[SCSI] Add 'eh_deadline' to limit SCSI EH runtime
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.
[jejb: add comments in Scsi_Host about new fields]
Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c
index 83e591b..edae9e2 100644
--- a/drivers/scsi/scsi_error.c
+++ b/drivers/scsi/scsi_error.c
@@ -87,6 +87,18 @@
}
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.
@@ -109,6 +121,9 @@
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);
@@ -138,6 +153,9 @@
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)
@@ -990,13 +1008,26 @@
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));
@@ -1082,11 +1113,28 @@
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)) ||
@@ -1122,14 +1170,28 @@
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)
@@ -1187,8 +1249,19 @@
{
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) &&
@@ -1241,9 +1314,20 @@
{
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) {
@@ -1303,6 +1387,21 @@
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);
@@ -1347,6 +1446,7 @@
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
@@ -1356,6 +1456,18 @@
*/
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)) {
@@ -1755,8 +1867,9 @@
* 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))
@@ -1883,6 +1996,10 @@
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);
}
@@ -1909,7 +2026,7 @@
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;
@@ -1917,8 +2034,9 @@
__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