Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752824Ab2JOFP3 (ORCPT ); Mon, 15 Oct 2012 01:15:29 -0400 Received: from mail-da0-f46.google.com ([209.85.210.46]:35964 "EHLO mail-da0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751750Ab2JOFPZ (ORCPT ); Mon, 15 Oct 2012 01:15:25 -0400 From: Ming Lei To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , linux-usb@vger.kernel.org, linux-pm@vger.kernel.org, Ming Lei , Alan Stern , Oliver Neukum , "Rafael J. Wysocki" Subject: [RFC PATCH 2/3] PM / Runtime: force memory allocation with no I/O during runtime_resume callbcack Date: Mon, 15 Oct 2012 13:14:18 +0800 Message-Id: <1350278059-14904-3-git-send-email-ming.lei@canonical.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1350278059-14904-1-git-send-email-ming.lei@canonical.com> References: <1350278059-14904-1-git-send-email-ming.lei@canonical.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1717 Lines: 45 This patch applies the introduces tsk_memalloc_forbid_io() and tsk_memalloc_allow_io() to force memory allocation with no I/O during runtime_resume callback. Cc: Alan Stern Cc: Oliver Neukum Cc: Rafael J. Wysocki Signed-off-by: Ming Lei --- drivers/base/power/runtime.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c index 3148b10..76836c1 100644 --- a/drivers/base/power/runtime.c +++ b/drivers/base/power/runtime.c @@ -652,7 +652,20 @@ static int rpm_resume(struct device *dev, int rpmflags) if (!callback && dev->driver && dev->driver->pm) callback = dev->driver->pm->runtime_resume; + /* + * Deadlock might be caused if memory allocation with GFP_KERNEL + * happens inside runtime_resume callback of one block device's + * ancestor or the block device itself. The easiest approach is + * to forbid I/O inside runtime_resume of all devices. + * + * In fact, it can be done only if the deivce is a block device + * or there is one block device descendant. But that may become + * complicated and not efficient because device tree traversing + * is involved. + */ + tsk_memalloc_forbid_io(current); retval = rpm_callback(callback, dev); + tsk_memalloc_allow_io(current); if (retval) { __update_runtime_status(dev, RPM_SUSPENDED); pm_runtime_cancel_pending(dev); -- 1.7.9.5 -- 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/