diff mbox series

[v3,1/4] scsi: st: Restore some drive settings after reset

Message ID 20250120194925.44432-2-Kai.Makisara@kolumbus.fi
State New
Headers show
Series scsi: st: scsi_error: More reset patches | expand

Commit Message

Kai Mäkisara Jan. 20, 2025, 7:49 p.m. UTC
Some of the allowed operations put the tape into a known position
to continue operation assuming only the tape position has changed.
But reset sets partition, density and block size to drive default
values. These should be restored to the values before reset.

Normally the current block size and density are stored by the drive.
If the settings have been changed, the changed values have to be
saved by the driver across reset.

Signed-off-by: Kai Mäkisara <Kai.Makisara@kolumbus.fi>
---
 drivers/scsi/st.c | 24 +++++++++++++++++++++---
 drivers/scsi/st.h |  2 ++
 2 files changed, 23 insertions(+), 3 deletions(-)
diff mbox series

Patch

diff --git a/drivers/scsi/st.c b/drivers/scsi/st.c
index ebbd50ec0cda..0fc9afe60862 100644
--- a/drivers/scsi/st.c
+++ b/drivers/scsi/st.c
@@ -952,7 +952,6 @@  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;
 	}
 }
 
@@ -2930,14 +2929,17 @@  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);
@@ -3636,9 +3638,25 @@  static long st_ioctl(struct file *file, unsigned int cmd_in, unsigned long arg)
 				retval = (-EIO);
 				goto out;
 			}
-			reset_state(STp);
+			reset_state(STp); /* Clears pos_unknown */
 			/* remove this when the midlevel properly clears was_reset */
 			STp->device->was_reset = 0;
+
+			/* 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 &&
diff --git a/drivers/scsi/st.h b/drivers/scsi/st.h
index 1aaaf5369a40..6d31b894ee84 100644
--- a/drivers/scsi/st.h
+++ b/drivers/scsi/st.h
@@ -165,6 +165,7 @@  struct scsi_tape {
 	unsigned char compression_changed;
 	unsigned char drv_buffer;
 	unsigned char density;
+	unsigned char changed_density;
 	unsigned char door_locked;
 	unsigned char autorew_dev;   /* auto-rewind device */
 	unsigned char rew_at_close;  /* rewind necessary at close */
@@ -172,6 +173,7 @@  struct scsi_tape {
 	unsigned char cleaning_req;  /* cleaning requested? */
 	unsigned char first_tur;     /* first TEST UNIT READY */
 	int block_size;
+	int changed_blksize;
 	int min_block;
 	int max_block;
 	int recover_count;     /* From tape opening */