The original error injection mechanism was based on scsi_host which
could not inject fault for a single SCSI device.
This patchset provides the ability to inject errors for a single
SCSI device. Now we support inject timeout errors, queuecommand
errors, and hostbyte, driverbyte, statusbyte, and sense data for
specific SCSI Command. Two new error injection is defined to make
abort command or reset LUN failed.
Besides error injection for single device, this patchset add a
new interface to make reset target failed for each scsi_target.
The first two patch add a debugfs interface to add and inquiry single
device's error injection info; the third patch defined how to remove
an injection which has been added. The following 5 patches use the
injection info and generate the related error type. The last two just
add a new interface to make reset target failed and control
scsi_device's allow_restart flag.
V6:
- Check return value of debugfs_create_xxx() and print error log
if debugfs_create_xxx() return error
- Fix typo in description of patch7 and patch8
- Update the description of patch10
V5:
- Using rcu list to sync between error inject add, remove and check
- Add module parameter "allow_restart" to control scsi_device's
allow_restart flag
V4:
- Fix BUG_ON triggered by schedule in atomic context when rmmod scsi_debug
Closes: https://lore.kernel.org/oe-lkp/[email protected]
V3:
- Add two more error types to fail abort command and lun reset
- Fix memleak when rmmod scsi_debug without clearing errors injected
- Fix memkeak because did not implement release in sdebug_error_fops
- Fix possible NULL point access in scsi_debug_slave_destroy
- Move specific error type's description to each single patch which
implement this error type
- Add interface to make target reset fail
V2:
- Using debugfs rather than sysfs attribute interface to manage error
Wenchao Hao (10):
scsi: scsi_debug: create scsi_debug directory in the debugfs filesystem
scsi: scsi_debug: Add interface to manage single device's error inject
scsi: scsi_debug: Define grammar to remove added error injection
scsi: scsi_debug: timeout command if the error is injected
scsi: scsi_debug: Return failed value if the error is injected
scsi: scsi_debug: set command's result and sense data if the error is injected
scsi: scsi_debug: Add new error injection abort failed
scsi: scsi_debug: Add new error injection reset lun failed
scsi: scsi_debug: Add debugfs interface to fail target reset
scsi: scsi_debug: Add param to control sdev's allow_restart
drivers/scsi/scsi_debug.c | 575 +++++++++++++++++++++++++++++++++++++-
1 file changed, 570 insertions(+), 5 deletions(-)
--
2.32.0
If a fail command error is injected, set the command's status and sense
data then finish this scsi command.
Set SCSI command's status and sense data format:
+--------+------+-------------------------------------------------------+
| Column | Type | Description |
+--------+------+-------------------------------------------------------+
| 1 | u8 | Error type, fixed to 0x2 |
+--------+------+-------------------------------------------------------+
| 2 | s32 | Error Count |
| | | 0: the rule will be ignored |
| | | positive: the rule will always take effect |
| | | negative: the rule takes effect n times where -n is |
| | | the value given. Ignored after n times |
+--------+------+-------------------------------------------------------+
| 3 | x8 | SCSI command opcode, 0xff for all commands |
+--------+------+-------------------------------------------------------+
| 4 | x8 | Host byte in scsi_cmd::status |
| | | [scsi_cmd::status has 32 bits holding these 3 bytes] |
+--------+------+-------------------------------------------------------+
| 5 | x8 | Driver byte in scsi_cmd::status |
+--------+------+-------------------------------------------------------+
| 6 | x8 | SCSI Status byte in scsi_cmd::status |
+--------+------+-------------------------------------------------------+
| 7 | x8 | SCSI Sense Key in scsi_cmnd |
+--------+------+-------------------------------------------------------+
| 8 | x8 | SCSI ASC in scsi_cmnd |
+--------+------+-------------------------------------------------------+
| 9 | x8 | SCSI ASCQ in scsi_cmnd |
+--------+------+-------------------------------------------------------+
Examples:
error=/sys/kernel/debug/scsi_debug/0:0:0:1/error
echo "2 -10 0x88 0 0 0x2 0x3 0x11 0x0" >${error}
will make device's read command return with media error with additional
sense of "Unrecovered read error" (UNC):
Acked-by: Douglas Gilbert <[email protected]>
Signed-off-by: Wenchao Hao <[email protected]>
---
drivers/scsi/scsi_debug.c | 53 +++++++++++++++++++++++++++++++++++++++
1 file changed, 53 insertions(+)
diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c
index efdd63dd6d25..d15d007f1317 100644
--- a/drivers/scsi/scsi_debug.c
+++ b/drivers/scsi/scsi_debug.c
@@ -7797,6 +7797,48 @@ static int sdebug_fail_queue_cmd(struct scsi_cmnd *cmnd)
return 0;
}
+static int sdebug_fail_cmd(struct scsi_cmnd *cmnd, int *retval,
+ struct sdebug_err_inject *info)
+{
+ struct scsi_device *sdp = cmnd->device;
+ struct sdebug_dev_info *devip = (struct sdebug_dev_info *)sdp->hostdata;
+ struct sdebug_err_inject *err;
+ unsigned char *cmd = cmnd->cmnd;
+ int ret = 0;
+ int result;
+
+ if (devip == NULL)
+ return 0;
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(err, &devip->inject_err_list, list) {
+ if (err->type == ERR_FAIL_CMD &&
+ (err->cmd == cmd[0] || err->cmd == 0xff)) {
+ if (!err->cnt) {
+ rcu_read_unlock();
+ return 0;
+ }
+
+ ret = !!err->cnt;
+ rcu_read_unlock();
+ goto out_handle;
+ }
+ }
+ rcu_read_unlock();
+
+ return 0;
+
+out_handle:
+ if (err->cnt < 0)
+ err->cnt++;
+ mk_sense_buffer(cmnd, err->sense_key, err->asc, err->asq);
+ result = err->status_byte | err->host_byte << 16 | err->driver_byte << 24;
+ *info = *err;
+ *retval = schedule_resp(cmnd, devip, result, NULL, 0, 0);
+
+ return ret;
+}
+
static int scsi_debug_queuecommand(struct Scsi_Host *shost,
struct scsi_cmnd *scp)
{
@@ -7817,6 +7859,7 @@ static int scsi_debug_queuecommand(struct Scsi_Host *shost,
bool has_wlun_rl;
bool inject_now;
int ret = 0;
+ struct sdebug_err_inject err;
scsi_set_resid(scp, 0);
if (sdebug_statistics) {
@@ -7869,6 +7912,16 @@ static int scsi_debug_queuecommand(struct Scsi_Host *shost,
return ret;
}
+ if (sdebug_fail_cmd(scp, &ret, &err)) {
+ scmd_printk(KERN_INFO, scp,
+ "fail command 0x%x with hostbyte=0x%x, "
+ "driverbyte=0x%x, statusbyte=0x%x, "
+ "sense_key=0x%x, asc=0x%x, asq=0x%x\n",
+ opcode, err.host_byte, err.driver_byte,
+ err.status_byte, err.sense_key, err.asc, err.asq);
+ return ret;
+ }
+
if (unlikely(inject_now && !atomic_read(&sdeb_inject_pending)))
atomic_set(&sdeb_inject_pending, 1);
--
2.32.0
If a timeout error is injected, return 0 from scsi_debug_queuecommand to
make the command timeout.
Timeout SCSI command format:
+--------+------+-------------------------------------------------------+
| Column | Type | Description |
+--------+------+-------------------------------------------------------+
| 1 | u8 | Error type, fixed to 0x0 |
+--------+------+-------------------------------------------------------+
| 2 | s32 | Error count |
| | | 0: this rule will be ignored |
| | | positive: the rule will always take effect |
| | | negative: the rule takes effect n times where -n is |
| | | the value given. Ignored after n times |
+--------+------+-------------------------------------------------------+
| 3 | x8 | SCSI command opcode, 0xff for all commands |
+--------+------+-------------------------------------------------------+
Examples:
error=/sys/kernel/debug/scsi_debug/0:0:0:1/error
echo "0 -10 0x12" > ${error}
will make the device's inquiry command timeout 10 times.
echo "0 1 0x12" > ${error}
will make the device's inquiry timeout each time it is invoked on this
device.
Acked-by: Douglas Gilbert <[email protected]>
Signed-off-by: Wenchao Hao <[email protected]>
---
drivers/scsi/scsi_debug.c | 34 ++++++++++++++++++++++++++++++++++
1 file changed, 34 insertions(+)
diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c
index 0d5a179dbd97..9081c9d22882 100644
--- a/drivers/scsi/scsi_debug.c
+++ b/drivers/scsi/scsi_debug.c
@@ -7741,6 +7741,34 @@ static int sdebug_blk_mq_poll(struct Scsi_Host *shost, unsigned int queue_num)
return num_entries;
}
+static int sdebug_timeout_cmd(struct scsi_cmnd *cmnd)
+{
+ struct scsi_device *sdp = cmnd->device;
+ struct sdebug_dev_info *devip = (struct sdebug_dev_info *)sdp->hostdata;
+ struct sdebug_err_inject *err;
+ unsigned char *cmd = cmnd->cmnd;
+ int ret = 0;
+
+ if (devip == NULL)
+ return 0;
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(err, &devip->inject_err_list, list) {
+ if (err->type == ERR_TMOUT_CMD &&
+ (err->cmd == cmd[0] || err->cmd == 0xff)) {
+ ret = !!err->cnt;
+ if (err->cnt < 0)
+ err->cnt++;
+
+ rcu_read_unlock();
+ return ret;
+ }
+ }
+ rcu_read_unlock();
+
+ return 0;
+}
+
static int scsi_debug_queuecommand(struct Scsi_Host *shost,
struct scsi_cmnd *scp)
{
@@ -7799,6 +7827,12 @@ static int scsi_debug_queuecommand(struct Scsi_Host *shost,
if (NULL == devip)
goto err_out;
}
+
+ if (sdebug_timeout_cmd(scp)) {
+ scmd_printk(KERN_INFO, scp, "timeout command 0x%x\n", opcode);
+ return 0;
+ }
+
if (unlikely(inject_now && !atomic_read(&sdeb_inject_pending)))
atomic_set(&sdeb_inject_pending, 1);
--
2.32.0
If a fail queuecommand error is injected, return the failed value defined
in the rule from queuecommand.
Make queuecommand return format:
+--------+------+-------------------------------------------------------+
| Column | Type | Description |
+--------+------+-------------------------------------------------------+
| 1 | u8 | Error type, fixed to 0x1 |
+--------+------+-------------------------------------------------------+
| 2 | s32 | Error count |
| | | 0: this rule will be ignored |
| | | positive: the rule will always take effect |
| | | negative: the rule takes effect n times where -n is |
| | | the value given. Ignored after n times |
+--------+------+-------------------------------------------------------+
| 3 | x8 | SCSI command opcode, 0xff for all commands |
+--------+------+-------------------------------------------------------+
| 4 | x32 | The queuecommand() return value we want |
+--------+------+-------------------------------------------------------+
Examples:
error=/sys/kernel/debug/scsi_debug/0:0:0:1/error
echo "1 1 0x12 0x1055" > ${error}
will make each INQUIRY command sent to that device return
0x1055 (SCSI_MLQUEUE_HOST_BUSY).
Acked-by: Douglas Gilbert <[email protected]>
Signed-off-by: Wenchao Hao <[email protected]>
---
drivers/scsi/scsi_debug.c | 36 ++++++++++++++++++++++++++++++++++++
1 file changed, 36 insertions(+)
diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c
index 9081c9d22882..efdd63dd6d25 100644
--- a/drivers/scsi/scsi_debug.c
+++ b/drivers/scsi/scsi_debug.c
@@ -7769,6 +7769,34 @@ static int sdebug_timeout_cmd(struct scsi_cmnd *cmnd)
return 0;
}
+static int sdebug_fail_queue_cmd(struct scsi_cmnd *cmnd)
+{
+ struct scsi_device *sdp = cmnd->device;
+ struct sdebug_dev_info *devip = (struct sdebug_dev_info *)sdp->hostdata;
+ struct sdebug_err_inject *err;
+ unsigned char *cmd = cmnd->cmnd;
+ int ret = 0;
+
+ if (devip == NULL)
+ return 0;
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(err, &devip->inject_err_list, list) {
+ if (err->type == ERR_FAIL_QUEUE_CMD &&
+ (err->cmd == cmd[0] || err->cmd == 0xff)) {
+ ret = err->cnt ? err->queuecmd_ret : 0;
+ if (err->cnt < 0)
+ err->cnt++;
+
+ rcu_read_unlock();
+ return ret;
+ }
+ }
+ rcu_read_unlock();
+
+ return 0;
+}
+
static int scsi_debug_queuecommand(struct Scsi_Host *shost,
struct scsi_cmnd *scp)
{
@@ -7788,6 +7816,7 @@ static int scsi_debug_queuecommand(struct Scsi_Host *shost,
u8 opcode = cmd[0];
bool has_wlun_rl;
bool inject_now;
+ int ret = 0;
scsi_set_resid(scp, 0);
if (sdebug_statistics) {
@@ -7833,6 +7862,13 @@ static int scsi_debug_queuecommand(struct Scsi_Host *shost,
return 0;
}
+ ret = sdebug_fail_queue_cmd(scp);
+ if (ret) {
+ scmd_printk(KERN_INFO, scp, "fail queue command 0x%x with 0x%x\n",
+ opcode, ret);
+ return ret;
+ }
+
if (unlikely(inject_now && !atomic_read(&sdeb_inject_pending)))
atomic_set(&sdeb_inject_pending, 1);
--
2.32.0
This new facility uses the debugfs pseudo file system which is typically
mounted under the /sys/kernel/debug directory and requires root permissions
to access.
The interface file is found at /sys/kernel/debug/scsi_debug/<h:c:t:l>/error
where <h:c:t:l> identifies the device (logical unit (LU)) to inject errors
on.
For the following description the ${error} environment variable is assumed
to be set to/sys/kernel/debug/scsi_debug/1:0:0:0/error where 1:0:0:0 is a
pseudo device (LU) owned by the scsi_debug driver. Rules are written to
${error} in the normal sysfs fashion (e.g. 'echo "0 -2 0x12" > ${error}').
More than one rule can be active on a device at a time and inactive rules
(i.e. those whose Error count is 0) remain in the rule listing. The
existing rules can be read with 'cat ${error}' with oneline output for
each rule.
The interface format is line-by-line, each line is an error injection rule.
Each rule contains integers separated by spaces, the first three columns
correspond to "Error code", "Error count" and "SCSI command", other
columns depend on Error code.
General rule format:
+--------+------+-------------------------------------------------------+
| Column | Type | Description |
+--------+------+-------------------------------------------------------+
| 1 | u8 | Error code |
| | | 0: timeout SCSI command |
| | | 1: fail queuecommand, make queuecommand return |
| | | given value |
| | | 2: fail command, finish command with SCSI status, |
| | | sense key and ASC/ASCQ values |
| | | 3: make abort commands for specific command fail |
| | | 4: make reset lun for specific command fail |
+--------+------+-------------------------------------------------------+
| 2 | s32 | Error count |
| | | 0: this rule will be ignored |
| | | positive: the rule will always take effect |
| | | negative: the rule takes effect n times where -n is |
| | | the value given. Ignored after n times |
+--------+------+-------------------------------------------------------+
| 3 | x8 | SCSI command opcode, 0xff for all commands |
+--------+------+-------------------------------------------------------+
| ... | xxx | Error type specific fields |
+--------+------+-------------------------------------------------------+
Notes:
- when multiple error inject rules are added for the same SCSI command, the
one with smaller error code will take effect (and the others will be
ignored).
- if an same error (i.e. same Error code and SCSI command) is added, the
older one will be overwritten.
- Currently, the basic types are (u8/u16/u32/u64/s8/s16/s32/s64) and the
hexadecimal types (x8/x16/x32/x64)
- where a hexadecimal value is expected (e.g. Column 3: SCSI command
opcode) the "0x" prefix is optional on the value (e.g. the INQUIRY opcode
can be given as '0x12' or '12')
- when the Error count is negative, reading ${error} will show that value
incrementing, stopping when it gets to 0
Acked-by: Douglas Gilbert <[email protected]>
Signed-off-by: Wenchao Hao <[email protected]>
---
drivers/scsi/scsi_debug.c | 214 +++++++++++++++++++++++++++++++++++++-
1 file changed, 210 insertions(+), 4 deletions(-)
diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c
index 562a48f53cda..46f1ee647b15 100644
--- a/drivers/scsi/scsi_debug.c
+++ b/drivers/scsi/scsi_debug.c
@@ -286,6 +286,42 @@ struct sdeb_zone_state { /* ZBC: per zone state */
sector_t z_wp;
};
+enum sdebug_err_type {
+ ERR_TMOUT_CMD = 0, /* make specific scsi command timeout */
+ ERR_FAIL_QUEUE_CMD = 1, /* make specific scsi command's */
+ /* queuecmd return failed */
+ ERR_FAIL_CMD = 2, /* make specific scsi command's */
+ /* queuecmd return succeed but */
+ /* with errors set in scsi_cmnd */
+};
+
+struct sdebug_err_inject {
+ int type;
+ struct list_head list;
+ int cnt;
+ unsigned char cmd;
+ struct rcu_head rcu;
+
+ union {
+ /*
+ * For ERR_FAIL_QUEUE_CMD
+ */
+ int queuecmd_ret;
+
+ /*
+ * For ERR_FAIL_CMD
+ */
+ struct {
+ unsigned char host_byte;
+ unsigned char driver_byte;
+ unsigned char status_byte;
+ unsigned char sense_key;
+ unsigned char asc;
+ unsigned char asq;
+ };
+ };
+};
+
struct sdebug_dev_info {
struct list_head dev_list;
unsigned int channel;
@@ -311,6 +347,10 @@ struct sdebug_dev_info {
unsigned int max_open;
ktime_t create_ts; /* time since bootup that this device was created */
struct sdeb_zone_state *zstate;
+
+ struct dentry *debugfs_entry;
+ struct spinlock list_lock;
+ struct list_head inject_err_list;
};
struct sdebug_host_info {
@@ -865,6 +905,143 @@ static const int condition_met_result = SAM_STAT_CONDITION_MET;
static struct dentry *sdebug_debugfs_root;
+static void sdebug_err_free(struct rcu_head *head)
+{
+ struct sdebug_err_inject *inject =
+ container_of(head, typeof(*inject), rcu);
+
+ kfree(inject);
+}
+
+static void sdebug_err_add(struct scsi_device *sdev, struct sdebug_err_inject *new)
+{
+ struct sdebug_dev_info *devip = (struct sdebug_dev_info *)sdev->hostdata;
+ struct sdebug_err_inject *err;
+
+ spin_lock(&devip->list_lock);
+ list_for_each_entry_rcu(err, &devip->inject_err_list, list) {
+ if (err->type == new->type && err->cmd == new->cmd) {
+ list_del_rcu(&err->list);
+ call_rcu(&err->rcu, sdebug_err_free);
+ }
+ }
+
+ list_add_tail_rcu(&new->list, &devip->inject_err_list);
+ spin_unlock(&devip->list_lock);
+}
+
+static int sdebug_error_show(struct seq_file *m, void *p)
+{
+ struct scsi_device *sdev = (struct scsi_device *)m->private;
+ struct sdebug_dev_info *devip = (struct sdebug_dev_info *)sdev->hostdata;
+ struct sdebug_err_inject *err;
+
+ seq_puts(m, "Type\tCount\tCommand\n");
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(err, &devip->inject_err_list, list) {
+ switch (err->type) {
+ case ERR_TMOUT_CMD:
+ seq_printf(m, "%d\t%d\t0x%x\n", err->type, err->cnt,
+ err->cmd);
+ break;
+
+ case ERR_FAIL_QUEUE_CMD:
+ seq_printf(m, "%d\t%d\t0x%x\t0x%x\n", err->type,
+ err->cnt, err->cmd, err->queuecmd_ret);
+ break;
+
+ case ERR_FAIL_CMD:
+ seq_printf(m, "%d\t%d\t0x%x\t0x%x 0x%x 0x%x 0x%x 0x%x 0x%x\n",
+ err->type, err->cnt, err->cmd,
+ err->host_byte, err->driver_byte,
+ err->status_byte, err->sense_key,
+ err->asc, err->asq);
+ break;
+ }
+ }
+ rcu_read_unlock();
+
+ return 0;
+}
+
+static int sdebug_error_open(struct inode *inode, struct file *file)
+{
+ return single_open(file, sdebug_error_show, inode->i_private);
+}
+
+static ssize_t sdebug_error_write(struct file *file, const char __user *ubuf,
+ size_t count, loff_t *ppos)
+{
+ char *buf;
+ unsigned int inject_type;
+ struct sdebug_err_inject *inject;
+ struct scsi_device *sdev = (struct scsi_device *)file->f_inode->i_private;
+
+ buf = kmalloc(count, GFP_KERNEL);
+ if (!buf)
+ return -ENOMEM;
+
+ if (copy_from_user(buf, ubuf, count)) {
+ kfree(buf);
+ return -EFAULT;
+ }
+
+ if (sscanf(buf, "%d", &inject_type) != 1) {
+ kfree(buf);
+ return -EINVAL;
+ }
+
+ inject = kzalloc(sizeof(struct sdebug_err_inject), GFP_KERNEL);
+ if (!inject) {
+ kfree(buf);
+ return -ENOMEM;
+ }
+
+ switch (inject_type) {
+ case ERR_TMOUT_CMD:
+ if (sscanf(buf, "%d %d %hhx", &inject->type, &inject->cnt,
+ &inject->cmd) != 3)
+ goto out_error;
+ break;
+
+ case ERR_FAIL_QUEUE_CMD:
+ if (sscanf(buf, "%d %d %hhx %x", &inject->type, &inject->cnt,
+ &inject->cmd, &inject->queuecmd_ret) != 4)
+ goto out_error;
+ break;
+
+ case ERR_FAIL_CMD:
+ if (sscanf(buf, "%d %d %hhx %hhx %hhx %hhx %hhx %hhx %hhx",
+ &inject->type, &inject->cnt, &inject->cmd,
+ &inject->host_byte, &inject->driver_byte,
+ &inject->status_byte, &inject->sense_key,
+ &inject->asc, &inject->asq) != 9)
+ goto out_error;
+ break;
+
+ default:
+ goto out_error;
+ break;
+ }
+
+ kfree(buf);
+ sdebug_err_add(sdev, inject);
+
+ return count;
+
+out_error:
+ kfree(buf);
+ kfree(inject);
+ return -EINVAL;
+}
+
+static const struct file_operations sdebug_error_fops = {
+ .open = sdebug_error_open,
+ .read = seq_read,
+ .write = sdebug_error_write,
+ .release = single_release,
+};
/* Only do the extra work involved in logical block provisioning if one or
* more of the lbpu, lbpws or lbpws10 parameters are given and we are doing
@@ -5099,6 +5276,8 @@ static struct sdebug_dev_info *sdebug_device_create(
}
devip->create_ts = ktime_get_boottime();
atomic_set(&devip->stopped, (sdeb_tur_ms_to_ready > 0 ? 2 : 0));
+ spin_lock_init(&devip->list_lock);
+ INIT_LIST_HEAD(&devip->inject_err_list);
list_add_tail(&devip->dev_list, &sdbg_host->dev_info_list);
}
return devip;
@@ -5144,6 +5323,7 @@ static int scsi_debug_slave_alloc(struct scsi_device *sdp)
if (sdebug_verbose)
pr_info("slave_alloc <%u %u %u %llu>\n",
sdp->host->host_no, sdp->channel, sdp->id, sdp->lun);
+
return 0;
}
@@ -5151,6 +5331,7 @@ static int scsi_debug_slave_configure(struct scsi_device *sdp)
{
struct sdebug_dev_info *devip =
(struct sdebug_dev_info *)sdp->hostdata;
+ struct dentry *dentry;
if (sdebug_verbose)
pr_info("slave_configure <%u %u %u %llu>\n",
@@ -5166,6 +5347,19 @@ static int scsi_debug_slave_configure(struct scsi_device *sdp)
if (sdebug_no_uld)
sdp->no_uld_attach = 1;
config_cdb_len(sdp);
+
+ devip->debugfs_entry = debugfs_create_dir(dev_name(&sdp->sdev_dev),
+ sdebug_debugfs_root);
+ if (IS_ERR_OR_NULL(devip->debugfs_entry))
+ pr_info("%s: failed to create debugfs directory for device %s\n",
+ __func__, dev_name(&sdp->sdev_gendev));
+
+ dentry = debugfs_create_file("error", 0600, devip->debugfs_entry, sdp,
+ &sdebug_error_fops);
+ if (IS_ERR_OR_NULL(dentry))
+ pr_info("%s: failed to create error file for device %s\n",
+ __func__, dev_name(&sdp->sdev_gendev));
+
return 0;
}
@@ -5173,15 +5367,27 @@ static void scsi_debug_slave_destroy(struct scsi_device *sdp)
{
struct sdebug_dev_info *devip =
(struct sdebug_dev_info *)sdp->hostdata;
+ struct sdebug_err_inject *err;
if (sdebug_verbose)
pr_info("slave_destroy <%u %u %u %llu>\n",
sdp->host->host_no, sdp->channel, sdp->id, sdp->lun);
- if (devip) {
- /* make this slot available for re-use */
- devip->used = false;
- sdp->hostdata = NULL;
+
+ if (!devip)
+ return;
+
+ spin_lock(&devip->list_lock);
+ list_for_each_entry_rcu(err, &devip->inject_err_list, list) {
+ list_del_rcu(&err->list);
+ call_rcu(&err->rcu, sdebug_err_free);
}
+ spin_unlock(&devip->list_lock);
+
+ debugfs_remove(devip->debugfs_entry);
+
+ /* make this slot available for re-use */
+ devip->used = false;
+ sdp->hostdata = NULL;
}
/* Returns true if we require the queued memory to be freed by the caller. */
--
2.32.0
Add error injection type 3 to make scsi_debug_abort() return FAILED.
Fail abort command format:
+--------+------+-------------------------------------------------------+
| Column | Type | Description |
+--------+------+-------------------------------------------------------+
| 1 | u8 | Error type, fixed to 0x3 |
+--------+------+-------------------------------------------------------+
| 2 | s32 | Error count |
| | | 0: this rule will be ignored |
| | | positive: the rule will always take effect |
| | | negative: the rule takes effect n times where -n is |
| | | the value given. Ignored after n times |
+--------+------+-------------------------------------------------------+
| 3 | x8 | SCSI command opcode, 0xff for all commands |
+--------+------+-------------------------------------------------------+
Examples:
error=/sys/kernel/debug/scsi_debug/0:0:0:1/error
echo "3 -10 0x12" > ${error}
will make the device return FAILED when abort inquiry command 10 times.
Signed-off-by: Wenchao Hao <[email protected]>
Tested-by: Douglas Gilbert <[email protected]>
---
drivers/scsi/scsi_debug.c | 40 +++++++++++++++++++++++++++++++++++++++
1 file changed, 40 insertions(+)
diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c
index d15d007f1317..89f47ded1e23 100644
--- a/drivers/scsi/scsi_debug.c
+++ b/drivers/scsi/scsi_debug.c
@@ -293,6 +293,8 @@ enum sdebug_err_type {
ERR_FAIL_CMD = 2, /* make specific scsi command's */
/* queuecmd return succeed but */
/* with errors set in scsi_cmnd */
+ ERR_ABORT_CMD_FAILED = 3, /* control return FAILED from */
+ /* scsi_debug_abort() */
};
struct sdebug_err_inject {
@@ -970,6 +972,7 @@ static int sdebug_error_show(struct seq_file *m, void *p)
list_for_each_entry_rcu(err, &devip->inject_err_list, list) {
switch (err->type) {
case ERR_TMOUT_CMD:
+ case ERR_ABORT_CMD_FAILED:
seq_printf(m, "%d\t%d\t0x%x\n", err->type, err->cnt,
err->cmd);
break;
@@ -1031,6 +1034,7 @@ static ssize_t sdebug_error_write(struct file *file, const char __user *ubuf,
switch (inject_type) {
case ERR_TMOUT_CMD:
+ case ERR_ABORT_CMD_FAILED:
if (sscanf(buf, "%d %d %hhx", &inject->type, &inject->cnt,
&inject->cmd) != 3)
goto out_error;
@@ -5512,9 +5516,39 @@ static void stop_all_queued(void)
mutex_unlock(&sdebug_host_list_mutex);
}
+static int sdebug_fail_abort(struct scsi_cmnd *cmnd)
+{
+ struct scsi_device *sdp = cmnd->device;
+ struct sdebug_dev_info *devip = (struct sdebug_dev_info *)sdp->hostdata;
+ struct sdebug_err_inject *err;
+ unsigned char *cmd = cmnd->cmnd;
+ int ret = 0;
+
+ if (devip == NULL)
+ return 0;
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(err, &devip->inject_err_list, list) {
+ if (err->type == ERR_ABORT_CMD_FAILED &&
+ (err->cmd == cmd[0] || err->cmd == 0xff)) {
+ ret = !!err->cnt;
+ if (err->cnt < 0)
+ err->cnt++;
+
+ rcu_read_unlock();
+ return ret;
+ }
+ }
+ rcu_read_unlock();
+
+ return 0;
+}
+
static int scsi_debug_abort(struct scsi_cmnd *SCpnt)
{
bool ok = scsi_debug_abort_cmnd(SCpnt);
+ u8 *cmd = SCpnt->cmnd;
+ u8 opcode = cmd[0];
++num_aborts;
@@ -5523,6 +5557,12 @@ static int scsi_debug_abort(struct scsi_cmnd *SCpnt)
"%s: command%s found\n", __func__,
ok ? "" : " not");
+ if (sdebug_fail_abort(SCpnt)) {
+ scmd_printk(KERN_INFO, SCpnt, "fail abort command 0x%x\n",
+ opcode);
+ return FAILED;
+ }
+
return SUCCESS;
}
--
2.32.0
Add new module param "allow_restart" to control if setup scsi_device's
allow_restart flag, this flag determines if trigger EH after command
finished with sense_key 0x6, asc 0x4 and ascq 0x2, EH would be triggered
if allow_restart=1 in this condition.
The new param can be used with error inject added in patch6 to test how
commands finished with sense_key 0x6, asc 0x4 and ascq 0x2 are handled.
Signed-off-by: Wenchao Hao <[email protected]>
Tested-by: Douglas Gilbert <[email protected]>
---
drivers/scsi/scsi_debug.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c
index 2743eb36c58e..67922e2c4c19 100644
--- a/drivers/scsi/scsi_debug.c
+++ b/drivers/scsi/scsi_debug.c
@@ -843,6 +843,7 @@ static bool have_dif_prot;
static bool write_since_sync;
static bool sdebug_statistics = DEF_STATISTICS;
static bool sdebug_wp;
+static bool sdebug_allow_restart;
/* Following enum: 0: no zbc, def; 1: host aware; 2: host managed */
static enum blk_zoned_model sdeb_zbc_model = BLK_ZONED_NONE;
static char *sdeb_zbc_model_s;
@@ -5478,6 +5479,9 @@ static int scsi_debug_slave_configure(struct scsi_device *sdp)
sdp->no_uld_attach = 1;
config_cdb_len(sdp);
+ if (sdebug_allow_restart)
+ sdp->allow_restart = 1;
+
devip->debugfs_entry = debugfs_create_dir(dev_name(&sdp->sdev_dev),
sdebug_debugfs_root);
if (IS_ERR_OR_NULL(devip->debugfs_entry))
@@ -6202,6 +6206,7 @@ module_param_named(zone_cap_mb, sdeb_zbc_zone_cap_mb, int, S_IRUGO);
module_param_named(zone_max_open, sdeb_zbc_max_open, int, S_IRUGO);
module_param_named(zone_nr_conv, sdeb_zbc_nr_conv, int, S_IRUGO);
module_param_named(zone_size_mb, sdeb_zbc_zone_size_mb, int, S_IRUGO);
+module_param_named(allow_restart, sdebug_allow_restart, bool, S_IRUGO | S_IWUSR);
MODULE_AUTHOR("Eric Youngdale + Douglas Gilbert");
MODULE_DESCRIPTION("SCSI debug adapter driver");
@@ -6274,6 +6279,7 @@ MODULE_PARM_DESC(zone_cap_mb, "Zone capacity in MiB (def=zone size)");
MODULE_PARM_DESC(zone_max_open, "Maximum number of open zones; [0] for no limit (def=auto)");
MODULE_PARM_DESC(zone_nr_conv, "Number of conventional zones (def=1)");
MODULE_PARM_DESC(zone_size_mb, "Zone size in MiB (def=auto)");
+MODULE_PARM_DESC(allow_restart, "Set scsi_device's allow_restart flag(def=0)");
#define SDEBUG_INFO_LEN 256
static char sdebug_info[SDEBUG_INFO_LEN];
--
2.32.0
Add error injection type 4 to make scsi_debug_device_reset() return FAILED.
Fail abort command format:
+--------+------+-------------------------------------------------------+
| Column | Type | Description |
+--------+------+-------------------------------------------------------+
| 1 | u8 | Error type, fixed to 0x4 |
+--------+------+-------------------------------------------------------+
| 2 | s32 | Error count |
| | | 0: this rule will be ignored |
| | | positive: the rule will always take effect |
| | | negative: the rule takes effect n times where -n is |
| | | the value given. Ignored after n times |
+--------+------+-------------------------------------------------------+
| 3 | x8 | SCSI command opcode, 0xff for all commands |
+--------+------+-------------------------------------------------------+
Examples:
error=/sys/kernel/debug/scsi_debug/0:0:0:1/error
echo "4 -10 0x12" > ${error}
will make the device return FAILED when try to reset lun with inquiry
command 10 times.
error=/sys/kernel/debug/scsi_debug/0:0:0:1/error
echo "4 -10 0xff" > ${error}
will make the device return FAILED when try to reset lun 10 times.
Usually we do not care about what command it is when trying to perform
reset LUN, so 0xff could be applied.
Signed-off-by: Wenchao Hao <[email protected]>
Tested-by: Douglas Gilbert <[email protected]>
---
drivers/scsi/scsi_debug.c | 39 +++++++++++++++++++++++++++++++++++++++
1 file changed, 39 insertions(+)
diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c
index 89f47ded1e23..e54ba0bfa0d6 100644
--- a/drivers/scsi/scsi_debug.c
+++ b/drivers/scsi/scsi_debug.c
@@ -295,6 +295,8 @@ enum sdebug_err_type {
/* with errors set in scsi_cmnd */
ERR_ABORT_CMD_FAILED = 3, /* control return FAILED from */
/* scsi_debug_abort() */
+ ERR_LUN_RESET_FAILED = 4, /* control return FAILED from */
+ /* scsi_debug_device_reseLUN_RESET_FAILEDt() */
};
struct sdebug_err_inject {
@@ -973,6 +975,7 @@ static int sdebug_error_show(struct seq_file *m, void *p)
switch (err->type) {
case ERR_TMOUT_CMD:
case ERR_ABORT_CMD_FAILED:
+ case ERR_LUN_RESET_FAILED:
seq_printf(m, "%d\t%d\t0x%x\n", err->type, err->cnt,
err->cmd);
break;
@@ -1035,6 +1038,7 @@ static ssize_t sdebug_error_write(struct file *file, const char __user *ubuf,
switch (inject_type) {
case ERR_TMOUT_CMD:
case ERR_ABORT_CMD_FAILED:
+ case ERR_LUN_RESET_FAILED:
if (sscanf(buf, "%d %d %hhx", &inject->type, &inject->cnt,
&inject->cmd) != 3)
goto out_error;
@@ -5586,10 +5590,40 @@ static void scsi_debug_stop_all_queued(struct scsi_device *sdp)
scsi_debug_stop_all_queued_iter, sdp);
}
+static int sdebug_fail_lun_reset(struct scsi_cmnd *cmnd)
+{
+ struct scsi_device *sdp = cmnd->device;
+ struct sdebug_dev_info *devip = (struct sdebug_dev_info *)sdp->hostdata;
+ struct sdebug_err_inject *err;
+ unsigned char *cmd = cmnd->cmnd;
+ int ret = 0;
+
+ if (devip == NULL)
+ return 0;
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(err, &devip->inject_err_list, list) {
+ if (err->type == ERR_LUN_RESET_FAILED &&
+ (err->cmd == cmd[0] || err->cmd == 0xff)) {
+ ret = !!err->cnt;
+ if (err->cnt < 0)
+ err->cnt++;
+
+ rcu_read_unlock();
+ return ret;
+ }
+ }
+ rcu_read_unlock();
+
+ return 0;
+}
+
static int scsi_debug_device_reset(struct scsi_cmnd *SCpnt)
{
struct scsi_device *sdp = SCpnt->device;
struct sdebug_dev_info *devip = sdp->hostdata;
+ u8 *cmd = SCpnt->cmnd;
+ u8 opcode = cmd[0];
++num_dev_resets;
@@ -5600,6 +5634,11 @@ static int scsi_debug_device_reset(struct scsi_cmnd *SCpnt)
if (devip)
set_bit(SDEBUG_UA_POR, devip->uas_bm);
+ if (sdebug_fail_lun_reset(SCpnt)) {
+ scmd_printk(KERN_INFO, SCpnt, "fail lun reset 0x%x\n", opcode);
+ return FAILED;
+ }
+
return SUCCESS;
}
--
2.32.0
The interface is found at
/sys/kernel/debug/scsi_debug/target<h:c:t>/fail_reset where <h:c:t>
identifies the target to inject errors on. It's a simple bool type
interface which would make this target's reset fail if set to 'Y'.
Signed-off-by: Wenchao Hao <[email protected]>
---
drivers/scsi/scsi_debug.c | 114 +++++++++++++++++++++++++++++++++++++-
1 file changed, 113 insertions(+), 1 deletion(-)
diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c
index e54ba0bfa0d6..2743eb36c58e 100644
--- a/drivers/scsi/scsi_debug.c
+++ b/drivers/scsi/scsi_debug.c
@@ -42,6 +42,7 @@
#include <linux/xarray.h>
#include <linux/prefetch.h>
#include <linux/debugfs.h>
+#include <linux/async.h>
#include <net/checksum.h>
@@ -357,6 +358,11 @@ struct sdebug_dev_info {
struct list_head inject_err_list;
};
+struct sdebug_target_info {
+ bool reset_fail;
+ struct dentry *debugfs_entry;
+};
+
struct sdebug_host_info {
struct list_head host_list;
int si_idx; /* sdeb_store_info (per host) xarray index */
@@ -1082,6 +1088,91 @@ static const struct file_operations sdebug_error_fops = {
.release = single_release,
};
+static int sdebug_target_reset_fail_show(struct seq_file *m, void *p)
+{
+ struct scsi_target *starget = (struct scsi_target *)m->private;
+ struct sdebug_target_info *targetip =
+ (struct sdebug_target_info *)starget->hostdata;
+
+ if (targetip)
+ seq_printf(m, "%c\n", targetip->reset_fail ? 'Y' : 'N');
+
+ return 0;
+}
+
+static int sdebug_target_reset_fail_open(struct inode *inode, struct file *file)
+{
+ return single_open(file, sdebug_target_reset_fail_show, inode->i_private);
+}
+
+static ssize_t sdebug_target_reset_fail_write(struct file *file,
+ const char __user *ubuf, size_t count, loff_t *ppos)
+{
+ int ret;
+ struct scsi_target *starget =
+ (struct scsi_target *)file->f_inode->i_private;
+ struct sdebug_target_info *targetip =
+ (struct sdebug_target_info *)starget->hostdata;
+
+ if (targetip) {
+ ret = kstrtobool_from_user(ubuf, count, &targetip->reset_fail);
+ return ret < 0 ? ret : count;
+ }
+ return -ENODEV;
+}
+
+static const struct file_operations sdebug_target_reset_fail_fops = {
+ .open = sdebug_target_reset_fail_open,
+ .read = seq_read,
+ .write = sdebug_target_reset_fail_write,
+ .release = single_release,
+};
+
+static int sdebug_target_alloc(struct scsi_target *starget)
+{
+ struct sdebug_target_info *targetip;
+ struct dentry *dentry;
+
+ targetip = kzalloc(sizeof(struct sdebug_target_info), GFP_KERNEL);
+ if (!targetip)
+ return -ENOMEM;
+
+ targetip->debugfs_entry = debugfs_create_dir(dev_name(&starget->dev),
+ sdebug_debugfs_root);
+ if (IS_ERR_OR_NULL(targetip->debugfs_entry))
+ pr_info("%s: failed to create debugfs directory for target %s\n",
+ __func__, dev_name(&starget->dev));
+
+ debugfs_create_file("fail_reset", 0600, targetip->debugfs_entry, starget,
+ &sdebug_target_reset_fail_fops);
+ if (IS_ERR_OR_NULL(dentry))
+ pr_info("%s: failed to create fail_reset file for target %s\n",
+ __func__, dev_name(&starget->dev));
+
+ starget->hostdata = targetip;
+
+ return 0;
+}
+
+static void sdebug_tartget_cleanup_async(void *data, async_cookie_t cookie)
+{
+ struct sdebug_target_info *targetip = data;
+
+ debugfs_remove(targetip->debugfs_entry);
+ kfree(targetip);
+}
+
+static void sdebug_target_destroy(struct scsi_target *starget)
+{
+ struct sdebug_target_info *targetip;
+
+ targetip = (struct sdebug_target_info *)starget->hostdata;
+ if (targetip) {
+ starget->hostdata = NULL;
+ async_schedule(sdebug_tartget_cleanup_async, targetip);
+ }
+}
+
/* Only do the extra work involved in logical block provisioning if one or
* more of the lbpu, lbpws or lbpws10 parameters are given and we are doing
* real reads and writes (i.e. not skipping them for speed).
@@ -5642,11 +5733,25 @@ static int scsi_debug_device_reset(struct scsi_cmnd *SCpnt)
return SUCCESS;
}
+static int sdebug_fail_target_reset(struct scsi_cmnd *cmnd)
+{
+ struct scsi_target *starget = scsi_target(cmnd->device);
+ struct sdebug_target_info *targetip =
+ (struct sdebug_target_info *)starget->hostdata;
+
+ if (targetip)
+ return targetip->reset_fail;
+
+ return 0;
+}
+
static int scsi_debug_target_reset(struct scsi_cmnd *SCpnt)
{
struct scsi_device *sdp = SCpnt->device;
struct sdebug_host_info *sdbg_host = shost_to_sdebug_host(sdp->host);
struct sdebug_dev_info *devip;
+ u8 *cmd = SCpnt->cmnd;
+ u8 opcode = cmd[0];
int k = 0;
++num_target_resets;
@@ -5664,6 +5769,12 @@ static int scsi_debug_target_reset(struct scsi_cmnd *SCpnt)
sdev_printk(KERN_INFO, sdp,
"%s: %d device(s) found in target\n", __func__, k);
+ if (sdebug_fail_target_reset(SCpnt)) {
+ scmd_printk(KERN_INFO, SCpnt, "fail target reset 0x%x\n",
+ opcode);
+ return FAILED;
+ }
+
return SUCCESS;
}
@@ -8119,7 +8230,6 @@ static int sdebug_init_cmd_priv(struct Scsi_Host *shost, struct scsi_cmnd *cmd)
return 0;
}
-
static struct scsi_host_template sdebug_driver_template = {
.show_info = scsi_debug_show_info,
.write_info = scsi_debug_write_info,
@@ -8149,6 +8259,8 @@ static struct scsi_host_template sdebug_driver_template = {
.track_queue_depth = 1,
.cmd_size = sizeof(struct sdebug_scsi_cmd),
.init_cmd_priv = sdebug_init_cmd_priv,
+ .target_alloc = sdebug_target_alloc,
+ .target_destroy = sdebug_target_destroy,
};
static int sdebug_driver_probe(struct device *dev)
--
2.32.0
On 2023/10/10 17:20, Wenchao Hao wrote:
> The original error injection mechanism was based on scsi_host which
> could not inject fault for a single SCSI device.
>
> This patchset provides the ability to inject errors for a single
> SCSI device. Now we support inject timeout errors, queuecommand
> errors, and hostbyte, driverbyte, statusbyte, and sense data for
> specific SCSI Command. Two new error injection is defined to make
> abort command or reset LUN failed.
>
> Besides error injection for single device, this patchset add a
> new interface to make reset target failed for each scsi_target.
>
> The first two patch add a debugfs interface to add and inquiry single
> device's error injection info; the third patch defined how to remove
> an injection which has been added. The following 5 patches use the
> injection info and generate the related error type. The last two just
> add a new interface to make reset target failed and control
> scsi_device's allow_restart flag.
>
Friendly ping...
> V6:
> - Check return value of debugfs_create_xxx() and print error log
> if debugfs_create_xxx() return error
> - Fix typo in description of patch7 and patch8
> - Update the description of patch10
>
> V5:
> - Using rcu list to sync between error inject add, remove and check
> - Add module parameter "allow_restart" to control scsi_device's
> allow_restart flag
>
> V4:
> - Fix BUG_ON triggered by schedule in atomic context when rmmod scsi_debug
> Closes: https://lore.kernel.org/oe-lkp/[email protected]
>
> V3:
> - Add two more error types to fail abort command and lun reset
> - Fix memleak when rmmod scsi_debug without clearing errors injected
> - Fix memkeak because did not implement release in sdebug_error_fops
> - Fix possible NULL point access in scsi_debug_slave_destroy
> - Move specific error type's description to each single patch which
> implement this error type
> - Add interface to make target reset fail
>
> V2:
> - Using debugfs rather than sysfs attribute interface to manage error
>
> Wenchao Hao (10):
> scsi: scsi_debug: create scsi_debug directory in the debugfs filesystem
> scsi: scsi_debug: Add interface to manage single device's error inject
> scsi: scsi_debug: Define grammar to remove added error injection
> scsi: scsi_debug: timeout command if the error is injected
> scsi: scsi_debug: Return failed value if the error is injected
> scsi: scsi_debug: set command's result and sense data if the error is injected
> scsi: scsi_debug: Add new error injection abort failed
> scsi: scsi_debug: Add new error injection reset lun failed
> scsi: scsi_debug: Add debugfs interface to fail target reset
> scsi: scsi_debug: Add param to control sdev's allow_restart
>
> drivers/scsi/scsi_debug.c | 575 +++++++++++++++++++++++++++++++++++++-
> 1 file changed, 570 insertions(+), 5 deletions(-)
>
Wenchao,
> The original error injection mechanism was based on scsi_host which
> could not inject fault for a single SCSI device.
Applied to 6.7/scsi-staging, thanks!
--
Martin K. Petersen Oracle Linux Engineering
On Tue, 10 Oct 2023 17:20:41 +0800, Wenchao Hao wrote:
> The original error injection mechanism was based on scsi_host which
> could not inject fault for a single SCSI device.
>
> This patchset provides the ability to inject errors for a single
> SCSI device. Now we support inject timeout errors, queuecommand
> errors, and hostbyte, driverbyte, statusbyte, and sense data for
> specific SCSI Command. Two new error injection is defined to make
> abort command or reset LUN failed.
>
> [...]
Applied to 6.7/scsi-queue, thanks!
[01/10] scsi: scsi_debug: create scsi_debug directory in the debugfs filesystem
https://git.kernel.org/mkp/scsi/c/6e2d15f59b1c
[02/10] scsi: scsi_debug: Add interface to manage single device's error inject
https://git.kernel.org/mkp/scsi/c/a9996d722b11
[03/10] scsi: scsi_debug: Define grammar to remove added error injection
https://git.kernel.org/mkp/scsi/c/962d77cd4c85
[04/10] scsi: scsi_debug: timeout command if the error is injected
https://git.kernel.org/mkp/scsi/c/32be8b6e22eb
[05/10] scsi: scsi_debug: Return failed value if the error is injected
https://git.kernel.org/mkp/scsi/c/33bccf55c20b
[06/10] scsi: scsi_debug: set command's result and sense data if the error is injected
https://git.kernel.org/mkp/scsi/c/33592274321e
[07/10] scsi: scsi_debug: Add new error injection abort failed
https://git.kernel.org/mkp/scsi/c/5551ce928805
[08/10] scsi: scsi_debug: Add new error injection reset lun failed
https://git.kernel.org/mkp/scsi/c/0267811625e1
[09/10] scsi: scsi_debug: Add debugfs interface to fail target reset
https://git.kernel.org/mkp/scsi/c/f084fe52c640
[10/10] scsi: scsi_debug: Add param to control sdev's allow_restart
https://git.kernel.org/mkp/scsi/c/573c2d066eb9
--
Martin K. Petersen Oracle Linux Engineering