scsi: storvsc: properly set residual data length on errors

On I/O errors, the Windows driver doesn't set data_transfer_length
on error conditions other than SRB_STATUS_DATA_OVERRUN.
In these cases we need to set data_transfer_length to 0,
indicating there is no data transferred. On SRB_STATUS_DATA_OVERRUN,
data_transfer_length is set by the Windows driver to the actual data transferred.

Reported-by: Shiva Krishna <Shiva.Krishna@nimblestorage.com>
Signed-off-by: Long Li <longli@microsoft.com>
Reviewed-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Cc: <stable@vger.kernel.org>
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 3c92dc2a25a01745bc86bba9b400899387020884..888e16ec8554c69d4426bfa45cd09b3b464b2cbc 100644 (file)
--- a/drivers/scsi/storvsc_drv.c
+++ b/drivers/scsi/storvsc_drv.c
@@ -377,6 +377,7 @@ enum storvsc_request_type {
 #define SRB_STATUS_SUCCESS     0x01
 #define SRB_STATUS_ABORTED     0x02
 #define SRB_STATUS_ERROR       0x04
+#define SRB_STATUS_DATA_OVERRUN        0x12
 
 #define SRB_STATUS(status) \
        (status & ~(SRB_STATUS_AUTOSENSE_VALID | SRB_STATUS_QUEUE_FROZEN))
@@ -996,6 +997,7 @@ static void storvsc_command_completion(struct storvsc_cmd_request *cmd_request,
        struct scsi_cmnd *scmnd = cmd_request->cmd;
        struct scsi_sense_hdr sense_hdr;
        struct vmscsi_request *vm_srb;
+       u32 data_transfer_length;
        struct Scsi_Host *host;
        u32 payload_sz = cmd_request->payload_sz;
        void *payload = cmd_request->payload;
@@ -1003,6 +1005,7 @@ static void storvsc_command_completion(struct storvsc_cmd_request *cmd_request,
        host = stor_dev->host;
 
        vm_srb = &cmd_request->vstor_packet.vm_srb;
+       data_transfer_length = vm_srb->data_transfer_length;
 
        scmnd->result = vm_srb->scsi_status;
 
@@ -1016,13 +1019,20 @@ static void storvsc_command_completion(struct storvsc_cmd_request *cmd_request,
                                             &sense_hdr);
        }
 
-       if (vm_srb->srb_status != SRB_STATUS_SUCCESS)
+       if (vm_srb->srb_status != SRB_STATUS_SUCCESS) {
                storvsc_handle_error(vm_srb, scmnd, host, sense_hdr.asc,
                                         sense_hdr.ascq);
+               /*
+                * The Windows driver set data_transfer_length on
+                * SRB_STATUS_DATA_OVERRUN. On other errors, this value
+                * is untouched.  In these cases we set it to 0.
+                */
+               if (vm_srb->srb_status != SRB_STATUS_DATA_OVERRUN)
+                       data_transfer_length = 0;
+       }
 
        scsi_set_resid(scmnd,
-               cmd_request->payload->range.len -
-               vm_srb->data_transfer_length);
+               cmd_request->payload->range.len - data_transfer_length);
 
        scmnd->scsi_done(scmnd);