[PATCH 4.9 060/153] scsi: storvsc: properly set residual data length on errors

Greg Kroah-Hartman
2017-03-10T09:20:07Z

From: Long Li <longli@microsoft.com>

commit 40630f462824ee24bc00d692865c86c3828094e0 upstream.

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>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/scsi/storvsc_drv.c | 16 +++++++++++++---
1 file changed, 13 insertions(+), 3 deletions(-)

--- 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))
@@ -962,6 +963,7 @@ static void storvsc_command_completion(s
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;
@@ -969,6 +971,7 @@ static void storvsc_command_completion(s
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;

@@ -982,13 +985,20 @@ static void storvsc_command_completion(s
&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);