Re: [PATCH v9 09/10] block, scsi: Make SCSI quiesce and resume work reliably

2017-10-17 Thread Hannes Reinecke
On 10/17/2017 10:18 PM, Bart Van Assche wrote: > On Tue, 2017-10-17 at 08:33 +0200, Hannes Reinecke wrote: >> How do you ensure that PREEMPT requests are not stuck in the queue >> _behind_ non-PREEMPT requests? >> Once they are in the queue the request are already allocated, so your >> deferred all

Re: [PATCH v9 09/10] block, scsi: Make SCSI quiesce and resume work reliably

2017-10-17 Thread Bart Van Assche
On Tue, 2017-10-17 at 08:33 +0200, Hannes Reinecke wrote: > How do you ensure that PREEMPT requests are not stuck in the queue > _behind_ non-PREEMPT requests? > Once they are in the queue the request are already allocated, so your > deferred allocation won't work. > _And_ deferred requests will be

Re: [PATCH v9 09/10] block, scsi: Make SCSI quiesce and resume work reliably

2017-10-17 Thread Bart Van Assche
On Tue, 2017-10-17 at 08:43 +0800, Ming Lei wrote: > On Mon, Oct 16, 2017 at 04:29:04PM -0700, Bart Van Assche wrote: > > [ ... ] > > int > > scsi_device_quiesce(struct scsi_device *sdev) > > { > > + struct request_queue *q = sdev->request_queue; > > int err; > > > > + /* > > +* It

Re: [PATCH v9 09/10] block, scsi: Make SCSI quiesce and resume work reliably

2017-10-17 Thread Ming Lei
On Tue, Oct 17, 2017 at 08:33:36AM +0200, Hannes Reinecke wrote: > On 10/17/2017 01:29 AM, Bart Van Assche wrote: > > The contexts from which a SCSI device can be quiesced or resumed are: > > * Writing into /sys/class/scsi_device/*/device/state. > > * SCSI parallel (SPI) domain validation. > > * Th

Re: [PATCH v9 09/10] block, scsi: Make SCSI quiesce and resume work reliably

2017-10-16 Thread Hannes Reinecke
On 10/17/2017 01:29 AM, Bart Van Assche wrote: > The contexts from which a SCSI device can be quiesced or resumed are: > * Writing into /sys/class/scsi_device/*/device/state. > * SCSI parallel (SPI) domain validation. > * The SCSI device power management methods. See also scsi_bus_pm_ops. > > It i

Re: [PATCH v9 09/10] block, scsi: Make SCSI quiesce and resume work reliably

2017-10-16 Thread Martin K. Petersen
Bart, > The contexts from which a SCSI device can be quiesced or resumed are: > * Writing into /sys/class/scsi_device/*/device/state. > * SCSI parallel (SPI) domain validation. > * The SCSI device power management methods. See also scsi_bus_pm_ops. The SCSI bits look fine to me. Acked-by: Marti

Re: [PATCH v9 09/10] block, scsi: Make SCSI quiesce and resume work reliably

2017-10-16 Thread Ming Lei
On Mon, Oct 16, 2017 at 04:29:04PM -0700, Bart Van Assche wrote: > The contexts from which a SCSI device can be quiesced or resumed are: > * Writing into /sys/class/scsi_device/*/device/state. > * SCSI parallel (SPI) domain validation. > * The SCSI device power management methods. See also scsi_bus

[PATCH v9 09/10] block, scsi: Make SCSI quiesce and resume work reliably

2017-10-16 Thread Bart Van Assche
The contexts from which a SCSI device can be quiesced or resumed are: * Writing into /sys/class/scsi_device/*/device/state. * SCSI parallel (SPI) domain validation. * The SCSI device power management methods. See also scsi_bus_pm_ops. It is essential during suspend and resume that neither the file