Re: [PATCH 1/3] scsi: fetch unit attention when creating the request

[Paolo Bonzini <pbonzini@redhat.com>]

On 7/12/23 15:43, Stefano Garzarella wrote:
> Commit 1880ad4f4e ("virtio-scsi: Batched prepare for cmd reqs") split
> calls to scsi_req_new() and scsi_req_enqueue() in the virtio-scsi device.
> This had no drawback, until commit 8cc5583abe ("virtio-scsi: Send

More precisely, it was pretty hard to trigger it; it might be possible 
using a CD-ROM, as it can report a MEDIUM_CHANGED unit attention.  I 
will change "This had no drawback" to "No ill effect was reported"

> "REPORTED LUNS CHANGED" sense data upon disk hotplug events") added a
> bus unit attention.

... that was fairly easy to trigger via SCSI device hotplug/hot-unplug.

Queued the series, thanks for the tests and for applying the cleanups on 
top.

> Co-developed-by: Paolo Bonzini <pbonzini@redhat.com>

Heh, I basically only wrote the "if (req->init_req)" statement so that's 
pretty generous, but I'll keep it anyway. :)

Paolo

> Having the two calls separated, all requests in the batch were prepared
> calling scsi_req_new() to report a sense.
> Then only the first one submitted calling scsi_req_enqueue() reported the
> right sense and reset it to NO_SENSE.
> The others reported NO_SENSE, causing SCSI errors in Linux.