sata_nv: complain on spurious completion notifiers

Recently Tejun wrote a patch to ahci.c to make it raise a HSM violation
if the drive attempted to complete a tag that wasn't outstanding. We could
run into the same problem with sata_nv ADMA. This adds code to raise a HSM
violation error if the controller gives us a notifier tag that isn't
outstanding, since the drive may be issuing spurious completions.
Signed-off-by: NRobert Hancock <hancockr@shaw.ca>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

drivers/ata/sata_nv.c

@@ -740,6 +740,17 @@ static int nv_adma_check_cpb(struct ata_port *ap, int cpb_num, int force_err)
 			DPRINTK("Completing qc from tag %d with err_mask %u\n",cpb_num,
 				qc->err_mask);
 			ata_qc_complete(qc);
+		} else {
+			struct ata_eh_info *ehi = &ap->eh_info;
+			/* Notifier bits set without a command may indicate the drive
+			   is misbehaving. Raise host state machine violation on this
+			   condition. */
+			ata_port_printk(ap, KERN_ERR, "notifier for tag %d with no command?\n",
+				cpb_num);
+			ehi->err_mask |= AC_ERR_HSM;
+			ehi->action |= ATA_EH_SOFTRESET;
+			ata_port_freeze(ap);
+			return 1;
 		}
 	}
 	return 0;