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Subject[Replacement][PATCH 1/2 v2] PM: Use spinlock instead of mutex in clock management functions
Date
From: Rafael J. Wysocki <rjw@sisk.pl>

The lock member of struct pm_clk_data is of type struct mutex,
which is a problem, because the suspend and resume routines
defined in drivers/base/power/clock_ops.c cannot be executed
with interrupts disabled for this reason. Modify
struct pm_clk_data so that its lock member is a spinlock.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
---
The previous [1/2] in this series was on top of the branch at

git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git pm-domains

but what is needed now is a version on top of the current mainline tree, which
is this one.

Thanks,
Rafael

---
drivers/base/power/clock_ops.c | 40 ++++++++++++++++++++++------------------
1 file changed, 22 insertions(+), 18 deletions(-)
Index: linux/drivers/base/power/clock_ops.c
===================================================================
--- linux.orig/drivers/base/power/clock_ops.c
+++ linux/drivers/base/power/clock_ops.c
@@ -19,7 +19,7 @@

struct pm_clk_data {
struct list_head clock_list;
- struct mutex lock;
+ spinlock_t lock;
};

enum pce_status {
@@ -73,9 +73,9 @@ int pm_clk_add(struct device *dev, const
}
}

- mutex_lock(&pcd->lock);
+ spin_lock_irq(&pcd->lock);
list_add_tail(&ce->node, &pcd->clock_list);
- mutex_unlock(&pcd->lock);
+ spin_unlock_irq(&pcd->lock);
return 0;
}

@@ -83,8 +83,8 @@ int pm_clk_add(struct device *dev, const
* __pm_clk_remove - Destroy PM clock entry.
* @ce: PM clock entry to destroy.
*
- * This routine must be called under the mutex protecting the PM list of clocks
- * corresponding the the @ce's device.
+ * This routine must be called under the spinlock protecting the PM list of
+ * clocks corresponding the the @ce's device.
*/
static void __pm_clk_remove(struct pm_clock_entry *ce)
{
@@ -123,7 +123,7 @@ void pm_clk_remove(struct device *dev, c
if (!pcd)
return;

- mutex_lock(&pcd->lock);
+ spin_lock_irq(&pcd->lock);

list_for_each_entry(ce, &pcd->clock_list, node) {
if (!con_id && !ce->con_id) {
@@ -137,7 +137,7 @@ void pm_clk_remove(struct device *dev, c
}
}

- mutex_unlock(&pcd->lock);
+ spin_unlock_irq(&pcd->lock);
}

/**
@@ -158,7 +158,7 @@ int pm_clk_init(struct device *dev)
}

INIT_LIST_HEAD(&pcd->clock_list);
- mutex_init(&pcd->lock);
+ spin_lock_init(&pcd->lock);
dev->power.subsys_data = pcd;
return 0;
}
@@ -181,12 +181,12 @@ void pm_clk_destroy(struct device *dev)

dev->power.subsys_data = NULL;

- mutex_lock(&pcd->lock);
+ spin_lock_irq(&pcd->lock);

list_for_each_entry_safe_reverse(ce, c, &pcd->clock_list, node)
__pm_clk_remove(ce);

- mutex_unlock(&pcd->lock);
+ spin_unlock_irq(&pcd->lock);

kfree(pcd);
}
@@ -220,13 +220,14 @@ int pm_clk_suspend(struct device *dev)
{
struct pm_clk_data *pcd = __to_pcd(dev);
struct pm_clock_entry *ce;
+ unsigned long flags;

dev_dbg(dev, "%s()\n", __func__);

if (!pcd)
return 0;

- mutex_lock(&pcd->lock);
+ spin_lock_irqsave(&pcd->lock, flags);

list_for_each_entry_reverse(ce, &pcd->clock_list, node) {
if (ce->status == PCE_STATUS_NONE)
@@ -238,7 +239,7 @@ int pm_clk_suspend(struct device *dev)
}
}

- mutex_unlock(&pcd->lock);
+ spin_unlock_irqrestore(&pcd->lock, flags);

return 0;
}
@@ -251,13 +252,14 @@ int pm_clk_resume(struct device *dev)
{
struct pm_clk_data *pcd = __to_pcd(dev);
struct pm_clock_entry *ce;
+ unsigned long flags;

dev_dbg(dev, "%s()\n", __func__);

if (!pcd)
return 0;

- mutex_lock(&pcd->lock);
+ spin_lock_irqsave(&pcd->lock, flags);

list_for_each_entry(ce, &pcd->clock_list, node) {
if (ce->status == PCE_STATUS_NONE)
@@ -269,7 +271,7 @@ int pm_clk_resume(struct device *dev)
}
}

- mutex_unlock(&pcd->lock);
+ spin_unlock_irqrestore(&pcd->lock, flags);

return 0;
}
@@ -344,6 +346,7 @@ int pm_clk_suspend(struct device *dev)
{
struct pm_clk_data *pcd = __to_pcd(dev);
struct pm_clock_entry *ce;
+ unsigned long flags;

dev_dbg(dev, "%s()\n", __func__);

@@ -351,12 +354,12 @@ int pm_clk_suspend(struct device *dev)
if (!pcd || !dev->driver)
return 0;

- mutex_lock(&pcd->lock);
+ spin_lock_irqsave(&pcd->lock, flags);

list_for_each_entry_reverse(ce, &pcd->clock_list, node)
clk_disable(ce->clk);

- mutex_unlock(&pcd->lock);
+ spin_unlock_irqrestore(&pcd->lock, flags);

return 0;
}
@@ -369,6 +372,7 @@ int pm_clk_resume(struct device *dev)
{
struct pm_clk_data *pcd = __to_pcd(dev);
struct pm_clock_entry *ce;
+ unsigned long flags;

dev_dbg(dev, "%s()\n", __func__);

@@ -376,12 +380,12 @@ int pm_clk_resume(struct device *dev)
if (!pcd || !dev->driver)
return 0;

- mutex_lock(&pcd->lock);
+ spin_lock_irqsave(&pcd->lock, flags);

list_for_each_entry(ce, &pcd->clock_list, node)
clk_enable(ce->clk);

- mutex_unlock(&pcd->lock);
+ spin_unlock_irqrestore(&pcd->lock, flags);

return 0;
}


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