[SCSI] libsas: don't treat underrun as an error on SMP tasks

[safe/jmp/linux-2.6] / drivers / scsi / libsas / sas_expander.c

diff --git a/drivers/scsi/libsas/sas_expander.c b/drivers/scsi/libsas/sas_expander.c
index 76555b1..8aeaad9 100644 (file)
--- a/drivers/scsi/libsas/sas_expander.c
+++ b/drivers/scsi/libsas/sas_expander.c
@@ -109,6 +109,16 @@ static int smp_execute_task(struct domain_device *dev, void *req, int req_size,
                    task->task_status.stat == SAM_GOOD) {
                        res = 0;
                        break;
+               } if (task->task_status.resp == SAS_TASK_COMPLETE &&
+                     task->task_status.stat == SAS_DATA_UNDERRUN) {
+                       /* no error, but return the number of bytes of
+                        * underrun */
+                       res = task->task_status.residual;
+                       break;
+               } if (task->task_status.resp == SAS_TASK_COMPLETE &&
+                     task->task_status.stat == SAS_DATA_OVERRUN) {
+                       res = -EMSGSIZE;
+                       break;
                } else {
                        SAS_DPRINTK("%s: task to dev %016llx response: 0x%x "
                                    "status 0x%x\n", __FUNCTION__,
@@ -1924,6 +1934,15 @@ int sas_smp_handler(struct Scsi_Host *shost, struct sas_rphy *rphy,
 
        ret = smp_execute_task(dev, bio_data(req->bio), req->data_len,
                               bio_data(rsp->bio), rsp->data_len);
+       if (ret > 0) {
+               /* positive number is the untransferred residual */
+               rsp->data_len = ret;
+               req->data_len = 0;
+               ret = 0;
+       } else if (ret == 0) {
+               rsp->data_len = 0;
+               req->data_len = 0;
+       }
 
        return ret;
 }