* Re: [PATCH] Rescan the entire target on transport reset when LUN is 0
2020-08-28 12:21 [PATCH] Rescan the entire target on transport reset when LUN is 0 Matej Genci
@ 2020-09-08 14:15 ` Michael S. Tsirkin
2020-09-08 14:22 ` Paolo Bonzini
` (2 subsequent siblings)
3 siblings, 0 replies; 7+ messages in thread
From: Michael S. Tsirkin @ 2020-09-08 14:15 UTC (permalink / raw)
To: Matej Genci
Cc: linux-kernel, jasowang, pbonzini, stefanha, jejb,
martin.petersen, virtualization, linux-scsi, Felipe Franciosi
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 <matej@nutanix.com>
> Suggested-by: Felipe Franciosi <felipe@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
^ permalink raw reply [flat|nested] 7+ messages in thread* Re: [PATCH] Rescan the entire target on transport reset when LUN is 0
2020-08-28 12:21 [PATCH] Rescan the entire target on transport reset when LUN is 0 Matej Genci
2020-09-08 14:15 ` Michael S. Tsirkin
@ 2020-09-08 14:22 ` Paolo Bonzini
2020-09-08 17:53 ` Felipe Franciosi
2020-09-16 1:52 ` Martin K. Petersen
2020-09-22 3:56 ` Martin K. Petersen
3 siblings, 1 reply; 7+ messages in thread
From: Paolo Bonzini @ 2020-09-08 14:22 UTC (permalink / raw)
To: Matej Genci, linux-kernel
Cc: mst, jasowang, stefanha, jejb, martin.petersen, virtualization,
linux-scsi, Felipe Franciosi
On 28/08/20 14:21, 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 <matej@nutanix.com>
> Suggested-by: Felipe Franciosi <felipe@nutanix.com>
> ---
> 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);
>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
^ permalink raw reply [flat|nested] 7+ messages in thread* Re: [PATCH] Rescan the entire target on transport reset when LUN is 0
2020-09-08 14:22 ` Paolo Bonzini
@ 2020-09-08 17:53 ` Felipe Franciosi
2020-09-09 5:54 ` Greg KH
0 siblings, 1 reply; 7+ messages in thread
From: Felipe Franciosi @ 2020-09-08 17:53 UTC (permalink / raw)
To: Paolo Bonzini, stable
Cc: Matej Genci, linux-kernel, mst, jasowang, stefanha, jejb,
martin.petersen, virtualization, linux-scsi
> On Sep 8, 2020, at 3:22 PM, Paolo Bonzini <pbonzini@redhat.com> wrote:
>
> On 28/08/20 14:21, 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 <matej@nutanix.com>
>> Suggested-by: Felipe Franciosi <felipe@nutanix.com>
>> ---
>> 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);
>>
>
>
> Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Cc: stable@vger.kernel.org
Thanks, Paolo.
I'm Cc'ing stable as I believe this fixes a driver bug where it
doesn't follow the spec. Per commit message, today devices are
required to issue RESCAN events for each LUN behind a target when
hotplugging, or risking the driver not seeing the new LUNs.
Is this enough? Or should we resend after merge per below?
https://www.kernel.org/doc/Documentation/process/stable-kernel-rules.rst
F.
^ permalink raw reply [flat|nested] 7+ messages in thread* Re: [PATCH] Rescan the entire target on transport reset when LUN is 0
2020-09-08 17:53 ` Felipe Franciosi
@ 2020-09-09 5:54 ` Greg KH
0 siblings, 0 replies; 7+ messages in thread
From: Greg KH @ 2020-09-09 5:54 UTC (permalink / raw)
To: Felipe Franciosi
Cc: Paolo Bonzini, stable, Matej Genci, linux-kernel, mst, jasowang,
stefanha, jejb, martin.petersen, virtualization, linux-scsi
On Tue, Sep 08, 2020 at 05:53:16PM +0000, Felipe Franciosi wrote:
>
>
> > On Sep 8, 2020, at 3:22 PM, Paolo Bonzini <pbonzini@redhat.com> wrote:
> >
> > On 28/08/20 14:21, 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 <matej@nutanix.com>
> >> Suggested-by: Felipe Franciosi <felipe@nutanix.com>
> >> ---
> >> 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);
> >>
> >
> >
> > Acked-by: Paolo Bonzini <pbonzini@redhat.com>
>
> Cc: stable@vger.kernel.org
>
> Thanks, Paolo.
>
> I'm Cc'ing stable as I believe this fixes a driver bug where it
> doesn't follow the spec. Per commit message, today devices are
> required to issue RESCAN events for each LUN behind a target when
> hotplugging, or risking the driver not seeing the new LUNs.
>
> Is this enough? Or should we resend after merge per below?
> https://www.kernel.org/doc/Documentation/process/stable-kernel-rules.rst
You need to let stable know the git commit id of the patch in Linus's
tree if the cc: stable is not on the final commit that gets merged.
thanks,
greg k-h
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] Rescan the entire target on transport reset when LUN is 0
2020-08-28 12:21 [PATCH] Rescan the entire target on transport reset when LUN is 0 Matej Genci
2020-09-08 14:15 ` Michael S. Tsirkin
2020-09-08 14:22 ` Paolo Bonzini
@ 2020-09-16 1:52 ` Martin K. Petersen
2020-09-22 3:56 ` Martin K. Petersen
3 siblings, 0 replies; 7+ messages in thread
From: Martin K. Petersen @ 2020-09-16 1:52 UTC (permalink / raw)
To: Matej Genci
Cc: linux-kernel, mst, jasowang, pbonzini, stefanha, jejb,
martin.petersen, virtualization, linux-scsi, Felipe Franciosi
Matej,
> 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.
Applied to 5.10/scsi-staging, thanks!
--
Martin K. Petersen Oracle Linux Engineering
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] Rescan the entire target on transport reset when LUN is 0
2020-08-28 12:21 [PATCH] Rescan the entire target on transport reset when LUN is 0 Matej Genci
` (2 preceding siblings ...)
2020-09-16 1:52 ` Martin K. Petersen
@ 2020-09-22 3:56 ` Martin K. Petersen
3 siblings, 0 replies; 7+ messages in thread
From: Martin K. Petersen @ 2020-09-22 3:56 UTC (permalink / raw)
To: Matej Genci, linux-kernel
Cc: Martin K . Petersen, jejb, linux-scsi, jasowang, stefanha,
pbonzini, virtualization, mst, Felipe Franciosi
On Fri, 28 Aug 2020 12:21:35 +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.
Applied to 5.10/scsi-queue, thanks!
[1/1] scsi: virtio_scsi: Rescan the entire target on transport reset when LUN is 0
https://git.kernel.org/mkp/scsi/c/beef6fd02b90
--
Martin K. Petersen Oracle Linux Engineering
^ permalink raw reply [flat|nested] 7+ messages in thread