From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ryan Mallon Subject: Re: Is spin_is_locked() safe to use with BUG_ON()/WARN_ON()? Date: Fri, 24 May 2013 11:29:38 +1000 Message-ID: <519EC282.1010800@gmail.com> References: <6402.1369320636@warthog.procyon.org.uk> <6788.1369321955@warthog.procyon.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <6788.1369321955@warthog.procyon.org.uk> Sender: linux-kernel-owner@vger.kernel.org To: David Howells Cc: Linus Torvalds , Ingo Molnar , milosz@adfin.com, "linux-arch@vger.kernel.org" , Linux Kernel Mailing List List-Id: linux-arch.vger.kernel.org On 24/05/13 01:12, David Howells wrote: > Linus Torvalds wrote: > >> We do *not* want to add some crazy "spin_is_nt_locked". We just want >> to get rid of these idiotic debug tests. > > Generally, I think you are right, though there are also some checks in > deallocation routines that check that a spinlock is not currently held before > releasing the memory holding it - should those be allowed to stay? I'd be > tempted to wrap the whole check in something, perhaps an "spin_lock_uninit()" > and move the check to a header file. Would this be useful for lockdep or > anything like that? lockdep has lockdep_assert_held(), which might be what you want. Though it looks like it possibly also has the false positive issues on SMP? ~Ryan From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pd0-f181.google.com ([209.85.192.181]:48747 "EHLO mail-pd0-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759393Ab3EXB3p (ORCPT ); Thu, 23 May 2013 21:29:45 -0400 Message-ID: <519EC282.1010800@gmail.com> Date: Fri, 24 May 2013 11:29:38 +1000 From: Ryan Mallon MIME-Version: 1.0 Subject: Re: Is spin_is_locked() safe to use with BUG_ON()/WARN_ON()? References: <6402.1369320636@warthog.procyon.org.uk> <6788.1369321955@warthog.procyon.org.uk> In-Reply-To: <6788.1369321955@warthog.procyon.org.uk> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-arch-owner@vger.kernel.org List-ID: To: David Howells Cc: Linus Torvalds , Ingo Molnar , milosz@adfin.com, "linux-arch@vger.kernel.org" , Linux Kernel Mailing List Message-ID: <20130524012938.KA2bAcnR2CV-WgnyDfyMn6ygCJ4pHOvYkIkUvvXsF1w@z> On 24/05/13 01:12, David Howells wrote: > Linus Torvalds wrote: > >> We do *not* want to add some crazy "spin_is_nt_locked". We just want >> to get rid of these idiotic debug tests. > > Generally, I think you are right, though there are also some checks in > deallocation routines that check that a spinlock is not currently held before > releasing the memory holding it - should those be allowed to stay? I'd be > tempted to wrap the whole check in something, perhaps an "spin_lock_uninit()" > and move the check to a header file. Would this be useful for lockdep or > anything like that? lockdep has lockdep_assert_held(), which might be what you want. Though it looks like it possibly also has the false positive issues on SMP? ~Ryan