Messages in this thread | | | Subject | Re: [PATCH i2c-next v9 5/5] i2c: aspeed: Add bus idle waiting logic for multi-master use cases | From | Jae Hyun Yoo <> | Date | Tue, 30 Oct 2018 16:04:24 -0700 |
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On 10/30/2018 3:22 PM, kbuild test robot wrote: > Hi Jae, > > Thank you for the patch! Perhaps something to improve: > > [auto build test WARNING on wsa/i2c/for-next] > [also build test WARNING on v4.19 next-20181030] > [if your patch is applied to the wrong git tree, please drop us a note to help improve the system] > > url: https://github.com/0day-ci/linux/commits/Jae-Hyun-Yoo/dt-bindings-i2c-Add-bus-timeout-ms-and-retries-properties-as-common-optional/20181031-051152 > base: https://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux.git i2c/for-next > config: xtensa-allyesconfig (attached as .config) > compiler: xtensa-linux-gcc (GCC) 8.1.0 > reproduce: > wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross > chmod +x ~/bin/make.cross > # save the attached .config to linux build tree > GCC_VERSION=8.1.0 make.cross ARCH=xtensa > > Note: it may well be a FALSE warning. FWIW you are at least aware of it now. > http://gcc.gnu.org/wiki/Better_Uninitialized_Warnings > > All warnings (new ones prefixed by >>): > > In file included from include/linux/ktime.h:25, > from include/linux/rcutiny.h:28, > from include/linux/rcupdate.h:209, > from include/linux/srcu.h:33, > from include/linux/notifier.h:16, > from include/linux/clk.h:17, > from drivers/i2c/busses/i2c-aspeed.c:13: > drivers/i2c/busses/i2c-aspeed.c: In function 'aspeed_i2c_master_xfer': >>> include/linux/jiffies.h:108:15: warning: 'timeout' may be used uninitialized in this function [-Wmaybe-uninitialized] > ((long)((b) - (a)) < 0)) > ^ > drivers/i2c/busses/i2c-aspeed.c:607:16: note: 'timeout' was declared here > unsigned long timeout; > ^~~~~~~ > -- > In file included from include/linux/ktime.h:25, > from include/linux/rcutiny.h:28, > from include/linux/rcupdate.h:209, > from include/linux/srcu.h:33, > from include/linux/notifier.h:16, > from include/linux/clk.h:17, > from drivers/i2c//busses/i2c-aspeed.c:13: > drivers/i2c//busses/i2c-aspeed.c: In function 'aspeed_i2c_master_xfer': >>> include/linux/jiffies.h:108:15: warning: 'timeout' may be used uninitialized in this function [-Wmaybe-uninitialized] > ((long)((b) - (a)) < 0)) > ^ > drivers/i2c//busses/i2c-aspeed.c:607:16: note: 'timeout' was declared here > unsigned long timeout; > ^~~~~~~ > > vim +/timeout +108 include/linux/jiffies.h > > ^1da177e Linus Torvalds 2005-04-16 91 > ^1da177e Linus Torvalds 2005-04-16 92 /* > ^1da177e Linus Torvalds 2005-04-16 93 * These inlines deal with timer wrapping correctly. You are > ^1da177e Linus Torvalds 2005-04-16 94 * strongly encouraged to use them > ^1da177e Linus Torvalds 2005-04-16 95 * 1. Because people otherwise forget > ^1da177e Linus Torvalds 2005-04-16 96 * 2. Because if the timer wrap changes in future you won't have to > ^1da177e Linus Torvalds 2005-04-16 97 * alter your driver code. > ^1da177e Linus Torvalds 2005-04-16 98 * > ^1da177e Linus Torvalds 2005-04-16 99 * time_after(a,b) returns true if the time a is after time b. > ^1da177e Linus Torvalds 2005-04-16 100 * > ^1da177e Linus Torvalds 2005-04-16 101 * Do this with "<0" and ">=0" to only test the sign of the result. A > ^1da177e Linus Torvalds 2005-04-16 102 * good compiler would generate better code (and a really good compiler > ^1da177e Linus Torvalds 2005-04-16 103 * wouldn't care). Gcc is currently neither. > ^1da177e Linus Torvalds 2005-04-16 104 */ > ^1da177e Linus Torvalds 2005-04-16 105 #define time_after(a,b) \ > ^1da177e Linus Torvalds 2005-04-16 106 (typecheck(unsigned long, a) && \ > ^1da177e Linus Torvalds 2005-04-16 107 typecheck(unsigned long, b) && \ > 5a581b36 Paul E. McKenney 2013-07-27 @108 ((long)((b) - (a)) < 0)) > ^1da177e Linus Torvalds 2005-04-16 109 #define time_before(a,b) time_after(b,a) > ^1da177e Linus Torvalds 2005-04-16 110 > > :::::: The code at line 108 was first introduced by commit > :::::: 5a581b367b5df0531265311fc681c2abd377e5e6 jiffies: Avoid undefined behavior from signed overflow > > :::::: TO: Paul E. McKenney <paulmck@linux.vnet.ibm.com> > :::::: CC: Paul E. McKenney <paulmck@linux.vnet.ibm.com> > > --- > 0-DAY kernel test infrastructure Open Source Technology Center > https://lists.01.org/pipermail/kbuild-all Intel Corporation >
This is a false warning.
The 'timeout' local variable will be initialized properly if it's gonna be used when the multi-master property is set.
-Jae
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