From ab7e9b067f3d9cbec28cfca51d341efb421b7a51 Mon Sep 17 00:00:00 2001 From: Domenico Andreoli Date: Thu, 7 May 2020 09:19:52 +0200 Subject: [PATCH] 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: Domenico Andreoli Signed-off-by: Rafael J. Wysocki --- kernel/power/hibernate.c | 20 ++++++++++++++++---- kernel/power/power.h | 4 ++-- kernel/power/user.c | 10 ++++------ 3 files changed, 22 insertions(+), 12 deletions(-) diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c index 30bd28d..02ec716 100644 --- a/kernel/power/hibernate.c +++ b/kernel/power/hibernate.c @@ -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); diff --git a/kernel/power/power.h b/kernel/power/power.h index 7cdc64d..ba2094d 100644 --- a/kernel/power/power.h +++ b/kernel/power/power.h @@ -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); diff --git a/kernel/power/user.c b/kernel/power/user.c index 7959449..98548d1 100644 --- a/kernel/power/user.c +++ b/kernel/power/user.c @@ -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(); -- 2.7.4