[Intel-gfx] [PATCH] drm/i915/buddy: document the unused header bits

kernel test robot lkp at intel.com
Mon Jan 25 07:40:00 UTC 2021


Hi Matthew,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on drm-intel/for-linux-next]
[also build test WARNING on drm-tip/drm-tip v5.11-rc5 next-20210122]
[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]

url:    https://github.com/0day-ci/linux/commits/Matthew-Auld/drm-i915-buddy-document-the-unused-header-bits/20210125-111101
base:   git://anongit.freedesktop.org/drm-intel for-linux-next
config: i386-randconfig-a012-20210125 (attached as .config)
compiler: gcc-9 (Debian 9.3.0-20) 9.3.0
reproduce (this is a W=1 build):
        # https://github.com/0day-ci/linux/commit/9d12a23788459bd678c0f5979acaaf94a88d808c
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Matthew-Auld/drm-i915-buddy-document-the-unused-header-bits/20210125-111101
        git checkout 9d12a23788459bd678c0f5979acaaf94a88d808c
        # save the attached .config to linux build tree
        make W=1 ARCH=i386 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp at intel.com>

All warnings (new ones prefixed by >>):

   In file included from include/asm-generic/bug.h:5,
                    from arch/x86/include/asm/bug.h:93,
                    from include/linux/bug.h:5,
                    from include/linux/mmdebug.h:5,
                    from include/linux/gfp.h:5,
                    from include/linux/slab.h:15,
                    from include/linux/kmemleak.h:12,
                    from drivers/gpu/drm/i915/i915_buddy.c:6:
   drivers/gpu/drm/i915/selftests/i915_buddy.c: In function 'igt_buddy_alloc_limit':
>> include/linux/log2.h:194:8: warning: left shift count >= width of type [-Wshift-count-overflow]
     194 |   (1UL << ilog2(n))) :  \
         |        ^~
   include/linux/compiler.h:58:52: note: in definition of macro '__trace_if_var'
      58 | #define __trace_if_var(cond) (__builtin_constant_p(cond) ? (cond) : __trace_if_value(cond))
         |                                                    ^~~~
   drivers/gpu/drm/i915/selftests/i915_buddy.c:761:2: note: in expansion of macro 'if'
     761 |  if (i915_buddy_block_size(&mm, block) != rounddown_pow_of_two(size)) {
         |  ^~
   drivers/gpu/drm/i915/selftests/i915_buddy.c:761:43: note: in expansion of macro 'rounddown_pow_of_two'
     761 |  if (i915_buddy_block_size(&mm, block) != rounddown_pow_of_two(size)) {
         |                                           ^~~~~~~~~~~~~~~~~~~~
>> include/linux/log2.h:194:8: warning: left shift count >= width of type [-Wshift-count-overflow]
     194 |   (1UL << ilog2(n))) :  \
         |        ^~
   include/linux/compiler.h:69:3: note: in definition of macro '__trace_if_value'
      69 |  (cond) ?     \
         |   ^~~~
   include/linux/compiler.h:56:28: note: in expansion of macro '__trace_if_var'
      56 | #define if(cond, ...) if ( __trace_if_var( !!(cond , ## __VA_ARGS__) ) )
         |                            ^~~~~~~~~~~~~~
   drivers/gpu/drm/i915/selftests/i915_buddy.c:761:2: note: in expansion of macro 'if'
     761 |  if (i915_buddy_block_size(&mm, block) != rounddown_pow_of_two(size)) {
         |  ^~
   drivers/gpu/drm/i915/selftests/i915_buddy.c:761:43: note: in expansion of macro 'rounddown_pow_of_two'
     761 |  if (i915_buddy_block_size(&mm, block) != rounddown_pow_of_two(size)) {
         |                                           ^~~~~~~~~~~~~~~~~~~~
   In file included from include/linux/kernel.h:12,
                    from include/asm-generic/bug.h:20,
                    from arch/x86/include/asm/bug.h:93,
                    from include/linux/bug.h:5,
                    from include/linux/mmdebug.h:5,
                    from include/linux/gfp.h:5,
                    from include/linux/slab.h:15,
                    from include/linux/kmemleak.h:12,
                    from drivers/gpu/drm/i915/i915_buddy.c:6:
>> include/linux/log2.h:194:8: warning: left shift count >= width of type [-Wshift-count-overflow]
     194 |   (1UL << ilog2(n))) :  \
         |        ^~
   include/linux/printk.h:343:33: note: in expansion of macro 'rounddown_pow_of_two'
     343 |  printk(KERN_ERR pr_fmt(fmt), ##__VA_ARGS__)
         |                                 ^~~~~~~~~~~
   drivers/gpu/drm/i915/selftests/i915_buddy.c:762:3: note: in expansion of macro 'pr_err'
     762 |   pr_err("block size(%llu) != %lu\n",
         |   ^~~~~~


vim +194 include/linux/log2.h

b311e921b385b5a Robert P. J. Day 2007-10-16   69  
f0d1b0b30d250a0 David Howells    2006-12-08   70  /**
dbef91ec5482239 Martin Wilck     2018-04-18   71   * const_ilog2 - log base 2 of 32-bit or a 64-bit constant unsigned value
a1c4d24e02d093e Randy Dunlap     2017-09-30   72   * @n: parameter
f0d1b0b30d250a0 David Howells    2006-12-08   73   *
dbef91ec5482239 Martin Wilck     2018-04-18   74   * Use this where sparse expects a true constant expression, e.g. for array
dbef91ec5482239 Martin Wilck     2018-04-18   75   * indices.
f0d1b0b30d250a0 David Howells    2006-12-08   76   */
dbef91ec5482239 Martin Wilck     2018-04-18   77  #define const_ilog2(n)				\
f0d1b0b30d250a0 David Howells    2006-12-08   78  (						\
f0d1b0b30d250a0 David Howells    2006-12-08   79  	__builtin_constant_p(n) ? (		\
474c90156c8dcc2 Linus Torvalds   2017-03-02   80  		(n) < 2 ? 0 :			\
f0d1b0b30d250a0 David Howells    2006-12-08   81  		(n) & (1ULL << 63) ? 63 :	\
f0d1b0b30d250a0 David Howells    2006-12-08   82  		(n) & (1ULL << 62) ? 62 :	\
f0d1b0b30d250a0 David Howells    2006-12-08   83  		(n) & (1ULL << 61) ? 61 :	\
f0d1b0b30d250a0 David Howells    2006-12-08   84  		(n) & (1ULL << 60) ? 60 :	\
f0d1b0b30d250a0 David Howells    2006-12-08   85  		(n) & (1ULL << 59) ? 59 :	\
f0d1b0b30d250a0 David Howells    2006-12-08   86  		(n) & (1ULL << 58) ? 58 :	\
f0d1b0b30d250a0 David Howells    2006-12-08   87  		(n) & (1ULL << 57) ? 57 :	\
f0d1b0b30d250a0 David Howells    2006-12-08   88  		(n) & (1ULL << 56) ? 56 :	\
f0d1b0b30d250a0 David Howells    2006-12-08   89  		(n) & (1ULL << 55) ? 55 :	\
f0d1b0b30d250a0 David Howells    2006-12-08   90  		(n) & (1ULL << 54) ? 54 :	\
f0d1b0b30d250a0 David Howells    2006-12-08   91  		(n) & (1ULL << 53) ? 53 :	\
f0d1b0b30d250a0 David Howells    2006-12-08   92  		(n) & (1ULL << 52) ? 52 :	\
f0d1b0b30d250a0 David Howells    2006-12-08   93  		(n) & (1ULL << 51) ? 51 :	\
f0d1b0b30d250a0 David Howells    2006-12-08   94  		(n) & (1ULL << 50) ? 50 :	\
f0d1b0b30d250a0 David Howells    2006-12-08   95  		(n) & (1ULL << 49) ? 49 :	\
f0d1b0b30d250a0 David Howells    2006-12-08   96  		(n) & (1ULL << 48) ? 48 :	\
f0d1b0b30d250a0 David Howells    2006-12-08   97  		(n) & (1ULL << 47) ? 47 :	\
f0d1b0b30d250a0 David Howells    2006-12-08   98  		(n) & (1ULL << 46) ? 46 :	\
f0d1b0b30d250a0 David Howells    2006-12-08   99  		(n) & (1ULL << 45) ? 45 :	\
f0d1b0b30d250a0 David Howells    2006-12-08  100  		(n) & (1ULL << 44) ? 44 :	\
f0d1b0b30d250a0 David Howells    2006-12-08  101  		(n) & (1ULL << 43) ? 43 :	\
f0d1b0b30d250a0 David Howells    2006-12-08  102  		(n) & (1ULL << 42) ? 42 :	\
f0d1b0b30d250a0 David Howells    2006-12-08  103  		(n) & (1ULL << 41) ? 41 :	\
f0d1b0b30d250a0 David Howells    2006-12-08  104  		(n) & (1ULL << 40) ? 40 :	\
f0d1b0b30d250a0 David Howells    2006-12-08  105  		(n) & (1ULL << 39) ? 39 :	\
f0d1b0b30d250a0 David Howells    2006-12-08  106  		(n) & (1ULL << 38) ? 38 :	\
f0d1b0b30d250a0 David Howells    2006-12-08  107  		(n) & (1ULL << 37) ? 37 :	\
f0d1b0b30d250a0 David Howells    2006-12-08  108  		(n) & (1ULL << 36) ? 36 :	\
f0d1b0b30d250a0 David Howells    2006-12-08  109  		(n) & (1ULL << 35) ? 35 :	\
f0d1b0b30d250a0 David Howells    2006-12-08  110  		(n) & (1ULL << 34) ? 34 :	\
f0d1b0b30d250a0 David Howells    2006-12-08  111  		(n) & (1ULL << 33) ? 33 :	\
f0d1b0b30d250a0 David Howells    2006-12-08  112  		(n) & (1ULL << 32) ? 32 :	\
f0d1b0b30d250a0 David Howells    2006-12-08  113  		(n) & (1ULL << 31) ? 31 :	\
f0d1b0b30d250a0 David Howells    2006-12-08  114  		(n) & (1ULL << 30) ? 30 :	\
f0d1b0b30d250a0 David Howells    2006-12-08  115  		(n) & (1ULL << 29) ? 29 :	\
f0d1b0b30d250a0 David Howells    2006-12-08  116  		(n) & (1ULL << 28) ? 28 :	\
f0d1b0b30d250a0 David Howells    2006-12-08  117  		(n) & (1ULL << 27) ? 27 :	\
f0d1b0b30d250a0 David Howells    2006-12-08  118  		(n) & (1ULL << 26) ? 26 :	\
f0d1b0b30d250a0 David Howells    2006-12-08  119  		(n) & (1ULL << 25) ? 25 :	\
f0d1b0b30d250a0 David Howells    2006-12-08  120  		(n) & (1ULL << 24) ? 24 :	\
f0d1b0b30d250a0 David Howells    2006-12-08  121  		(n) & (1ULL << 23) ? 23 :	\
f0d1b0b30d250a0 David Howells    2006-12-08  122  		(n) & (1ULL << 22) ? 22 :	\
f0d1b0b30d250a0 David Howells    2006-12-08  123  		(n) & (1ULL << 21) ? 21 :	\
f0d1b0b30d250a0 David Howells    2006-12-08  124  		(n) & (1ULL << 20) ? 20 :	\
f0d1b0b30d250a0 David Howells    2006-12-08  125  		(n) & (1ULL << 19) ? 19 :	\
f0d1b0b30d250a0 David Howells    2006-12-08  126  		(n) & (1ULL << 18) ? 18 :	\
f0d1b0b30d250a0 David Howells    2006-12-08  127  		(n) & (1ULL << 17) ? 17 :	\
f0d1b0b30d250a0 David Howells    2006-12-08  128  		(n) & (1ULL << 16) ? 16 :	\
f0d1b0b30d250a0 David Howells    2006-12-08  129  		(n) & (1ULL << 15) ? 15 :	\
f0d1b0b30d250a0 David Howells    2006-12-08  130  		(n) & (1ULL << 14) ? 14 :	\
f0d1b0b30d250a0 David Howells    2006-12-08  131  		(n) & (1ULL << 13) ? 13 :	\
f0d1b0b30d250a0 David Howells    2006-12-08  132  		(n) & (1ULL << 12) ? 12 :	\
f0d1b0b30d250a0 David Howells    2006-12-08  133  		(n) & (1ULL << 11) ? 11 :	\
f0d1b0b30d250a0 David Howells    2006-12-08  134  		(n) & (1ULL << 10) ? 10 :	\
f0d1b0b30d250a0 David Howells    2006-12-08  135  		(n) & (1ULL <<  9) ?  9 :	\
f0d1b0b30d250a0 David Howells    2006-12-08  136  		(n) & (1ULL <<  8) ?  8 :	\
f0d1b0b30d250a0 David Howells    2006-12-08  137  		(n) & (1ULL <<  7) ?  7 :	\
f0d1b0b30d250a0 David Howells    2006-12-08  138  		(n) & (1ULL <<  6) ?  6 :	\
f0d1b0b30d250a0 David Howells    2006-12-08  139  		(n) & (1ULL <<  5) ?  5 :	\
f0d1b0b30d250a0 David Howells    2006-12-08  140  		(n) & (1ULL <<  4) ?  4 :	\
f0d1b0b30d250a0 David Howells    2006-12-08  141  		(n) & (1ULL <<  3) ?  3 :	\
f0d1b0b30d250a0 David Howells    2006-12-08  142  		(n) & (1ULL <<  2) ?  2 :	\
474c90156c8dcc2 Linus Torvalds   2017-03-02  143  		1) :				\
dbef91ec5482239 Martin Wilck     2018-04-18  144  	-1)
dbef91ec5482239 Martin Wilck     2018-04-18  145  
dbef91ec5482239 Martin Wilck     2018-04-18  146  /**
dbef91ec5482239 Martin Wilck     2018-04-18  147   * ilog2 - log base 2 of 32-bit or a 64-bit unsigned value
dbef91ec5482239 Martin Wilck     2018-04-18  148   * @n: parameter
dbef91ec5482239 Martin Wilck     2018-04-18  149   *
dbef91ec5482239 Martin Wilck     2018-04-18  150   * constant-capable log of base 2 calculation
dbef91ec5482239 Martin Wilck     2018-04-18  151   * - this can be used to initialise global variables from constant data, hence
dbef91ec5482239 Martin Wilck     2018-04-18  152   * the massive ternary operator construction
dbef91ec5482239 Martin Wilck     2018-04-18  153   *
dbef91ec5482239 Martin Wilck     2018-04-18  154   * selects the appropriately-sized optimised version depending on sizeof(n)
dbef91ec5482239 Martin Wilck     2018-04-18  155   */
dbef91ec5482239 Martin Wilck     2018-04-18  156  #define ilog2(n) \
dbef91ec5482239 Martin Wilck     2018-04-18  157  ( \
dbef91ec5482239 Martin Wilck     2018-04-18  158  	__builtin_constant_p(n) ?	\
2f78788b55baa34 Jakub Jelinek    2020-12-15  159  	((n) < 2 ? 0 :			\
2f78788b55baa34 Jakub Jelinek    2020-12-15  160  	 63 - __builtin_clzll(n)) :	\
f0d1b0b30d250a0 David Howells    2006-12-08  161  	(sizeof(n) <= 4) ?		\
f0d1b0b30d250a0 David Howells    2006-12-08  162  	__ilog2_u32(n) :		\
f0d1b0b30d250a0 David Howells    2006-12-08  163  	__ilog2_u64(n)			\
f0d1b0b30d250a0 David Howells    2006-12-08  164   )
f0d1b0b30d250a0 David Howells    2006-12-08  165  
312a0c170945b49 David Howells    2006-12-08  166  /**
312a0c170945b49 David Howells    2006-12-08  167   * roundup_pow_of_two - round the given value up to nearest power of two
a1c4d24e02d093e Randy Dunlap     2017-09-30  168   * @n: parameter
312a0c170945b49 David Howells    2006-12-08  169   *
6fb189c2a4f3bea Robert P. J. Day 2007-02-17  170   * round the given value up to the nearest power of two
312a0c170945b49 David Howells    2006-12-08  171   * - the result is undefined when n == 0
312a0c170945b49 David Howells    2006-12-08  172   * - this can be used to initialise global variables from constant data
312a0c170945b49 David Howells    2006-12-08  173   */
312a0c170945b49 David Howells    2006-12-08  174  #define roundup_pow_of_two(n)			\
312a0c170945b49 David Howells    2006-12-08  175  (						\
312a0c170945b49 David Howells    2006-12-08  176  	__builtin_constant_p(n) ? (		\
428fc0aff4e5939 Jason Gunthorpe  2020-09-04  177  		((n) == 1) ? 1 :		\
312a0c170945b49 David Howells    2006-12-08  178  		(1UL << (ilog2((n) - 1) + 1))	\
312a0c170945b49 David Howells    2006-12-08  179  				   ) :		\
312a0c170945b49 David Howells    2006-12-08  180  	__roundup_pow_of_two(n)			\
312a0c170945b49 David Howells    2006-12-08  181   )
312a0c170945b49 David Howells    2006-12-08  182  
b311e921b385b5a Robert P. J. Day 2007-10-16  183  /**
b311e921b385b5a Robert P. J. Day 2007-10-16  184   * rounddown_pow_of_two - round the given value down to nearest power of two
a1c4d24e02d093e Randy Dunlap     2017-09-30  185   * @n: parameter
b311e921b385b5a Robert P. J. Day 2007-10-16  186   *
b311e921b385b5a Robert P. J. Day 2007-10-16  187   * round the given value down to the nearest power of two
b311e921b385b5a Robert P. J. Day 2007-10-16  188   * - the result is undefined when n == 0
b311e921b385b5a Robert P. J. Day 2007-10-16  189   * - this can be used to initialise global variables from constant data
b311e921b385b5a Robert P. J. Day 2007-10-16  190   */
b311e921b385b5a Robert P. J. Day 2007-10-16  191  #define rounddown_pow_of_two(n)			\
b311e921b385b5a Robert P. J. Day 2007-10-16  192  (						\
b311e921b385b5a Robert P. J. Day 2007-10-16  193  	__builtin_constant_p(n) ? (		\
b311e921b385b5a Robert P. J. Day 2007-10-16 @194  		(1UL << ilog2(n))) :		\
b311e921b385b5a Robert P. J. Day 2007-10-16  195  	__rounddown_pow_of_two(n)		\
b311e921b385b5a Robert P. J. Day 2007-10-16  196   )
b311e921b385b5a Robert P. J. Day 2007-10-16  197  

---
0-DAY CI Kernel Test Service, Intel Corporation
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