Commit ab7e9b06 authored by Domenico Andreoli's avatar Domenico Andreoli Committed by Rafael J. Wysocki
Browse files

PM: hibernate: Incorporate concurrency handling 



Hibernation concurrency handling is currently delegated to user.c,
where it's also used for regulating the access to the snapshot device.

In the prospective of making user.c a separate configuration option,
such mutual exclusion is brought into hibernate.c and made available
through accessor helpers hereby introduced.

Signed-off-by: default avatarDomenico Andreoli <domenico.andreoli@linux.com>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent 3a4ccdb9

kernel/power/hibernate.c

+16 −4
Original line number Diff line number Diff line
@@ -67,6 +67,18 @@ bool freezer_test_done; 


static const struct platform_hibernation_ops *hibernation_ops;



static atomic_t hibernate_atomic = ATOMIC_INIT(1);



bool hibernate_acquire(void)

{

	return atomic_add_unless(&hibernate_atomic, -1, 0);

}



void hibernate_release(void)

{

	atomic_inc(&hibernate_atomic);

}



bool hibernation_available(void)

{

	return nohibernate == 0 && !security_locked_down(LOCKDOWN_HIBERNATION);
@@ -704,7 +716,7 @@ int hibernate(void) 


	lock_system_sleep();

	/* The snapshot device should not be opened while we're running */

	if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {

	if (!hibernate_acquire()) {

		error = -EBUSY;

		goto Unlock;

	}
@@ -775,7 +787,7 @@ int hibernate(void) 
 Exit:

	__pm_notifier_call_chain(PM_POST_HIBERNATION, nr_calls, NULL);

	pm_restore_console();

	atomic_inc(&snapshot_device_available);

	hibernate_release();

 Unlock:

	unlock_system_sleep();

	pr_info("hibernation exit\n");
@@ -880,7 +892,7 @@ static int software_resume(void) 
		goto Unlock;



	/* The snapshot device should not be opened while we're running */

	if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {

	if (!hibernate_acquire()) {

		error = -EBUSY;

		swsusp_close(FMODE_READ);

		goto Unlock;
@@ -911,7 +923,7 @@ static int software_resume(void) 
	__pm_notifier_call_chain(PM_POST_RESTORE, nr_calls, NULL);

	pm_restore_console();

	pr_info("resume failed (%d)\n", error);

	atomic_inc(&snapshot_device_available);

	hibernate_release();

	/* For success case, the suspend path will release the lock */

 Unlock:

	mutex_unlock(&system_transition_mutex);

kernel/power/power.h

+2 −2
Original line number Diff line number Diff line
@@ -154,8 +154,8 @@ extern int snapshot_write_next(struct snapshot_handle *handle); 
extern void snapshot_write_finalize(struct snapshot_handle *handle);

extern int snapshot_image_loaded(struct snapshot_handle *handle);



/* If unset, the snapshot device cannot be open. */

extern atomic_t snapshot_device_available;

extern bool hibernate_acquire(void);

extern void hibernate_release(void);



extern sector_t alloc_swapdev_block(int swap);

extern void free_all_swap_pages(int swap);

kernel/power/user.c

+4 −6
Original line number Diff line number Diff line
@@ -37,8 +37,6 @@ static struct snapshot_data { 
	bool free_bitmaps;

} snapshot_state;



atomic_t snapshot_device_available = ATOMIC_INIT(1);



static int snapshot_open(struct inode *inode, struct file *filp)

{

	struct snapshot_data *data;
@@ -49,13 +47,13 @@ static int snapshot_open(struct inode *inode, struct file *filp) 


	lock_system_sleep();



	if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {

	if (!hibernate_acquire()) {

		error = -EBUSY;

		goto Unlock;

	}



	if ((filp->f_flags & O_ACCMODE) == O_RDWR) {

		atomic_inc(&snapshot_device_available);

		hibernate_release();

		error = -ENOSYS;

		goto Unlock;

	}
@@ -92,7 +90,7 @@ static int snapshot_open(struct inode *inode, struct file *filp) 
			__pm_notifier_call_chain(PM_POST_RESTORE, nr_calls, NULL);

	}

	if (error)

		atomic_inc(&snapshot_device_available);

		hibernate_release();



	data->frozen = false;

	data->ready = false;
@@ -122,7 +120,7 @@ static int snapshot_release(struct inode *inode, struct file *filp) 
	}

	pm_notifier_call_chain(data->mode == O_RDONLY ?

			PM_POST_HIBERNATION : PM_POST_RESTORE);

	atomic_inc(&snapshot_device_available);

	hibernate_release();



	unlock_system_sleep();

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