diff options
| author | Kai Mäkisara <Kai.Makisara@kolumbus.fi> | 2025-02-01 17:11:06 +0200 |
|---|---|---|
| committer | Martin K. Petersen <martin.petersen@oracle.com> | 2025-02-03 17:51:31 -0500 |
| commit | 2c445d5f832a51dfd8527fcce7323f79d37c0432 (patch) | |
| tree | 098cb3766a58f5cb2531a398411aaffe8798e070 | |
| parent | 341128dfe10a7c8681d86e81b5bc63902da644ef (diff) | |
scsi: st: Add sysfs file position_lost_in_reset
If the value read from the file is 1, reads and writes from/to the device
are blocked because the tape position may not match user's expectation
(tape rewound after device reset).
Signed-off-by: Kai Mäkisara <Kai.Makisara@kolumbus.fi>
Link: https://lore.kernel.org/r/20250201151106.25529-1-Kai.Makisara@kolumbus.fi
Reviewed-by: John Meneghini <jmeneghi@redhat.com>
Tested-by: John Meneghini <jmeneghi@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
| -rw-r--r-- | Documentation/scsi/st.rst | 5 | ||||
| -rw-r--r-- | drivers/scsi/st.c | 19 |
2 files changed, 24 insertions, 0 deletions
diff --git a/Documentation/scsi/st.rst b/Documentation/scsi/st.rst index d3b28c28d74c..b4a092faa9c8 100644 --- a/Documentation/scsi/st.rst +++ b/Documentation/scsi/st.rst @@ -157,6 +157,11 @@ enabled driver and mode options. The value in the file is a bit mask where the bit definitions are the same as those used with MTSETDRVBUFFER in setting the options. +Each directory contains the entry 'position_lost_in_reset'. If this value is +one, reading and writing to the device is blocked after device reset. Most +devices rewind the tape after reset and the writes/read don't access the +tape position the user expects. + A link named 'tape' is made from the SCSI device directory to the class directory corresponding to the mode 0 auto-rewind device (e.g., st0). diff --git a/drivers/scsi/st.c b/drivers/scsi/st.c index 6ec1cfeb92ff..85867120c8a9 100644 --- a/drivers/scsi/st.c +++ b/drivers/scsi/st.c @@ -4703,6 +4703,24 @@ 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 */ /** @@ -4887,6 +4905,7 @@ 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, }; |