[PATCH 1/2 v2] PM: Change PM subsys_data lock type into spinlock

From: Rafael J. Wysocki
Date: Sun Aug 21 2011 - 15:11:06 EST


From: Rafael J. Wysocki <rjw@xxxxxxx>

The lock member of struct pm_subsys_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_subsys_data so that its lock member is a spinlock.

Signed-off-by: Rafael J. Wysocki <rjw@xxxxxxx>
---
drivers/base/power/clock_ops.c | 35 +++++++++++++++++++++--------------
drivers/base/power/common.c | 2 +-
include/linux/pm.h | 2 +-
3 files changed, 23 insertions(+), 16 deletions(-)

Index: linux/include/linux/pm.h
===================================================================
--- linux.orig/include/linux/pm.h
+++ linux/include/linux/pm.h
@@ -438,7 +438,7 @@ struct pm_domain_data {
};

struct pm_subsys_data {
- struct mutex lock;
+ spinlock_t lock;
unsigned int refcount;
#ifdef CONFIG_PM_CLK
struct list_head clock_list;
Index: linux/drivers/base/power/clock_ops.c
===================================================================
--- linux.orig/drivers/base/power/clock_ops.c
+++ linux/drivers/base/power/clock_ops.c
@@ -43,6 +43,7 @@ int pm_clk_add(struct device *dev, const
{
struct pm_subsys_data *psd = dev_to_psd(dev);
struct pm_clock_entry *ce;
+ unsigned long flags;

if (!psd)
return -EINVAL;
@@ -63,9 +64,9 @@ int pm_clk_add(struct device *dev, const
}
}

- mutex_lock(&psd->lock);
+ spin_lock_irqsave(&psd->lock, flags);
list_add_tail(&ce->node, &psd->clock_list);
- mutex_unlock(&psd->lock);
+ spin_unlock_irqrestore(&psd->lock, flags);
return 0;
}

@@ -109,11 +110,12 @@ void pm_clk_remove(struct device *dev, c
{
struct pm_subsys_data *psd = dev_to_psd(dev);
struct pm_clock_entry *ce;
+ unsigned long flags;

if (!psd)
return;

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

list_for_each_entry(ce, &psd->clock_list, node) {
if (!con_id && !ce->con_id) {
@@ -127,7 +129,7 @@ void pm_clk_remove(struct device *dev, c
}
}

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

/**
@@ -169,16 +171,17 @@ void pm_clk_destroy(struct device *dev)
{
struct pm_subsys_data *psd = dev_to_psd(dev);
struct pm_clock_entry *ce, *c;
+ unsigned long flags;

if (!psd)
return;

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

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

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

dev_pm_put_subsys_data(dev);
}
@@ -212,13 +215,14 @@ int pm_clk_suspend(struct device *dev)
{
struct pm_subsys_data *psd = dev_to_psd(dev);
struct pm_clock_entry *ce;
+ unsigned long flags;

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

if (!psd)
return 0;

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

list_for_each_entry_reverse(ce, &psd->clock_list, node) {
if (ce->status == PCE_STATUS_NONE)
@@ -230,7 +234,7 @@ int pm_clk_suspend(struct device *dev)
}
}

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

return 0;
}
@@ -243,13 +247,14 @@ int pm_clk_resume(struct device *dev)
{
struct pm_subsys_data *psd = dev_to_psd(dev);
struct pm_clock_entry *ce;
+ unsigned long flags;

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

if (!psd)
return 0;

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

list_for_each_entry(ce, &psd->clock_list, node) {
if (ce->status == PCE_STATUS_NONE)
@@ -261,7 +266,7 @@ int pm_clk_resume(struct device *dev)
}
}

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

return 0;
}
@@ -336,6 +341,7 @@ int pm_clk_suspend(struct device *dev)
{
struct pm_subsys_data *psd = dev_to_psd(dev);
struct pm_clock_entry *ce;
+ unsigned long flags;

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

@@ -343,12 +349,12 @@ int pm_clk_suspend(struct device *dev)
if (!psd || !dev->driver)
return 0;

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

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

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

return 0;
}
@@ -361,6 +367,7 @@ int pm_clk_resume(struct device *dev)
{
struct pm_subsys_data *psd = dev_to_psd(dev);
struct pm_clock_entry *ce;
+ unsigned long flags;

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

@@ -368,12 +375,12 @@ int pm_clk_resume(struct device *dev)
if (!psd || !dev->driver)
return 0;

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

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

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

return 0;
}
Index: linux/drivers/base/power/common.c
===================================================================
--- linux.orig/drivers/base/power/common.c
+++ linux/drivers/base/power/common.c
@@ -34,7 +34,7 @@ int dev_pm_get_subsys_data(struct device
if (dev->power.subsys_data) {
dev->power.subsys_data->refcount++;
} else {
- mutex_init(&psd->lock);
+ spin_lock_init(&psd->lock);
psd->refcount = 1;
dev->power.subsys_data = psd;
pm_clk_init(dev);

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