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charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.10.1 (2018-07-13) tree: https://github.com/l1k/linux smsc95xx_5.17 head: 240f56c27361c195cd502d95aba51c6b8e5b808c commit: 375b90433562ce3545ccda0376716268ff974114 [74/888] Improve __copy_to_user and __copy_from_user performance config: arm-multi_v5_defconfig (https://download.01.org/0day-ci/archive/20220409/202204091831.fSZgY5jM-lkp@intel.com/config) compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project 893e1c18b98d8bbc7b8d7d22cc2c348f65c72ad9) 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/l1k/linux/commit/375b90433562ce3545ccda0376716268ff974114 git remote add l1k https://github.com/l1k/linux git fetch --no-tags l1k smsc95xx_5.17 git checkout 375b90433562ce3545ccda0376716268ff974114 # save the config file to linux build tree mkdir build_dir COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=arm SHELL=/bin/bash If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot All warnings (new ones prefixed by >>): >> arch/arm/lib/uaccess_with_memcpy.c:137:1: warning: no previous prototype for function '__copy_to_user_memcpy' [-Wmissing-prototypes] __copy_to_user_memcpy(void __user *to, const void *from, unsigned long n) ^ arch/arm/lib/uaccess_with_memcpy.c:136:1: note: declare 'static' if the function is not intended to be used outside of this translation unit unsigned long noinline ^ static >> arch/arm/lib/uaccess_with_memcpy.c:190:1: warning: no previous prototype for function '__copy_from_user_memcpy' [-Wmissing-prototypes] __copy_from_user_memcpy(void *to, const void __user *from, unsigned long n) ^ arch/arm/lib/uaccess_with_memcpy.c:189:1: note: declare 'static' if the function is not intended to be used outside of this translation unit unsigned long noinline ^ static 2 warnings generated. vim +/__copy_to_user_memcpy +137 arch/arm/lib/uaccess_with_memcpy.c 375b90433562ce popcornmix 2016-11-28 135 375b90433562ce popcornmix 2016-11-28 136 unsigned long noinline cb9dc92c0a1b76 Nicolas Pitre 2009-05-21 @137 __copy_to_user_memcpy(void __user *to, const void *from, unsigned long n) 39ec58f3fea47c Lennert Buytenhek 2009-03-09 138 { c014953d84ec21 Russell King 2015-12-05 139 unsigned long ua_flags; 39ec58f3fea47c Lennert Buytenhek 2009-03-09 140 int atomic; 39ec58f3fea47c Lennert Buytenhek 2009-03-09 141 db68ce10c4f0a2 Al Viro 2017-03-20 142 if (uaccess_kernel()) { 39ec58f3fea47c Lennert Buytenhek 2009-03-09 143 memcpy((void *)to, from, n); 39ec58f3fea47c Lennert Buytenhek 2009-03-09 144 return 0; 39ec58f3fea47c Lennert Buytenhek 2009-03-09 145 } 39ec58f3fea47c Lennert Buytenhek 2009-03-09 146 39ec58f3fea47c Lennert Buytenhek 2009-03-09 147 /* the mmap semaphore is taken only if not in an atomic context */ 0f64b247e63ac8 Nicolas Pitre 2015-08-12 148 atomic = faulthandler_disabled(); 39ec58f3fea47c Lennert Buytenhek 2009-03-09 149 39ec58f3fea47c Lennert Buytenhek 2009-03-09 150 if (!atomic) d8ed45c5dcd455 Michel Lespinasse 2020-06-08 151 mmap_read_lock(current->mm); 39ec58f3fea47c Lennert Buytenhek 2009-03-09 152 while (n) { 39ec58f3fea47c Lennert Buytenhek 2009-03-09 153 pte_t *pte; 39ec58f3fea47c Lennert Buytenhek 2009-03-09 154 spinlock_t *ptl; 39ec58f3fea47c Lennert Buytenhek 2009-03-09 155 int tocopy; 39ec58f3fea47c Lennert Buytenhek 2009-03-09 156 39ec58f3fea47c Lennert Buytenhek 2009-03-09 157 while (!pin_page_for_write(to, &pte, &ptl)) { 39ec58f3fea47c Lennert Buytenhek 2009-03-09 158 if (!atomic) d8ed45c5dcd455 Michel Lespinasse 2020-06-08 159 mmap_read_unlock(current->mm); 39ec58f3fea47c Lennert Buytenhek 2009-03-09 160 if (__put_user(0, (char __user *)to)) 39ec58f3fea47c Lennert Buytenhek 2009-03-09 161 goto out; 39ec58f3fea47c Lennert Buytenhek 2009-03-09 162 if (!atomic) d8ed45c5dcd455 Michel Lespinasse 2020-06-08 163 mmap_read_lock(current->mm); 39ec58f3fea47c Lennert Buytenhek 2009-03-09 164 } 39ec58f3fea47c Lennert Buytenhek 2009-03-09 165 39ec58f3fea47c Lennert Buytenhek 2009-03-09 166 tocopy = (~(unsigned long)to & ~PAGE_MASK) + 1; 39ec58f3fea47c Lennert Buytenhek 2009-03-09 167 if (tocopy > n) 39ec58f3fea47c Lennert Buytenhek 2009-03-09 168 tocopy = n; 39ec58f3fea47c Lennert Buytenhek 2009-03-09 169 c014953d84ec21 Russell King 2015-12-05 170 ua_flags = uaccess_save_and_enable(); 39ec58f3fea47c Lennert Buytenhek 2009-03-09 171 memcpy((void *)to, from, tocopy); c014953d84ec21 Russell King 2015-12-05 172 uaccess_restore(ua_flags); 39ec58f3fea47c Lennert Buytenhek 2009-03-09 173 to += tocopy; 39ec58f3fea47c Lennert Buytenhek 2009-03-09 174 from += tocopy; 39ec58f3fea47c Lennert Buytenhek 2009-03-09 175 n -= tocopy; 39ec58f3fea47c Lennert Buytenhek 2009-03-09 176 a3a9ea656d1925 Steven Capper 2013-10-14 177 if (pte) 39ec58f3fea47c Lennert Buytenhek 2009-03-09 178 pte_unmap_unlock(pte, ptl); a3a9ea656d1925 Steven Capper 2013-10-14 179 else a3a9ea656d1925 Steven Capper 2013-10-14 180 spin_unlock(ptl); 39ec58f3fea47c Lennert Buytenhek 2009-03-09 181 } 39ec58f3fea47c Lennert Buytenhek 2009-03-09 182 if (!atomic) d8ed45c5dcd455 Michel Lespinasse 2020-06-08 183 mmap_read_unlock(current->mm); 39ec58f3fea47c Lennert Buytenhek 2009-03-09 184 39ec58f3fea47c Lennert Buytenhek 2009-03-09 185 out: 39ec58f3fea47c Lennert Buytenhek 2009-03-09 186 return n; 39ec58f3fea47c Lennert Buytenhek 2009-03-09 187 } 39ec58f3fea47c Lennert Buytenhek 2009-03-09 188 375b90433562ce popcornmix 2016-11-28 189 unsigned long noinline 375b90433562ce popcornmix 2016-11-28 @190 __copy_from_user_memcpy(void *to, const void __user *from, unsigned long n) 375b90433562ce popcornmix 2016-11-28 191 { 375b90433562ce popcornmix 2016-11-28 192 unsigned long ua_flags; 375b90433562ce popcornmix 2016-11-28 193 int atomic; 375b90433562ce popcornmix 2016-11-28 194 375b90433562ce popcornmix 2016-11-28 195 if (unlikely(uaccess_kernel())) { 375b90433562ce popcornmix 2016-11-28 196 memcpy(to, (const void *)from, n); 375b90433562ce popcornmix 2016-11-28 197 return 0; 375b90433562ce popcornmix 2016-11-28 198 } 375b90433562ce popcornmix 2016-11-28 199 375b90433562ce popcornmix 2016-11-28 200 /* the mmap semaphore is taken only if not in an atomic context */ 375b90433562ce popcornmix 2016-11-28 201 atomic = in_atomic(); 375b90433562ce popcornmix 2016-11-28 202 375b90433562ce popcornmix 2016-11-28 203 if (!atomic) 375b90433562ce popcornmix 2016-11-28 204 mmap_read_lock(current->mm); 375b90433562ce popcornmix 2016-11-28 205 while (n) { 375b90433562ce popcornmix 2016-11-28 206 pte_t *pte; 375b90433562ce popcornmix 2016-11-28 207 spinlock_t *ptl; 375b90433562ce popcornmix 2016-11-28 208 int tocopy; 375b90433562ce popcornmix 2016-11-28 209 375b90433562ce popcornmix 2016-11-28 210 while (!pin_page_for_read(from, &pte, &ptl)) { 375b90433562ce popcornmix 2016-11-28 211 char temp; 375b90433562ce popcornmix 2016-11-28 212 if (!atomic) 375b90433562ce popcornmix 2016-11-28 213 mmap_read_unlock(current->mm); 375b90433562ce popcornmix 2016-11-28 214 if (__get_user(temp, (char __user *)from)) 375b90433562ce popcornmix 2016-11-28 215 goto out; 375b90433562ce popcornmix 2016-11-28 216 if (!atomic) 375b90433562ce popcornmix 2016-11-28 217 mmap_read_lock(current->mm); 375b90433562ce popcornmix 2016-11-28 218 } 375b90433562ce popcornmix 2016-11-28 219 375b90433562ce popcornmix 2016-11-28 220 tocopy = (~(unsigned long)from & ~PAGE_MASK) + 1; 375b90433562ce popcornmix 2016-11-28 221 if (tocopy > n) 375b90433562ce popcornmix 2016-11-28 222 tocopy = n; 375b90433562ce popcornmix 2016-11-28 223 375b90433562ce popcornmix 2016-11-28 224 ua_flags = uaccess_save_and_enable(); 375b90433562ce popcornmix 2016-11-28 225 memcpy(to, (const void *)from, tocopy); 375b90433562ce popcornmix 2016-11-28 226 uaccess_restore(ua_flags); 375b90433562ce popcornmix 2016-11-28 227 to += tocopy; 375b90433562ce popcornmix 2016-11-28 228 from += tocopy; 375b90433562ce popcornmix 2016-11-28 229 n -= tocopy; 375b90433562ce popcornmix 2016-11-28 230 375b90433562ce popcornmix 2016-11-28 231 pte_unmap_unlock(pte, ptl); 375b90433562ce popcornmix 2016-11-28 232 } 375b90433562ce popcornmix 2016-11-28 233 if (!atomic) 375b90433562ce popcornmix 2016-11-28 234 mmap_read_unlock(current->mm); 375b90433562ce popcornmix 2016-11-28 235 375b90433562ce popcornmix 2016-11-28 236 out: 375b90433562ce popcornmix 2016-11-28 237 return n; 375b90433562ce popcornmix 2016-11-28 238 } 375b90433562ce popcornmix 2016-11-28 239 :::::: The code at line 137 was first introduced by commit :::::: cb9dc92c0a1b76165c8c334402e27191084b2047 [ARM] lower overhead with alternative copy_to_user for small copies :::::: TO: Nicolas Pitre :::::: CC: Nicolas Pitre -- 0-DAY CI Kernel Test Service https://01.org/lkp