Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756520AbZDPFz4 (ORCPT ); Thu, 16 Apr 2009 01:55:56 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755609AbZDPFzF (ORCPT ); Thu, 16 Apr 2009 01:55:05 -0400 Received: from outbound.icp-qv1-irony-out2.iinet.net.au ([203.59.1.107]:64304 "EHLO outbound.icp-qv1-irony-out2.iinet.net.au" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756112AbZDPFzB (ORCPT ); Thu, 16 Apr 2009 01:55:01 -0400 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: ArgBAJxk5kl8qNY8/2dsb2JhbAAI0BuDfQY X-IronPort-AV: E=Sophos;i="4.40,197,1238947200"; d="scan'208";a="467881579" Subject: [PATCH 3/9] omap-keypad: Use disable_irq_nosync() from within irq handlers. From: Ben Nizette To: dmitry.torokhov@gmail.com Cc: linux-kernel , linux-input@vger.kernel.org Content-Type: text/plain Date: Thu, 16 Apr 2009 15:54:34 +1000 Message-Id: <1239861274.29831.118.camel@linux-51e8.site> Mime-Version: 1.0 X-Mailer: Evolution 2.22.1.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1755 Lines: 46 disable_irq() should wait for all running handlers to complete before returning. As such, if it's used to disable an interrupt from that interrupt's handler it will deadlock. This replaces the dangerous instances with the _nosync() variant which doesn't have this problem. This patch may be overly paranoid, it'd be cleaner to just disable all the row irqs _nosync() but it wouldn't be as correct. Up to $MAINTAINER :-) Signed-off-by: Ben Nizette --- diff --git a/drivers/input/keyboard/omap-keypad.c b/drivers/input/keyboard/omap-keypad.c index 058fa8b..9606a1c 100644 --- a/drivers/input/keyboard/omap-keypad.c +++ b/drivers/input/keyboard/omap-keypad.c @@ -100,8 +100,16 @@ static irqreturn_t omap_kp_interrupt(int irq, void *dev_id) /* disable keyboard interrupt and schedule for handling */ if (cpu_is_omap24xx()) { int i; - for (i = 0; i < omap_kp->rows; i++) - disable_irq(gpio_to_irq(row_gpios[i])); + for (i = 0; i < omap_kp->rows; i++) { + /* The interrupt which we're currently handling should + * be disabled _nosync() to avoid deadlocks waiting + * for this handler to complete. All others should + * be disabled the regular way for SMP safety. */ + if (gpio_to_irq(row_gpios[i]) == irq) + disable_irq_nosync(gpio_to_irq(row_gpios[i])); + else + disable_irq(gpio_to_irq(row_gpios[i])); + } } else /* disable keyboard interrupt and schedule for handling */ omap_writew(1, OMAP_MPUIO_BASE + OMAP_MPUIO_KBD_MASKIT); -- 1.6.0.2 -- 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/