Add support for periodically reconnecting to an SRP target until
the dev_loss timer expires. After the tenth reconnection attempt,
gradually slow down subsequent reconnect attempts.
Signed-off-by: Bart Van Assche <bvanassche@xxxxxxx>
Cc: David Dillow <dillowda@xxxxxxxx>
Cc: Roland Dreier <roland@xxxxxxxxxx>
Cc: James Bottomley <JBottomley@xxxxxxxxxxxxx>
Cc: Vu Pham <vu@xxxxxxxxxxxx>
Cc: Sebastian Riemer <sebastian.riemer@xxxxxxxxxxxxxxxx>
---
drivers/scsi/scsi_transport_srp.c | 106 +++++++++++++++++++++++++++++++++++---
include/scsi/scsi_transport_srp.h | 11 +++-
2 files changed, 108 insertions(+), 9 deletions(-)
diff --git a/drivers/scsi/scsi_transport_srp.c b/drivers/scsi/scsi_transport_srp.c
index 675e203..04a97b6 100644
--- a/drivers/scsi/scsi_transport_srp.c
+++ b/drivers/scsi/scsi_transport_srp.c
@@ -41,7 +41,7 @@ struct srp_host_attrs {
#define to_srp_host_attrs(host) ((struct srp_host_attrs *)(host)->shost_data)
#define SRP_HOST_ATTRS 0
-#define SRP_RPORT_ATTRS 6
+#define SRP_RPORT_ATTRS 8
struct srp_internal {
struct scsi_transport_template t;
@@ -69,11 +69,13 @@ static inline struct Scsi_Host *rport_to_shost(struct srp_rport *r)
* are finished in a reasonable time. Hence do not allow the fast I/O fail
* timeout to exceed SCSI_DEVICE_BLOCK_MAX_TIMEOUT. Furthermore, these
* parameters must be such that multipath can detect failed paths timely.
- * Hence do not allow both parameters to be disabled simultaneously.
+ * Hence do not allow all three parameters to be disabled simultaneously.
*/
-int srp_tmo_valid(int fast_io_fail_tmo, int dev_loss_tmo)
+int srp_tmo_valid(int reconnect_delay, int fast_io_fail_tmo, int dev_loss_tmo)
{
- if (fast_io_fail_tmo < 0 && dev_loss_tmo < 0)
+ if (reconnect_delay < 0 && fast_io_fail_tmo < 0 && dev_loss_tmo < 0)
+ return -EINVAL;
+ if (reconnect_delay == 0)
return -EINVAL;
if (fast_io_fail_tmo > SCSI_DEVICE_BLOCK_MAX_TIMEOUT)
return -EINVAL;
@@ -202,6 +204,56 @@ static int srp_parse_tmo(int *tmo, const char *buf)
return res;
}
+static ssize_t show_reconnect_delay(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct srp_rport *rport = transport_class_to_srp_rport(dev);
+
+ return srp_show_tmo(buf, rport->reconnect_delay);
+}
+
+static ssize_t store_reconnect_delay(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, const size_t count)
+{
+ struct srp_rport *rport = transport_class_to_srp_rport(dev);
+ int res, delay;
+
+ res = srp_parse_tmo(&delay, buf);
+ if (res)
+ goto out;
+ res = srp_tmo_valid(delay, rport->fast_io_fail_tmo,
+ rport->dev_loss_tmo);
+ if (res)
+ goto out;
+
+ if (rport->reconnect_delay <= 0 && delay > 0 &&
+ rport->state != SRP_RPORT_RUNNING) {
+ queue_delayed_work(system_long_wq, &rport->reconnect_work,
+ delay * HZ);
+ } else if (delay <= 0) {
+ cancel_delayed_work(&rport->reconnect_work);
+ }
+ rport->reconnect_delay = delay;
+ res = count;
+
+out:
+ return res;
+}
+
+static DEVICE_ATTR(reconnect_delay, S_IRUGO | S_IWUSR, show_reconnect_delay,
+ store_reconnect_delay);
+
+static ssize_t show_failed_reconnects(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct srp_rport *rport = transport_class_to_srp_rport(dev);
+
+ return sprintf(buf, "%d\n", rport->failed_reconnects);
+}
+
+static DEVICE_ATTR(failed_reconnects, S_IRUGO, show_failed_reconnects, NULL);
+
static ssize_t show_srp_rport_fast_io_fail_tmo(struct device *dev,
struct device_attribute *attr,
char *buf)
@@ -222,7 +274,8 @@ static ssize_t store_srp_rport_fast_io_fail_tmo(struct device *dev,
res = srp_parse_tmo(&fast_io_fail_tmo, buf);
if (res)
goto out;
- res = srp_tmo_valid(fast_io_fail_tmo, rport->dev_loss_tmo);
+ res = srp_tmo_valid(rport->reconnect_delay, fast_io_fail_tmo,
+ rport->dev_loss_tmo);
if (res)
goto out;
rport->fast_io_fail_tmo = fast_io_fail_tmo;
@@ -256,7 +309,8 @@ static ssize_t store_srp_rport_dev_loss_tmo(struct device *dev,
res = srp_parse_tmo(&dev_loss_tmo, buf);
if (res)
goto out;
- res = srp_tmo_valid(rport->fast_io_fail_tmo, dev_loss_tmo);
+ res = srp_tmo_valid(rport->reconnect_delay, rport->fast_io_fail_tmo,
+ dev_loss_tmo);
if (res)
goto out;
rport->dev_loss_tmo = dev_loss_tmo;
@@ -312,6 +366,29 @@ invalid:
return -EINVAL;
}
+/**
+ * srp_reconnect_work() - reconnect and schedule a new attempt if necessary
+ */
+static void srp_reconnect_work(struct work_struct *work)
+{
+ struct srp_rport *rport = container_of(to_delayed_work(work),
+ struct srp_rport, reconnect_work);
+ struct Scsi_Host *shost = rport_to_shost(rport);
+ int delay, res;
+
+ res = srp_reconnect_rport(rport);
+ if (res != 0) {
+ shost_printk(KERN_ERR, shost,
+ "reconnect attempt %d failed (%d)\n",
+ ++rport->failed_reconnects, res);
+ delay = rport->reconnect_delay *
+ min(100, max(1, rport->failed_reconnects - 10));
+ if (delay > 0)
+ queue_delayed_work(system_long_wq,
+ &rport->reconnect_work, delay * HZ);
+ }
+}
+
static void __rport_fail_io_fast(struct srp_rport *rport)
{
struct Scsi_Host *shost = rport_to_shost(rport);
@@ -370,16 +447,21 @@ static void rport_dev_loss_timedout(struct work_struct *work)
static void __srp_start_tl_fail_timers(struct srp_rport *rport)
{
struct Scsi_Host *shost = rport_to_shost(rport);
- int fast_io_fail_tmo, dev_loss_tmo;
+ int delay, fast_io_fail_tmo, dev_loss_tmo;
lockdep_assert_held(&rport->mutex);
if (!rport->deleted) {
+ delay = rport->reconnect_delay;
fast_io_fail_tmo = rport->fast_io_fail_tmo;
dev_loss_tmo = rport->dev_loss_tmo;
pr_debug("%s current state: %d\n",
dev_name(&shost->shost_gendev), rport->state);
+ if (delay > 0)
+ queue_delayed_work(system_long_wq,
+ &rport->reconnect_work,
+ 1UL * delay * HZ);
if (fast_io_fail_tmo >= 0 &&
srp_rport_set_state(rport, SRP_RPORT_BLOCKED) == 0) {
pr_debug("%s new state: %d\n",
@@ -480,6 +562,7 @@ int srp_reconnect_rport(struct srp_rport *rport)
cancel_delayed_work(&rport->fast_io_fail_work);
cancel_delayed_work(&rport->dev_loss_work);
+ rport->failed_reconnects = 0;
srp_rport_set_state(rport, SRP_RPORT_RUNNING);
scsi_target_unblock(&shost->shost_gendev, SDEV_RUNNING);
/*
@@ -538,6 +621,7 @@ static void srp_rport_release(struct device *dev)
{
struct srp_rport *rport = dev_to_rport(dev);
+ cancel_delayed_work_sync(&rport->reconnect_work);
cancel_delayed_work_sync(&rport->fast_io_fail_work);
cancel_delayed_work_sync(&rport->dev_loss_work);
@@ -634,6 +718,10 @@ struct srp_rport *srp_rport_add(struct Scsi_Host *shost,
memcpy(rport->port_id, ids->port_id, sizeof(rport->port_id));
rport->roles = ids->roles;
+ if (i->f->reconnect)
+ rport->reconnect_delay = i->f->reconnect_delay ?
+ *i->f->reconnect_delay : 10;
+ INIT_DELAYED_WORK(&rport->reconnect_work, srp_reconnect_work);
rport->fast_io_fail_tmo = i->f->fast_io_fail_tmo ?
*i->f->fast_io_fail_tmo : 15;
rport->dev_loss_tmo = i->f->dev_loss_tmo ? *i->f->dev_loss_tmo : 60;
@@ -772,6 +860,10 @@ srp_attach_transport(struct srp_function_template *ft)
i->rport_attrs[count++] = &dev_attr_fast_io_fail_tmo;
i->rport_attrs[count++] = &dev_attr_dev_loss_tmo;
}
+ if (ft->reconnect) {
+ i->rport_attrs[count++] = &dev_attr_reconnect_delay;
+ i->rport_attrs[count++] = &dev_attr_failed_reconnects;
+ }
if (ft->rport_delete)
i->rport_attrs[count++] = &dev_attr_delete;
i->rport_attrs[count++] = NULL;
diff --git a/include/scsi/scsi_transport_srp.h b/include/scsi/scsi_transport_srp.h
index ee70016..4ebf691 100644
--- a/include/scsi/scsi_transport_srp.h
+++ b/include/scsi/scsi_transport_srp.h
@@ -31,7 +31,8 @@ enum srp_rport_state {
/**
* struct srp_rport
* @lld_data: LLD private data.
- * @mutex: Protects against concurrent rport fast_io_fail / dev_loss_tmo.
+ * @mutex: Protects against concurrent rport reconnect / fast_io_fail /
+ * dev_loss_tmo activity.
*/
struct srp_rport {
/* for initiator and target drivers */
@@ -48,6 +49,9 @@ struct srp_rport {
struct mutex mutex;
enum srp_rport_state state;
bool deleted;
+ int reconnect_delay;
+ int failed_reconnects;
+ struct delayed_work reconnect_work;
int fast_io_fail_tmo;
int dev_loss_tmo;
struct delayed_work fast_io_fail_work;
@@ -60,6 +64,7 @@ struct srp_rport {
* dev_loss_tmo sysfs attribute for an rport.
* @reset_timer_if_blocked: Whether or srp_timed_out() should reset the command
* timer if the device on which it has been queued is blocked.
+ * @reconnect_delay: If not NULL, points to the default reconnect_delay value.
* @fast_io_fail_tmo: If not NULL, points to the default fast_io_fail_tmo value.
* @dev_loss_tmo: If not NULL, points to the default dev_loss_tmo value.
* @reconnect: Callback function for reconnecting to the target. See also
@@ -71,6 +76,7 @@ struct srp_function_template {
/* for initiator drivers */
bool has_rport_state;
bool reset_timer_if_blocked;
+ int *reconnect_delay;
int *fast_io_fail_tmo;
int *dev_loss_tmo;
int (*reconnect)(struct srp_rport *rport);
@@ -90,7 +96,8 @@ extern void srp_rport_put(struct srp_rport *rport);
extern struct srp_rport *srp_rport_add(struct Scsi_Host *,
struct srp_rport_identifiers *);
extern void srp_rport_del(struct srp_rport *);
-extern int srp_tmo_valid(int fast_io_fail_tmo, int dev_loss_tmo);
+extern int srp_tmo_valid(int reconnect_delay, int fast_io_fail_tmo,
+ int dev_loss_tmo);
extern int srp_reconnect_rport(struct srp_rport *rport);
extern void srp_start_tl_fail_timers(struct srp_rport *rport);
extern void srp_remove_host(struct Scsi_Host *);
--
1.8.1.4
--
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