Subject: Re: [PATCH net 1/2] net/sched: taprio: fix picos_per_byte miscalculation

From: kbuild test robot <[email-masked]>
Date: Fri, 15 Mar 2019 00:21:24 +0800

Hi Leandro,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on net/master]

url:    https://github.com/0day-ci/linux/commits/Leandro-Dorileo/net-sched-taprio-fix-picos_per_byte-miscalculation/20190314-231519
config: sparc64-allmodconfig (attached as .config)
compiler: sparc64-linux-gnu-gcc (Debian 7.2.0-11) 7.2.0
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=7.2.0 make.cross ARCH=sparc64 

All warnings (new ones prefixed by >>):

   In file included from include/linux/printk.h:7:0,
                    from include/linux/kernel.h:14,
                    from include/asm-generic/bug.h:18,
                    from arch/sparc/include/asm/bug.h:25,
                    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 net//sched/sch_taprio.c:10:
   net//sched/sch_taprio.c: In function 'taprio_set_picos_per_byte':
   include/linux/kern_levels.h:5:18: warning: format '%llu' expects argument of type 'long long unsigned int', but argument 3 has type 'long int' [-Wformat=]
    #define KERN_SOH "\001"  /* ASCII Start Of Header */
                     ^
   include/linux/kern_levels.h:14:19: note: in expansion of macro 'KERN_SOH'
    #define KERN_INFO KERN_SOH "6" /* informational */
                      ^~~~~~~~
   include/linux/printk.h:310:9: note: in expansion of macro 'KERN_INFO'
     printk(KERN_INFO pr_fmt(fmt), ##__VA_ARGS__)
            ^~~~~~~~~
>> net//sched/sch_taprio.c:600:2: note: in expansion of macro 'pr_info'
     pr_info("taprio: set %s's picos_per_byte to: %llu, linkspeed: %d\n",
     ^~~~~~~
   net//sched/sch_taprio.c:600:50: note: format string is defined here
     pr_info("taprio: set %s's picos_per_byte to: %llu, linkspeed: %d\n",
                                                  ~~~^
                                                  %lu

vim +/pr_info +600 net//sched/sch_taprio.c

   587	
   588	static void taprio_set_picos_per_byte(struct net_device *dev,
   589					      struct taprio_sched *q)
   590	{
   591		struct ethtool_link_ksettings ecmd;
   592		int picos_per_byte = -1;
   593	
   594		if (!__ethtool_get_link_ksettings(dev, &ecmd) &&
   595		    ecmd.base.speed != SPEED_UNKNOWN)
   596			picos_per_byte = div64_s64(NSEC_PER_SEC * 1000LL * 8,
   597						   ecmd.base.speed * 1000 * 1000);
   598	
   599		atomic64_set(&q->picos_per_byte, picos_per_byte);
 > 600		pr_info("taprio: set %s's picos_per_byte to: %llu, linkspeed: %d\n",
   601			dev->name, atomic64_read(&q->picos_per_byte), ecmd.base.speed);
   602	}
   603	

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