scsi: storvsc: Limit max_sectors for virtual Fibre Channel devices

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>

diff --git a/drivers/scsi/storvsc_drv.c b/drivers/scsi/storvsc_drv.c
index 7f12d931fe7c1464c4e39d123666f0444efc5417..f2823218670ab7ecd549f149b7b57da42fa15185 100644 (file)
--- a/drivers/scsi/storvsc_drv.c
+++ b/drivers/scsi/storvsc_drv.c
@@ -366,6 +366,7 @@ static void storvsc_on_channel_callback(void *context);
 #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
@@ -2006,6 +2007,9 @@ static int storvsc_probe(struct hv_device *device,
         * 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;
        /*