Re: [PATCH v2 2/3] PM / Sleep: Replace mutex_[un]lock(&pm_mutex)with [un]lock_system_sleep()

[Simon Horman]

On Wed, Dec 07, 2011 at 12:54:02AM +0530, Srivatsa S. Bhat wrote:
> Using [un]lock_system_sleep() is safer than directly using mutex_[un]lock()
> on 'pm_mutex', since the latter could lead to freezing failures. Hence convert
> all the present users of mutex_[un]lock(&pm_mutex) to use these safe APIs
> instead.
> 
> Suggested-by: Tejun Heo <tj@xxxxxxxxxx>
> Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@xxxxxxxxxxxxxxxxxx>

I am happy with this from a kexec point of view.

Reviewed-by: Simon Horman <horms@xxxxxxxxxxxx>

> ---
> 
>  kernel/kexec.c           |    4 ++--
>  kernel/power/hibernate.c |   16 ++++++++--------
>  kernel/power/main.c      |    4 ++--
>  kernel/power/suspend.c   |    4 ++--
>  kernel/power/user.c      |   16 ++++++++--------
>  5 files changed, 22 insertions(+), 22 deletions(-)
> 
> diff --git a/kernel/kexec.c b/kernel/kexec.c
> index dc7bc08..090ee10 100644
> --- a/kernel/kexec.c
> +++ b/kernel/kexec.c
> @@ -1523,7 +1523,7 @@ int kernel_kexec(void)
>  
>  #ifdef CONFIG_KEXEC_JUMP
>  	if (kexec_image->preserve_context) {
> -		mutex_lock(&pm_mutex);
> +		lock_system_sleep();
>  		pm_prepare_console();
>  		error = freeze_processes();
>  		if (error) {
> @@ -1576,7 +1576,7 @@ int kernel_kexec(void)
>  		thaw_processes();
>   Restore_console:
>  		pm_restore_console();
> -		mutex_unlock(&pm_mutex);
> +		unlock_system_sleep();
>  	}
>  #endif
>  
> diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c
> index 605149a..6d6d288 100644
> --- a/kernel/power/hibernate.c
> +++ b/kernel/power/hibernate.c
> @@ -69,14 +69,14 @@ void hibernation_set_ops(const struct platform_hibernation_ops *ops)
>  		WARN_ON(1);
>  		return;
>  	}
> -	mutex_lock(&pm_mutex);
> +	lock_system_sleep();
>  	hibernation_ops = ops;
>  	if (ops)
>  		hibernation_mode = HIBERNATION_PLATFORM;
>  	else if (hibernation_mode == HIBERNATION_PLATFORM)
>  		hibernation_mode = HIBERNATION_SHUTDOWN;
>  
> -	mutex_unlock(&pm_mutex);
> +	unlock_system_sleep();
>  }
>  
>  static bool entering_platform_hibernation;
> @@ -597,7 +597,7 @@ int hibernate(void)
>  {
>  	int error;
>  
> -	mutex_lock(&pm_mutex);
> +	lock_system_sleep();
>  	/* The snapshot device should not be opened while we're running */
>  	if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
>  		error = -EBUSY;
> @@ -665,7 +665,7 @@ int hibernate(void)
>  	pm_restore_console();
>  	atomic_inc(&snapshot_device_available);
>   Unlock:
> -	mutex_unlock(&pm_mutex);
> +	unlock_system_sleep();
>  	return error;
>  }
>  
> @@ -893,7 +893,7 @@ static ssize_t disk_store(struct kobject *kobj, struct kobj_attribute *attr,
>  	p = memchr(buf, '\n', n);
>  	len = p ? p - buf : n;
>  
> -	mutex_lock(&pm_mutex);
> +	lock_system_sleep();
>  	for (i = HIBERNATION_FIRST; i <= HIBERNATION_MAX; i++) {
>  		if (len == strlen(hibernation_modes[i])
>  		    && !strncmp(buf, hibernation_modes[i], len)) {
> @@ -919,7 +919,7 @@ static ssize_t disk_store(struct kobject *kobj, struct kobj_attribute *attr,
>  	if (!error)
>  		pr_debug("PM: Hibernation mode set to '%s'\n",
>  			 hibernation_modes[mode]);
> -	mutex_unlock(&pm_mutex);
> +	unlock_system_sleep();
>  	return error ? error : n;
>  }
>  
> @@ -946,9 +946,9 @@ static ssize_t resume_store(struct kobject *kobj, struct kobj_attribute *attr,
>  	if (maj != MAJOR(res) || min != MINOR(res))
>  		goto out;
>  
> -	mutex_lock(&pm_mutex);
> +	lock_system_sleep();
>  	swsusp_resume_device = res;
> -	mutex_unlock(&pm_mutex);
> +	unlock_system_sleep();
>  	printk(KERN_INFO "PM: Starting manual resume from disk\n");
>  	noresume = 0;
>  	software_resume();
> diff --git a/kernel/power/main.c b/kernel/power/main.c
> index 7d36fb3..9824b41e 100644
> --- a/kernel/power/main.c
> +++ b/kernel/power/main.c
> @@ -116,7 +116,7 @@ static ssize_t pm_test_store(struct kobject *kobj, struct kobj_attribute *attr,
>  	p = memchr(buf, '\n', n);
>  	len = p ? p - buf : n;
>  
> -	mutex_lock(&pm_mutex);
> +	lock_system_sleep();
>  
>  	level = TEST_FIRST;
>  	for (s = &pm_tests[level]; level <= TEST_MAX; s++, level++)
> @@ -126,7 +126,7 @@ static ssize_t pm_test_store(struct kobject *kobj, struct kobj_attribute *attr,
>  			break;
>  		}
>  
> -	mutex_unlock(&pm_mutex);
> +	unlock_system_sleep();
>  
>  	return error ? error : n;
>  }
> diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c
> index d336b27..4fd51be 100644
> --- a/kernel/power/suspend.c
> +++ b/kernel/power/suspend.c
> @@ -42,9 +42,9 @@ static const struct platform_suspend_ops *suspend_ops;
>   */
>  void suspend_set_ops(const struct platform_suspend_ops *ops)
>  {
> -	mutex_lock(&pm_mutex);
> +	lock_system_sleep();
>  	suspend_ops = ops;
> -	mutex_unlock(&pm_mutex);
> +	unlock_system_sleep();
>  }
>  EXPORT_SYMBOL_GPL(suspend_set_ops);
>  
> diff --git a/kernel/power/user.c b/kernel/power/user.c
> index 06ea33d..98ade21 100644
> --- a/kernel/power/user.c
> +++ b/kernel/power/user.c
> @@ -71,7 +71,7 @@ static int snapshot_open(struct inode *inode, struct file *filp)
>  	struct snapshot_data *data;
>  	int error;
>  
> -	mutex_lock(&pm_mutex);
> +	lock_system_sleep();
>  
>  	if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
>  		error = -EBUSY;
> @@ -123,7 +123,7 @@ static int snapshot_open(struct inode *inode, struct file *filp)
>  	data->platform_support = 0;
>  
>   Unlock:
> -	mutex_unlock(&pm_mutex);
> +	unlock_system_sleep();
>  
>  	return error;
>  }
> @@ -132,7 +132,7 @@ static int snapshot_release(struct inode *inode, struct file *filp)
>  {
>  	struct snapshot_data *data;
>  
> -	mutex_lock(&pm_mutex);
> +	lock_system_sleep();
>  
>  	swsusp_free();
>  	free_basic_memory_bitmaps();
> @@ -146,7 +146,7 @@ static int snapshot_release(struct inode *inode, struct file *filp)
>  			PM_POST_HIBERNATION : PM_POST_RESTORE);
>  	atomic_inc(&snapshot_device_available);
>  
> -	mutex_unlock(&pm_mutex);
> +	unlock_system_sleep();
>  
>  	return 0;
>  }
> @@ -158,7 +158,7 @@ static ssize_t snapshot_read(struct file *filp, char __user *buf,
>  	ssize_t res;
>  	loff_t pg_offp = *offp & ~PAGE_MASK;
>  
> -	mutex_lock(&pm_mutex);
> +	lock_system_sleep();
>  
>  	data = filp->private_data;
>  	if (!data->ready) {
> @@ -179,7 +179,7 @@ static ssize_t snapshot_read(struct file *filp, char __user *buf,
>  		*offp += res;
>  
>   Unlock:
> -	mutex_unlock(&pm_mutex);
> +	unlock_system_sleep();
>  
>  	return res;
>  }
> @@ -191,7 +191,7 @@ static ssize_t snapshot_write(struct file *filp, const char __user *buf,
>  	ssize_t res;
>  	loff_t pg_offp = *offp & ~PAGE_MASK;
>  
> -	mutex_lock(&pm_mutex);
> +	lock_system_sleep();
>  
>  	data = filp->private_data;
>  
> @@ -208,7 +208,7 @@ static ssize_t snapshot_write(struct file *filp, const char __user *buf,
>  	if (res > 0)
>  		*offp += res;
>  unlock:
> -	mutex_unlock(&pm_mutex);
> +	unlock_system_sleep();
>  
>  	return res;
>  }
> 
> 
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> kexec@xxxxxxxxxxxxxxxxxxx
> http://lists.infradead.org/mailman/listinfo/kexec
> 
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