[PATCH 1/3] storvsc: use tagged SRB requests if supported by the device

Long Li longli at microsoft.com
Wed Sep 7 17:19:29 UTC 2016


> -----Original Message-----
> From: Johannes Thumshirn [mailto:jthumshirn at suse.de]
> Sent: Wednesday, September 7, 2016 12:47 AM
> To: Long Li <longli at exchange.microsoft.com>
> Cc: KY Srinivasan <kys at microsoft.com>; Haiyang Zhang
> <haiyangz at microsoft.com>; James E.J. Bottomley
> <jejb at linux.vnet.ibm.com>; Martin K. Petersen
> <martin.petersen at oracle.com>; devel at linuxdriverproject.org; linux-
> scsi at vger.kernel.org; linux-kernel at vger.kernel.org; Long Li
> <longli at microsoft.com>
> Subject: Re: [PATCH 1/3] storvsc: use tagged SRB requests if supported by
> the device
> 
> On Tue, Sep 06, 2016 at 02:25:41PM -0700, Long Li wrote:
> > From: Long Li <longli at microsoft.com>
> >
> > Properly set SRB flags when hosting device supports tagged queuing. This
> patch improves the performance on Fiber Channel disks.
> 
> ENOSIGNEDOFF and please use checkpatch.pl on the patch.

Thanks for pointing that out. I'll re-send the patches.
> 
> >
> > ---
> >  drivers/scsi/storvsc_drv.c | 8 ++++++++
> >  1 file changed, 8 insertions(+)
> >
> > diff --git a/drivers/scsi/storvsc_drv.c b/drivers/scsi/storvsc_drv.c
> > index 8ccfc9e..a8f3e4c 100644
> > --- a/drivers/scsi/storvsc_drv.c
> > +++ b/drivers/scsi/storvsc_drv.c
> > @@ -136,6 +136,8 @@ struct hv_fc_wwn_packet {
> >  #define SRB_FLAGS_PORT_DRIVER_RESERVED		0x0F000000
> >  #define SRB_FLAGS_CLASS_DRIVER_RESERVED		0xF0000000
> >
> > +#define SP_UNTAGGED			((unsigned char) ~0)
> > +#define SRB_SIMPLE_TAG_REQUEST		0x20
> >
> >  /*
> >   * Platform neutral description of a scsi request - @@ -1451,6
> > +1453,12 @@ static int storvsc_queuecommand(struct Scsi_Host *host,
> struct scsi_cmnd *scmnd)
> >  	vm_srb->win8_extension.srb_flags |=
> >  		SRB_FLAGS_DISABLE_SYNCH_TRANSFER;
> >
> > +	if(scmnd->device->tagged_supported) {
> > +		vm_srb->win8_extension.srb_flags |=
> (SRB_FLAGS_QUEUE_ACTION_ENABLE | SRB_FLAGS_NO_QUEUE_FREEZE);
> > +		vm_srb->win8_extension.queue_tag = SP_UNTAGGED;
> > +		vm_srb->win8_extension.queue_action =
> SRB_SIMPLE_TAG_REQUEST;
> > +	}
> > +
> >  	/* Build the SRB */
> >  	switch (scmnd->sc_data_direction) {
> >  	case DMA_TO_DEVICE:
> > --
> > 1.8.5.6
> >
> > --
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> --
> Johannes Thumshirn                                          Storage
> jthumshirn at suse.de                                +49 911 74053 689
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