From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755517AbbCCIiA (ORCPT ); Tue, 3 Mar 2015 03:38:00 -0500 Received: from mail-wg0-f46.google.com ([74.125.82.46]:45438 "EHLO mail-wg0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752603AbbCCIh5 (ORCPT ); Tue, 3 Mar 2015 03:37:57 -0500 Date: Tue, 3 Mar 2015 09:37:53 +0100 From: Ingo Molnar To: Andrew Morton Cc: Valentin Rothberg , iss_storagedev@hp.com, linux-kernel@vger.kernel.org, Ingo Molnar Subject: Re: [PATCH] block/cpqarray.c: remove IRQF_DISABLED flag Message-ID: <20150303083753.GA1352@gmail.com> References: <1425040375-20528-1-git-send-email-Valentin.Rothberg@lip6.fr> <20150302135657.e8a3dfa54fae3d15f658b3b5@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150302135657.e8a3dfa54fae3d15f658b3b5@linux-foundation.org> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Andrew Morton wrote: > On Fri, 27 Feb 2015 13:32:55 +0100 Valentin Rothberg wrote: > > > The IRQF_DISABLED is a NOOP and scheduled to be removed. According to > > Ingo Molnar (e58aa3d2d0cc01ad8d6f7f640a0670433f794922) running IRQ > > handlers with interrupts enabled can cause stack overflows when the > > interrupt line of the issuing device is still active. > > > > I suggest you prepare a patch which removes IRQF_DISABLED entirely. Yes. > Several drivers still use it and it is possible that they have been > buggy for some time, [...] Well, IRQF_DISABLED is now the unconditional default, so requesting irqs with IRQF_DISABLED is simply superfluous, not buggy, AFAICS. > [...] so we should be careful to cc the relevant maintainers (they > probably don't exist) so they can check out what's going on in their > code. I think part of it might be the stale spinlock related comment in Documentation/PCI/MSI-HOWTO.txt which explicitly recommends IRQF_DISABLED use. So that reference should be zapped as well. So maybe drivers still using IRQF_DISABLED might not be potentially broken drivers at all, but are drivers written by exceptionally capable driver authors, who read kernel documentation! Thanks, Ingo