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Date: Fri, 10 Jun 2016 16:00:04 +0200
From: "Rafael J. Wysocki" <rjw@...ysocki.net>
To: Lianwei Wang <lianwei.wang@...il.com>
Cc: tglx@...utronix.de, peterz@...radead.org, mingo@...nel.org,
oleg@...hat.com, linux-kernel@...r.kernel.org,
linux-pm@...r.kernel.org
Subject: Re: [PATCH v1] PM / sleep: make pm notifier called symmetrically
On Thursday, June 09, 2016 11:47:32 PM Lianwei Wang wrote:
> This makes pm notifier PREPARE/POST symmetrical: if PREPARE
> fails, we will only undo what ever happened on PREPARE.
>
> It fixes the unbalanced cpu hotplug enable in cpu pm notifier.
>
> Signed-off-by: Lianwei Wang <lianwei.wang@...il.com>
Did you fix the build issue with the previous iteration reported by 0-day?
> ---
> kernel/power/hibernate.c | 20 ++++++++++++--------
> kernel/power/main.c | 11 +++++++++--
> kernel/power/power.h | 2 ++
> kernel/power/suspend.c | 10 ++++++----
> kernel/power/user.c | 18 ++++++++++++------
> 5 files changed, 41 insertions(+), 20 deletions(-)
>
> diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c
> index fca9254280ee..126e24caa82e 100644
> --- a/kernel/power/hibernate.c
> +++ b/kernel/power/hibernate.c
> @@ -647,7 +647,7 @@ static void power_down(void)
> */
> int hibernate(void)
> {
> - int error;
> + int error, nr_calls = 0;
>
> if (!hibernation_available()) {
> pr_debug("PM: Hibernation not available.\n");
> @@ -662,9 +662,11 @@ int hibernate(void)
> }
>
> pm_prepare_console();
> - error = pm_notifier_call_chain(PM_HIBERNATION_PREPARE);
> - if (error)
> + error = __pm_notifier_call_chain(PM_HIBERNATION_PREPARE, -1, &nr_calls);
> + if (error) {
> + nr_calls--;
> goto Exit;
> + }
>
> printk(KERN_INFO "PM: Syncing filesystems ... ");
> sys_sync();
> @@ -714,7 +716,7 @@ int hibernate(void)
> /* Don't bother checking whether freezer_test_done is true */
> freezer_test_done = false;
> Exit:
> - pm_notifier_call_chain(PM_POST_HIBERNATION);
> + __pm_notifier_call_chain(PM_POST_HIBERNATION, nr_calls, NULL);
> pm_restore_console();
> atomic_inc(&snapshot_device_available);
> Unlock:
> @@ -740,7 +742,7 @@ int hibernate(void)
> */
> static int software_resume(void)
> {
> - int error;
> + int error, nr_calls = 0;
> unsigned int flags;
>
> /*
> @@ -827,9 +829,11 @@ static int software_resume(void)
> }
>
> pm_prepare_console();
> - error = pm_notifier_call_chain(PM_RESTORE_PREPARE);
> - if (error)
> + error = __pm_notifier_call_chain(PM_RESTORE_PREPARE, -1, &nr_calls);
> + if (error) {
> + nr_calls--;
> goto Close_Finish;
> + }
>
> pr_debug("PM: Preparing processes for restore.\n");
> error = freeze_processes();
> @@ -855,7 +859,7 @@ static int software_resume(void)
> unlock_device_hotplug();
> thaw_processes();
> Finish:
> - pm_notifier_call_chain(PM_POST_RESTORE);
> + __pm_notifier_call_chain(PM_POST_RESTORE, nr_calls, NULL);
> pm_restore_console();
> atomic_inc(&snapshot_device_available);
> /* For success case, the suspend path will release the lock */
> diff --git a/kernel/power/main.c b/kernel/power/main.c
> index 27946975eff0..577a5dec5b35 100644
> --- a/kernel/power/main.c
> +++ b/kernel/power/main.c
> @@ -38,12 +38,19 @@ int unregister_pm_notifier(struct notifier_block *nb)
> }
> EXPORT_SYMBOL_GPL(unregister_pm_notifier);
>
> -int pm_notifier_call_chain(unsigned long val)
> +int __pm_notifier_call_chain(unsigned long val, int nr_to_call, int *nr_calls)
> {
> - int ret = blocking_notifier_call_chain(&pm_chain_head, val, NULL);
> + int ret;
> +
> + ret = __blocking_notifier_call_chain(&pm_chain_head, val, NULL,
> + nr_to_call, nr_calls);
>
> return notifier_to_errno(ret);
> }
> +int pm_notifier_call_chain(unsigned long val)
> +{
> + return __pm_notifier_call_chain(val, -1, NULL);
> +}
>
> /* If set, devices may be suspended and resumed asynchronously. */
> int pm_async_enabled = 1;
> diff --git a/kernel/power/power.h b/kernel/power/power.h
> index efe1b3b17c88..51f02ecaf125 100644
> --- a/kernel/power/power.h
> +++ b/kernel/power/power.h
> @@ -200,6 +200,8 @@ static inline void suspend_test_finish(const char *label) {}
>
> #ifdef CONFIG_PM_SLEEP
> /* kernel/power/main.c */
> +extern int __pm_notifier_call_chain(unsigned long val, int nr_to_call,
> + int *nr_calls);
> extern int pm_notifier_call_chain(unsigned long val);
> #endif
>
> diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c
> index 5b70d64b871e..0acab9d7f96f 100644
> --- a/kernel/power/suspend.c
> +++ b/kernel/power/suspend.c
> @@ -266,16 +266,18 @@ static int suspend_test(int level)
> */
> static int suspend_prepare(suspend_state_t state)
> {
> - int error;
> + int error, nr_calls = 0;
>
> if (!sleep_state_supported(state))
> return -EPERM;
>
> pm_prepare_console();
>
> - error = pm_notifier_call_chain(PM_SUSPEND_PREPARE);
> - if (error)
> + error = __pm_notifier_call_chain(PM_SUSPEND_PREPARE, -1, &nr_calls);
> + if (error) {
> + nr_calls--;
> goto Finish;
> + }
>
> trace_suspend_resume(TPS("freeze_processes"), 0, true);
> error = suspend_freeze_processes();
> @@ -286,7 +288,7 @@ static int suspend_prepare(suspend_state_t state)
> suspend_stats.failed_freeze++;
> dpm_save_failed_step(SUSPEND_FREEZE);
> Finish:
> - pm_notifier_call_chain(PM_POST_SUSPEND);
> + __pm_notifier_call_chain(PM_POST_SUSPEND, nr_calls, NULL);
> pm_restore_console();
> return error;
> }
> diff --git a/kernel/power/user.c b/kernel/power/user.c
> index 526e8911460a..14ad11dd7eb7 100644
> --- a/kernel/power/user.c
> +++ b/kernel/power/user.c
> @@ -47,7 +47,7 @@ atomic_t snapshot_device_available = ATOMIC_INIT(1);
> static int snapshot_open(struct inode *inode, struct file *filp)
> {
> struct snapshot_data *data;
> - int error;
> + int error, nr_calls = 0;
>
> if (!hibernation_available())
> return -EPERM;
> @@ -74,9 +74,11 @@ static int snapshot_open(struct inode *inode, struct file *filp)
> swap_type_of(swsusp_resume_device, 0, NULL) : -1;
> data->mode = O_RDONLY;
> data->free_bitmaps = false;
> - error = pm_notifier_call_chain(PM_HIBERNATION_PREPARE);
> + error = __pm_notifier_call_chain(PM_HIBERNATION_PREPARE,
> + -1, &nr_calls);
> if (error)
> - pm_notifier_call_chain(PM_POST_HIBERNATION);
> + __pm_notifier_call_chain(PM_POST_HIBERNATION,
> + --nr_calls, NULL);
I wouldn't break these lines, it looks weird.
> } else {
> /*
> * Resuming. We may need to wait for the image device to
> @@ -86,13 +88,17 @@ static int snapshot_open(struct inode *inode, struct file *filp)
>
> data->swap = -1;
> data->mode = O_WRONLY;
> - error = pm_notifier_call_chain(PM_RESTORE_PREPARE);
> + error = __pm_notifier_call_chain(PM_RESTORE_PREPARE,
> + -1, &nr_calls);
> if (!error) {
> error = create_basic_memory_bitmaps();
> data->free_bitmaps = !error;
> - }
> + } else
> + nr_calls--;
> +
> if (error)
> - pm_notifier_call_chain(PM_POST_RESTORE);
> + __pm_notifier_call_chain(PM_POST_RESTORE,
> + nr_calls, NULL);
> }
> if (error)
> atomic_inc(&snapshot_device_available);
>
Thanks,
Rafael
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