tree: https://github.com/norov/linux find_bit_static head: a18d2664b9ad8a08be90d073ef0673f62d8a186e commit: 0cbe876d91e58013824b3628bd98ccf7ec1c87f4 [5/6] lib: add fast path for find_first_*_bit() and find_last_bit() config: m68k-allmodconfig (attached as .config) compiler: m68k-linux-gcc (GCC) 9.3.0 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/norov/linux/commit/0cbe876d91e58013824b3628bd98ccf7ec1... git remote add norov https://github.com/norov/linux git fetch --no-tags norov find_bit_static git checkout 0cbe876d91e58013824b3628bd98ccf7ec1c87f4 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=m68k If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All errors (new ones prefixed by >>): In file included from arch/m68k/include/asm/bitops.h:443, from include/linux/bitops.h:50, from include/linux/kernel.h:11, from include/asm-generic/bug.h:20, from arch/m68k/include/asm/bug.h:32, from include/linux/bug.h:5, from include/linux/page-flags.h:10, from kernel/bounds.c:10: include/asm-generic/bitops/find.h: In function 'find_next_and_bit': include/asm-generic/bitops/find.h:60:16: error: implicit declaration of function '__ffs' [-Werror=implicit-function-declaration] 60 | return val ? __ffs(val) : size; | ^~~~~ include/asm-generic/bitops/find.h: In function 'find_last_bit': 164 | return val ? __fls(val) : size; | ^~~~~ In file included from include/linux/bitops.h:50, from include/linux/kernel.h:11, from include/asm-generic/bug.h:20, from arch/m68k/include/asm/bug.h:32, from include/linux/bug.h:5, from include/linux/page-flags.h:10, from kernel/bounds.c:10: arch/m68k/include/asm/bitops.h: At top level: arch/m68k/include/asm/bitops.h:497:29: error: conflicting types for '__ffs' 497 | static inline unsigned long __ffs(unsigned long x) | ^~~~~ In file included from arch/m68k/include/asm/bitops.h:443, from include/linux/bitops.h:50, from include/linux/kernel.h:11, from include/asm-generic/bug.h:20, from arch/m68k/include/asm/bug.h:32, from include/linux/bug.h:5, from include/linux/page-flags.h:10, from kernel/bounds.c:10: include/asm-generic/bitops/find.h:60:16: note: previous implicit declaration of '__ffs' was here 60 | return val ? __ffs(val) : size; | ^~~~~ In file included from include/linux/bitops.h:50, from include/linux/kernel.h:11, from include/asm-generic/bug.h:20, from arch/m68k/include/asm/bug.h:32, from include/linux/bug.h:5, from include/linux/page-flags.h:10, from kernel/bounds.c:10: 515 | static inline int __fls(int x) | ^~~~~ In file included from arch/m68k/include/asm/bitops.h:443, from include/linux/bitops.h:50, from include/linux/kernel.h:11, from include/asm-generic/bug.h:20, from arch/m68k/include/asm/bug.h:32, from include/linux/bug.h:5, from include/linux/page-flags.h:10, from kernel/bounds.c:10: include/asm-generic/bitops/find.h:164:16: note: previous implicit declaration of '__fls' was here 164 | return val ? __fls(val) : size; | ^~~~~ In file included from arch/m68k/include/asm/bitops.h:528, from include/linux/bitops.h:50, from include/linux/kernel.h:11, from include/asm-generic/bug.h:20, from arch/m68k/include/asm/bug.h:32, from include/linux/bug.h:5, from include/linux/page-flags.h:10, from kernel/bounds.c:10: include/asm-generic/bitops/le.h: In function 'find_next_zero_bit_le': include/asm-generic/bitops/le.h:45:17: warning: dereferencing 'void *' pointer 45 | fz = ffz(swab(*addr & BITMAP_FIRST_WORD_MASK(offset))); | ^~~~~ include/asm-generic/bitops/le.h:45:17: error: void value not ignored as it ought to be include/asm-generic/bitops/le.h: In function 'find_next_bit_le': include/asm-generic/bitops/le.h:64:19: warning: dereferencing 'void *' pointer 64 | fs = __ffs(swab(*addr & BITMAP_FIRST_WORD_MASK(offset))); | ^~~~~ include/asm-generic/bitops/le.h:64:19: error: void value not ignored as it ought to be cc1: some warnings being treated as errors -- In file included from arch/m68k/include/asm/bitops.h:443, from include/linux/bitops.h:50, from include/linux/kernel.h:11, from include/linux/list.h:9, from include/linux/wait.h:7, from include/linux/wait_bit.h:8, from include/linux/fs.h:6, from include/linux/debugfs.h:15, from kernel//time/test_udelay.c:13: include/asm-generic/bitops/find.h: In function 'find_next_and_bit': include/asm-generic/bitops/find.h:60:16: error: implicit declaration of function '__ffs' [-Werror=implicit-function-declaration] 60 | return val ? __ffs(val) : size; | ^~~~~ include/asm-generic/bitops/find.h: In function 'find_last_bit': 164 | return val ? __fls(val) : size; | ^~~~~ In file included from include/linux/bitops.h:50, from include/linux/kernel.h:11, from include/linux/list.h:9, from include/linux/wait.h:7, from include/linux/wait_bit.h:8, from include/linux/fs.h:6, from include/linux/debugfs.h:15, from kernel//time/test_udelay.c:13: arch/m68k/include/asm/bitops.h: At top level: arch/m68k/include/asm/bitops.h:497:29: error: conflicting types for '__ffs' 497 | static inline unsigned long __ffs(unsigned long x) | ^~~~~ In file included from arch/m68k/include/asm/bitops.h:443, from include/linux/bitops.h:50, from include/linux/kernel.h:11, from include/linux/list.h:9, from include/linux/wait.h:7, from include/linux/wait_bit.h:8, from include/linux/fs.h:6, from include/linux/debugfs.h:15, from kernel//time/test_udelay.c:13: include/asm-generic/bitops/find.h:60:16: note: previous implicit declaration of '__ffs' was here 60 | return val ? __ffs(val) : size; | ^~~~~ In file included from include/linux/bitops.h:50, from include/linux/kernel.h:11, from include/linux/list.h:9, from include/linux/wait.h:7, from include/linux/wait_bit.h:8, from include/linux/fs.h:6, from include/linux/debugfs.h:15, from kernel//time/test_udelay.c:13: 515 | static inline int __fls(int x) | ^~~~~ In file included from arch/m68k/include/asm/bitops.h:443, from include/linux/bitops.h:50, from include/linux/kernel.h:11, from include/linux/list.h:9, from include/linux/wait.h:7, from include/linux/wait_bit.h:8, from include/linux/fs.h:6, from include/linux/debugfs.h:15, from kernel//time/test_udelay.c:13: include/asm-generic/bitops/find.h:164:16: note: previous implicit declaration of '__fls' was here 164 | return val ? __fls(val) : size; | ^~~~~ In file included from arch/m68k/include/asm/bitops.h:528, from include/linux/bitops.h:50, from include/linux/kernel.h:11, from include/linux/list.h:9, from include/linux/wait.h:7, from include/linux/wait_bit.h:8, from include/linux/fs.h:6, from include/linux/debugfs.h:15, from kernel//time/test_udelay.c:13: include/asm-generic/bitops/le.h: In function 'find_next_zero_bit_le': include/asm-generic/bitops/le.h:45:17: warning: dereferencing 'void *' pointer 45 | fz = ffz(swab(*addr & BITMAP_FIRST_WORD_MASK(offset))); | ^~~~~ include/asm-generic/bitops/le.h:45:17: error: void value not ignored as it ought to be include/asm-generic/bitops/le.h: In function 'find_next_bit_le': include/asm-generic/bitops/le.h:64:19: warning: dereferencing 'void *' pointer 64 | fs = __ffs(swab(*addr & BITMAP_FIRST_WORD_MASK(offset))); | ^~~~~ include/asm-generic/bitops/le.h:64:19: error: void value not ignored as it ought to be In file included from include/linux/dcache.h:14, from include/linux/fs.h:8, from include/linux/debugfs.h:15, from kernel//time/test_udelay.c:13: include/linux/lockref.h: At top level: include/linux/lockref.h:19:10: fatal error: generated/bounds.h: No such file or directory 19 | #include <generated/bounds.h> | ^~~~~~~~~~~~~~~~~~~~ cc1: some warnings being treated as errors compilation terminated. -- In file included from arch/m68k/include/asm/bitops.h:443, from include/linux/bitops.h:50, from include/linux/kernel.h:11, from include/asm-generic/bug.h:20, from arch/m68k/include/asm/bug.h:32, from include/linux/bug.h:5, from include/linux/page-flags.h:10, from kernel/bounds.c:10: include/asm-generic/bitops/find.h: In function 'find_next_and_bit': include/asm-generic/bitops/find.h:60:16: error: implicit declaration of function '__ffs' [-Werror=implicit-function-declaration] 60 | return val ? __ffs(val) : size; | ^~~~~ include/asm-generic/bitops/find.h: In function 'find_last_bit': 164 | return val ? __fls(val) : size; | ^~~~~ In file included from include/linux/bitops.h:50, from include/linux/kernel.h:11, from include/asm-generic/bug.h:20, from arch/m68k/include/asm/bug.h:32, from include/linux/bug.h:5, from include/linux/page-flags.h:10, from kernel/bounds.c:10: arch/m68k/include/asm/bitops.h: At top level: arch/m68k/include/asm/bitops.h:497:29: error: conflicting types for '__ffs' 497 | static inline unsigned long __ffs(unsigned long x) | ^~~~~ In file included from arch/m68k/include/asm/bitops.h:443, from include/linux/bitops.h:50, from include/linux/kernel.h:11, from include/asm-generic/bug.h:20, from arch/m68k/include/asm/bug.h:32, from include/linux/bug.h:5, from include/linux/page-flags.h:10, from kernel/bounds.c:10: include/asm-generic/bitops/find.h:60:16: note: previous implicit declaration of '__ffs' was here 60 | return val ? __ffs(val) : size; | ^~~~~ In file included from include/linux/bitops.h:50, from include/linux/kernel.h:11, from include/asm-generic/bug.h:20, from arch/m68k/include/asm/bug.h:32, from include/linux/bug.h:5, from include/linux/page-flags.h:10, from kernel/bounds.c:10: 515 | static inline int __fls(int x) | ^~~~~ In file included from arch/m68k/include/asm/bitops.h:443, from include/linux/bitops.h:50, from include/linux/kernel.h:11, from include/asm-generic/bug.h:20, from arch/m68k/include/asm/bug.h:32, from include/linux/bug.h:5, from include/linux/page-flags.h:10, from kernel/bounds.c:10: include/asm-generic/bitops/find.h:164:16: note: previous implicit declaration of '__fls' was here 164 | return val ? __fls(val) : size; | ^~~~~ In file included from arch/m68k/include/asm/bitops.h:528, from include/linux/bitops.h:50, from include/linux/kernel.h:11, from include/asm-generic/bug.h:20, from arch/m68k/include/asm/bug.h:32, from include/linux/bug.h:5, from include/linux/page-flags.h:10, from kernel/bounds.c:10: include/asm-generic/bitops/le.h: In function 'find_next_zero_bit_le': include/asm-generic/bitops/le.h:45:17: warning: dereferencing 'void *' pointer 45 | fz = ffz(swab(*addr & BITMAP_FIRST_WORD_MASK(offset))); | ^~~~~ include/asm-generic/bitops/le.h:45:17: error: void value not ignored as it ought to be include/asm-generic/bitops/le.h: In function 'find_next_bit_le': include/asm-generic/bitops/le.h:64:19: warning: dereferencing 'void *' pointer 64 | fs = __ffs(swab(*addr & BITMAP_FIRST_WORD_MASK(offset))); | ^~~~~ include/asm-generic/bitops/le.h:64:19: error: void value not ignored as it ought to be cc1: some warnings being treated as errors make[2]: *** [scripts/Makefile.build:117: kernel/bounds.s] Error 1 make[2]: Target '__build' not remade because of errors. make[1]: *** [Makefile:1220: prepare0] Error 2 make[1]: Target 'modules_prepare' not remade because of errors. make: *** [Makefile:185: __sub-make] Error 2 make: Target 'modules_prepare' not remade because of errors. -- In file included from arch/m68k/include/asm/bitops.h:443, from include/linux/bitops.h:50, from include/linux/kernel.h:11, from include/asm-generic/bug.h:20, from arch/m68k/include/asm/bug.h:32, from include/linux/bug.h:5, from include/linux/page-flags.h:10, from kernel/bounds.c:10: include/asm-generic/bitops/find.h: In function 'find_next_and_bit': include/asm-generic/bitops/find.h:60:16: error: implicit declaration of function '__ffs' [-Werror=implicit-function-declaration] 60 | return val ? __ffs(val) : size; | ^~~~~ include/asm-generic/bitops/find.h: In function 'find_last_bit': 164 | return val ? __fls(val) : size; | ^~~~~ In file included from include/linux/bitops.h:50, from include/linux/kernel.h:11, from include/asm-generic/bug.h:20, from arch/m68k/include/asm/bug.h:32, from include/linux/bug.h:5, from include/linux/page-flags.h:10, from kernel/bounds.c:10: arch/m68k/include/asm/bitops.h: At top level: arch/m68k/include/asm/bitops.h:497:29: error: conflicting types for '__ffs' 497 | static inline unsigned long __ffs(unsigned long x) | ^~~~~ In file included from arch/m68k/include/asm/bitops.h:443, from include/linux/bitops.h:50, from include/linux/kernel.h:11, from include/asm-generic/bug.h:20, from arch/m68k/include/asm/bug.h:32, from include/linux/bug.h:5, from include/linux/page-flags.h:10, from kernel/bounds.c:10: include/asm-generic/bitops/find.h:60:16: note: previous implicit declaration of '__ffs' was here 60 | return val ? __ffs(val) : size; | ^~~~~ In file included from include/linux/bitops.h:50, from include/linux/kernel.h:11, from include/asm-generic/bug.h:20, from arch/m68k/include/asm/bug.h:32, from include/linux/bug.h:5, from include/linux/page-flags.h:10, from kernel/bounds.c:10: 515 | static inline int __fls(int x) | ^~~~~ In file included from arch/m68k/include/asm/bitops.h:443, from include/linux/bitops.h:50, from include/linux/kernel.h:11, from include/asm-generic/bug.h:20, from arch/m68k/include/asm/bug.h:32, from include/linux/bug.h:5, from include/linux/page-flags.h:10, from kernel/bounds.c:10: include/asm-generic/bitops/find.h:164:16: note: previous implicit declaration of '__fls' was here 164 | return val ? __fls(val) : size; | ^~~~~ In file included from arch/m68k/include/asm/bitops.h:528, from include/linux/bitops.h:50, from include/linux/kernel.h:11, from include/asm-generic/bug.h:20, from arch/m68k/include/asm/bug.h:32, from include/linux/bug.h:5, from include/linux/page-flags.h:10, from kernel/bounds.c:10: include/asm-generic/bitops/le.h: In function 'find_next_zero_bit_le': include/asm-generic/bitops/le.h:45:17: warning: dereferencing 'void *' pointer 45 | fz = ffz(swab(*addr & BITMAP_FIRST_WORD_MASK(offset))); | ^~~~~ include/asm-generic/bitops/le.h:45:17: error: void value not ignored as it ought to be include/asm-generic/bitops/le.h: In function 'find_next_bit_le': include/asm-generic/bitops/le.h:64:19: warning: dereferencing 'void *' pointer 64 | fs = __ffs(swab(*addr & BITMAP_FIRST_WORD_MASK(offset))); | ^~~~~ include/asm-generic/bitops/le.h:64:19: error: void value not ignored as it ought to be cc1: some warnings being treated as errors make[2]: *** [scripts/Makefile.build:117: kernel/bounds.s] Error 1 make[2]: Target '__build' not remade because of errors. make[1]: *** [Makefile:1220: prepare0] Error 2 make[1]: Target 'prepare' not remade because of errors. make: *** [Makefile:185: __sub-make] Error 2 make: Target 'prepare' not remade because of errors. vim +/__fls +164 include/asm-generic/bitops/find.h 34 35 #ifndef find_next_and_bit 36 /** 37 * find_next_and_bit - find the next set bit in both memory regions 38 * @addr1: The first address to base the search on 39 * @addr2: The second address to base the search on 40 * @offset: The bitnumber to start searching at 41 * @size: The bitmap size in bits 42 * 43 * Returns the bit number for the next set bit 44 * If no bits are set, returns @size. 45 */ 46 static __always_inline 47 unsigned long find_next_and_bit(const unsigned long *addr1, 48 const unsigned long *addr2, unsigned long size, 49 unsigned long offset) 50 { 51 if (small_const_nbits(size)) { 52 unsigned long val; 53 54 if (unlikely(offset >= size)) 55 return size; 56 57 val = *addr1 & *addr2 & BITMAP_FIRST_WORD_MASK(offset) 58 & BITMAP_LAST_WORD_MASK(size); 59 61 } 62 63 return _find_next_bit(addr1, addr2, size, offset, 0UL, 0); 64 } 65 #endif 66 67 #ifndef find_next_zero_bit 68 /** 69 * find_next_zero_bit - find the next cleared bit in a memory region 70 * @addr: The address to base the search on 71 * @offset: The bitnumber to start searching at 72 * @size: The bitmap size in bits 73 * 74 * Returns the bit number of the next zero bit 75 * If no bits are zero, returns @size. 76 */ 77 static __always_inline 78 unsigned long find_next_zero_bit(const unsigned long *addr, unsigned long size, 79 unsigned long offset) 80 { 81 if (small_const_nbits(size)) { 82 unsigned long val; 83 84 if (unlikely(offset >= size)) 85 return size; 86 87 val = *addr | !BITMAP_FIRST_WORD_MASK(offset) 88 | !BITMAP_LAST_WORD_MASK(size); 89 90 return val == ~0UL ? size : ffz(val); 91 } 92 93 return _find_next_bit(addr, NULL, size, offset, ~0UL, 0); 94 } 95 #endif 96 97 #ifdef CONFIG_GENERIC_FIND_FIRST_BIT 98 99 /** 100 * find_first_bit - find the first set bit in a memory region 101 * @addr: The address to start the search at 102 * @size: The maximum number of bits to search 103 * 104 * Returns the bit number of the first set bit. 105 * If no bits are set, returns @size. 106 */ 107 static __always_inline 108 unsigned long find_first_bit(const unsigned long *addr, unsigned long size) 109 { 110 if (small_const_nbits(size)) { 111 unsigned long val = *addr & BITMAP_LAST_WORD_MASK(size); 112 return val ? __ffs(val) : size; 113 } 114 115 return _find_first_bit(addr, size); 116 } 117 118 /** 119 * find_first_zero_bit - find the first cleared bit in a memory region 120 * @addr: The address to start the search at 121 * @size: The maximum number of bits to search 122 * 123 * Returns the bit number of the first cleared bit. 124 * If no bits are zero, returns @size. 125 */ 126 static __always_inline 127 unsigned long find_first_zero_bit(const unsigned long *addr, unsigned long size) 128 { 129 if (small_const_nbits(size)) { 130 unsigned long idx; 131 if (*addr == ~0UL) 132 return size; 133 134 idx = ffz(*addr); 135 return idx < size ? idx : size; 136 } 137 138 return _find_first_bit(addr, size); 139 } 140 #else /* CONFIG_GENERIC_FIND_FIRST_BIT */ 141 142 #ifndef find_first_bit 143 #define find_first_bit(addr, size) find_next_bit((addr), (size), 0) 144 #endif 145 #ifndef find_first_zero_bit 146 #define find_first_zero_bit(addr, size) find_next_zero_bit((addr), (size), 0) 147 #endif 148 149 #endif /* CONFIG_GENERIC_FIND_FIRST_BIT */ 150 151 #ifndef find_last_bit 152 /** 153 * find_last_bit - find the last set bit in a memory region 154 * @addr: The address to start the search at 155 * @size: The number of bits to search 156 * 157 * Returns the bit number of the last set bit, or size. 158 */ 159 static __always_inline 160 unsigned long find_last_bit(const unsigned long *addr, unsigned long size) 161 { 162 if (small_const_nbits(size)) { 163 unsigned long val = *addr & BITMAP_LAST_WORD_MASK(size); 165 } 166 167 return _find_last_bit(addr, size); 168 } 169 #endif 170 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org