Re: [PATCH RFC v3 03/22] scsi: core: Implement reserved command handling

[John Garry]

On 27/10/2022 08:51, Hannes Reinecke wrote:
> > > Signed-off-by: Hannes Reinecke <hare@xxxxxxx>
> > > #jpg: Set tag_set->queue_depth = shost->can_queue, and not
> > > = shost->can_queue + shost->nr_reserved_cmds;
> > > Signed-off-by: John Garry <john.garry@xxxxxxxxxx>
> > > ---
> > >   drivers/scsi/hosts.c     |  3 +++
> > >   drivers/scsi/scsi_lib.c  |  2 ++
> > >   include/scsi/scsi_host.h | 15 ++++++++++++++-
> > >   3 files changed, 19 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/scsi/hosts.c b/drivers/scsi/hosts.c
> > > index 12346e2297fd..db89afc37bc9 100644
> > > --- a/drivers/scsi/hosts.c
> > > +++ b/drivers/scsi/hosts.c
> > > @@ -489,6 +489,9 @@ struct Scsi_Host *scsi_host_alloc(struct 
> > > scsi_host_template *sht, int privsize)
> > >       if (sht->virt_boundary_mask)
> > >           shost->virt_boundary_mask = sht->virt_boundary_mask;
> > > +    if (sht->nr_reserved_cmds)
> > > +        shost->nr_reserved_cmds = sht->nr_reserved_cmds;
> > > +
> >
> > Nit: the if is not really necessary I think. But it does not hurt.
> Yes, we do.
> Not all HBAs are able to figure out the number of reserved commands 
> upfront; some modify that based on the PCI device used etc.
> So I'd keep it for now.

I think logically Damien is right as in the shost alloc 
shost->nr_reserved_cmds is initially zero, so:

if (sht->nr_reserved_cmds)
       shost->nr_reserved_cmds = sht->nr_reserved_cmds;

is same as simply:

	shost->nr_reserved_cmds = sht->nr_reserved_cmds;

However I am just copying the coding style.

Thanks,
John