From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Rafael J. Wysocki" Subject: Re: [PATCH] PM: runtime: fix recursive locking warning of lockdep from rpm_resume Date: Fri, 22 Oct 2010 23:50:14 +0200 Message-ID: <201010222350.14480.rjw@sisk.pl> References: Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-pm-bounces@lists.linux-foundation.org Errors-To: linux-pm-bounces@lists.linux-foundation.org To: Alan Stern Cc: linux-pm@lists.linux-foundation.org List-Id: linux-pm@vger.kernel.org On Friday, October 22, 2010, Alan Stern wrote: > On Fri, 22 Oct 2010 tom.leiming@gmail.com wrote: > > > From: Ming Lei > > > > For device with no_callbacks flag set, its power lock and its parent's > > power lock may be held nestedly in rpm_resume, so we should take > > spin_lock_nested(lock, SINGLE_DEPTH_NESTING) to acquire parent power lock > > to avoid lockdep warning. > > > > Signed-off-by: Ming Lei > > --- > > drivers/base/power/runtime.c | 2 +- > > 1 files changed, 1 insertions(+), 1 deletions(-) > > > > diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c > > index 1dd8676..126ca49 100644 > > --- a/drivers/base/power/runtime.c > > +++ b/drivers/base/power/runtime.c > > @@ -503,7 +503,7 @@ static int rpm_resume(struct device *dev, int rpmflags) > > * the resume will actually succeed. > > */ > > if (dev->power.no_callbacks && !parent && dev->parent) { > > - spin_lock(&dev->parent->power.lock); > > + spin_lock_nested(&dev->parent->power.lock, SINGLE_DEPTH_NESTING); > > if (dev->parent->power.disable_depth > 0 > > || dev->parent->power.ignore_children > > || dev->parent->power.runtime_status == RPM_ACTIVE) { > > Quite correct; I don't know why this didn't show up during my testing. > > Acked-by: Alan Stern Applied to suspend-2.6/pm-fixes, will push to Linus early next week. Thanks, Rafael