From: Stephen Hemminger <stephen@xxxxxxxxxxxxxxxxxx>
commit f1c635b439a5c01776fe3a25b1e2dc546ea82e6f upstream
Hyper-V host emulation of SCSI for virtual DVD device reports SCSI
version 0 (UNKNOWN) but is still capable of supporting REPORTLUN.
Without this patch, a GEN2 Linux guest on Hyper-V will not boot
successfully with virtual DVD ROM device. What happens is that the SCSI
scan process falls back to doing sequential probing by INQUIRY. But the
storvsc driver has a previous workaround that masks/blocks all errors
reports from INQUIRY (or MODE_SENSE) commands. This workaround causes
the scan to then populate a full set of bogus LUN's on the target and
then sends kernel spinning off into a death spiral doing block reads on
the non-existent LUNs.
By setting the correct blacklist flags, the target with the DVD device
is scanned with REPORTLUN which works correctly.
Signed-off-by: Stephen Hemminger <sthemmin@xxxxxxxxxxxxx>
Reviewed-by: K. Y. Srinivasan <kys@xxxxxxxxxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
---
drivers/scsi/storvsc_drv.c | 27 +++++++++++++++++----------
1 file changed, 17 insertions(+), 10 deletions(-)
diff --git a/drivers/scsi/storvsc_drv.c b/drivers/scsi/storvsc_drv.c
index 7be04fc0d0e7..6f5d173ea9ff 100644
--- a/drivers/scsi/storvsc_drv.c
+++ b/drivers/scsi/storvsc_drv.c
@@ -400,8 +400,6 @@ MODULE_PARM_DESC(storvsc_vcpus_per_sub_channel, "Ratio of VCPUs to subchannels")
*/
static int storvsc_timeout = 180;
-static int msft_blist_flags = BLIST_TRY_VPD_PAGES;
-
#if IS_ENABLED(CONFIG_SCSI_FC_ATTRS)
static struct scsi_transport_template *fc_transport_template;
#endif
@@ -1283,6 +1281,22 @@ static int storvsc_do_io(struct hv_device *device,
return ret;
}
+static int storvsc_device_alloc(struct scsi_device *sdevice)
+{
+ /*
+ * Set blist flag to permit the reading of the VPD pages even when
+ * the target may claim SPC-2 compliance. MSFT targets currently
+ * claim SPC-2 compliance while they implement post SPC-2 features.
+ * With this flag we can correctly handle WRITE_SAME_16 issues.
+ *
+ * Hypervisor reports SCSI_UNKNOWN type for DVD ROM device but
+ * still supports REPORT LUN.
+ */
+ sdevice->sdev_bflags = BLIST_REPORTLUN2 | BLIST_TRY_VPD_PAGES;
+
+ return 0;
+}
+
static int storvsc_device_configure(struct scsi_device *sdevice)
{
@@ -1298,14 +1312,6 @@ static int storvsc_device_configure(struct scsi_device *sdevice)
sdevice->no_write_same = 1;
/*
- * Add blist flags to permit the reading of the VPD pages even when
- * the target may claim SPC-2 compliance. MSFT targets currently
- * claim SPC-2 compliance while they implement post SPC-2 features.
- * With this patch we can correctly handle WRITE_SAME_16 issues.
- */
- sdevice->sdev_bflags |= msft_blist_flags;
-
- /*
* If the host is WIN8 or WIN8 R2, claim conformance to SPC-3
* if the device is a MSFT virtual device. If the host is
* WIN10 or newer, allow write_same.
@@ -1569,6 +1575,7 @@ static struct scsi_host_template scsi_driver = {
.eh_host_reset_handler = storvsc_host_reset_handler,
.proc_name = "storvsc_host",
.eh_timed_out = storvsc_eh_timed_out,
+ .slave_alloc = storvsc_device_alloc,
.slave_configure = storvsc_device_configure,
.cmd_per_lun = 255,
.this_id = -1,
--
2.11.0