From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Mon, 24 Feb 2003 05:30:42 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Mon, 24 Feb 2003 05:30:41 -0500 Received: from bdpp-p-144-138-18-161.prem.tmns.net.au ([144.138.18.161]:48774 "EHLO portal.frood.au") by vger.kernel.org with ESMTP id ; Mon, 24 Feb 2003 05:30:40 -0500 Message-ID: <3E59F611.3020206@bigpond.com> Date: Mon, 24 Feb 2003 21:38:09 +1100 From: James Harper User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.0.0) Gecko/20020615 Debian/1.0.0-3 MIME-Version: 1.0 To: linux-kernel@vger.kernel.org Subject: PATCH to fix irq sharing and SA_INTERRUPT on x86. please review Content-Type: multipart/mixed; boundary="------------000506020201080706070907" Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org This is a multi-part message in MIME format. --------------000506020201080706070907 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit further to my email yesterday (to which i've had no response :) i propose the attached patch to arch/i386/kernel/irq.c. it corrects what i see as a bug in interrupt handling. currently if a driver requests SA_INTERRUPT in an interrupt handler, it is only called with interrupts disabled if it is the first handler in the list. my patch modifies setup_irq to put any interrupt with SA_INTERRUPT in the front of the handler queue (eg before any handlers without the flag). and also modifies handle_IRQ_event to only enable interrupts when it hits the first handler with SA_INTERRUPT not set. the patch is against 2.5.62 and greatly improves stability on my SMP system. james --------------000506020201080706070907 Content-Type: text/plain; name="SA_INTERRUPT_fix.diff" Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="SA_INTERRUPT_fix.diff" --- linux/arch/i386/kernel/irq.c Wed Feb 12 21:36:34 2003 +++ linux.test/arch/i386/kernel/irq.c Mon Feb 24 21:01:04 2003 @@ -201,11 +201,13 @@ int handle_IRQ_event(unsigned int irq, struct pt_regs * regs, struct irqaction * action) { int status = 1; /* Force the "do bottom halves" bit */ - - if (!(action->flags & SA_INTERRUPT)) - local_irq_enable(); + int enabled = SA_INTERRUPT; do { + if (~action->flags & enabled) { + local_irq_enable(); + enabled = 0; + } status |= action->flags; action->handler(irq, action->dev_id, regs); action = action->next; @@ -761,23 +763,38 @@ * The following block of code has to be executed atomically */ spin_lock_irqsave(&desc->lock,flags); - p = &desc->action; - if ((old = *p) != NULL) { - /* Can't share interrupts unless both agree to */ - if (!(old->flags & new->flags & SA_SHIRQ)) { - spin_unlock_irqrestore(&desc->lock,flags); - return -EBUSY; + if (new->flags & SA_INTERRUPT) { + p = &desc->action; + old = *p; + /* Add SA_INTERRUPT interrupts to the front of the queue + * 'cos it's faster than adding them in the middle */ + if (old) { + if (!(old->flags & new->flags & SA_SHIRQ)) { + spin_unlock_irqrestore(&desc->lock,flags); + return -EBUSY; + } + new->next = old; + shared = 1; } + *p = new; + } else { + p = &desc->action; + if ((old = *p) != NULL) { + /* Can't share interrupts unless both agree to */ + if (!(old->flags & new->flags & SA_SHIRQ)) { + spin_unlock_irqrestore(&desc->lock,flags); + return -EBUSY; + } - /* add new interrupt at end of irq queue */ - do { - p = &old->next; - old = *p; - } while (old); - shared = 1; + /* add new interrupt at end of irq queue */ + do { + p = &old->next; + old = *p; + } while (old); + shared = 1; + } + *p = new; } - - *p = new; if (!shared) { desc->depth = 0; --------------000506020201080706070907--