linux-kernel - [221/272] PM / Runtime: Dont enable interrupts while running in

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Message-Id: <20110216001447.238238082@clark.kroah.org>
Date:	Tue, 15 Feb 2011 16:14:38 -0800
From:	Greg KH <gregkh@...e.de>
To:	linux-kernel@...r.kernel.org, stable@...nel.org
Cc:	stable-review@...nel.org, torvalds@...ux-foundation.org,
	akpm@...ux-foundation.org, alan@...rguk.ukuu.org.uk,
	Alan Stern <stern@...land.harvard.edu>,
	"Rafael J. Wysocki" <rjw@...k.pl>
Subject: [221/272] PM / Runtime: Dont enable interrupts while running in_interrupt

2.6.37-stable review patch.  If anyone has any objections, please let us know.

------------------

From: Alan Stern <stern@...land.harvard.edu>

commit c3810c88788d505d4ffd786addd111b745e42161 upstream.

This patch (as1445) fixes a bug in the runtime PM core left over from
the addition of the no_callbacks flag.  If this flag is set then it is
possible for rpm_suspend() to be called in_interrupt, so when
releasing spinlocks it's important not to re-enable interrupts.

To avoid an unnecessary save-and-restore of the interrupt flag, the
patch also inlines a pm_request_idle() call.

This fixes Bugzilla #27482.

(The offending code was added in 2.6.37, so it's not necessary to apply
this to any earlier stable kernels.)

Signed-off-by: Alan Stern <stern@...land.harvard.edu>
Reported-by: tim blechmann <tim@...ngt.org>
Signed-off-by: Rafael J. Wysocki <rjw@...k.pl>
Signed-off-by: Greg Kroah-Hartman <gregkh@...e.de>

---
 drivers/base/power/runtime.c |    9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

--- a/drivers/base/power/runtime.c
+++ b/drivers/base/power/runtime.c
@@ -404,12 +404,15 @@ static int rpm_suspend(struct device *de
 		goto out;
 	}
 
+	/* Maybe the parent is now able to suspend. */
 	if (parent && !parent->power.ignore_children) {
-		spin_unlock_irq(&dev->power.lock);
+		spin_unlock(&dev->power.lock);
 
-		pm_request_idle(parent);
+		spin_lock(&parent->power.lock);
+		rpm_idle(parent, RPM_ASYNC);
+		spin_unlock(&parent->power.lock);
 
-		spin_lock_irq(&dev->power.lock);
+		spin_lock(&dev->power.lock);
 	}
 
  out:


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