Re: [PATCH 05/13] scsi: alua: Add scsi_alua_tur()

[John Garry]

On 23/03/2026 13:42, John Garry wrote:
> On 18/03/2026 07:54, Hannes Reinecke wrote:
> > >   /*
> > >    * submit_rtpg - Issue a REPORT TARGET GROUP STATES command
> > >    * @sdev: sdev the command should be sent to
> >
> > ???
> > And this function is useful _why_?
> > We're just sending a normal 'TEST UNIT READY', it has nothing to
> > do with ALUA. Why do we have a special function here?
>
> This is used in the STPG code, and I added the STPG code to scsi_alua.c

I meant to say that this is used in RTPG code from the following:


commit 9d2c30395213166e0b5614fe97576a789864e5de
Author: Hannes Reinecke <hare@xxxxxxx>
Date:   Fri Feb 19 09:17:15 2016 +0100

    scsi_dh_alua: Send TEST UNIT READY to poll for transitioning

    Sending a 'REPORT TARGET PORT GROUP' command is a costly operation,
    as the array has to gather information about all ports.
    So instead of using RTPG to poll for a status update when a port
    is in transitioning we should be sending a TEST UNIT READY, and
    wait for the sense code to report success.