Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755801AbaGIQpx (ORCPT ); Wed, 9 Jul 2014 12:45:53 -0400 Received: from mail-ie0-f182.google.com ([209.85.223.182]:62999 "EHLO mail-ie0-f182.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751948AbaGIQpw (ORCPT ); Wed, 9 Jul 2014 12:45:52 -0400 Message-ID: <53BD71BD.9010308@linaro.org> Date: Wed, 09 Jul 2014 11:45:49 -0500 From: Alex Elder User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.6.0 MIME-Version: 1.0 To: =?ISO-8859-1?Q?Petr_Ml=E1dek?= , Alex Elder CC: akpm@linux-foundation.org, ak@linux.intel.com, bp@suse.de, jack@suse.cz, john.stultz@linaro.org, rostedt@goodmis.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 4/4] printk: miscellaneous cleanups References: <1404911056-29064-1-git-send-email-elder@linaro.org> <1404911056-29064-5-git-send-email-elder@linaro.org> <20140709162935.GB26508@pathway.suse.cz> In-Reply-To: <20140709162935.GB26508@pathway.suse.cz> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 07/09/2014 11:29 AM, Petr Ml?dek wrote: > Sending once again as a correct reply. I am sorry for the > confusion. I think that it is high time for me to go home and sleep :-) > > On Wed 2014-07-09 08:04:16, Alex Elder wrote: >> This patch contains some small cleanups to kernel/printk/printk.c. >> None of them should cause any change in behavior. >> - When CONFIG_PRINTK is defined, parenthesize the value of LOG_LINE_MAX. >> - When CONFIG_PRINTK is *not* defined, there is an extra LOG_LINE_MAX >> definition; delete it. >> - Pull an assignment out of a conditional expression in console_setup(). >> - Use isdigit() in console_setup() rather than open coding it. >> - In update_console_cmdline(), drop a NUL-termination assignment; >> the strlcpy() call that precedes it guarantees it's not needed. >> - Simplify some logic in printk_timed_ratelimit(). >> >> Signed-off-by: Alex Elder >> --- >> kernel/printk/printk.c | 26 +++++++++++++------------- >> 1 file changed, 13 insertions(+), 13 deletions(-) >> >> diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c >> index 6f75e8a..909029e 100644 >> --- a/kernel/printk/printk.c >> +++ b/kernel/printk/printk.c . . . >> @@ -2611,14 +2612,13 @@ EXPORT_SYMBOL(__printk_ratelimit); >> bool printk_timed_ratelimit(unsigned long *caller_jiffies, >> unsigned int interval_msecs) >> { >> - if (*caller_jiffies == 0 >> - || !time_in_range(jiffies, *caller_jiffies, >> - *caller_jiffies >> - + msecs_to_jiffies(interval_msecs))) { >> - *caller_jiffies = jiffies; >> - return true; >> - } >> - return false; >> + unsigned long elapsed = jiffies - *caller_jiffies; > Currently, all callers pass a 0 value in *caller_jiffies initially (using a static/BSS variable), and a value updated by a previous call to __printk_ratelimit() thereafter. If a caller passed something different, yes, it's possible the result would wrap to a high unsigned value (i.e., go negative). However the logic used here involves the same subtraction operation as was used before--though previously that was buried inside the time_after() macro called by time_in_range(). -Alex > I wondered if the deduction might be negative. Well, it should not be > if none manipulates *caller_jiffies in a strange way. If it happens, > the following condition will most likely fail and *caller_jiffies will > get reset to jiffies. It looks reasonable to me. > > Reviewed-by: Petr Mladek > >> + if (*caller_jiffies && elapsed <= msecs_to_jiffies(interval_msecs)) >> + return false; >> + >> + *caller_jiffies = jiffies; >> + return true; >> } >> EXPORT_SYMBOL(printk_timed_ratelimit); > > Best Regards, > Petr > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/