[PATCH 6.1 072/127] scsi: storvsc: Limit max_sectors for virtual Fibre Channel devices

Greg Kroah-Hartman
2023-08-09T10:55:57Z

From: Michael Kelley <mikelley@microsoft.com>

commit 010c1e1c5741365dbbf44a5a5bb9f30192875c4c upstream.

The Hyper-V host is queried to get the max transfer size that it supports,
and this value is used to set max_sectors for the synthetic SCSI
controller. However, this max transfer size may be too large for virtual
Fibre Channel devices, which are limited to 512 Kbytes. If a larger
transfer size is used with a vFC device, Hyper-V always returns an error,
and storvsc logs a message like this where the SRB status and SCSI status
are both zero:

hv_storvsc <GUID>: tag#197 cmd 0x8a status: scsi 0x0 srb 0x0 hv 0xc0000001

Add logic to limit the max transfer size to 512 Kbytes for vFC devices.

Fixes: 1d3e0980782f ("scsi: storvsc: Correct reporting of Hyper-V I/O size limits")
Cc: stable@vger.kernel.org
Signed-off-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/1689887102-32806-1-git-send-email-mikelley@microsoft.com
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/scsi/storvsc_drv.c | 4 ++++
1 file changed, 4 insertions(+)

--- a/drivers/scsi/storvsc_drv.c
+++ b/drivers/scsi/storvsc_drv.c
@@ -365,6 +365,7 @@ static void storvsc_on_channel_callback(
#define STORVSC_FC_MAX_LUNS_PER_TARGET 255
#define STORVSC_FC_MAX_TARGETS 128
#define STORVSC_FC_MAX_CHANNELS 8
+#define STORVSC_FC_MAX_XFER_SIZE ((u32)(512 * 1024))

#define STORVSC_IDE_MAX_LUNS_PER_TARGET 64
#define STORVSC_IDE_MAX_TARGETS 1
@@ -2002,6 +2003,9 @@ static int storvsc_probe(struct hv_devic
* protecting it from any weird value.
*/
max_xfer_bytes = round_down(stor_device->max_transfer_bytes, HV_HYP_PAGE_SIZE);
+ if (is_fc)
+ max_xfer_bytes = min(max_xfer_bytes, STORVSC_FC_MAX_XFER_SIZE);
+
/* max_hw_sectors_kb */
host->max_sectors = max_xfer_bytes >> 9;
/*