Compare the stored values of por_ctr and new_media_ctr against
the values in the device struct. In case of mismatch, the
Unit Attention corresponding to the counter has happened.
This is a safeguard against another ULD catching the
Unit Attention sense data.
Macros scsi_get_ua_new_media_ctr and scsi_get_ua_por_ctr are added to
read the current values of the counters.
Signed-off-by: Kai Mäkisara <Kai.Makisara@xxxxxxxxxxx>
---
drivers/scsi/st.c | 30 +++++++++++++++++++++++++-----
drivers/scsi/st.h | 4 ++++
include/scsi/scsi_device.h | 6 ++++++
3 files changed, 35 insertions(+), 5 deletions(-)
diff --git a/drivers/scsi/st.c b/drivers/scsi/st.c
index 0fc9afe60862..6ec1cfeb92ff 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
@@ -968,6 +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;
@@ -1024,6 +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;
@@ -3639,8 +3658,6 @@ static long st_ioctl(struct file *file, unsigned int cmd_in, unsigned long arg)
goto out;
}
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 ||
@@ -4402,6 +4419,9 @@ 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);
diff --git a/drivers/scsi/st.h b/drivers/scsi/st.h
index 6d31b894ee84..0d7c4b8c2c8a 100644
--- a/drivers/scsi/st.h
+++ b/drivers/scsi/st.h
@@ -179,6 +179,10 @@ struct scsi_tape {
int recover_count; /* From tape opening */
int recover_reg; /* From last status call */
+ /* The saved values of midlevel counters */
+ unsigned int new_media_ctr;
+ unsigned int por_ctr;
+
#if DEBUG
unsigned char write_pending;
int nbr_finished;
diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h
index f5c0f07a053a..013018608370 100644
--- a/include/scsi/scsi_device.h
+++ b/include/scsi/scsi_device.h
@@ -687,6 +687,12 @@ static inline int scsi_device_busy(struct scsi_device *sdev)
return sbitmap_weight(&sdev->budget_map);
}
+/* Macros to access the UNIT ATTENTION counters */
+#define scsi_get_ua_new_media_ctr(sdev) \
+ ((const unsigned int)(sdev->ua_new_media_ctr))
+#define scsi_get_ua_por_ctr(sdev) \
+ ((const unsigned int)(sdev->ua_por_ctr))
+
#define MODULE_ALIAS_SCSI_DEVICE(type) \
MODULE_ALIAS("scsi:t-" __stringify(type) "*")
#define SCSI_DEVICE_MODALIAS_FMT "scsi:t-0x%02x"
--
2.43.0
