~
   drivers/staging/fbtft/fbtft.h:234:44: note: expanded from macro 'NUMARGS'
   #define NUMARGS(...)  ARRAY_SIZE(((int[]){ __VA_ARGS__ }))
                                              ^~~~~~~~~~~
   include/linux/kernel.h:55:75: note: expanded from macro 'ARRAY_SIZE'
   #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]) + __must_be_array(arr))
                                                                             ^~~
   include/linux/compiler.h:232:59: note: expanded from macro '__must_be_array'
   #define __must_be_array(a)      BUILD_BUG_ON_ZERO(__same_type((a), &(a)[0]))
                                                                  ^
   include/linux/compiler_types.h:298:63: note: expanded from macro '__same_type'
   #define __same_type(a, b) __builtin_types_compatible_p(typeof(a), typeof(b))
                                                                 ^
   include/linux/build_bug.h:16:62: note: expanded from macro 'BUILD_BUG_ON_ZERO'
   #define BUILD_BUG_ON_ZERO(e) ((int)(sizeof(struct { int:(-!!(e)); })))
                                                                ^
   3 errors generated.
..


vim +206 drivers/staging/fbtft/fbtft-core.c

c296d5f9957c03 Thomas Petazzoni  2014-12-31  201  
ed2084360d040a Krzysztof Adamski 2015-01-22  202  static void fbtft_set_addr_win(struct fbtft_par *par, int xs, int ys, int xe,
ed2084360d040a Krzysztof Adamski 2015-01-22  203  			       int ye)
c296d5f9957c03 Thomas Petazzoni  2014-12-31  204  {
a79cb3901ee3e0 Priit Laes        2015-12-20  205  	write_reg(par, MIPI_DCS_SET_COLUMN_ADDRESS,
c296d5f9957c03 Thomas Petazzoni  2014-12-31 @206  		  (xs >> 8) & 0xFF, xs & 0xFF, (xe >> 8) & 0xFF, xe & 0xFF);
c296d5f9957c03 Thomas Petazzoni  2014-12-31  207  
a79cb3901ee3e0 Priit Laes        2015-12-20  208  	write_reg(par, MIPI_DCS_SET_PAGE_ADDRESS,
c296d5f9957c03 Thomas Petazzoni  2014-12-31  209  		  (ys >> 8) & 0xFF, ys & 0xFF, (ye >> 8) & 0xFF, ye & 0xFF);
c296d5f9957c03 Thomas Petazzoni  2014-12-31  210  
a79cb3901ee3e0 Priit Laes        2015-12-20  211  	write_reg(par, MIPI_DCS_WRITE_MEMORY_START);
c296d5f9957c03 Thomas Petazzoni  2014-12-31  212  }
c296d5f9957c03 Thomas Petazzoni  2014-12-31  213
  
Greg KH Oct. 29, 2022, 7:32 a.m. UTC | #2
On Fri, Oct 28, 2022 at 07:00:05PM +0530, Deepak R Varma wrote:
> The ARRAY_SIZE(foo) macro should be preferred over sizeof operator
> based computation such as sizeof(foo)/sizeof(foo[0]) for finding
> number of elements in an array. Issue identified using coccicheck.
> 
> Signed-off-by: Deepak R Varma <drv@mailo.com>
> ---
>  drivers/staging/fbtft/fbtft.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/staging/fbtft/fbtft.h b/drivers/staging/fbtft/fbtft.h
> index 2c2b5f1c1df3..5506a473be91 100644
> --- a/drivers/staging/fbtft/fbtft.h
> +++ b/drivers/staging/fbtft/fbtft.h
> @@ -231,7 +231,7 @@ struct fbtft_par {
>  	bool polarity;
>  };
> 
> -#define NUMARGS(...)  (sizeof((int[]){__VA_ARGS__}) / sizeof(int))
> +#define NUMARGS(...)  ARRAY_SIZE(((int[]){ __VA_ARGS__ }))

Please please please test-build your patches before sending them out.
To not do so just wastes reviewer resources :(

thanks,

greg k-h
  
Deepak R Varma Oct. 29, 2022, 4:58 p.m. UTC | #3
On Sat, Oct 29, 2022 at 09:32:50AM +0200, Greg Kroah-Hartman wrote:
> On Fri, Oct 28, 2022 at 07:00:05PM +0530, Deepak R Varma wrote:
> > The ARRAY_SIZE(foo) macro should be preferred over sizeof operator
> > based computation such as sizeof(foo)/sizeof(foo[0]) for finding
> > number of elements in an array. Issue identified using coccicheck.
> >
> > Signed-off-by: Deepak R Varma <drv@mailo.com>
> > ---
> >  drivers/staging/fbtft/fbtft.h | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/staging/fbtft/fbtft.h b/drivers/staging/fbtft/fbtft.h
> > index 2c2b5f1c1df3..5506a473be91 100644
> > --- a/drivers/staging/fbtft/fbtft.h
> > +++ b/drivers/staging/fbtft/fbtft.h
> > @@ -231,7 +231,7 @@ struct fbtft_par {
> >  	bool polarity;
> >  };
> >
> > -#define NUMARGS(...)  (sizeof((int[]){__VA_ARGS__}) / sizeof(int))
> > +#define NUMARGS(...)  ARRAY_SIZE(((int[]){ __VA_ARGS__ }))
>
> Please please please test-build your patches before sending them out.
> To not do so just wastes reviewer resources :(

Hello Greg,
I did build the .ko files by making the driver/staging/fbtft/ path. I verified
.o and .ko files were built.

I did a make clean just now and was again able to rebuild without any errors.
Please see the attached log file.

Is there something wrong with the way I am firing the build?

Thank you,
./drv

>
> thanks,
>
> greg k-h
drv@ubunlion:~/git/kernels/staging$ git show HEAD
commit d7f07b9179428a4b84bcb7a90574edcea8c37fc4 (HEAD -> cocci-patches)
Author: Deepak R Varma <drv@mailo.com>
Date:   Fri Oct 28 18:40:54 2022 +0530

    staging: fbtft: Use ARRAY_SIZE() to get argument count

    The ARRAY_SIZE(foo) macro should be preferred over sizeof operator
    based computation such as sizeof(foo)/sizeof(foo[0]) for finding
    number of elements in an array. Issue identified using coccicheck.

    Signed-off-by: Deepak R Varma <drv@mailo.com>

diff --git a/drivers/staging/fbtft/fbtft.h b/drivers/staging/fbtft/fbtft.h
index 2c2b5f1c1df3..5506a473be91 100644
--- a/drivers/staging/fbtft/fbtft.h
+++ b/drivers/staging/fbtft/fbtft.h
@@ -231,7 +231,7 @@ struct fbtft_par {
        bool polarity;
 };

-#define NUMARGS(...)  (sizeof((int[]){__VA_ARGS__}) / sizeof(int))
+#define NUMARGS(...)  ARRAY_SIZE(((int[]){ __VA_ARGS__ }))

 #define write_reg(par, ...)                                            \
        ((par)->fbtftops.write_register(par, NUMARGS(__VA_ARGS__), __VA_ARGS__))
drv@ubunlion:~/git/kernels/staging$ make M=drivers/staging/fbtft/
drv@ubunlion:~/git/kernels/staging$ make M=drivers/staging/fbtft/ clean
  CLEAN   drivers/staging/fbtft/Module.symvers
drv@ubunlion:~/git/kernels/staging$ make M=drivers/staging/fbtft/
  CC [M]  drivers/staging/fbtft/fbtft-core.o
  CC [M]  drivers/staging/fbtft/fbtft-sysfs.o
  CC [M]  drivers/staging/fbtft/fbtft-bus.o
  CC [M]  drivers/staging/fbtft/fbtft-io.o
  LD [M]  drivers/staging/fbtft/fbtft.o
  CC [M]  drivers/staging/fbtft/fb_agm1264k-fl.o
  CC [M]  drivers/staging/fbtft/fb_bd663474.o
  CC [M]  drivers/staging/fbtft/fb_hx8340bn.o
  CC [M]  drivers/staging/fbtft/fb_hx8347d.o
  CC [M]  drivers/staging/fbtft/fb_hx8353d.o
  CC [M]  drivers/staging/fbtft/fb_hx8357d.o
  CC [M]  drivers/staging/fbtft/fb_ili9163.o
  CC [M]  drivers/staging/fbtft/fb_ili9320.o
  CC [M]  drivers/staging/fbtft/fb_ili9325.o
  CC [M]  drivers/staging/fbtft/fb_ili9340.o
  CC [M]  drivers/staging/fbtft/fb_ili9341.o
  CC [M]  drivers/staging/fbtft/fb_ili9481.o
  CC [M]  drivers/staging/fbtft/fb_ili9486.o
  CC [M]  drivers/staging/fbtft/fb_pcd8544.o
  CC [M]  drivers/staging/fbtft/fb_ra8875.o
  CC [M]  drivers/staging/fbtft/fb_s6d02a1.o
  CC [M]  drivers/staging/fbtft/fb_s6d1121.o
  CC [M]  drivers/staging/fbtft/fb_seps525.o
  CC [M]  drivers/staging/fbtft/fb_sh1106.o
  CC [M]  drivers/staging/fbtft/fb_ssd1289.o
  CC [M]  drivers/staging/fbtft/fb_ssd1305.o
  CC [M]  drivers/staging/fbtft/fb_ssd1306.o
  CC [M]  drivers/staging/fbtft/fb_ssd1325.o
  CC [M]  drivers/staging/fbtft/fb_ssd1331.o
  CC [M]  drivers/staging/fbtft/fb_ssd1351.o
  CC [M]  drivers/staging/fbtft/fb_st7735r.o
  CC [M]  drivers/staging/fbtft/fb_st7789v.o
  CC [M]  drivers/staging/fbtft/fb_tinylcd.o
  CC [M]  drivers/staging/fbtft/fb_tls8204.o
  CC [M]  drivers/staging/fbtft/fb_uc1611.o
  CC [M]  drivers/staging/fbtft/fb_uc1701.o
  CC [M]  drivers/staging/fbtft/fb_upd161704.o
  MODPOST drivers/staging/fbtft/Module.symvers
  CC [M]  drivers/staging/fbtft/fb_agm1264k-fl.mod.o
  LD [M]  drivers/staging/fbtft/fb_agm1264k-fl.ko
  BTF [M] drivers/staging/fbtft/fb_agm1264k-fl.ko
Skipping BTF generation for drivers/staging/fbtft/fb_agm1264k-fl.ko due to unavailability of vmlinux
  CC [M]  drivers/staging/fbtft/fb_bd663474.mod.o
  LD [M]  drivers/staging/fbtft/fb_bd663474.ko
  BTF [M] drivers/staging/fbtft/fb_bd663474.ko
Skipping BTF generation for drivers/staging/fbtft/fb_bd663474.ko due to unavailability of vmlinux
  CC [M]  drivers/staging/fbtft/fb_hx8340bn.mod.o
  LD [M]  drivers/staging/fbtft/fb_hx8340bn.ko
  BTF [M] drivers/staging/fbtft/fb_hx8340bn.ko
Skipping BTF generation for drivers/staging/fbtft/fb_hx8340bn.ko due to unavailability of vmlinux
  CC [M]  drivers/staging/fbtft/fb_hx8347d.mod.o
  LD [M]  drivers/staging/fbtft/fb_hx8347d.ko
  BTF [M] drivers/staging/fbtft/fb_hx8347d.ko
Skipping BTF generation for drivers/staging/fbtft/fb_hx8347d.ko due to unavailability of vmlinux
  CC [M]  drivers/staging/fbtft/fb_hx8353d.mod.o
  LD [M]  drivers/staging/fbtft/fb_hx8353d.ko
  BTF [M] drivers/staging/fbtft/fb_hx8353d.ko
Skipping BTF generation for drivers/staging/fbtft/fb_hx8353d.ko due to unavailability of vmlinux
  CC [M]  drivers/staging/fbtft/fb_hx8357d.mod.o
  LD [M]  drivers/staging/fbtft/fb_hx8357d.ko
  BTF [M] drivers/staging/fbtft/fb_hx8357d.ko
Skipping BTF generation for drivers/staging/fbtft/fb_hx8357d.ko due to unavailability of vmlinux
  CC [M]  drivers/staging/fbtft/fb_ili9163.mod.o
  LD [M]  drivers/staging/fbtft/fb_ili9163.ko
  BTF [M] drivers/staging/fbtft/fb_ili9163.ko
Skipping BTF generation for drivers/staging/fbtft/fb_ili9163.ko due to unavailability of vmlinux
  CC [M]  drivers/staging/fbtft/fb_ili9320.mod.o
  LD [M]  drivers/staging/fbtft/fb_ili9320.ko
  BTF [M] drivers/staging/fbtft/fb_ili9320.ko
Skipping BTF generation for drivers/staging/fbtft/fb_ili9320.ko due to unavailability of vmlinux
  CC [M]  drivers/staging/fbtft/fb_ili9325.mod.o
  LD [M]  drivers/staging/fbtft/fb_ili9325.ko
  BTF [M] drivers/staging/fbtft/fb_ili9325.ko
Skipping BTF generation for drivers/staging/fbtft/fb_ili9325.ko due to unavailability of vmlinux
  CC [M]  drivers/staging/fbtft/fb_ili9340.mod.o
  LD [M]  drivers/staging/fbtft/fb_ili9340.ko
  BTF [M] drivers/staging/fbtft/fb_ili9340.ko
Skipping BTF generation for drivers/staging/fbtft/fb_ili9340.ko due to unavailability of vmlinux
  CC [M]  drivers/staging/fbtft/fb_ili9341.mod.o
  LD [M]  drivers/staging/fbtft/fb_ili9341.ko
  BTF [M] drivers/staging/fbtft/fb_ili9341.ko
Skipping BTF generation for drivers/staging/fbtft/fb_ili9341.ko due to unavailability of vmlinux
  CC [M]  drivers/staging/fbtft/fb_ili9481.mod.o
  LD [M]  drivers/staging/fbtft/fb_ili9481.ko
  BTF [M] drivers/staging/fbtft/fb_ili9481.ko
Skipping BTF generation for drivers/staging/fbtft/fb_ili9481.ko due to unavailability of vmlinux
  CC [M]  drivers/staging/fbtft/fb_ili9486.mod.o
  LD [M]  drivers/staging/fbtft/fb_ili9486.ko
  BTF [M] drivers/staging/fbtft/fb_ili9486.ko
Skipping BTF generation for drivers/staging/fbtft/fb_ili9486.ko due to unavailability of vmlinux
  CC [M]  drivers/staging/fbtft/fb_pcd8544.mod.o
  LD [M]  drivers/staging/fbtft/fb_pcd8544.ko
  BTF [M] drivers/staging/fbtft/fb_pcd8544.ko
Skipping BTF generation for drivers/staging/fbtft/fb_pcd8544.ko due to unavailability of vmlinux
  CC [M]  drivers/staging/fbtft/fb_ra8875.mod.o
  LD [M]  drivers/staging/fbtft/fb_ra8875.ko
  BTF [M] drivers/staging/fbtft/fb_ra8875.ko
Skipping BTF generation for drivers/staging/fbtft/fb_ra8875.ko due to unavailability of vmlinux
  CC [M]  drivers/staging/fbtft/fb_s6d02a1.mod.o
  LD [M]  drivers/staging/fbtft/fb_s6d02a1.ko
  BTF [M] drivers/staging/fbtft/fb_s6d02a1.ko
Skipping BTF generation for drivers/staging/fbtft/fb_s6d02a1.ko due to unavailability of vmlinux
  CC [M]  drivers/staging/fbtft/fb_s6d1121.mod.o
  LD [M]  drivers/staging/fbtft/fb_s6d1121.ko
  BTF [M] drivers/staging/fbtft/fb_s6d1121.ko
Skipping BTF generation for drivers/staging/fbtft/fb_s6d1121.ko due to unavailability of vmlinux
  CC [M]  drivers/staging/fbtft/fb_seps525.mod.o
  LD [M]  drivers/staging/fbtft/fb_seps525.ko
  BTF [M] drivers/staging/fbtft/fb_seps525.ko
Skipping BTF generation for drivers/staging/fbtft/fb_seps525.ko due to unavailability of vmlinux
  CC [M]  drivers/staging/fbtft/fb_sh1106.mod.o
  LD [M]  drivers/staging/fbtft/fb_sh1106.ko
  BTF [M] drivers/staging/fbtft/fb_sh1106.ko
Skipping BTF generation for drivers/staging/fbtft/fb_sh1106.ko due to unavailability of vmlinux
  CC [M]  drivers/staging/fbtft/fb_ssd1289.mod.o
  LD [M]  drivers/staging/fbtft/fb_ssd1289.ko
  BTF [M] drivers/staging/fbtft/fb_ssd1289.ko
Skipping BTF generation for drivers/staging/fbtft/fb_ssd1289.ko due to unavailability of vmlinux
  CC [M]  drivers/staging/fbtft/fb_ssd1305.mod.o
  LD [M]  drivers/staging/fbtft/fb_ssd1305.ko
  BTF [M] drivers/staging/fbtft/fb_ssd1305.ko
Skipping BTF generation for drivers/staging/fbtft/fb_ssd1305.ko due to unavailability of vmlinux
  CC [M]  drivers/staging/fbtft/fb_ssd1306.mod.o
  LD [M]  drivers/staging/fbtft/fb_ssd1306.ko
  BTF [M] drivers/staging/fbtft/fb_ssd1306.ko
Skipping BTF generation for drivers/staging/fbtft/fb_ssd1306.ko due to unavailability of vmlinux
  CC [M]  drivers/staging/fbtft/fb_ssd1325.mod.o
  LD [M]  drivers/staging/fbtft/fb_ssd1325.ko
  BTF [M] drivers/staging/fbtft/fb_ssd1325.ko
Skipping BTF generation for drivers/staging/fbtft/fb_ssd1325.ko due to unavailability of vmlinux
  CC [M]  drivers/staging/fbtft/fb_ssd1331.mod.o
  LD [M]  drivers/staging/fbtft/fb_ssd1331.ko
  BTF [M] drivers/staging/fbtft/fb_ssd1331.ko
Skipping BTF generation for drivers/staging/fbtft/fb_ssd1331.ko due to unavailability of vmlinux
  CC [M]  drivers/staging/fbtft/fb_ssd1351.mod.o
  LD [M]  drivers/staging/fbtft/fb_ssd1351.ko
  BTF [M] drivers/staging/fbtft/fb_ssd1351.ko
Skipping BTF generation for drivers/staging/fbtft/fb_ssd1351.ko due to unavailability of vmlinux
  CC [M]  drivers/staging/fbtft/fb_st7735r.mod.o
  LD [M]  drivers/staging/fbtft/fb_st7735r.ko
  BTF [M] drivers/staging/fbtft/fb_st7735r.ko
Skipping BTF generation for drivers/staging/fbtft/fb_st7735r.ko due to unavailability of vmlinux
  CC [M]  drivers/staging/fbtft/fb_st7789v.mod.o
  LD [M]  drivers/staging/fbtft/fb_st7789v.ko
  BTF [M] drivers/staging/fbtft/fb_st7789v.ko
Skipping BTF generation for drivers/staging/fbtft/fb_st7789v.ko due to unavailability of vmlinux
  CC [M]  drivers/staging/fbtft/fb_tinylcd.mod.o
  LD [M]  drivers/staging/fbtft/fb_tinylcd.ko
  BTF [M] drivers/staging/fbtft/fb_tinylcd.ko
Skipping BTF generation for drivers/staging/fbtft/fb_tinylcd.ko due to unavailability of vmlinux
  CC [M]  drivers/staging/fbtft/fb_tls8204.mod.o
  LD [M]  drivers/staging/fbtft/fb_tls8204.ko
  BTF [M] drivers/staging/fbtft/fb_tls8204.ko
Skipping BTF generation for drivers/staging/fbtft/fb_tls8204.ko due to unavailability of vmlinux
  CC [M]  drivers/staging/fbtft/fb_uc1611.mod.o
  LD [M]  drivers/staging/fbtft/fb_uc1611.ko
  BTF [M] drivers/staging/fbtft/fb_uc1611.ko
Skipping BTF generation for drivers/staging/fbtft/fb_uc1611.ko due to unavailability of vmlinux
  CC [M]  drivers/staging/fbtft/fb_uc1701.mod.o
  LD [M]  drivers/staging/fbtft/fb_uc1701.ko
  BTF [M] drivers/staging/fbtft/fb_uc1701.ko
Skipping BTF generation for drivers/staging/fbtft/fb_uc1701.ko due to unavailability of vmlinux
  CC [M]  drivers/staging/fbtft/fb_upd161704.mod.o
  LD [M]  drivers/staging/fbtft/fb_upd161704.ko
  BTF [M] drivers/staging/fbtft/fb_upd161704.ko
Skipping BTF generation for drivers/staging/fbtft/fb_upd161704.ko due to unavailability of vmlinux
  CC [M]  drivers/staging/fbtft/fbtft.mod.o
  LD [M]  drivers/staging/fbtft/fbtft.ko
  BTF [M] drivers/staging/fbtft/fbtft.ko
Skipping BTF generation for drivers/staging/fbtft/fbtft.ko due to unavailability of vmlinux
drv@ubunlion:~/git/kernels/staging$
  
Julia Lawall Oct. 29, 2022, 5:34 p.m. UTC | #4
On Sat, 29 Oct 2022, Deepak R Varma wrote:

> On Sat, Oct 29, 2022 at 09:32:50AM +0200, Greg Kroah-Hartman wrote:
> > On Fri, Oct 28, 2022 at 07:00:05PM +0530, Deepak R Varma wrote:
> > > The ARRAY_SIZE(foo) macro should be preferred over sizeof operator
> > > based computation such as sizeof(foo)/sizeof(foo[0]) for finding
> > > number of elements in an array. Issue identified using coccicheck.
> > >
> > > Signed-off-by: Deepak R Varma <drv@mailo.com>
> > > ---
> > >  drivers/staging/fbtft/fbtft.h | 2 +-
> > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/staging/fbtft/fbtft.h b/drivers/staging/fbtft/fbtft.h
> > > index 2c2b5f1c1df3..5506a473be91 100644
> > > --- a/drivers/staging/fbtft/fbtft.h
> > > +++ b/drivers/staging/fbtft/fbtft.h
> > > @@ -231,7 +231,7 @@ struct fbtft_par {
> > >  	bool polarity;
> > >  };
> > >
> > > -#define NUMARGS(...)  (sizeof((int[]){__VA_ARGS__}) / sizeof(int))
> > > +#define NUMARGS(...)  ARRAY_SIZE(((int[]){ __VA_ARGS__ }))
> >
> > Please please please test-build your patches before sending them out.
> > To not do so just wastes reviewer resources :(
>
> Hello Greg,
> I did build the .ko files by making the driver/staging/fbtft/ path. I verified
> .o and .ko files were built.
>
> I did a make clean just now and was again able to rebuild without any errors.
> Please see the attached log file.
>
> Is there something wrong with the way I am firing the build?

The change is in the definition of a macro.  The compiler won't help you
in this case unless the macro is actually used in code that is compiled.
Find the uses and check for any nearby ifdefs.  For file foo.c you can
also do make foo.i to see the result of reducing ifdef and expanding
macros.  Then you can see if the code you changed is actually included in
the build.

julia
  
Deepak R Varma Oct. 31, 2022, 7:11 a.m. UTC | #5
On Sat, Oct 29, 2022 at 07:34:26PM +0200, Julia Lawall wrote:
>
>
> On Sat, 29 Oct 2022, Deepak R Varma wrote:
>
> > On Sat, Oct 29, 2022 at 09:32:50AM +0200, Greg Kroah-Hartman wrote:
> > > On Fri, Oct 28, 2022 at 07:00:05PM +0530, Deepak R Varma wrote:
> > > > The ARRAY_SIZE(foo) macro should be preferred over sizeof operator
> > > > based computation such as sizeof(foo)/sizeof(foo[0]) for finding
> > > > number of elements in an array. Issue identified using coccicheck.
> > > >
> > > > Signed-off-by: Deepak R Varma <drv@mailo.com>
> > > > ---
> > > >  drivers/staging/fbtft/fbtft.h | 2 +-
> > > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > > >
> > > > diff --git a/drivers/staging/fbtft/fbtft.h b/drivers/staging/fbtft/fbtft.h
> > > > index 2c2b5f1c1df3..5506a473be91 100644
> > > > --- a/drivers/staging/fbtft/fbtft.h
> > > > +++ b/drivers/staging/fbtft/fbtft.h
> > > > @@ -231,7 +231,7 @@ struct fbtft_par {
> > > >  	bool polarity;
> > > >  };
> > > >
> > > > -#define NUMARGS(...)  (sizeof((int[]){__VA_ARGS__}) / sizeof(int))
> > > > +#define NUMARGS(...)  ARRAY_SIZE(((int[]){ __VA_ARGS__ }))
> > >
> > > Please please please test-build your patches before sending them out.
> > > To not do so just wastes reviewer resources :(
> >
> > Hello Greg,
> > I did build the .ko files by making the driver/staging/fbtft/ path. I verified
> > .o and .ko files were built.
> >
> > I did a make clean just now and was again able to rebuild without any errors.
> > Please see the attached log file.
> >
> > Is there something wrong with the way I am firing the build?
>
> The change is in the definition of a macro.  The compiler won't help you
> in this case unless the macro is actually used in code that is compiled.
> Find the uses and check for any nearby ifdefs.  For file foo.c you can
> also do make foo.i to see the result of reducing ifdef and expanding
> macros.  Then you can see if the code you changed is actually included in
> the build.

Okay. This is helpful. I understand. Looking into the file where the macro
expansion is reported to be failed.

Thank you,
./drv

>
> julia
>
  
Deepak R Varma Oct. 31, 2022, 9:40 a.m. UTC | #6
On Mon, Oct 31, 2022 at 12:41:40PM +0530, Deepak Varma wrote:
> On Sat, Oct 29, 2022 at 07:34:26PM +0200, Julia Lawall wrote:
> >
> >
> > On Sat, 29 Oct 2022, Deepak R Varma wrote:
> >
> > > On Sat, Oct 29, 2022 at 09:32:50AM +0200, Greg Kroah-Hartman wrote:
> > > > On Fri, Oct 28, 2022 at 07:00:05PM +0530, Deepak R Varma wrote:
> > > > > The ARRAY_SIZE(foo) macro should be preferred over sizeof operator
> > > > > based computation such as sizeof(foo)/sizeof(foo[0]) for finding
> > > > > number of elements in an array. Issue identified using coccicheck.
> > > > >
> > > > > Signed-off-by: Deepak R Varma <drv@mailo.com>
> > > > > ---
> > > > >  drivers/staging/fbtft/fbtft.h | 2 +-
> > > > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > > > >
> > > > > diff --git a/drivers/staging/fbtft/fbtft.h b/drivers/staging/fbtft/fbtft.h
> > > > > index 2c2b5f1c1df3..5506a473be91 100644
> > > > > --- a/drivers/staging/fbtft/fbtft.h
> > > > > +++ b/drivers/staging/fbtft/fbtft.h
> > > > > @@ -231,7 +231,7 @@ struct fbtft_par {
> > > > >  	bool polarity;
> > > > >  };
> > > > >
> > > > > -#define NUMARGS(...)  (sizeof((int[]){__VA_ARGS__}) / sizeof(int))
> > > > > +#define NUMARGS(...)  ARRAY_SIZE(((int[]){ __VA_ARGS__ }))
> > > >
> > > > Please please please test-build your patches before sending them out.
> > > > To not do so just wastes reviewer resources :(
> > >
> > > Hello Greg,
> > > I did build the .ko files by making the driver/staging/fbtft/ path. I verified
> > > .o and .ko files were built.
> > >
> > > I did a make clean just now and was again able to rebuild without any errors.
> > > Please see the attached log file.
> > >
> > > Is there something wrong with the way I am firing the build?
> >
> > The change is in the definition of a macro.  The compiler won't help you
> > in this case unless the macro is actually used in code that is compiled.
> > Find the uses and check for any nearby ifdefs.  For file foo.c you can
> > also do make foo.i to see the result of reducing ifdef and expanding
> > macros.  Then you can see if the code you changed is actually included in
> > the build.
>
> Okay. This is helpful. I understand. Looking into the file where the macro
> expansion is reported to be failed.

Hi Julia,
I could see the macro expansions in the .i files for the fbtft-core.c and
fb_hx8353d.c file. I am not sure why it built successfully on my x86 though. The
error in Kerbel bot seems to be specific to ARM arch. I will try that later
today. I am on the right track to the build error triage?

Also, while reviewing the macro expansion, I saw change in the computation that
seems odd to me. In the denominator of the expanded macro, there is a "+
((int)...." computation that I am not sure if is result of ARRAY_SIZE. I have
attached the old anf the new .i file diff for your review. If you get a change
could you help me understand why this additional computation is added to the
denominator?

Thank you,
./drv
>
> Thank you,
> ./drv
>
> >
> > julia
> >
>
>
>
  
Deepak R Varma Oct. 31, 2022, 9:41 a.m. UTC | #7
On Mon, Oct 31, 2022 at 03:10:27PM +0530, Deepak Varma wrote:
> On Mon, Oct 31, 2022 at 12:41:40PM +0530, Deepak Varma wrote:
> > On Sat, Oct 29, 2022 at 07:34:26PM +0200, Julia Lawall wrote:
> > >
> > >
> > > On Sat, 29 Oct 2022, Deepak R Varma wrote:
> > >
> > > > On Sat, Oct 29, 2022 at 09:32:50AM +0200, Greg Kroah-Hartman wrote:
> > > > > On Fri, Oct 28, 2022 at 07:00:05PM +0530, Deepak R Varma wrote:
> > > > > > The ARRAY_SIZE(foo) macro should be preferred over sizeof operator
> > > > > > based computation such as sizeof(foo)/sizeof(foo[0]) for finding
> > > > > > number of elements in an array. Issue identified using coccicheck.
> > > > > >
> > > > > > Signed-off-by: Deepak R Varma <drv@mailo.com>
> > > > > > ---
> > > > > >  drivers/staging/fbtft/fbtft.h | 2 +-
> > > > > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > > > > >
> > > > > > diff --git a/drivers/staging/fbtft/fbtft.h b/drivers/staging/fbtft/fbtft.h
> > > > > > index 2c2b5f1c1df3..5506a473be91 100644
> > > > > > --- a/drivers/staging/fbtft/fbtft.h
> > > > > > +++ b/drivers/staging/fbtft/fbtft.h
> > > > > > @@ -231,7 +231,7 @@ struct fbtft_par {
> > > > > >  	bool polarity;
> > > > > >  };
> > > > > >
> > > > > > -#define NUMARGS(...)  (sizeof((int[]){__VA_ARGS__}) / sizeof(int))
> > > > > > +#define NUMARGS(...)  ARRAY_SIZE(((int[]){ __VA_ARGS__ }))
> > > > >
> > > > > Please please please test-build your patches before sending them out.
> > > > > To not do so just wastes reviewer resources :(
> > > >
> > > > Hello Greg,
> > > > I did build the .ko files by making the driver/staging/fbtft/ path. I verified
> > > > .o and .ko files were built.
> > > >
> > > > I did a make clean just now and was again able to rebuild without any errors.
> > > > Please see the attached log file.
> > > >
> > > > Is there something wrong with the way I am firing the build?
> > >
> > > The change is in the definition of a macro.  The compiler won't help you
> > > in this case unless the macro is actually used in code that is compiled.
> > > Find the uses and check for any nearby ifdefs.  For file foo.c you can
> > > also do make foo.i to see the result of reducing ifdef and expanding
> > > macros.  Then you can see if the code you changed is actually included in
> > > the build.
> >
> > Okay. This is helpful. I understand. Looking into the file where the macro
> > expansion is reported to be failed.
>
> Hi Julia,
> I could see the macro expansions in the .i files for the fbtft-core.c and
> fb_hx8353d.c file. I am not sure why it built successfully on my x86 though. The
> error in Kerbel bot seems to be specific to ARM arch. I will try that later
> today. I am on the right track to the build error triage?
>
> Also, while reviewing the macro expansion, I saw change in the computation that
> seems odd to me. In the denominator of the expanded macro, there is a "+
> ((int)...." computation that I am not sure if is result of ARRAY_SIZE. I have
> attached the old anf the new .i file diff for your review. If you get a change
> could you help me understand why this additional computation is added to the
> denominator?

File now attached.

>
> Thank you,
> ./drv
> >
> > Thank you,
> > ./drv
> >
> > >
> > > julia
> > >
> >
> >
> >
>
>
>
  
Julia Lawall Oct. 31, 2022, 12:05 p.m. UTC | #8
On Mon, 31 Oct 2022, Deepak R Varma wrote:

> On Mon, Oct 31, 2022 at 12:41:40PM +0530, Deepak Varma wrote:
> > On Sat, Oct 29, 2022 at 07:34:26PM +0200, Julia Lawall wrote:
> > >
> > >
> > > On Sat, 29 Oct 2022, Deepak R Varma wrote:
> > >
> > > > On Sat, Oct 29, 2022 at 09:32:50AM +0200, Greg Kroah-Hartman wrote:
> > > > > On Fri, Oct 28, 2022 at 07:00:05PM +0530, Deepak R Varma wrote:
> > > > > > The ARRAY_SIZE(foo) macro should be preferred over sizeof operator
> > > > > > based computation such as sizeof(foo)/sizeof(foo[0]) for finding
> > > > > > number of elements in an array. Issue identified using coccicheck.
> > > > > >
> > > > > > Signed-off-by: Deepak R Varma <drv@mailo.com>
> > > > > > ---
> > > > > >  drivers/staging/fbtft/fbtft.h | 2 +-
> > > > > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > > > > >
> > > > > > diff --git a/drivers/staging/fbtft/fbtft.h b/drivers/staging/fbtft/fbtft.h
> > > > > > index 2c2b5f1c1df3..5506a473be91 100644
> > > > > > --- a/drivers/staging/fbtft/fbtft.h
> > > > > > +++ b/drivers/staging/fbtft/fbtft.h
> > > > > > @@ -231,7 +231,7 @@ struct fbtft_par {
> > > > > >  	bool polarity;
> > > > > >  };
> > > > > >
> > > > > > -#define NUMARGS(...)  (sizeof((int[]){__VA_ARGS__}) / sizeof(int))
> > > > > > +#define NUMARGS(...)  ARRAY_SIZE(((int[]){ __VA_ARGS__ }))
> > > > >
> > > > > Please please please test-build your patches before sending them out.
> > > > > To not do so just wastes reviewer resources :(
> > > >
> > > > Hello Greg,
> > > > I did build the .ko files by making the driver/staging/fbtft/ path. I verified
> > > > .o and .ko files were built.
> > > >
> > > > I did a make clean just now and was again able to rebuild without any errors.
> > > > Please see the attached log file.
> > > >
> > > > Is there something wrong with the way I am firing the build?
> > >
> > > The change is in the definition of a macro.  The compiler won't help you
> > > in this case unless the macro is actually used in code that is compiled.
> > > Find the uses and check for any nearby ifdefs.  For file foo.c you can
> > > also do make foo.i to see the result of reducing ifdef and expanding
> > > macros.  Then you can see if the code you changed is actually included in
> > > the build.
> >
> > Okay. This is helpful. I understand. Looking into the file where the macro
> > expansion is reported to be failed.
>
> Hi Julia,
> I could see the macro expansions in the .i files for the fbtft-core.c and
> fb_hx8353d.c file. I am not sure why it built successfully on my x86 though. The
> error in Kerbel bot seems to be specific to ARM arch. I will try that later
> today. I am on the right track to the build error triage?
>
> Also, while reviewing the macro expansion, I saw change in the computation that
> seems odd to me. In the denominator of the expanded macro, there is a "+
> ((int)...." computation that I am not sure if is result of ARRAY_SIZE. I have
> attached the old anf the new .i file diff for your review. If you get a change
> could you help me understand why this additional computation is added to the
> denominator?

I took a look, but it's pretty complex.  You could take the code and
reorganize it so that it is more readable, and then take the definition of
the ARRAY_SIZE macro, to better see what is going on.

julia

>
> Thank you,
> ./drv
> >
> > Thank you,
> > ./drv
> >
> > >
> > > julia
> > >
> >
> >
> >
>
>
>
  
Deepak R Varma Nov. 4, 2022, 12:01 p.m. UTC | #9
On Mon, Oct 31, 2022 at 01:05:32PM +0100, Julia Lawall wrote:
>
>
> I took a look, but it's pretty complex.  You could take the code and
> reorganize it so that it is more readable, and then take the definition of
> the ARRAY_SIZE macro, to better see what is going on.
>
> julia
>

Hello Greg, Julia,
I was able to successfully build the fbtft object file for arm architecture as
well. I used gcc 6.5.0 and 9.5.0 tool chains. It was successful using both. I
have attached the build log from my machine for your reference.

I am also looking at the .i file and rearrange the expanded macro to understand
it. However, since it is built successfully, I am not sure if that is truly the
problem area.

Should I resend the patch and check if it still errors the kernel build bot?
Anything else I can try?

Thank you,
./drv
drv@qemulion:~/git/kernels/staging$ git status
On branch patches-11022022
Changes not staged for commit:
  (use "git add <file>..." to update what will be committed)
  (use "git restore <file>..." to discard changes in working directory)
	modified:   drivers/staging/fbtft/fbtft.h

no changes added to commit (use "git add" and/or "git commit -a")
drv@qemulion:~/git/kernels/staging$ git diff
diff --git a/drivers/staging/fbtft/fbtft.h b/drivers/staging/fbtft/fbtft.h
index 2c2b5f1c1df3..f2ed23123849 100644
--- a/drivers/staging/fbtft/fbtft.h
+++ b/drivers/staging/fbtft/fbtft.h
@@ -231,7 +231,7 @@ struct fbtft_par {
        bool polarity;
 };

-#define NUMARGS(...)  (sizeof((int[]){__VA_ARGS__}) / sizeof(int))
+#define NUMARGS(...)   ARRAY_SIZE(((int[]){ __VA_ARGS__ }))

 #define write_reg(par, ...)                                            \
        ((par)->fbtftops.write_register(par, NUMARGS(__VA_ARGS__), __VA_ARGS__))
drv@qemulion:~/git/kernels/staging$ make CROSS_COMPILE=/opt/gcc-9.5.0-nolibc/arm-linux-gnueabi/bin/arm-linux-gnueabi- --jobs=8 ARCH=arm drivers/staging/fbtft/fbtft-core.o
  CALL    scripts/checksyscalls.sh
  CC      drivers/staging/fbtft/fbtft-core.o
drv@qemulion:~/git/kernels/staging$ make CROSS_COMPILE=/opt/gcc-9.5.0-nolibc/arm-linux-gnueabi/bin/arm-linux-gnueabi- --jobs=8 ARCH=arm drivers/staging/fbtft/
  CALL    scripts/checksyscalls.sh
  CC      drivers/staging/fbtft/fbtft-sysfs.o
  CC      drivers/staging/fbtft/fbtft-bus.o
  CC      drivers/staging/fbtft/fbtft-io.o
  CC      drivers/staging/fbtft/fb_agm1264k-fl.o
  CC      drivers/staging/fbtft/fb_bd663474.o
  CC      drivers/staging/fbtft/fb_hx8340bn.o
  CC      drivers/staging/fbtft/fb_hx8347d.o
  CC      drivers/staging/fbtft/fb_hx8353d.o
  CC      drivers/staging/fbtft/fb_hx8357d.o
  CC      drivers/staging/fbtft/fb_ili9163.o
  CC      drivers/staging/fbtft/fb_ili9320.o
  CC      drivers/staging/fbtft/fb_ili9325.o
  CC      drivers/staging/fbtft/fb_ili9340.o
  CC      drivers/staging/fbtft/fb_ili9341.o
  CC      drivers/staging/fbtft/fb_ili9481.o
  CC      drivers/staging/fbtft/fb_ili9486.o
  CC      drivers/staging/fbtft/fb_pcd8544.o
  CC      drivers/staging/fbtft/fb_ra8875.o
  CC      drivers/staging/fbtft/fb_s6d02a1.o
  CC      drivers/staging/fbtft/fb_s6d1121.o
  CC      drivers/staging/fbtft/fb_seps525.o
  CC      drivers/staging/fbtft/fb_sh1106.o
  CC      drivers/staging/fbtft/fb_ssd1289.o
  CC      drivers/staging/fbtft/fb_ssd1305.o
  CC      drivers/staging/fbtft/fb_ssd1306.o
  CC      drivers/staging/fbtft/fb_ssd1325.o
  CC      drivers/staging/fbtft/fb_ssd1331.o
  CC      drivers/staging/fbtft/fb_ssd1351.o
  CC      drivers/staging/fbtft/fb_st7735r.o
  CC      drivers/staging/fbtft/fb_st7789v.o
  CC      drivers/staging/fbtft/fb_tinylcd.o
  CC      drivers/staging/fbtft/fb_tls8204.o
  CC      drivers/staging/fbtft/fb_uc1611.o
  CC      drivers/staging/fbtft/fb_uc1701.o
  CC      drivers/staging/fbtft/fb_upd161704.o
  AR      drivers/staging/fbtft/built-in.a
drv@qemulion:~/git/kernels/staging$
  
Deepak R Varma Nov. 4, 2022, 2:42 p.m. UTC | #10
On Fri, Nov 04, 2022 at 05:31:24PM +0530, Deepak R Varma wrote:
> On Mon, Oct 31, 2022 at 01:05:32PM +0100, Julia Lawall wrote:
> >
> >
> > I took a look, but it's pretty complex.  You could take the code and
> > reorganize it so that it is more readable, and then take the definition of
> > the ARRAY_SIZE macro, to better see what is going on.
> >
> > julia
> >
>
> Hello Greg, Julia,
> I was able to successfully build the fbtft object file for arm architecture as
> well. I used gcc 6.5.0 and 9.5.0 tool chains. It was successful using both. I
> have attached the build log from my machine for your reference.
>
> I am also looking at the .i file and rearrange the expanded macro to understand
> it. However, since it is built successfully, I am not sure if that is truly the
> problem area.
>
> Should I resend the patch and check if it still errors the kernel build bot?
> Anything else I can try?

Looks like the change I proposed is causing nesting inside the write_reg
function due to additional set of { & } brackets for the __VA_ARGS__ symbol.

Am I understanding it right?

>
> Thank you,
> ./drv
  
Deepak R Varma Nov. 9, 2022, 3 p.m. UTC | #11
On Fri, Nov 04, 2022 at 08:12:11PM +0530, Deepak R Varma wrote:
> On Fri, Nov 04, 2022 at 05:31:24PM +0530, Deepak R Varma wrote:
> > On Mon, Oct 31, 2022 at 01:05:32PM +0100, Julia Lawall wrote:
> > >
> > >
> > > I took a look, but it's pretty complex.  You could take the code and
> > > reorganize it so that it is more readable, and then take the definition of
> > > the ARRAY_SIZE macro, to better see what is going on.
> > >
> > > julia
> > >
> >
> > Hello Greg, Julia,
> > I was able to successfully build the fbtft object file for arm architecture as
> > well. I used gcc 6.5.0 and 9.5.0 tool chains. It was successful using both. I
> > have attached the build log from my machine for your reference.
> >
> > I am also looking at the .i file and rearrange the expanded macro to understand
> > it. However, since it is built successfully, I am not sure if that is truly the
> > problem area.
> >
> > Should I resend the patch and check if it still errors the kernel build bot?
> > Anything else I can try?
>
> Looks like the change I proposed is causing nesting inside the write_reg
> function due to additional set of { & } brackets for the __VA_ARGS__ symbol.
>
> Am I understanding it right?

Hello Julia, Greg,
I am unable to reproduce this build failure on my local machine. I tried the X86
and arm based build. I am unable to troubleshoot this further. Do you have any
other suggestions? If not, I will drop this patch from my watch list.

Thank you,
./drv

>
> >
> > Thank you,
> > ./drv
>
>
>
>
  
Greg KH Nov. 9, 2022, 4 p.m. UTC | #12
On Wed, Nov 09, 2022 at 08:30:52PM +0530, Deepak R Varma wrote:
> On Fri, Nov 04, 2022 at 08:12:11PM +0530, Deepak R Varma wrote:
> > On Fri, Nov 04, 2022 at 05:31:24PM +0530, Deepak R Varma wrote:
> > > On Mon, Oct 31, 2022 at 01:05:32PM +0100, Julia Lawall wrote:
> > > >
> > > >
> > > > I took a look, but it's pretty complex.  You could take the code and
> > > > reorganize it so that it is more readable, and then take the definition of
> > > > the ARRAY_SIZE macro, to better see what is going on.
> > > >
> > > > julia
> > > >
> > >
> > > Hello Greg, Julia,
> > > I was able to successfully build the fbtft object file for arm architecture as
> > > well. I used gcc 6.5.0 and 9.5.0 tool chains. It was successful using both. I
> > > have attached the build log from my machine for your reference.
> > >
> > > I am also looking at the .i file and rearrange the expanded macro to understand
> > > it. However, since it is built successfully, I am not sure if that is truly the
> > > problem area.
> > >
> > > Should I resend the patch and check if it still errors the kernel build bot?
> > > Anything else I can try?
> >
> > Looks like the change I proposed is causing nesting inside the write_reg
> > function due to additional set of { & } brackets for the __VA_ARGS__ symbol.
> >
> > Am I understanding it right?
> 
> Hello Julia, Greg,
> I am unable to reproduce this build failure on my local machine. I tried the X86
> and arm based build. I am unable to troubleshoot this further. Do you have any
> other suggestions? If not, I will drop this patch from my watch list.

Please just drop it, it is not a correct change to make.

thanks,

greg k-h
  

Patch

diff --git a/drivers/staging/fbtft/fbtft.h b/drivers/staging/fbtft/fbtft.h
index 2c2b5f1c1df3..5506a473be91 100644
--- a/drivers/staging/fbtft/fbtft.h
+++ b/drivers/staging/fbtft/fbtft.h
@@ -231,7 +231,7 @@  struct fbtft_par {
 	bool polarity;
 };

-#define NUMARGS(...)  (sizeof((int[]){__VA_ARGS__}) / sizeof(int))
+#define NUMARGS(...)  ARRAY_SIZE(((int[]){ __VA_ARGS__ }))

 #define write_reg(par, ...)                                            \
 	((par)->fbtftops.write_register(par, NUMARGS(__VA_ARGS__), __VA_ARGS__))