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Date:   Wed, 7 Jun 2023 15:34:49 +0200
From:   Christoph Hellwig <hch@lst.de>
To:     Martin Wilck <mwilck@suse.com>
Cc:     Christoph Hellwig <hch@lst.de>,
        "Martin K. Petersen" <martin.petersen@oracle.com>,
        Ming Lei <ming.lei@redhat.com>,
        Bart Van Assche <Bart.VanAssche@sandisk.com>,
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        linux-scsi@vger.kernel.org, linux-block@vger.kernel.org,
        Hannes Reinecke <hare@suse.de>
Subject: Re: [PATCH v2 3/3] scsi: simplify scsi_stop_queue()
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On Wed, Jun 07, 2023 at 11:26:04AM +0200, Martin Wilck wrote:
> > cleanups:
> > 
> >   1) remove scsi_internal_device_block and fold it into device_block
> 
> ok
> 
> >   2) move the scsi_internal_device_block in what was
> 
> You mean scsi_stop_queue() here, right?

Yes.

> The reason is simple: I wasn't certain if dev_to_shost() could return
> NULL, and preferred skipping the wait over an Oops. I hear you say that
> dev_to_shost() can't go wrong, so I'll remove the NULL test.

Well, the parent device can't really go away while we have a reference
to a child.  So the only case where it can return NULL is if the
passed in device isn't the child of a SCSI host, which would be a grave
programming error.

> 
> > Btw, as far as I can tell scsi_target_block is never called for
> > a device that is a target device.  It might be worth throwing in
> > another patch to remove support for that case and simplify things
> > further.
> 
> Can we do this separately, maybe? 

Sure.  Would be nice to just tack into onto the end of this series
if you touch the area, though.

> On Wed, 2023-06-07 at 11:26 +0200, Martin Wilck wrote:
> > On Wed, 2023-06-07 at 07:27 +0200, Christoph Hellwig wrote:
> > > 
> > >   3) remove scsi_stop_queue and open code it in the two callers,
> > > one
> > >      of which currently wants nowait semantics, and one that
> > > doesn't.
> > ok
> 
> Hm, scsi_stop_queue() pairs with scsi_start_queue(), do we really want
> to open-code it?

Oh well, feel free to keep it if you prefer it that way.