[SCSI] FC transport: Add dev_loss_tmo callbacks, and new fast_io_fail_tmo w/ callback
This patch adds the following functionality to the FC transport:
- dev_loss_tmo LLDD callback :
Called to essentially confirm the deletion of an rport. Thus, it is
called whenever the dev_loss_tmo fires, or when the rport is deleted
due to other circumstances (module unload, etc). It is expected that
the callback will initiate the termination of any outstanding i/o on
the rport.
- fast_io_fail_tmo and LLD callback:
There are some cases where it may take a long while to truly determine
device loss, but the system is in a multipathing configuration that if
the i/o was failed quickly (faster than dev_loss_tmo), it could be
redirected to a different path and completed sooner.
Many thanks to Mike Reed who cleaned up the initial RFC in support
of this post.
The original RFC is at:
http://marc.theaimsgroup.com/?l=linux-scsi&m=115505981027246&w=2
Signed-off-by: James Smart <James.Smart@emulex.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
diff --git a/drivers/scsi/scsi_transport_fc.c b/drivers/scsi/scsi_transport_fc.c
index 293188c..4ab176e 100644
--- a/drivers/scsi/scsi_transport_fc.c
+++ b/drivers/scsi/scsi_transport_fc.c
@@ -242,6 +242,7 @@
static void fc_timeout_deleted_rport(void *data);
+static void fc_timeout_fail_rport_io(void *data);
static void fc_scsi_scan_rport(void *data);
/*
@@ -249,7 +250,7 @@
* Increase these values if you add attributes
*/
#define FC_STARGET_NUM_ATTRS 3
-#define FC_RPORT_NUM_ATTRS 9
+#define FC_RPORT_NUM_ATTRS 10
#define FC_HOST_NUM_ATTRS 17
struct fc_internal {
@@ -622,11 +623,14 @@
struct fc_rport *rport = transport_class_to_rport(cdev); \
struct Scsi_Host *shost = rport_to_shost(rport); \
struct fc_internal *i = to_fc_internal(shost->transportt); \
+ char *cp; \
if ((rport->port_state == FC_PORTSTATE_BLOCKED) || \
(rport->port_state == FC_PORTSTATE_DELETED) || \
(rport->port_state == FC_PORTSTATE_NOTPRESENT)) \
return -EBUSY; \
- val = simple_strtoul(buf, NULL, 0); \
+ val = simple_strtoul(buf, &cp, 0); \
+ if (*cp && (*cp != '\n')) \
+ return -EINVAL; \
i->f->set_rport_##field(rport, val); \
return count; \
}
@@ -708,6 +712,13 @@
if (i->f->show_rport_##field) \
count++
+#define SETUP_PRIVATE_RPORT_ATTRIBUTE_RW(field) \
+{ \
+ i->private_rport_attrs[count] = class_device_attr_rport_##field; \
+ i->rport_attrs[count] = &i->private_rport_attrs[count]; \
+ count++; \
+}
+
/* The FC Transport Remote Port Attributes: */
@@ -740,12 +751,14 @@
struct fc_rport *rport = transport_class_to_rport(cdev);
struct Scsi_Host *shost = rport_to_shost(rport);
struct fc_internal *i = to_fc_internal(shost->transportt);
+ char *cp;
if ((rport->port_state == FC_PORTSTATE_BLOCKED) ||
(rport->port_state == FC_PORTSTATE_DELETED) ||
(rport->port_state == FC_PORTSTATE_NOTPRESENT))
return -EBUSY;
- val = simple_strtoul(buf, NULL, 0);
- if ((val < 0) || (val > SCSI_DEVICE_BLOCK_MAX_TIMEOUT))
+ val = simple_strtoul(buf, &cp, 0);
+ if ((*cp && (*cp != '\n')) ||
+ (val < 0) || (val > SCSI_DEVICE_BLOCK_MAX_TIMEOUT))
return -EINVAL;
i->f->set_rport_dev_loss_tmo(rport, val);
return count;
@@ -795,6 +808,44 @@
fc_private_rport_rd_enum_attr(port_state, FC_PORTSTATE_MAX_NAMELEN);
fc_private_rport_rd_attr(scsi_target_id, "%d\n", 20);
+/*
+ * fast_io_fail_tmo attribute
+ */
+static ssize_t
+show_fc_rport_fast_io_fail_tmo (struct class_device *cdev, char *buf)
+{
+ struct fc_rport *rport = transport_class_to_rport(cdev);
+
+ if (rport->fast_io_fail_tmo == -1)
+ return snprintf(buf, 5, "off\n");
+ return snprintf(buf, 20, "%d\n", rport->fast_io_fail_tmo);
+}
+
+static ssize_t
+store_fc_rport_fast_io_fail_tmo(struct class_device *cdev, const char *buf,
+ size_t count)
+{
+ int val;
+ char *cp;
+ struct fc_rport *rport = transport_class_to_rport(cdev);
+
+ if ((rport->port_state == FC_PORTSTATE_BLOCKED) ||
+ (rport->port_state == FC_PORTSTATE_DELETED) ||
+ (rport->port_state == FC_PORTSTATE_NOTPRESENT))
+ return -EBUSY;
+ if (strncmp(buf, "off", 3) == 0)
+ rport->fast_io_fail_tmo = -1;
+ else {
+ val = simple_strtoul(buf, &cp, 0);
+ if ((*cp && (*cp != '\n')) ||
+ (val < 0) || (val >= rport->dev_loss_tmo))
+ return -EINVAL;
+ rport->fast_io_fail_tmo = val;
+ }
+ return count;
+}
+static FC_CLASS_DEVICE_ATTR(rport, fast_io_fail_tmo, S_IRUGO | S_IWUSR,
+ show_fc_rport_fast_io_fail_tmo, store_fc_rport_fast_io_fail_tmo);
/*
@@ -880,8 +931,11 @@
int val; \
struct Scsi_Host *shost = transport_class_to_shost(cdev); \
struct fc_internal *i = to_fc_internal(shost->transportt); \
+ char *cp; \
\
- val = simple_strtoul(buf, NULL, 0); \
+ val = simple_strtoul(buf, &cp, 0); \
+ if (*cp && (*cp != '\n')) \
+ return -EINVAL; \
i->f->set_host_##field(shost, val); \
return count; \
}
@@ -1481,6 +1535,8 @@
SETUP_PRIVATE_RPORT_ATTRIBUTE_RD(roles);
SETUP_PRIVATE_RPORT_ATTRIBUTE_RD(port_state);
SETUP_PRIVATE_RPORT_ATTRIBUTE_RD(scsi_target_id);
+ if (ft->terminate_rport_io)
+ SETUP_PRIVATE_RPORT_ATTRIBUTE_RW(fast_io_fail_tmo);
BUG_ON(count > FC_RPORT_NUM_ATTRS);
@@ -1552,7 +1608,7 @@
* @delay: jiffies to delay the work queuing
*
* Return value:
- * 0 on success / != 0 for error
+ * 1 on success / 0 already queued / < 0 for error
**/
static int
fc_queue_devloss_work(struct Scsi_Host *shost, struct work_struct *work,
@@ -1567,6 +1623,9 @@
return -EINVAL;
}
+ if (delay == 0)
+ return queue_work(fc_host_devloss_work_q(shost), work);
+
return queue_delayed_work(fc_host_devloss_work_q(shost), work, delay);
}
@@ -1659,10 +1718,23 @@
struct fc_rport *rport = (struct fc_rport *)data;
struct Scsi_Host *shost = rport_to_shost(rport);
unsigned long flags;
+ struct fc_internal *i = to_fc_internal(shost->transportt);
+
+ /*
+ * Involve the LLDD if possible. All io on the rport is to
+ * be terminated, either as part of the dev_loss_tmo callback
+ * processing, or via the terminate_rport_io function.
+ */
+ if (i->f->dev_loss_tmo_callbk)
+ i->f->dev_loss_tmo_callbk(rport);
+ else if (i->f->terminate_rport_io)
+ i->f->terminate_rport_io(rport);
spin_lock_irqsave(shost->host_lock, flags);
if (rport->flags & FC_RPORT_DEVLOSS_PENDING) {
spin_unlock_irqrestore(shost->host_lock, flags);
+ if (!cancel_delayed_work(&rport->fail_io_work))
+ fc_flush_devloss(shost);
if (!cancel_delayed_work(&rport->dev_loss_work))
fc_flush_devloss(shost);
spin_lock_irqsave(shost->host_lock, flags);
@@ -1685,10 +1757,7 @@
struct fc_rport *rport = (struct fc_rport *)data;
struct device *dev = &rport->dev;
struct Scsi_Host *shost = rport_to_shost(rport);
-
- /* Delete SCSI target and sdevs */
- if (rport->scsi_target_id != -1)
- fc_starget_delete(data);
+ struct fc_internal *i = to_fc_internal(shost->transportt);
/*
* if a scan is pending, flush the SCSI Host work_q so that
@@ -1697,6 +1766,14 @@
if (rport->flags & FC_RPORT_SCAN_PENDING)
scsi_flush_work(shost);
+ /* Delete SCSI target and sdevs */
+ if (rport->scsi_target_id != -1)
+ fc_starget_delete(data);
+ else if (i->f->dev_loss_tmo_callbk)
+ i->f->dev_loss_tmo_callbk(rport);
+ else if (i->f->terminate_rport_io)
+ i->f->terminate_rport_io(rport);
+
transport_remove_device(dev);
device_del(dev);
transport_destroy_device(dev);
@@ -1748,8 +1825,10 @@
if (fci->f->dd_fcrport_size)
rport->dd_data = &rport[1];
rport->channel = channel;
+ rport->fast_io_fail_tmo = -1;
INIT_WORK(&rport->dev_loss_work, fc_timeout_deleted_rport, rport);
+ INIT_WORK(&rport->fail_io_work, fc_timeout_fail_rport_io, rport);
INIT_WORK(&rport->scan_work, fc_scsi_scan_rport, rport);
INIT_WORK(&rport->stgt_delete_work, fc_starget_delete, rport);
INIT_WORK(&rport->rport_delete_work, fc_rport_final_delete, rport);
@@ -1913,11 +1992,13 @@
/* restart the target */
/*
- * Stop the target timer first. Take no action
+ * Stop the target timers first. Take no action
* on the del_timer failure as the state
* machine state change will validate the
* transaction.
*/
+ if (!cancel_delayed_work(&rport->fail_io_work))
+ fc_flush_devloss(shost);
if (!cancel_delayed_work(work))
fc_flush_devloss(shost);
@@ -2061,6 +2142,7 @@
fc_remote_port_delete(struct fc_rport *rport)
{
struct Scsi_Host *shost = rport_to_shost(rport);
+ struct fc_internal *i = to_fc_internal(shost->transportt);
int timeout = rport->dev_loss_tmo;
unsigned long flags;
@@ -2091,6 +2173,12 @@
scsi_target_block(&rport->dev);
+ /* see if we need to kill io faster than waiting for device loss */
+ if ((rport->fast_io_fail_tmo != -1) &&
+ (rport->fast_io_fail_tmo < timeout) && (i->f->terminate_rport_io))
+ fc_queue_devloss_work(shost, &rport->fail_io_work,
+ rport->fast_io_fail_tmo * HZ);
+
/* cap the length the devices can be blocked until they are deleted */
fc_queue_devloss_work(shost, &rport->dev_loss_work, timeout * HZ);
}
@@ -2150,6 +2238,8 @@
* machine state change will validate the
* transaction.
*/
+ if (!cancel_delayed_work(&rport->fail_io_work))
+ fc_flush_devloss(shost);
if (!cancel_delayed_work(&rport->dev_loss_work))
fc_flush_devloss(shost);
@@ -2271,6 +2361,28 @@
}
/**
+ * fc_timeout_fail_rport_io - Timeout handler for a fast io failing on a
+ * disconnected SCSI target.
+ *
+ * @data: rport to terminate io on.
+ *
+ * Notes: Only requests the failure of the io, not that all are flushed
+ * prior to returning.
+ **/
+static void
+fc_timeout_fail_rport_io(void *data)
+{
+ struct fc_rport *rport = (struct fc_rport *)data;
+ struct Scsi_Host *shost = rport_to_shost(rport);
+ struct fc_internal *i = to_fc_internal(shost->transportt);
+
+ if (rport->port_state != FC_PORTSTATE_BLOCKED)
+ return;
+
+ i->f->terminate_rport_io(rport);
+}
+
+/**
* fc_scsi_scan_rport - called to perform a scsi scan on a remote port.
*
* @data: remote port to be scanned.