From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Hurley Subject: Re: [PATCH 13/26] locking: Add non-fatal spin lock assert Date: Wed, 03 Sep 2014 10:50:01 -0400 Message-ID: <54072A99.1080306@hurleysoftware.com> References: <1409693975-1028-1-git-send-email-peter@hurleysoftware.com> <1409693975-1028-14-git-send-email-peter@hurleysoftware.com> <20140903092723.GA4783@worktop.ger.corp.intel.com> <5406F964.6060900@hurleysoftware.com> <20140903144029.GA7083@twins.programming.kicks-ass.net> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: Received: from mailout32.mail01.mtsvc.net ([216.70.64.70]:40213 "EHLO n23.mail01.mtsvc.net" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S932616AbaICOuJ (ORCPT ); Wed, 3 Sep 2014 10:50:09 -0400 In-Reply-To: <20140903144029.GA7083@twins.programming.kicks-ass.net> Sender: linux-serial-owner@vger.kernel.org List-Id: linux-serial@vger.kernel.org To: Peter Zijlstra Cc: Greg Kroah-Hartman , Jiri Slaby , One Thousand Gnomes , linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org, Ingo Molnar , Thomas Gleixner On 09/03/2014 10:40 AM, Peter Zijlstra wrote: > On Wed, Sep 03, 2014 at 07:20:04AM -0400, Peter Hurley wrote: >> Hi Peter, >> >> On 09/03/2014 05:27 AM, Peter Zijlstra wrote: >>> On Tue, Sep 02, 2014 at 05:39:22PM -0400, Peter Hurley wrote: >>>> Provide method for non-essential or non-critical code to warn of >>>> invariant errors. >>>> >>>> CC: Ingo Molnar >>>> CC: Peter Zijlstra >>>> CC: Thomas Gleixner >>>> Signed-off-by: Peter Hurley >>>> --- >>>> include/linux/spinlock.h | 1 + >>>> include/linux/spinlock_api_smp.h | 1 + >>>> include/linux/spinlock_api_up.h | 1 + >>>> 3 files changed, 3 insertions(+) >>>> >>>> diff --git a/include/linux/spinlock.h b/include/linux/spinlock.h >>>> index 3f2867f..8a9aaf1 100644 >>>> --- a/include/linux/spinlock.h >>>> +++ b/include/linux/spinlock.h >>>> @@ -394,6 +394,7 @@ static inline int spin_can_lock(spinlock_t *lock) >>>> } >>>> >>>> #define assert_spin_locked(lock) assert_raw_spin_locked(&(lock)->rlock) >>>> +#define warn_not_spin_locked(lock) warn_not_raw_spin_locked(&(lock)->rlock) >>>> >>>> /* >>>> * Pull the atomic_t declaration: >>>> diff --git a/include/linux/spinlock_api_smp.h b/include/linux/spinlock_api_smp.h >>>> index 42dfab8..0ddd499 100644 >>>> --- a/include/linux/spinlock_api_smp.h >>>> +++ b/include/linux/spinlock_api_smp.h >>>> @@ -18,6 +18,7 @@ >>>> int in_lock_functions(unsigned long addr); >>>> >>>> #define assert_raw_spin_locked(x) BUG_ON(!raw_spin_is_locked(x)) >>>> +#define warn_not_raw_spin_locked(x) WARN_ON_ONCE(!raw_spin_is_locked(x)) >>> >>> No we should remove assert_spin_locked() not add to it. Use >>> lockdep_assert_held() instead. >> >> I probably should have been more descriptive in the changelog: this >> is not for a test configuration, but rather, an assertion in an >> exported api. > > So ? So a lockdep-only assert is unlikely to draw attention to existing bugs, especially in established drivers.