On Thursday, 1 November 2007 15:40, Alan Stern wrote:
> On Wed, 31 Oct 2007, Rafael J. Wysocki wrote:
>
> > > (Strictly speaking, we should have two different notification codes for
> > > PM_POST_HIBERNATION: one for use after the atomic snapshot has been
> > > created and one for use after it has been restored. But I'm not going
> > > to worry about that right now.)
> >
> > IIRC, the notifiers are not called after creating the image. Do you think that
> > they should be called at that time? If so, then why?
>
> My mistake. It's easy to forget that even though devices get resumed
> for writing after the image is created, tasks don't get thawed. And
> since tasks don't get thawed, the notifiers shouldn't be called.
>
> > As far as the patch is concerned, I'd prefer not to add new ioctls(), mainly
> > because there's userland out there that doesn't know about them and we can't
> > make people switch overnight. I'd prever to move the notifier calls to
> > snapshot_open() and snapshot_release().
>
> Okay, here's a patch to do things that way.
Thanks. [I was going to write that myself, but you were faster. :-)]
The patch looks good.
Please sign it off and provide a changelog and I'll forward it to Len.
Greetings,
Rafael
> Index: usb-2.6/Documentation/power/notifiers.txt
> ===================================================================
> --- usb-2.6.orig/Documentation/power/notifiers.txt
> +++ usb-2.6/Documentation/power/notifiers.txt
> @@ -28,6 +28,14 @@ PM_POST_HIBERNATION The system memory st
> hibernation. Device drivers' .resume() callbacks have
> been executed and tasks have been thawed.
>
> +PM_RESTORE_PREPARE The system is going to restore a hibernation image.
> + If all goes well the restored kernel will issue a
> + PM_POST_HIBERNATION notification.
> +
> +PM_POST_RESTORE An error occurred during the hibernation restore.
> + Device drivers' .resume() callbacks have been executed
> + and tasks have been thawed.
> +
> PM_SUSPEND_PREPARE The system is preparing for a suspend.
>
> PM_POST_SUSPEND The system has just resumed or an error occured during
> Index: usb-2.6/include/linux/notifier.h
> ===================================================================
> --- usb-2.6.orig/include/linux/notifier.h
> +++ usb-2.6/include/linux/notifier.h
> @@ -230,6 +230,8 @@ static inline int notifier_to_errno(int
> #define PM_POST_HIBERNATION 0x0002 /* Hibernation finished */
> #define PM_SUSPEND_PREPARE 0x0003 /* Going to suspend the system */
> #define PM_POST_SUSPEND 0x0004 /* Suspend finished */
> +#define PM_RESTORE_PREPARE 0x0005 /* Going to restore a saved image */
> +#define PM_POST_RESTORE 0x0006 /* Restore failed */
>
> /* Console keyboard events.
> * Note: KBD_KEYCODE is always sent before KBD_UNBOUND_KEYCODE, KBD_UNICODE and
> Index: usb-2.6/kernel/power/disk.c
> ===================================================================
> --- usb-2.6.orig/kernel/power/disk.c
> +++ usb-2.6/kernel/power/disk.c
> @@ -489,6 +489,10 @@ static int software_resume(void)
> goto Unlock;
> }
>
> + error = pm_notifier_call_chain(PM_RESTORE_PREPARE);
> + if (error)
> + goto Exit;
> +
> error = create_basic_memory_bitmaps();
> if (error)
> goto Finish;
> @@ -512,6 +516,8 @@ static int software_resume(void)
> Done:
> free_basic_memory_bitmaps();
> Finish:
> + pm_notifier_call_chain(PM_POST_RESTORE);
> + Exit:
> atomic_inc(&snapshot_device_available);
> /* For success case, the suspend path will release the lock */
> Unlock:
> Index: usb-2.6/kernel/power/user.c
> ===================================================================
> --- usb-2.6.orig/kernel/power/user.c
> +++ usb-2.6/kernel/power/user.c
> @@ -44,6 +44,7 @@ atomic_t snapshot_device_available = ATO
> static int snapshot_open(struct inode *inode, struct file *filp)
> {
> struct snapshot_data *data;
> + int error;
>
> if (!atomic_add_unless(&snapshot_device_available, -1, 0))
> return -EBUSY;
> @@ -64,9 +65,15 @@ static int snapshot_open(struct inode *i
> data->swap = swsusp_resume_device ?
> swap_type_of(swsusp_resume_device, 0, NULL) : -1;
> data->mode = O_RDONLY;
> + error = pm_notifier_call_chain(PM_RESTORE_PREPARE);
> } else {
> data->swap = -1;
> data->mode = O_WRONLY;
> + error = pm_notifier_call_chain(PM_HIBERNATION_PREPARE);
> + }
> + if (error) {
> + atomic_inc(&snapshot_device_available);
> + return error;
> }
> data->frozen = 0;
> data->ready = 0;
> @@ -88,6 +95,8 @@ static int snapshot_release(struct inode
> thaw_processes();
> mutex_unlock(&pm_mutex);
> }
> + pm_notifier_call_chain(data->mode == O_WRONLY ?
> + PM_POST_HIBERNATION : PM_POST_RESTORE);
> atomic_inc(&snapshot_device_available);
> return 0;
> }
> @@ -151,18 +160,13 @@ static int snapshot_ioctl(struct inode *
> if (data->frozen)
> break;
> mutex_lock(&pm_mutex);
> - error = pm_notifier_call_chain(PM_HIBERNATION_PREPARE);
> - if (!error) {
> - printk("Syncing filesystems ... ");
> - sys_sync();
> - printk("done.\n");
> -
> - error = freeze_processes();
> - if (error)
> - thaw_processes();
> - }
> + printk("Syncing filesystems ... ");
> + sys_sync();
> + printk("done.\n");
> +
> + error = freeze_processes();
> if (error)
> - pm_notifier_call_chain(PM_POST_HIBERNATION);
> + thaw_processes();
> mutex_unlock(&pm_mutex);
> if (!error)
> data->frozen = 1;
> @@ -173,7 +177,6 @@ static int snapshot_ioctl(struct inode *
> break;
> mutex_lock(&pm_mutex);
> thaw_processes();
> - pm_notifier_call_chain(PM_POST_HIBERNATION);
> mutex_unlock(&pm_mutex);
> data->frozen = 0;
> break;
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