powerpc/cell: Use system_wq in cpufreq_spudemand

With cmwq, there's no reason to use a separate workqueue in
cpufreq_spudemand.  Use system_wq instead.  The work items are already
sync canceled on stop, so it's already guaranteed that no work is
running when spu_gov_exit() is entered.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: linuxppc-dev@lists.ozlabs.org
Cc: Dave Jones <davej@redhat.com>
Cc: cpufreq@vger.kernel.org
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/kernel/time.c

@@ -265,11 +265,26 @@ void accumulate_stolen_time(void)
 {
 	u64 sst, ust;
 
-	sst = scan_dispatch_log(get_paca()->starttime_user);
-	ust = scan_dispatch_log(get_paca()->starttime);
-	get_paca()->system_time -= sst;
-	get_paca()->user_time -= ust;
-	get_paca()->stolen_time += ust + sst;
+	u8 save_soft_enabled = local_paca->soft_enabled;
+	u8 save_hard_enabled = local_paca->hard_enabled;
+
+	/* We are called early in the exception entry, before
+	 * soft/hard_enabled are sync'ed to the expected state
+	 * for the exception. We are hard disabled but the PACA
+	 * needs to reflect that so various debug stuff doesn't
+	 * complain
+	 */
+	local_paca->soft_enabled = 0;
+	local_paca->hard_enabled = 0;
+
+	sst = scan_dispatch_log(local_paca->starttime_user);
+	ust = scan_dispatch_log(local_paca->starttime);
+	local_paca->system_time -= sst;
+	local_paca->user_time -= ust;
+	local_paca->stolen_time += ust + sst;
+
+	local_paca->soft_enabled = save_soft_enabled;
+	local_paca->hard_enabled = save_hard_enabled;
 }
 
 static inline u64 calculate_stolen_time(u64 stop_tb)

arch/powerpc/platforms/cell/cpufreq_spudemand.c

@@ -39,8 +39,6 @@ struct spu_gov_info_struct {
 };
 static DEFINE_PER_CPU(struct spu_gov_info_struct, spu_gov_info);
 
-static struct workqueue_struct *kspugov_wq;
-
 static int calc_freq(struct spu_gov_info_struct *info)
 {
 	int cpu;
@@ -71,14 +69,14 @@ static void spu_gov_work(struct work_struct *work)
 	__cpufreq_driver_target(info->policy, target_freq, CPUFREQ_RELATION_H);
 
 	delay = usecs_to_jiffies(info->poll_int);
-	queue_delayed_work_on(info->policy->cpu, kspugov_wq, &info->work, delay);
+	schedule_delayed_work_on(info->policy->cpu, &info->work, delay);
 }
 
 static void spu_gov_init_work(struct spu_gov_info_struct *info)
 {
 	int delay = usecs_to_jiffies(info->poll_int);
 	INIT_DELAYED_WORK_DEFERRABLE(&info->work, spu_gov_work);
-	queue_delayed_work_on(info->policy->cpu, kspugov_wq, &info->work, delay);
+	schedule_delayed_work_on(info->policy->cpu, &info->work, delay);
 }
 
 static void spu_gov_cancel_work(struct spu_gov_info_struct *info)
@@ -152,27 +150,15 @@ static int __init spu_gov_init(void)
 {
 	int ret;
 
-	kspugov_wq = create_workqueue("kspugov");
-	if (!kspugov_wq) {
-		printk(KERN_ERR "creation of kspugov failed\n");
-		ret = -EFAULT;
-		goto out;
-	}
-
 	ret = cpufreq_register_governor(&spu_governor);
-	if (ret) {
+	if (ret)
 		printk(KERN_ERR "registration of governor failed\n");
-		destroy_workqueue(kspugov_wq);
-		goto out;
-	}
-out:
 	return ret;
 }
 
 static void __exit spu_gov_exit(void)
 {
 	cpufreq_unregister_governor(&spu_governor);
-	destroy_workqueue(kspugov_wq);
 }