[PATCH] libata: don't request sense if the port is frozen

If EH command is issued to a frozen port, it fails with AC_ERR_SYSTEM.
libata used to request sense even when the port is frozen needlessly
adding AC_ERR_SYSTEM to err_mask.  Don't do it.
Signed-off-by: Tejun Heo <htejun@gmail.com>

drivers/ata/libata-eh.c

@@ -1136,12 +1136,13 @@ static unsigned int ata_eh_analyze_tf(struct ata_queued_cmd *qc,
 		break;
 
 	case ATA_DEV_ATAPI:
+		if (!(qc->ap->pflags & ATA_PFLAG_FROZEN)) {
 			tmp = atapi_eh_request_sense(qc->dev,
 						     qc->scsicmd->sense_buffer);
 			if (!tmp) {
-			/* ATA_QCFLAG_SENSE_VALID is used to tell
-			 * atapi_qc_complete() that sense data is
-			 * already valid.
+				/* ATA_QCFLAG_SENSE_VALID is used to
+				 * tell atapi_qc_complete() that sense
+				 * data is already valid.
 				 *
 				 * TODO: interpret sense data and set
 				 * appropriate err_mask.
@@ -1150,6 +1151,7 @@ static unsigned int ata_eh_analyze_tf(struct ata_queued_cmd *qc,
 			} else
 				qc->err_mask |= tmp;
 		}
+	}
 
 	if (qc->err_mask & (AC_ERR_HSM | AC_ERR_TIMEOUT | AC_ERR_ATA_BUS))
 		action |= ATA_EH_SOFTRESET;