On Fri, Aug 28, 2020 at 12:21:35PM +0000, Matej Genci wrote:
> VirtIO 1.0 spec says
> The removed and rescan events ... when sent for LUN 0, they MAY
> apply to the entire target so the driver can ask the initiator
> to rescan the target to detect this.
>
> This change introduces the behaviour described above by scanning the
> entire scsi target when LUN is set to 0. This is both a functional and a
> performance fix. It aligns the driver with the spec and allows control
> planes to hotplug targets with large numbers of LUNs without having to
> request a RESCAN for each one of them.
>
> Signed-off-by: Matej Genci <ma...@nutanix.com>
> Suggested-by: Felipe Franciosi <fel...@nutanix.com>
Stefan, Paolo, could you review this pls?
> ---
> drivers/scsi/virtio_scsi.c | 7 ++++++-
> 1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/scsi/virtio_scsi.c b/drivers/scsi/virtio_scsi.c
> index bfec84aacd90..a4b9bc7b4b4a 100644
> --- a/drivers/scsi/virtio_scsi.c
> +++ b/drivers/scsi/virtio_scsi.c
> @@ -284,7 +284,12 @@ static void virtscsi_handle_transport_reset(struct
> virtio_scsi *vscsi,
>
> switch (virtio32_to_cpu(vscsi->vdev, event->reason)) {
> case VIRTIO_SCSI_EVT_RESET_RESCAN:
> - scsi_add_device(shost, 0, target, lun);
> + if (lun == 0) {
> + scsi_scan_target(&shost->shost_gendev, 0, target,
> + SCAN_WILD_CARD, SCSI_SCAN_INITIAL);
> + } else {
> + scsi_add_device(shost, 0, target, lun);
> + }
> break;
> case VIRTIO_SCSI_EVT_RESET_REMOVED:
> sdev = scsi_device_lookup(shost, 0, target, lun);
> --
> 2.20.1
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