mmc: core: host: only use wakelock for detect work

There is no need to take a wakelock for delayed lazy disable
work, it will be cancelled in the suspend handler and force
disabled.  Only take the wakelock when the detect work is
queued, and make sure to drop the wakelock if the work is
cancelled.

Change-Id: I1e507a5f98848954ea21d45e23b6192c3132a349
Signed-off-by: Colin Cross <ccross@android.com>

3 files changed, 18 insertions, 13 deletions

diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index 297367ab548..812f3d98bfc 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -53,7 +53,6 @@
 #define MMC_BKOPS_MAX_TIMEOUT	(4 * 60 * 1000) /* max time to wait in ms */
 
 static struct workqueue_struct *workqueue;
-static struct wake_lock mmc_delayed_work_wake_lock;
 static const unsigned freqs[] = { 400000, 300000, 200000, 100000 };
 
 /*
@@ -87,7 +86,6 @@ MODULE_PARM_DESC(
 static int mmc_schedule_delayed_work(struct delayed_work *work,
 				     unsigned long delay)
 {
-	wake_lock(&mmc_delayed_work_wake_lock);
 	return queue_delayed_work(workqueue, work, delay);
 }
 
@@ -1689,6 +1687,8 @@ void mmc_detect_change(struct mmc_host *host, unsigned long delay)
 	spin_unlock_irqrestore(&host->lock, flags);
 #endif
 	host->detect_change = 1;
+
+	wake_lock(&host->detect_wake_lock);
 	mmc_schedule_delayed_work(&host->detect, delay);
 }
 
@@ -2451,11 +2451,13 @@ void mmc_rescan(struct work_struct *work)
 
  out:
 	if (extend_wakelock)
-		wake_lock_timeout(&mmc_delayed_work_wake_lock, HZ / 2);
+		wake_lock_timeout(&host->detect_wake_lock, HZ / 2);
 	else
-		wake_unlock(&mmc_delayed_work_wake_lock);
-	if (host->caps & MMC_CAP_NEEDS_POLL)
+		wake_unlock(&host->detect_wake_lock);
+	if (host->caps & MMC_CAP_NEEDS_POLL) {
+		wake_lock(&host->detect_wake_lock);
 		mmc_schedule_delayed_work(&host->detect, HZ);
+	}
 }
 
 void mmc_start_host(struct mmc_host *host)
@@ -2479,7 +2481,8 @@ void mmc_stop_host(struct mmc_host *host)
 #endif
 
 	host->rescan_disable = 1;
-	cancel_delayed_work_sync(&host->detect);
+	if (cancel_delayed_work_sync(&host->detect))
+		wake_unlock(&host->detect_wake_lock);
 	mmc_flush_scheduled_work();
 
 	/* clear pm flags now and let card drivers set them as needed */
@@ -2677,7 +2680,8 @@ int mmc_suspend_host(struct mmc_host *host)
 	if (mmc_bus_needs_resume(host))
 		return 0;
 
-	cancel_delayed_work(&host->detect);
+	if (cancel_delayed_work(&host->detect))
+		wake_unlock(&host->detect_wake_lock);
 	mmc_flush_scheduled_work();
 
 	mmc_bus_get(host);
@@ -2800,7 +2804,8 @@ int mmc_pm_notify(struct notifier_block *notify_block,
 		}
 		host->rescan_disable = 1;
 		spin_unlock_irqrestore(&host->lock, flags);
-		cancel_delayed_work_sync(&host->detect);
+		if (cancel_delayed_work_sync(&host->detect))
+			wake_unlock(&host->detect_wake_lock);
 
 		if (!host->bus_ops || host->bus_ops->suspend)
 			break;
@@ -2876,9 +2881,6 @@ static int __init mmc_init(void)
 	if (!workqueue)
 		return -ENOMEM;
 
-	wake_lock_init(&mmc_delayed_work_wake_lock, WAKE_LOCK_SUSPEND,
-		       "mmc_delayed_work");
-
 	ret = mmc_register_bus();
 	if (ret)
 		goto destroy_workqueue;
@@ -2899,7 +2901,6 @@ unregister_bus:
 	mmc_unregister_bus();
 destroy_workqueue:
 	destroy_workqueue(workqueue);
-	wake_lock_destroy(&mmc_delayed_work_wake_lock);
 
 	return ret;
 }
@@ -2910,7 +2911,6 @@ static void __exit mmc_exit(void)
 	mmc_unregister_host_class();
 	mmc_unregister_bus();
 	destroy_workqueue(workqueue);
-	wake_lock_destroy(&mmc_delayed_work_wake_lock);
 }
 
 subsys_initcall(mmc_init);
diff --git a/drivers/mmc/core/host.c b/drivers/mmc/core/host.c
index f5bb7c769c3..56dadd667ec 100644
--- a/drivers/mmc/core/host.c
+++ b/drivers/mmc/core/host.c
@@ -459,6 +459,8 @@ struct mmc_host *mmc_alloc_host(int extra, struct device *dev)
 
 	spin_lock_init(&host->lock);
 	init_waitqueue_head(&host->wq);
+	wake_lock_init(&host->detect_wake_lock, WAKE_LOCK_SUSPEND,
+		kasprintf(GFP_KERNEL, "%s_detect", mmc_hostname(host)));
 	INIT_DELAYED_WORK(&host->detect, mmc_rescan);
 #ifdef CONFIG_PM
 	host->pm_notify.notifier_call = mmc_pm_notify;
@@ -558,6 +560,7 @@ void mmc_free_host(struct mmc_host *host)
 	spin_lock(&mmc_host_lock);
 	idr_remove(&mmc_host_idr, host->index);
 	spin_unlock(&mmc_host_lock);
+	wake_lock_destroy(&host->detect_wake_lock);
 
 	put_device(&host->class_dev);
 }
diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
index d286d7ecaee..66b46592760 100644
--- a/include/linux/mmc/host.h
+++ b/include/linux/mmc/host.h
@@ -15,6 +15,7 @@
 #include <linux/sched.h>
 #include <linux/device.h>
 #include <linux/fault-inject.h>
+#include <linux/wakelock.h>
 
 #include <linux/mmc/core.h>
 #include <linux/mmc/pm.h>
@@ -329,6 +330,7 @@ struct mmc_host {
 	int			claim_cnt;	/* "claim" nesting count */
 
 	struct delayed_work	detect;
+	struct wake_lock	detect_wake_lock;
 	int			detect_change;	/* card detect flag */
 	struct mmc_slot		slot;