scsi: storvsc: Set up correct queue depth values for IDE devices

Unlike SCSI and FC, we don't use multiple channels for IDE.  Also fix
the calculation for sub-channels.

Signed-off-by: Long Li <longli@microsoft.com>
Reviewed-by: Michael Kelley <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 8c51d62..a2ec0bc 100644 (file)
--- a/drivers/scsi/storvsc_drv.c
+++ b/drivers/scsi/storvsc_drv.c
@@ -1722,11 +1722,14 @@ static int storvsc_probe(struct hv_device *device,
                max_targets = STORVSC_MAX_TARGETS;
                max_channels = STORVSC_MAX_CHANNELS;
                /*
-                * On Windows8 and above, we support sub-channels for storage.
+                * On Windows8 and above, we support sub-channels for storage
+                * on SCSI and FC controllers.
                 * The number of sub-channels offerred is based on the number of
                 * VCPUs in the guest.
                 */
-               max_sub_channels = (num_cpus / storvsc_vcpus_per_sub_channel);
+               if (!dev_is_ide)
+                       max_sub_channels =
+                               (num_cpus - 1) / storvsc_vcpus_per_sub_channel;
        }
 
        scsi_driver.can_queue = (max_outstanding_req_per_channel *