[kbuild-all] [driver-core:tty-test 13/13] drivers/tty/tty_baudrate.c:92:9: warning: no previous prototype for function 'tty_termios_input_baud_rate'

tree: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core.git tty-test head: 8a67b4c2f3f14e73a8ddfbef9c032d9f2fa6979a commit: 8a67b4c2f3f14e73a8ddfbef9c032d9f2fa6979a [13/13] tty: clean include/linux/tty.h up config: x86_64-randconfig-r013-20210408 (attached as .config) compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project 56ea2e2fdd691136d5e6631fa0e447173694b82c) 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 x86_64 cross compiling tool for clang build # apt-get install binutils-x86-64-linux-gnu # https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core.git/co... git remote add driver-core https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core.git git fetch --no-tags driver-core tty-test git checkout 8a67b4c2f3f14e73a8ddfbef9c032d9f2fa6979a # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=x86_64 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All warnings (new ones prefixed by >>): speed_t tty_termios_input_baud_rate(struct ktermios *termios) ^ drivers/tty/tty_baudrate.c:92:1: note: declare 'static' if the function is not intended to be used outside of this translation unit speed_t tty_termios_input_baud_rate(struct ktermios *termios) ^ static 1 warning generated. vim +/tty_termios_input_baud_rate +92 drivers/tty/tty_baudrate.c fff0a2ca3a061c Nicolas Pitre 2017-04-12 79 fff0a2ca3a061c Nicolas Pitre 2017-04-12 80 /** fff0a2ca3a061c Nicolas Pitre 2017-04-12 81 * tty_termios_input_baud_rate fff0a2ca3a061c Nicolas Pitre 2017-04-12 82 * @termios: termios structure fff0a2ca3a061c Nicolas Pitre 2017-04-12 83 * fff0a2ca3a061c Nicolas Pitre 2017-04-12 84 * Convert termios baud rate data into a speed. This should be called fff0a2ca3a061c Nicolas Pitre 2017-04-12 85 * with the termios lock held if this termios is a terminal termios fff0a2ca3a061c Nicolas Pitre 2017-04-12 86 * structure. May change the termios data. Device drivers can call this fff0a2ca3a061c Nicolas Pitre 2017-04-12 87 * function but should use ->c_[io]speed directly as they are updated. fff0a2ca3a061c Nicolas Pitre 2017-04-12 88 * fff0a2ca3a061c Nicolas Pitre 2017-04-12 89 * Locking: none fff0a2ca3a061c Nicolas Pitre 2017-04-12 90 */ fff0a2ca3a061c Nicolas Pitre 2017-04-12 91 fff0a2ca3a061c Nicolas Pitre 2017-04-12 @92 speed_t tty_termios_input_baud_rate(struct ktermios *termios) fff0a2ca3a061c Nicolas Pitre 2017-04-12 93 { fff0a2ca3a061c Nicolas Pitre 2017-04-12 94 #ifdef IBSHIFT fff0a2ca3a061c Nicolas Pitre 2017-04-12 95 unsigned int cbaud = (termios->c_cflag >> IBSHIFT) & CBAUD; fff0a2ca3a061c Nicolas Pitre 2017-04-12 96 fff0a2ca3a061c Nicolas Pitre 2017-04-12 97 if (cbaud == B0) fff0a2ca3a061c Nicolas Pitre 2017-04-12 98 return tty_termios_baud_rate(termios); fefe287e4bf6ee Johan Hovold 2018-07-15 99 #ifdef BOTHER fff0a2ca3a061c Nicolas Pitre 2017-04-12 100 /* Magic token for arbitrary speed via c_ispeed*/ fff0a2ca3a061c Nicolas Pitre 2017-04-12 101 if (cbaud == BOTHER) fff0a2ca3a061c Nicolas Pitre 2017-04-12 102 return termios->c_ispeed; fefe287e4bf6ee Johan Hovold 2018-07-15 103 #endif fff0a2ca3a061c Nicolas Pitre 2017-04-12 104 if (cbaud & CBAUDEX) { fff0a2ca3a061c Nicolas Pitre 2017-04-12 105 cbaud &= ~CBAUDEX; fff0a2ca3a061c Nicolas Pitre 2017-04-12 106 fff0a2ca3a061c Nicolas Pitre 2017-04-12 107 if (cbaud < 1 || cbaud + 15 > n_baud_table) fff0a2ca3a061c Nicolas Pitre 2017-04-12 108 termios->c_cflag &= ~(CBAUDEX << IBSHIFT); fff0a2ca3a061c Nicolas Pitre 2017-04-12 109 else fff0a2ca3a061c Nicolas Pitre 2017-04-12 110 cbaud += 15; fff0a2ca3a061c Nicolas Pitre 2017-04-12 111 } 991a2519409700 H. Peter Anvin 2018-10-22 112 return cbaud >= n_baud_table ? 0 : baud_table[cbaud]; fefe287e4bf6ee Johan Hovold 2018-07-15 113 #else /* IBSHIFT */ fff0a2ca3a061c Nicolas Pitre 2017-04-12 114 return tty_termios_baud_rate(termios); fefe287e4bf6ee Johan Hovold 2018-07-15 115 #endif /* IBSHIFT */ fff0a2ca3a061c Nicolas Pitre 2017-04-12 116 } fff0a2ca3a061c Nicolas Pitre 2017-04-12 117 EXPORT_SYMBOL(tty_termios_input_baud_rate); fff0a2ca3a061c Nicolas Pitre 2017-04-12 118 :::::: The code at line 92 was first introduced by commit :::::: fff0a2ca3a061c230b0e905e7586267a517538ac tty: move baudrate handling code to a file of its own :::::: TO: Nicolas Pitre <nicolas.pitre(a)linaro.org&gt; :::::: CC: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org&gt; --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org