Re: [PATCH v1] PM / sleep: make pm notifier called symmetrically

[Lianwei Wang <lianwei.wang@gmail.com>]

On Fri, Jun 10, 2016 at 7:00 AM, Rafael J. Wysocki <rjw@rjwysocki.net> wrote:
> 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@gmail.com>
>
> Did you fix the build issue with the previous iteration reported by 0-day?
>
Yes. I had fix the build issue.

>> ---
>>  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.
Ok, I will put them on the same line.
>
>>       } 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
>