Re: [PATCH] scsi: target: core: Set MULTIP bit in INQUIRY

[Dmitry Bogdanov <d.bogdanov@yadro.com>]

On Wed, Sep 07, 2022 at 03:06:04PM -0500, Mike Christie wrote:
> 
> On 9/6/22 2:48 AM, Dmitry Bogdanov wrote:
> >
> > diff --git a/drivers/target/target_core_spc.c b/drivers/target/target_core_spc.c
> > index c14441c89bed..32fb38ce98f4 100644
> > --- a/drivers/target/target_core_spc.c
> > +++ b/drivers/target/target_core_spc.c
> > @@ -75,6 +75,8 @@ spc_emulate_inquiry_std(struct se_cmd *cmd, unsigned char *buf)
> >       struct se_portal_group *tpg = lun->lun_tpg;
> >       struct se_device *dev = cmd->se_dev;
> >       struct se_session *sess = cmd->se_sess;
> > +     struct se_lun *tmp_lun;
> > +     size_t dev_ports = 0;
> >
> >       /* Set RMB (removable media) for tape devices */
> >       if (dev->transport->get_device_type(dev) == TYPE_TAPE)
> > @@ -115,6 +117,20 @@ spc_emulate_inquiry_std(struct se_cmd *cmd, unsigned char *buf)
> >                       buf[5] |= 0x1;
> >       }
> >
> > +     spin_lock(&dev->se_port_lock);
> > +     list_for_each_entry(tmp_lun, &dev->dev_sep_list, lun_dev_link) {
> > +             dev_ports++;
> > +             /* Exact number of ports does not matter for MULTIP bit */
> > +             if (dev_ports > 1)
> > +                     break;
> 
> Can you just check se_deice->export_count instead of looping?
Yes, of course, dev->export_count exactly fits here.
> 
> Also, setting the bit seems fine. I was just wondering what uses it?
There is no way to find it out. At least just to conform to the
standard. May be for some archaic users like AIX.
Btw, SCST reports MULTIP=1 always.

BR,
 Dmitry