4.9-stable patches

[thirdparty/kernel/stable-queue.git] / releases / 2.6.32.17 / revert-remove-rwsem-lock-from-cpufreq_gov_stop-call-second-call-site.patch

From accd846698439ba18250e8fd5681af280446b853 Mon Sep 17 00:00:00 2001
From: Andrej Gelenberg <andrej.gelenberg@udo.edu>
Date: Fri, 14 May 2010 15:15:58 -0700
Subject: [CPUFREQ] revert "[CPUFREQ] remove rwsem lock from CPUFREQ_GOV_STOP call (second call site)"

From: Andrej Gelenberg <andrej.gelenberg@udo.edu>

commit accd846698439ba18250e8fd5681af280446b853 upstream.

395913d0b1db37092ea3d9d69b832183b1dd84c5 ("[CPUFREQ] remove rwsem lock
from CPUFREQ_GOV_STOP call (second call site)") is not needed, because
there is no rwsem lock in cpufreq_ondemand and cpufreq_conservative
anymore.  Lock should not be released until the work done.

Addresses https://bugzilla.kernel.org/show_bug.cgi?id=1594

Signed-off-by: Andrej Gelenberg <andrej.gelenberg@udo.edu>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Dave Jones <davej@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
 drivers/cpufreq/cpufreq.c |   11 +----------
 1 file changed, 1 insertion(+), 10 deletions(-)

--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -1741,17 +1741,8 @@ static int __cpufreq_set_policy(struct c
 			dprintk("governor switch\n");
 
 			/* end old governor */
-			if (data->governor) {
-				/*
-				 * Need to release the rwsem around governor
-				 * stop due to lock dependency between
-				 * cancel_delayed_work_sync and the read lock
-				 * taken in the delayed work handler.
-				 */
-				unlock_policy_rwsem_write(data->cpu);
+			if (data->governor)
 				__cpufreq_governor(data, CPUFREQ_GOV_STOP);
-				lock_policy_rwsem_write(data->cpu);
-			}
 
 			/* start new governor */
 			data->governor = policy->governor;