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 <[email protected]> Cc: David Dillow <[email protected]> Cc: Roland Dreier <[email protected]> Cc: James Bottomley <[email protected]> Cc: Vu Pham <[email protected]> Cc: Sebastian Riemer <[email protected]> --- 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 -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
