[PATCH v2 1/7] scsi: scsi_debug: First fixes for tapes

Kai Mäkisara
2025-02-13T09:27:34Z

Patch includes the following:
- enable MODE SENSE/SELECT without actual page (to read/write only
the Block Descriptor)
- store the density code and block size in the Block Descriptor
(only short version for tapes)
- fix REWIND not to use the wrong page filling function

Signed-off-by: Kai Mäkisara <Kai.Makisara@kolumbus.fi>
---
drivers/scsi/scsi_debug.c | 55 ++++++++++++++++++++++++++++++++++-----
1 file changed, 49 insertions(+), 6 deletions(-)

diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c
index 5ceaa4665e5d..4da0c259390b 100644
--- a/drivers/scsi/scsi_debug.c
+++ b/drivers/scsi/scsi_debug.c
@@ -173,6 +173,10 @@ static const char *sdebug_version_date = "20210520";
#define DEF_ZBC_MAX_OPEN_ZONES 8
#define DEF_ZBC_NR_CONV_ZONES 1

+/* Default parameters for tape drives */
+#define TAPE_DEF_DENSITY 0x0
+#define TAPE_DEF_BLKSIZE 0
+
#define SDEBUG_LUN_0_VAL 0

/* bit mask values for sdebug_opts */
@@ -363,6 +367,10 @@ struct sdebug_dev_info {
ktime_t create_ts; /* time since bootup that this device was created */
struct sdeb_zone_state *zstate;

+ /* For tapes */
+ unsigned int tape_blksize;
+ unsigned int tape_density;
+
struct dentry *debugfs_entry;
struct spinlock list_lock;
struct list_head inject_err_list;
@@ -773,7 +781,7 @@ static const struct opcode_info_t opcode_info_arr[SDEB_I_LAST_ELEM_P1 + 1] = {
/* 20 */
{0, 0x1e, 0, 0, NULL, NULL, /* ALLOW REMOVAL */
{6, 0, 0, 0, 0x3, 0xc7, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0} },
- {0, 0x1, 0, 0, resp_start_stop, NULL, /* REWIND ?? */
+ {0, 0x1, 0, 0, NULL, NULL, /* REWIND ?? */
{6, 0x1, 0, 0, 0, 0xc7, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0} },
{0, 0, 0, F_INV_OP | FF_RESPOND, NULL, NULL, /* ATA_PT */
{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0} },
@@ -2742,7 +2750,7 @@ static int resp_mode_sense(struct scsi_cmnd *scp,
unsigned char *ap;
unsigned char *arr __free(kfree);
unsigned char *cmd = scp->cmnd;
- bool dbd, llbaa, msense_6, is_disk, is_zbc;
+ bool dbd, llbaa, msense_6, is_disk, is_zbc, is_tape;

arr = kzalloc(SDEBUG_MAX_MSENSE_SZ, GFP_ATOMIC);
if (!arr)
@@ -2755,7 +2763,8 @@ static int resp_mode_sense(struct scsi_cmnd *scp,
llbaa = msense_6 ? false : !!(cmd[1] & 0x10);
is_disk = (sdebug_ptype == TYPE_DISK);
is_zbc = devip->zoned;
- if ((is_disk || is_zbc) && !dbd)
+ is_tape = (sdebug_ptype == TYPE_TAPE);
+ if ((is_disk || is_zbc || is_tape) && !dbd)
bd_len = llbaa ? 16 : 8;
else
bd_len = 0;
@@ -2793,15 +2802,25 @@ static int resp_mode_sense(struct scsi_cmnd *scp,
put_unaligned_be32(0xffffffff, ap + 0);
else
put_unaligned_be32(sdebug_capacity, ap + 0);
- put_unaligned_be16(sdebug_sector_size, ap + 6);
+ if (is_tape) {
+ ap[0] = devip->tape_density;
+ put_unaligned_be16(devip->tape_blksize, ap + 6);
+ } else
+ put_unaligned_be16(sdebug_sector_size, ap + 6);
offset += bd_len;
ap = arr + offset;
} else if (16 == bd_len) {
+ if (is_tape) {
+ mk_sense_invalid_fld(scp, SDEB_IN_DATA, 1, 4);
+ return check_condition_result;
+ }
put_unaligned_be64((u64)sdebug_capacity, ap + 0);
put_unaligned_be32(sdebug_sector_size, ap + 12);
offset += bd_len;
ap = arr + offset;
}
+ if (cmd[2] == 0)
+ goto only_bd; /* Only block descriptor requested */

/*
* N.B. If len>0 before resp_*_pg() call, then form of that call should be:
@@ -2902,6 +2921,7 @@ static int resp_mode_sense(struct scsi_cmnd *scp,
default:
goto bad_pcode;
}
+only_bd:
if (msense_6)
arr[0] = offset - 1;
else
@@ -2945,8 +2965,27 @@ static int resp_mode_select(struct scsi_cmnd *scp,
__func__, param_len, res);
md_len = mselect6 ? (arr[0] + 1) : (get_unaligned_be16(arr + 0) + 2);
bd_len = mselect6 ? arr[3] : get_unaligned_be16(arr + 6);
- off = bd_len + (mselect6 ? 4 : 8);
- if (md_len > 2 || off >= res) {
+ off = (mselect6 ? 4 : 8);
+ if (sdebug_ptype == TYPE_TAPE) {
+ int blksize;
+
+ if (bd_len != 8) {
+ mk_sense_invalid_fld(scp, SDEB_IN_DATA,
+ mselect6 ? 3 : 6, -1);
+ return check_condition_result;
+ }
+ blksize = get_unaligned_be16(arr + off + 6);
+ if ((blksize % 4) != 0) {
+ mk_sense_invalid_fld(scp, SDEB_IN_DATA, off + 6, -1);
+ return check_condition_result;
+ }
+ devip->tape_density = arr[off];
+ devip->tape_blksize = blksize;
+ }
+ off += bd_len;
+ if (off >= res)
+ return 0; /* No page written, just descriptors */
+ if (md_len > 2) {
mk_sense_invalid_fld(scp, SDEB_IN_DATA, 0, -1);
return check_condition_result;
}
@@ -5835,6 +5874,10 @@ static struct sdebug_dev_info *sdebug_device_create(
} else {
devip->zoned = false;
}
+ if (sdebug_ptype == TYPE_TAPE) {
+ devip->tape_density = TAPE_DEF_DENSITY;
+ devip->tape_blksize = TAPE_DEF_BLKSIZE;
+ }
devip->create_ts = ktime_get_boottime();
atomic_set(&devip->stopped, (sdeb_tur_ms_to_ready > 0 ? 2 : 0));
spin_lock_init(&devip->list_lock);
--
2.43.0