This patchs adds an 'eh_deadline' sysfs attribute to the scsi
host which limits the overall runtime of the SCSI EH.
The 'eh_deadline' value is stored in the now obsolete field
'resetting'.
When a command is failed the start time of the EH is stored
in 'last_reset'. If the overall runtime of the SCSI EH is longer
than last_reset + eh_deadline, the EH is short-circuited and
falls through to issue a host reset only.
Signed-off-by: Hannes Reinecke <hare@xxxxxxx>
---
drivers/scsi/hosts.c | 7 +++
drivers/scsi/scsi_error.c | 130 +++++++++++++++++++++++++++++++++++++++++++---
drivers/scsi/scsi_sysfs.c | 37 +++++++++++++
include/scsi/scsi_host.h | 4 +-
4 files changed, 170 insertions(+), 8 deletions(-)
diff --git a/drivers/scsi/hosts.c b/drivers/scsi/hosts.c
index df0c3c7..f334859 100644
--- a/drivers/scsi/hosts.c
+++ b/drivers/scsi/hosts.c
@@ -316,6 +316,12 @@ static void scsi_host_dev_release(struct device *dev)
kfree(shost);
}
+static unsigned int shost_eh_deadline;
+
+module_param_named(eh_deadline, shost_eh_deadline, uint, S_IRUGO|S_IWUSR);
+MODULE_PARM_DESC(eh_deadline,
+ "SCSI EH timeout in seconds (should be between 1 and 2^32-1)");
+
static struct device_type scsi_host_type = {
.name = "scsi_host",
.release = scsi_host_dev_release,
@@ -388,6 +394,7 @@ struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
shost->unchecked_isa_dma = sht->unchecked_isa_dma;
shost->use_clustering = sht->use_clustering;
shost->ordered_tag = sht->ordered_tag;
+ shost->eh_deadline = shost_eh_deadline * HZ;
if (sht->supported_mode == MODE_UNKNOWN)
/* means we didn't set it ... default to INITIATOR */
diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c
index f43de1e..84369f2 100644
--- a/drivers/scsi/scsi_error.c
+++ b/drivers/scsi/scsi_error.c
@@ -89,6 +89,18 @@ void scsi_schedule_eh(struct Scsi_Host *shost)
}
EXPORT_SYMBOL_GPL(scsi_schedule_eh);
+static int scsi_host_eh_past_deadline(struct Scsi_Host *shost)
+{
+ if (!shost->last_reset || !shost->eh_deadline)
+ return 0;
+
+ if (time_before(jiffies,
+ shost->last_reset + shost->eh_deadline))
+ return 0;
+
+ return 1;
+}
+
/**
* scsi_eh_scmd_add - add scsi cmd to error handling.
* @scmd: scmd to run eh on.
@@ -111,6 +123,9 @@ int scsi_eh_scmd_add(struct scsi_cmnd *scmd, int eh_flag)
if (scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY))
goto out_unlock;
+ if (shost->eh_deadline && !shost->last_reset)
+ shost->last_reset = jiffies;
+
ret = 1;
scmd->eh_eflags |= eh_flag;
list_add_tail(&scmd->eh_entry, &shost->eh_cmd_q);
@@ -140,6 +155,9 @@ enum blk_eh_timer_return scsi_times_out(struct request *req)
trace_scsi_dispatch_cmd_timeout(scmd);
scsi_log_completion(scmd, TIMEOUT_ERROR);
+ if (host->eh_deadline && !host->last_reset)
+ host->last_reset = jiffies;
+
if (host->transportt->eh_timed_out)
rtn = host->transportt->eh_timed_out(scmd);
else if (host->hostt->eh_timed_out)
@@ -928,13 +946,26 @@ int scsi_eh_get_sense(struct list_head *work_q,
struct list_head *done_q)
{
struct scsi_cmnd *scmd, *next;
+ struct Scsi_Host *shost;
int rtn;
+ unsigned long flags;
list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
if ((scmd->eh_eflags & SCSI_EH_CANCEL_CMD) ||
SCSI_SENSE_VALID(scmd))
continue;
+ shost = scmd->device->host;
+ spin_lock_irqsave(shost->host_lock, flags);
+ if (scsi_host_eh_past_deadline(shost)) {
+ spin_unlock_irqrestore(shost->host_lock, flags);
+ SCSI_LOG_ERROR_RECOVERY(3,
+ shost_printk(KERN_INFO, shost,
+ "skip %s, past eh deadline\n",
+ __func__));
+ break;
+ }
+ spin_unlock_irqrestore(shost->host_lock, flags);
SCSI_LOG_ERROR_RECOVERY(2, scmd_printk(KERN_INFO, scmd,
"%s: requesting sense\n",
current->comm));
@@ -1019,11 +1050,28 @@ static int scsi_eh_test_devices(struct list_head *cmd_list,
struct scsi_cmnd *scmd, *next;
struct scsi_device *sdev;
int finish_cmds;
+ unsigned long flags;
while (!list_empty(cmd_list)) {
scmd = list_entry(cmd_list->next, struct scsi_cmnd, eh_entry);
sdev = scmd->device;
+ if (!try_stu) {
+ spin_lock_irqsave(sdev->host->host_lock, flags);
+ if (scsi_host_eh_past_deadline(sdev->host)) {
+ /* Push items back onto work_q */
+ list_splice_init(cmd_list, work_q);
+ spin_unlock_irqrestore(sdev->host->host_lock,
+ flags);
+ SCSI_LOG_ERROR_RECOVERY(3,
+ shost_printk(KERN_INFO, sdev->host,
+ "skip %s, past eh deadline",
+ __func__));
+ break;
+ }
+ spin_unlock_irqrestore(sdev->host->host_lock, flags);
+ }
+
finish_cmds = !scsi_device_online(scmd->device) ||
(try_stu && !scsi_eh_try_stu(scmd) &&
!scsi_eh_tur(scmd)) ||
@@ -1059,14 +1107,28 @@ static int scsi_eh_abort_cmds(struct list_head *work_q,
struct scsi_cmnd *scmd, *next;
LIST_HEAD(check_list);
int rtn;
+ struct Scsi_Host *shost;
+ unsigned long flags;
list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
if (!(scmd->eh_eflags & SCSI_EH_CANCEL_CMD))
continue;
+ shost = scmd->device->host;
+ spin_lock_irqsave(shost->host_lock, flags);
+ if (scsi_host_eh_past_deadline(shost)) {
+ spin_unlock_irqrestore(shost->host_lock, flags);
+ list_splice_init(&check_list, work_q);
+ SCSI_LOG_ERROR_RECOVERY(3,
+ shost_printk(KERN_INFO, shost,
+ "skip %s, past eh deadline\n",
+ __func__));
+ return list_empty(work_q);
+ }
+ spin_unlock_irqrestore(shost->host_lock, flags);
SCSI_LOG_ERROR_RECOVERY(3, printk("%s: aborting cmd:"
"0x%p\n", current->comm,
scmd));
- rtn = scsi_try_to_abort_cmd(scmd->device->host->hostt, scmd);
+ rtn = scsi_try_to_abort_cmd(shost->hostt, scmd);
if (rtn == SUCCESS || rtn == FAST_IO_FAIL) {
scmd->eh_eflags &= ~SCSI_EH_CANCEL_CMD;
if (rtn == FAST_IO_FAIL)
@@ -1124,8 +1186,19 @@ static int scsi_eh_stu(struct Scsi_Host *shost,
{
struct scsi_cmnd *scmd, *stu_scmd, *next;
struct scsi_device *sdev;
+ unsigned long flags;
shost_for_each_device(sdev, shost) {
+ spin_lock_irqsave(shost->host_lock, flags);
+ if (scsi_host_eh_past_deadline(shost)) {
+ spin_unlock_irqrestore(shost->host_lock, flags);
+ SCSI_LOG_ERROR_RECOVERY(3,
+ shost_printk(KERN_INFO, shost,
+ "skip %s, past eh deadline\n",
+ __func__));
+ break;
+ }
+ spin_unlock_irqrestore(shost->host_lock, flags);
stu_scmd = NULL;
list_for_each_entry(scmd, work_q, eh_entry)
if (scmd->device == sdev && SCSI_SENSE_VALID(scmd) &&
@@ -1178,9 +1251,20 @@ static int scsi_eh_bus_device_reset(struct Scsi_Host *shost,
{
struct scsi_cmnd *scmd, *bdr_scmd, *next;
struct scsi_device *sdev;
+ unsigned long flags;
int rtn;
shost_for_each_device(sdev, shost) {
+ spin_lock_irqsave(shost->host_lock, flags);
+ if (scsi_host_eh_past_deadline(shost)) {
+ spin_unlock_irqrestore(shost->host_lock, flags);
+ SCSI_LOG_ERROR_RECOVERY(3,
+ shost_printk(KERN_INFO, shost,
+ "skip %s, past eh deadline\n",
+ __func__));
+ break;
+ }
+ spin_unlock_irqrestore(shost->host_lock, flags);
bdr_scmd = NULL;
list_for_each_entry(scmd, work_q, eh_entry)
if (scmd->device == sdev) {
@@ -1240,6 +1324,21 @@ static int scsi_eh_target_reset(struct Scsi_Host *shost,
struct scsi_cmnd *next, *scmd;
int rtn;
unsigned int id;
+ unsigned long flags;
+
+ spin_lock_irqsave(shost->host_lock, flags);
+ if (scsi_host_eh_past_deadline(shost)) {
+ spin_unlock_irqrestore(shost->host_lock, flags);
+ /* push back on work queue for further processing */
+ list_splice_init(&check_list, work_q);
+ list_splice_init(&tmp_list, work_q);
+ SCSI_LOG_ERROR_RECOVERY(3,
+ shost_printk(KERN_INFO, shost,
+ "skip %s, past eh deadline\n",
+ __func__));
+ return list_empty(work_q);
+ }
+ spin_unlock_irqrestore(shost->host_lock, flags);
scmd = list_entry(tmp_list.next, struct scsi_cmnd, eh_entry);
id = scmd_id(scmd);
@@ -1284,6 +1383,7 @@ static int scsi_eh_bus_reset(struct Scsi_Host *shost,
LIST_HEAD(check_list);
unsigned int channel;
int rtn;
+ unsigned long flags;
/*
* we really want to loop over the various channels, and do this on
@@ -1293,6 +1393,18 @@ static int scsi_eh_bus_reset(struct Scsi_Host *shost,
*/
for (channel = 0; channel <= shost->max_channel; channel++) {
+ spin_lock_irqsave(shost->host_lock, flags);
+ if (scsi_host_eh_past_deadline(shost)) {
+ spin_unlock_irqrestore(shost->host_lock, flags);
+ list_splice_init(&check_list, work_q);
+ SCSI_LOG_ERROR_RECOVERY(3,
+ shost_printk(KERN_INFO, shost,
+ "skip %s, past eh deadline\n",
+ __func__));
+ return list_empty(work_q);
+ }
+ spin_unlock_irqrestore(shost->host_lock, flags);
+
chan_scmd = NULL;
list_for_each_entry(scmd, work_q, eh_entry) {
if (channel == scmd_channel(scmd)) {
@@ -1698,8 +1810,9 @@ static void scsi_restart_operations(struct Scsi_Host *shost)
* will be requests for character device operations, and also for
* ioctls to queued block devices.
*/
- SCSI_LOG_ERROR_RECOVERY(3, printk("%s: waking up host to restart\n",
- __func__));
+ SCSI_LOG_ERROR_RECOVERY(3,
+ printk("scsi_eh_%d waking up host to restart\n",
+ shost->host_no));
spin_lock_irqsave(shost->host_lock, flags);
if (scsi_host_set_state(shost, SHOST_RUNNING))
@@ -1826,6 +1939,10 @@ static void scsi_unjam_host(struct Scsi_Host *shost)
if (!scsi_eh_abort_cmds(&eh_work_q, &eh_done_q))
scsi_eh_ready_devs(shost, &eh_work_q, &eh_done_q);
+ spin_lock_irqsave(shost->host_lock, flags);
+ if (shost->eh_deadline)
+ shost->last_reset = 0;
+ spin_unlock_irqrestore(shost->host_lock, flags);
scsi_eh_flush_done_q(&eh_done_q);
}
@@ -1852,7 +1969,7 @@ int scsi_error_handler(void *data)
if ((shost->host_failed == 0 && shost->host_eh_scheduled == 0) ||
shost->host_failed != shost->host_busy) {
SCSI_LOG_ERROR_RECOVERY(1,
- printk("Error handler scsi_eh_%d sleeping\n",
+ printk("scsi_eh_%d: sleeping\n",
shost->host_no));
schedule();
continue;
@@ -1860,8 +1977,9 @@ int scsi_error_handler(void *data)
__set_current_state(TASK_RUNNING);
SCSI_LOG_ERROR_RECOVERY(1,
- printk("Error handler scsi_eh_%d waking up\n",
- shost->host_no));
+ printk("scsi_eh_%d: waking up %d/%d/%d\n",
+ shost->host_no, shost->host_eh_scheduled,
+ shost->host_failed, shost->host_busy));
/*
* We have a host that is failing for some reason. Figure out
diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c
index 931a7d9..1c597ab 100644
--- a/drivers/scsi/scsi_sysfs.c
+++ b/drivers/scsi/scsi_sysfs.c
@@ -281,6 +281,42 @@ exit_store_host_reset:
static DEVICE_ATTR(host_reset, S_IWUSR, NULL, store_host_reset);
+static ssize_t
+show_shost_eh_deadline(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct Scsi_Host *shost = class_to_shost(dev);
+
+ return sprintf(buf, "%d\n", shost->eh_deadline / HZ);
+}
+
+static ssize_t
+store_shost_eh_deadline(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct Scsi_Host *shost = class_to_shost(dev);
+ int ret = -EINVAL;
+ int deadline;
+ unsigned long flags;
+
+ if (shost->transportt && shost->transportt->eh_strategy_handler)
+ return ret;
+
+ if (sscanf(buf, "%d\n", &deadline) == 1) {
+ spin_lock_irqsave(shost->host_lock, flags);
+ if (scsi_host_in_recovery(shost))
+ ret = -EBUSY;
+ else {
+ shost->eh_deadline = deadline * HZ;
+ ret = count;
+ }
+ spin_unlock_irqrestore(shost->host_lock, flags);
+ }
+ return ret;
+}
+
+static DEVICE_ATTR(eh_deadline, S_IRUGO | S_IWUSR, show_shost_eh_deadline, store_shost_eh_deadline);
+
shost_rd_attr(unique_id, "%u\n");
shost_rd_attr(host_busy, "%hu\n");
shost_rd_attr(cmd_per_lun, "%hd\n");
@@ -308,6 +344,7 @@ static struct attribute *scsi_sysfs_shost_attrs[] = {
&dev_attr_prot_capabilities.attr,
&dev_attr_prot_guard_type.attr,
&dev_attr_host_reset.attr,
+ &dev_attr_eh_deadline.attr,
NULL
};
diff --git a/include/scsi/scsi_host.h b/include/scsi/scsi_host.h
index 7552435..896bb05 100644
--- a/include/scsi/scsi_host.h
+++ b/include/scsi/scsi_host.h
@@ -596,9 +596,9 @@ struct Scsi_Host {
unsigned int host_busy; /* commands actually active on low-level */
unsigned int host_failed; /* commands that failed. */
unsigned int host_eh_scheduled; /* EH scheduled without command */
-
+
unsigned int host_no; /* Used for IOCTL_GET_IDLUN, /proc/scsi et al. */
- int resetting; /* if set, it means that last_reset is a valid value */
+ int eh_deadline;
unsigned long last_reset;
/*
--
1.7.12.4
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