Re: [PATCH v3 1/6] freezer: Have {,un}lock_system_sleep() save/restore flags

Rafael J. Wysocki
2022-08-23T18:59:42Z

On Mon, Aug 22, 2022 at 1:48 PM Peter Zijlstra <peterz@infradead.org> wrote:
>
> Rafael explained that the reason for having both PF_NOFREEZE and
> PF_FREEZER_SKIP is that {,un}lock_system_sleep() is callable from
> kthread context that has previously called set_freezable().
>
> In preparation of merging the flags, have {,un}lock_system_slee() save
> and restore current->flags.
>
> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>

Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

> ---
> drivers/acpi/x86/s2idle.c | 12 ++++++++----
> drivers/scsi/scsi_transport_spi.c | 7 ++++---
> include/linux/suspend.h | 8 ++++----
> kernel/power/hibernate.c | 35 ++++++++++++++++++++++-------------
> kernel/power/main.c | 16 ++++++++++------
> kernel/power/suspend.c | 12 ++++++++----
> kernel/power/user.c | 24 ++++++++++++++----------
> 7 files changed, 70 insertions(+), 44 deletions(-)
>
> --- a/drivers/acpi/x86/s2idle.c
> +++ b/drivers/acpi/x86/s2idle.c
> @@ -541,12 +541,14 @@ void acpi_s2idle_setup(void)
>
> int acpi_register_lps0_dev(struct acpi_s2idle_dev_ops *arg)
> {
> + unsigned int sleep_flags;
> +
> if (!lps0_device_handle || sleep_no_lps0)
> return -ENODEV;
>
> - lock_system_sleep();
> + sleep_flags = lock_system_sleep();
> list_add(&arg->list_node, &lps0_s2idle_devops_head);
> - unlock_system_sleep();
> + unlock_system_sleep(sleep_flags);
>
> return 0;
> }
> @@ -554,12 +556,14 @@ EXPORT_SYMBOL_GPL(acpi_register_lps0_dev
>
> void acpi_unregister_lps0_dev(struct acpi_s2idle_dev_ops *arg)
> {
> + unsigned int sleep_flags;
> +
> if (!lps0_device_handle || sleep_no_lps0)
> return;
>
> - lock_system_sleep();
> + sleep_flags = lock_system_sleep();
> list_del(&arg->list_node);
> - unlock_system_sleep();
> + unlock_system_sleep(sleep_flags);
> }
> EXPORT_SYMBOL_GPL(acpi_unregister_lps0_dev);
>
> --- a/drivers/scsi/scsi_transport_spi.c
> +++ b/drivers/scsi/scsi_transport_spi.c
> @@ -998,8 +998,9 @@ void
> spi_dv_device(struct scsi_device *sdev)
> {
> struct scsi_target *starget = sdev->sdev_target;
> - u8 *buffer;
> const int len = SPI_MAX_ECHO_BUFFER_SIZE*2;
> + unsigned int sleep_flags;
> + u8 *buffer;
>
> /*
> * Because this function and the power management code both call
> @@ -1007,7 +1008,7 @@ spi_dv_device(struct scsi_device *sdev)
> * while suspend or resume is in progress. Hence the
> * lock/unlock_system_sleep() calls.
> */
> - lock_system_sleep();
> + sleep_flags = lock_system_sleep();
>
> if (scsi_autopm_get_device(sdev))
> goto unlock_system_sleep;
> @@ -1058,7 +1059,7 @@ spi_dv_device(struct scsi_device *sdev)
> scsi_autopm_put_device(sdev);
>
> unlock_system_sleep:
> - unlock_system_sleep();
> + unlock_system_sleep(sleep_flags);
> }
> EXPORT_SYMBOL(spi_dv_device);
>
> --- a/include/linux/suspend.h
> +++ b/include/linux/suspend.h
> @@ -510,8 +510,8 @@ extern bool pm_save_wakeup_count(unsigne
> extern void pm_wakep_autosleep_enabled(bool set);
> extern void pm_print_active_wakeup_sources(void);
>
> -extern void lock_system_sleep(void);
> -extern void unlock_system_sleep(void);
> +extern unsigned int lock_system_sleep(void);
> +extern void unlock_system_sleep(unsigned int);
>
> #else /* !CONFIG_PM_SLEEP */
>
> @@ -534,8 +534,8 @@ static inline void pm_system_wakeup(void
> static inline void pm_wakeup_clear(bool reset) {}
> static inline void pm_system_irq_wakeup(unsigned int irq_number) {}
>
> -static inline void lock_system_sleep(void) {}
> -static inline void unlock_system_sleep(void) {}
> +static inline unsigned int lock_system_sleep(void) { return 0; }
> +static inline void unlock_system_sleep(unsigned int flags) {}
>
> #endif /* !CONFIG_PM_SLEEP */
>
> --- a/kernel/power/hibernate.c
> +++ b/kernel/power/hibernate.c
> @@ -92,20 +92,24 @@ bool hibernation_available(void)
> */
> void hibernation_set_ops(const struct platform_hibernation_ops *ops)
> {
> + unsigned int sleep_flags;
> +
> if (ops && !(ops->begin && ops->end && ops->pre_snapshot
> && ops->prepare && ops->finish && ops->enter && ops->pre_restore
> && ops->restore_cleanup && ops->leave)) {
> WARN_ON(1);
> return;
> }
> - lock_system_sleep();
> +
> + sleep_flags = lock_system_sleep();
> +
> hibernation_ops = ops;
> if (ops)
> hibernation_mode = HIBERNATION_PLATFORM;
> else if (hibernation_mode == HIBERNATION_PLATFORM)
> hibernation_mode = HIBERNATION_SHUTDOWN;
>
> - unlock_system_sleep();
> + unlock_system_sleep(sleep_flags);
> }
> EXPORT_SYMBOL_GPL(hibernation_set_ops);
>
> @@ -713,6 +717,7 @@ static int load_image_and_restore(void)
> int hibernate(void)
> {
> bool snapshot_test = false;
> + unsigned int sleep_flags;
> int error;
>
> if (!hibernation_available()) {
> @@ -720,7 +725,7 @@ int hibernate(void)
> return -EPERM;
> }
>
> - lock_system_sleep();
> + sleep_flags = lock_system_sleep();
> /* The snapshot device should not be opened while we're running */
> if (!hibernate_acquire()) {
> error = -EBUSY;
> @@ -794,7 +799,7 @@ int hibernate(void)
> pm_restore_console();
> hibernate_release();
> Unlock:
> - unlock_system_sleep();
> + unlock_system_sleep(sleep_flags);
> pr_info("hibernation exit\n");
>
> return error;
> @@ -809,9 +814,10 @@ int hibernate(void)
> */
> int hibernate_quiet_exec(int (*func)(void *data), void *data)
> {
> + unsigned int sleep_flags;
> int error;
>
> - lock_system_sleep();
> + sleep_flags = lock_system_sleep();
>
> if (!hibernate_acquire()) {
> error = -EBUSY;
> @@ -891,7 +897,7 @@ int hibernate_quiet_exec(int (*func)(voi
> hibernate_release();
>
> unlock:
> - unlock_system_sleep();
> + unlock_system_sleep(sleep_flags);
>
> return error;
> }
> @@ -1100,11 +1106,12 @@ static ssize_t disk_show(struct kobject
> static ssize_t disk_store(struct kobject *kobj, struct kobj_attribute *attr,
> const char *buf, size_t n)
> {
> + int mode = HIBERNATION_INVALID;
> + unsigned int sleep_flags;
> int error = 0;
> - int i;
> int len;
> char *p;
> - int mode = HIBERNATION_INVALID;
> + int i;
>
> if (!hibernation_available())
> return -EPERM;
> @@ -1112,7 +1119,7 @@ static ssize_t disk_store(struct kobject
> p = memchr(buf, '\n', n);
> len = p ? p - buf : n;
>
> - lock_system_sleep();
> + sleep_flags = lock_system_sleep();
> for (i = HIBERNATION_FIRST; i <= HIBERNATION_MAX; i++) {
> if (len == strlen(hibernation_modes[i])
> && !strncmp(buf, hibernation_modes[i], len)) {
> @@ -1142,7 +1149,7 @@ static ssize_t disk_store(struct kobject
> if (!error)
> pm_pr_dbg("Hibernation mode set to '%s'\n",
> hibernation_modes[mode]);
> - unlock_system_sleep();
> + unlock_system_sleep(sleep_flags);
> return error ? error : n;
> }
>
> @@ -1158,9 +1165,10 @@ static ssize_t resume_show(struct kobjec
> static ssize_t resume_store(struct kobject *kobj, struct kobj_attribute *attr,
> const char *buf, size_t n)
> {
> - dev_t res;
> + unsigned int sleep_flags;
> int len = n;
> char *name;
> + dev_t res;
>
> if (len && buf[len-1] == '\n')
> len--;
> @@ -1173,9 +1181,10 @@ static ssize_t resume_store(struct kobje
> if (!res)
> return -EINVAL;
>
> - lock_system_sleep();
> + sleep_flags = lock_system_sleep();
> swsusp_resume_device = res;
> - unlock_system_sleep();
> + unlock_system_sleep(sleep_flags);
> +
> pm_pr_dbg("Configured hibernation resume from disk to %u\n",
> swsusp_resume_device);
> noresume = 0;
> --- a/kernel/power/main.c
> +++ b/kernel/power/main.c
> @@ -21,14 +21,16 @@
>
> #ifdef CONFIG_PM_SLEEP
>
> -void lock_system_sleep(void)
> +unsigned int lock_system_sleep(void)
> {
> + unsigned int flags = current->flags;
> current->flags |= PF_FREEZER_SKIP;
> mutex_lock(&system_transition_mutex);
> + return flags;
> }
> EXPORT_SYMBOL_GPL(lock_system_sleep);
>
> -void unlock_system_sleep(void)
> +void unlock_system_sleep(unsigned int flags)
> {
> /*
> * Don't use freezer_count() because we don't want the call to
> @@ -46,7 +48,8 @@ void unlock_system_sleep(void)
> * Which means, if we use try_to_freeze() here, it would make them
> * enter the refrigerator, thus causing hibernation to lockup.
> */
> - current->flags &= ~PF_FREEZER_SKIP;
> + if (!(flags & PF_FREEZER_SKIP))
> + current->flags &= ~PF_FREEZER_SKIP;
> mutex_unlock(&system_transition_mutex);
> }
> EXPORT_SYMBOL_GPL(unlock_system_sleep);
> @@ -263,16 +266,17 @@ static ssize_t pm_test_show(struct kobje
> static ssize_t pm_test_store(struct kobject *kobj, struct kobj_attribute *attr,
> const char *buf, size_t n)
> {
> + unsigned int sleep_flags;
> const char * const *s;
> + int error = -EINVAL;
> int level;
> char *p;
> int len;
> - int error = -EINVAL;
>
> p = memchr(buf, '\n', n);
> len = p ? p - buf : n;
>
> - lock_system_sleep();
> + sleep_flags = lock_system_sleep();
>
> level = TEST_FIRST;
> for (s = &pm_tests[level]; level <= TEST_MAX; s++, level++)
> @@ -282,7 +286,7 @@ static ssize_t pm_test_store(struct kobj
> break;
> }
>
> - unlock_system_sleep();
> + unlock_system_sleep(sleep_flags);
>
> return error ? error : n;
> }
> --- a/kernel/power/suspend.c
> +++ b/kernel/power/suspend.c
> @@ -75,9 +75,11 @@ EXPORT_SYMBOL_GPL(pm_suspend_default_s2i
>
> void s2idle_set_ops(const struct platform_s2idle_ops *ops)
> {
> - lock_system_sleep();
> + unsigned int sleep_flags;
> +
> + sleep_flags = lock_system_sleep();
> s2idle_ops = ops;
> - unlock_system_sleep();
> + unlock_system_sleep(sleep_flags);
> }
>
> static void s2idle_begin(void)
> @@ -200,7 +202,9 @@ __setup("mem_sleep_default=", mem_sleep_
> */
> void suspend_set_ops(const struct platform_suspend_ops *ops)
> {
> - lock_system_sleep();
> + unsigned int sleep_flags;
> +
> + sleep_flags = lock_system_sleep();
>
> suspend_ops = ops;
>
> @@ -216,7 +220,7 @@ void suspend_set_ops(const struct platfo
> mem_sleep_current = PM_SUSPEND_MEM;
> }
>
> - unlock_system_sleep();
> + unlock_system_sleep(sleep_flags);
> }
> EXPORT_SYMBOL_GPL(suspend_set_ops);
>
> --- a/kernel/power/user.c
> +++ b/kernel/power/user.c
> @@ -47,12 +47,13 @@ int is_hibernate_resume_dev(dev_t dev)
> static int snapshot_open(struct inode *inode, struct file *filp)
> {
> struct snapshot_data *data;
> + unsigned int sleep_flags;
> int error;
>
> if (!hibernation_available())
> return -EPERM;
>
> - lock_system_sleep();
> + sleep_flags = lock_system_sleep();
>
> if (!hibernate_acquire()) {
> error = -EBUSY;
> @@ -98,7 +99,7 @@ static int snapshot_open(struct inode *i
> data->dev = 0;
>
> Unlock:
> - unlock_system_sleep();
> + unlock_system_sleep(sleep_flags);
>
> return error;
> }
> @@ -106,8 +107,9 @@ static int snapshot_open(struct inode *i
> static int snapshot_release(struct inode *inode, struct file *filp)
> {
> struct snapshot_data *data;
> + unsigned int sleep_flags;
>
> - lock_system_sleep();
> + sleep_flags = lock_system_sleep();
>
> swsusp_free();
> data = filp->private_data;
> @@ -124,7 +126,7 @@ static int snapshot_release(struct inode
> PM_POST_HIBERNATION : PM_POST_RESTORE);
> hibernate_release();
>
> - unlock_system_sleep();
> + unlock_system_sleep(sleep_flags);
>
> return 0;
> }
> @@ -132,11 +134,12 @@ static int snapshot_release(struct inode
> static ssize_t snapshot_read(struct file *filp, char __user *buf,
> size_t count, loff_t *offp)
> {
> + loff_t pg_offp = *offp & ~PAGE_MASK;
> struct snapshot_data *data;
> + unsigned int sleep_flags;
> ssize_t res;
> - loff_t pg_offp = *offp & ~PAGE_MASK;
>
> - lock_system_sleep();
> + sleep_flags = lock_system_sleep();
>
> data = filp->private_data;
> if (!data->ready) {
> @@ -157,7 +160,7 @@ static ssize_t snapshot_read(struct file
> *offp += res;
>
> Unlock:
> - unlock_system_sleep();
> + unlock_system_sleep(sleep_flags);
>
> return res;
> }
> @@ -165,16 +168,17 @@ static ssize_t snapshot_read(struct file
> static ssize_t snapshot_write(struct file *filp, const char __user *buf,
> size_t count, loff_t *offp)
> {
> + loff_t pg_offp = *offp & ~PAGE_MASK;
> struct snapshot_data *data;
> + unsigned long sleep_flags;
> ssize_t res;
> - loff_t pg_offp = *offp & ~PAGE_MASK;
>
> if (need_wait) {
> wait_for_device_probe();
> need_wait = false;
> }
>
> - lock_system_sleep();
> + sleep_flags = lock_system_sleep();
>
> data = filp->private_data;
>
> @@ -196,7 +200,7 @@ static ssize_t snapshot_write(struct fil
> if (res > 0)
> *offp += res;
> unlock:
> - unlock_system_sleep();
> + unlock_system_sleep(sleep_flags);
>
> return res;
> }
>
>