Re: [PATCH 1/1] mpt3sas: Ignore unaligned completion length for ZBC_IN

[Bart Van Assche <Bart.VanAssche@sandisk.com>]

On Tue, 2017-02-14 at 12:45 +0900, Damien Le Moal wrote:
> On 2/14/17 03:57, Bart Van Assche wrote:
> > On Mon, 2017-02-13 at 14:11 +0900, Damien Le Moal wrote:
> > > The ZBC_IN command (REPORT ZONES) reply length is always a multiple of
> > > 64B and thus may not be aligned on the device LBA size.
> > > For this command, retry due to the unaligned completion length is
> > > incorrect so do not check alignment of the reply length.
> > > 
> > > Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
> > > ---
> > >  drivers/scsi/mpt3sas/mpt3sas_scsih.c | 5 +++--
> > >  1 file changed, 3 insertions(+), 2 deletions(-)
> > > 
> > > diff --git a/drivers/scsi/mpt3sas/mpt3sas_scsih.c b/drivers/scsi/mpt3sas/mpt3sas_scsih.c
> > > index 0b5b423..f04b872 100644
> > > --- a/drivers/scsi/mpt3sas/mpt3sas_scsih.c
> > > +++ b/drivers/scsi/mpt3sas/mpt3sas_scsih.c
> > > @@ -4723,8 +4723,9 @@ _scsih_io_done(struct MPT3SAS_ADAPTER *ioc, u16 smid, u8 msix_index, u32 reply)
> > >  	 * then scsi-ml does not need to handle this misbehavior.
> > >  	 */
> > >  	sector_sz = scmd->device->sector_size;
> > > -	if (unlikely(scmd->request->cmd_type == REQ_TYPE_FS && sector_sz &&
> > > -		     xfer_cnt % sector_sz)) {
> > > +	if (scmd->request->cmd_type == REQ_TYPE_FS &&
> > > +	    scmd->cmnd[0] != ZBC_IN &&
> > > +	    sector_sz && xfer_cnt % sector_sz) {
> > >  		sdev_printk(KERN_INFO, scmd->device,
> > >  		    "unaligned partial completion avoided (xfer_cnt=%u, sector_sz=%u)\n",
> > >  			    xfer_cnt, sector_sz);
> > 
> > What software generated a ZBC_IN request with type REQ_TYPE_FS? Shouldn't
> > all ZBC_IN requests be assigned type REQ_TYPE_BLOCK_PC?
> 
> Any application that issues a BLKREPORTZONE ioctl (e.g. mkfs.f2fs or
> libzbc tools) or kernel component calling blkdev_report_zones (e.g.
> f2fs) will generate one or more REQ_OP_ZONE_REPORT BIO which translate
> into a REQ_TYPE_FS requests for the command ZBC_IN. That command does
> not operate on LBAs. The transfer length of the request can be any
> length larger than 64B and the reply length will be at least 64B and
> aligned on a multiple of 64.
> 
> The patch "mpt3sas: Force request partial completion alignment" applied
> last week forgot this case, and frankly, I did too despite having looked
> at it.

Hello Damien,

How about modifying the block layer core such that it sets REQ_TYPE_BLOCK_PC
for REQ_OP_ZONE_REPORT requests? Would that be a valid alternative to the
above patch?

Thanks,

Bart.