1 files changed, 69 insertions, 11 deletions
diff --git a/drivers/scsi/st.c b/drivers/scsi/st.c
index ebbd50ec0cda..74a6830b7ed8 100644
--- a/drivers/scsi/st.c
+++ b/drivers/scsi/st.c
@@ -163,9 +163,11 @@ static const char *st_formats[] = {
 
 static int debugging = DEBUG;
 
+/* Setting these non-zero may risk recognizing resets */
 #define MAX_RETRIES 0
 #define MAX_WRITE_RETRIES 0
 #define MAX_READY_RETRIES 0
+
 #define NO_TAPE  NOT_READY
 
 #define ST_TIMEOUT (900 * HZ)
@@ -357,10 +359,18 @@ static int st_chk_result(struct scsi_tape *STp, struct st_request * SRpnt)
 {
 	int result = SRpnt->result;
 	u8 scode;
+	unsigned int ctr;
 	DEB(const char *stp;)
 	char *name = STp->name;
 	struct st_cmdstatus *cmdstatp;
 
+	ctr = scsi_get_ua_por_ctr(STp->device);
+	if (ctr != STp->por_ctr) {
+		STp->por_ctr = ctr;
+		STp->pos_unknown = 1; /* ASC => power on / reset */
+		st_printk(KERN_WARNING, STp, "Power on/reset recognized.");
+	}
+
 	if (!result)
 		return 0;
 
@@ -413,10 +423,11 @@ static int st_chk_result(struct scsi_tape *STp, struct st_request * SRpnt)
 	if (cmdstatp->have_sense &&
 	    cmdstatp->sense_hdr.asc == 0 && cmdstatp->sense_hdr.ascq == 0x17)
 		STp->cleaning_req = 1; /* ASC and ASCQ => cleaning requested */
-	if (cmdstatp->have_sense && scode == UNIT_ATTENTION && cmdstatp->sense_hdr.asc == 0x29)
+	if (cmdstatp->have_sense && scode == UNIT_ATTENTION &&
+		cmdstatp->sense_hdr.asc == 0x29 && !STp->pos_unknown) {
 		STp->pos_unknown = 1; /* ASC => power on / reset */
-
-	STp->pos_unknown |= STp->device->was_reset;
+		st_printk(KERN_WARNING, STp, "Power on/reset recognized.");
+	}
 
 	if (cmdstatp->have_sense &&
 	    scode == RECOVERED_ERROR
@@ -952,7 +963,6 @@ static void reset_state(struct scsi_tape *STp)
 		STp->partition = find_partition(STp);
 		if (STp->partition < 0)
 			STp->partition = 0;
-		STp->new_partition = STp->partition;
 	}
 }
 
@@ -969,6 +979,7 @@ static int test_ready(struct scsi_tape *STp, int do_wait)
 {
 	int attentions, waits, max_wait, scode;
 	int retval = CHKRES_READY, new_session = 0;
+	unsigned int ctr;
 	unsigned char cmd[MAX_COMMAND_SIZE];
 	struct st_request *SRpnt = NULL;
 	struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
@@ -1025,6 +1036,13 @@ static int test_ready(struct scsi_tape *STp, int do_wait)
 			}
 		}
 
+		ctr = scsi_get_ua_new_media_ctr(STp->device);
+		if (ctr != STp->new_media_ctr) {
+			STp->new_media_ctr = ctr;
+			new_session = 1;
+			DEBC_printk(STp, "New tape session.");
+		}
+
 		retval = (STp->buffer)->syscall_result;
 		if (!retval)
 			retval = new_session ? CHKRES_NEW_SESSION : CHKRES_READY;
@@ -2897,7 +2915,6 @@ static int st_int_ioctl(struct scsi_tape *STp, unsigned int cmd_in, unsigned lon
 			timeout = STp->long_timeout * 8;
 
 		DEBC_printk(STp, "Erasing tape.\n");
-		fileno = blkno = at_sm = 0;
 		break;
 	case MTSETBLK:		/* Set block length */
 	case MTSETDENSITY:	/* Set tape density */
@@ -2930,14 +2947,17 @@ static int st_int_ioctl(struct scsi_tape *STp, unsigned int cmd_in, unsigned lon
 		if (cmd_in == MTSETDENSITY) {
 			(STp->buffer)->b_data[4] = arg;
 			STp->density_changed = 1;	/* At least we tried ;-) */
+			STp->changed_density = arg;
 		} else if (cmd_in == SET_DENS_AND_BLK)
 			(STp->buffer)->b_data[4] = arg >> 24;
 		else
 			(STp->buffer)->b_data[4] = STp->density;
 		if (cmd_in == MTSETBLK || cmd_in == SET_DENS_AND_BLK) {
 			ltmp = arg & MT_ST_BLKSIZE_MASK;
-			if (cmd_in == MTSETBLK)
+			if (cmd_in == MTSETBLK) {
 				STp->blksize_changed = 1; /* At least we tried ;-) */
+				STp->changed_blksize = arg;
+			}
 		} else
 			ltmp = STp->block_size;
 		(STp->buffer)->b_data[9] = (ltmp >> 16);
@@ -3084,7 +3104,9 @@ static int st_int_ioctl(struct scsi_tape *STp, unsigned int cmd_in, unsigned lon
 			   cmd_in == MTSETDRVBUFFER ||
 			   cmd_in == SET_DENS_AND_BLK) {
 			if (cmdstatp->sense_hdr.sense_key == ILLEGAL_REQUEST &&
-			    !(STp->use_pf & PF_TESTED)) {
+				cmdstatp->sense_hdr.asc == 0x24 &&
+				(STp->device)->scsi_level <= SCSI_2 &&
+				!(STp->use_pf & PF_TESTED)) {
 				/* Try the other possible state of Page Format if not
 				   already tried */
 				STp->use_pf = (STp->use_pf ^ USE_PF) | PF_TESTED;
@@ -3636,9 +3658,23 @@ static long st_ioctl(struct file *file, unsigned int cmd_in, unsigned long arg)
 				retval = (-EIO);
 				goto out;
 			}
-			reset_state(STp);
-			/* remove this when the midlevel properly clears was_reset */
-			STp->device->was_reset = 0;
+			reset_state(STp); /* Clears pos_unknown */
+
+			/* Fix the device settings after reset, ignore errors */
+			if (mtc.mt_op == MTREW || mtc.mt_op == MTSEEK ||
+				mtc.mt_op == MTEOM) {
+				if (STp->can_partitions) {
+					/* STp->new_partition contains the
+					 *  latest partition set
+					 */
+					STp->partition = 0;
+					switch_partition(STp);
+				}
+				if (STp->density_changed)
+					st_int_ioctl(STp, MTSETDENSITY, STp->changed_density);
+				if (STp->blksize_changed)
+					st_int_ioctl(STp, MTSETBLK, STp->changed_blksize);
+			}
 		}
 
 		if (mtc.mt_op != MTNOP && mtc.mt_op != MTSETBLK &&
@@ -4122,7 +4158,7 @@ static void validate_options(void)
  */
 static int __init st_setup(char *str)
 {
-	int i, len, ints[5];
+	int i, len, ints[ARRAY_SIZE(parms) + 1];
 	char *stp;
 
 	stp = get_options(str, ARRAY_SIZE(ints), ints);
@@ -4384,6 +4420,9 @@ static int st_probe(struct device *dev)
 		goto out_idr_remove;
 	}
 
+	tpnt->new_media_ctr = scsi_get_ua_new_media_ctr(SDp);
+	tpnt->por_ctr = scsi_get_ua_por_ctr(SDp);
+
 	dev_set_drvdata(dev, tpnt);
 
 
@@ -4665,6 +4704,24 @@ options_show(struct device *dev, struct device_attribute *attr, char *buf)
 }
 static DEVICE_ATTR_RO(options);
 
+/**
+ * position_lost_in_reset_show - Value 1 indicates that reads, writes, etc.
+ * are blocked because a device reset has occurred and no operation positioning
+ * the tape has been issued.
+ * @dev: struct device
+ * @attr: attribute structure
+ * @buf: buffer to return formatted data in
+ */
+static ssize_t position_lost_in_reset_show(struct device *dev,
+	struct device_attribute *attr, char *buf)
+{
+	struct st_modedef *STm = dev_get_drvdata(dev);
+	struct scsi_tape *STp = STm->tape;
+
+	return sprintf(buf, "%d", STp->pos_unknown);
+}
+static DEVICE_ATTR_RO(position_lost_in_reset);
+
 /* Support for tape stats */
 
 /**
@@ -4849,6 +4906,7 @@ static struct attribute *st_dev_attrs[] = {
 	&dev_attr_default_density.attr,
 	&dev_attr_default_compression.attr,
 	&dev_attr_options.attr,
+	&dev_attr_position_lost_in_reset.attr,
 	NULL,
 };