Re: [PATCH V3 23/25] smartpqi: correct system hangs when resuming from hibernation

[Martin Wilck <mwilck@suse.com>]

On Thu, 2020-12-10 at 14:36 -0600, Don Brace wrote:
> From: Kevin Barnett <kevin.barnett@microchip.com>
> 
> * Correct system hangs when resuming from hibernation after
>   first successful hibernation/resume cycle.
>   * Rare condition involving OFA.
> 
> Reviewed-by: Scott Benesh <scott.benesh@microchip.com>
> Signed-off-by: Kevin Barnett <kevin.barnett@microchip.com>
> Signed-off-by: Don Brace <don.brace@microchip.com>
> ---
>  drivers/scsi/smartpqi/smartpqi_init.c |    5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/drivers/scsi/smartpqi/smartpqi_init.c
> b/drivers/scsi/smartpqi/smartpqi_init.c
> index 40ae82470d8c..5ca265babaa2 100644
> --- a/drivers/scsi/smartpqi/smartpqi_init.c
> +++ b/drivers/scsi/smartpqi/smartpqi_init.c
> @@ -8688,6 +8688,11 @@ static __maybe_unused int pqi_resume(struct
> pci_dev *pci_dev)
>         pci_set_power_state(pci_dev, PCI_D0);
>         pci_restore_state(pci_dev);
>  
> +       pqi_ctrl_unblock_device_reset(ctrl_info);
> +       pqi_ctrl_unblock_requests(ctrl_info);
> +       pqi_scsi_unblock_requests(ctrl_info);
> +       pqi_ctrl_unblock_scan(ctrl_info);
> +
>         return pqi_ctrl_init_resume(ctrl_info);
>  }

Like I said in my comments on 14/25:

pqi_ctrl_unblock_scan() and pqi_ctrl_unblock_device_reset() expand
to mutex_unlock(). Unlocking an already-unlocked mutex is wrong, and
a mutex has to be unlocked by the task that owns the lock. How
can you be sure that these conditions are met here?

Regards
Martin