scsi_transport_srp: Add periodic reconnect support
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@acm.org> Acked-by: David Dillow <dillowda@ornl.gov> Signed-off-by: Roland Dreier <roland@purestorage.com>
This commit is contained in:
Bart Van Assche
Roland Dreier
parent
c1120f8981
commit
8c64e4531c
4 changed files with 118 additions and 11 deletions
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@ -30,6 +30,14 @@ Contact: linux-scsi@vger.kernel.org
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Description: 16-byte local SRP port identifier in hexadecimal format. An
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example: 4c:49:4e:55:58:20:56:49:4f:00:00:00:00:00:00:00.
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What: /sys/class/srp_remote_ports/port-<h>:<n>/reconnect_delay
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Date: February 1, 2014
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KernelVersion: 3.13
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Contact: linux-scsi@vger.kernel.org, linux-rdma@vger.kernel.org
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Description: Number of seconds the SCSI layer will wait after a reconnect
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attempt failed before retrying. Setting this attribute to
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"off" will disable time-based reconnecting.
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What: /sys/class/srp_remote_ports/port-<h>:<n>/roles
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Date: June 27, 2007
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KernelVersion: 2.6.24
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@ -145,9 +145,9 @@ static int srp_tmo_set(const char *val, const struct kernel_param *kp)
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tmo = -1;
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}
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if (kp->arg == &srp_fast_io_fail_tmo)
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res = srp_tmo_valid(tmo, srp_dev_loss_tmo);
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res = srp_tmo_valid(-1, tmo, srp_dev_loss_tmo);
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else
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res = srp_tmo_valid(srp_fast_io_fail_tmo, tmo);
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res = srp_tmo_valid(-1, srp_fast_io_fail_tmo, tmo);
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if (res)
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goto out;
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*(int *)kp->arg = tmo;
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@ -41,7 +41,7 @@ struct srp_host_attrs {
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#define to_srp_host_attrs(host) ((struct srp_host_attrs *)(host)->shost_data)
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#define SRP_HOST_ATTRS 0
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#define SRP_RPORT_ATTRS 6
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#define SRP_RPORT_ATTRS 8
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struct srp_internal {
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struct scsi_transport_template t;
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@ -69,11 +69,13 @@ static inline struct Scsi_Host *rport_to_shost(struct srp_rport *r)
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* are finished in a reasonable time. Hence do not allow the fast I/O fail
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* timeout to exceed SCSI_DEVICE_BLOCK_MAX_TIMEOUT. Furthermore, these
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* parameters must be such that multipath can detect failed paths timely.
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* Hence do not allow both parameters to be disabled simultaneously.
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* Hence do not allow all three parameters to be disabled simultaneously.
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*/
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int srp_tmo_valid(int fast_io_fail_tmo, int dev_loss_tmo)
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int srp_tmo_valid(int reconnect_delay, int fast_io_fail_tmo, int dev_loss_tmo)
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{
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if (fast_io_fail_tmo < 0 && dev_loss_tmo < 0)
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if (reconnect_delay < 0 && fast_io_fail_tmo < 0 && dev_loss_tmo < 0)
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return -EINVAL;
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if (reconnect_delay == 0)
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return -EINVAL;
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if (fast_io_fail_tmo > SCSI_DEVICE_BLOCK_MAX_TIMEOUT)
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return -EINVAL;
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@ -202,6 +204,56 @@ static int srp_parse_tmo(int *tmo, const char *buf)
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return res;
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}
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static ssize_t show_reconnect_delay(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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struct srp_rport *rport = transport_class_to_srp_rport(dev);
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return srp_show_tmo(buf, rport->reconnect_delay);
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}
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static ssize_t store_reconnect_delay(struct device *dev,
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struct device_attribute *attr,
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const char *buf, const size_t count)
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{
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struct srp_rport *rport = transport_class_to_srp_rport(dev);
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int res, delay;
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res = srp_parse_tmo(&delay, buf);
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if (res)
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goto out;
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res = srp_tmo_valid(delay, rport->fast_io_fail_tmo,
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rport->dev_loss_tmo);
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if (res)
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goto out;
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if (rport->reconnect_delay <= 0 && delay > 0 &&
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rport->state != SRP_RPORT_RUNNING) {
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queue_delayed_work(system_long_wq, &rport->reconnect_work,
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delay * HZ);
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} else if (delay <= 0) {
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cancel_delayed_work(&rport->reconnect_work);
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}
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rport->reconnect_delay = delay;
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res = count;
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out:
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return res;
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}
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static DEVICE_ATTR(reconnect_delay, S_IRUGO | S_IWUSR, show_reconnect_delay,
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store_reconnect_delay);
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static ssize_t show_failed_reconnects(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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struct srp_rport *rport = transport_class_to_srp_rport(dev);
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return sprintf(buf, "%d\n", rport->failed_reconnects);
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}
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static DEVICE_ATTR(failed_reconnects, S_IRUGO, show_failed_reconnects, NULL);
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static ssize_t show_srp_rport_fast_io_fail_tmo(struct device *dev,
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struct device_attribute *attr,
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char *buf)
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@ -222,7 +274,8 @@ static ssize_t store_srp_rport_fast_io_fail_tmo(struct device *dev,
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res = srp_parse_tmo(&fast_io_fail_tmo, buf);
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if (res)
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goto out;
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res = srp_tmo_valid(fast_io_fail_tmo, rport->dev_loss_tmo);
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res = srp_tmo_valid(rport->reconnect_delay, fast_io_fail_tmo,
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rport->dev_loss_tmo);
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if (res)
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goto out;
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rport->fast_io_fail_tmo = fast_io_fail_tmo;
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@ -256,7 +309,8 @@ static ssize_t store_srp_rport_dev_loss_tmo(struct device *dev,
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res = srp_parse_tmo(&dev_loss_tmo, buf);
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if (res)
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goto out;
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res = srp_tmo_valid(rport->fast_io_fail_tmo, dev_loss_tmo);
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res = srp_tmo_valid(rport->reconnect_delay, rport->fast_io_fail_tmo,
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dev_loss_tmo);
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if (res)
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goto out;
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rport->dev_loss_tmo = dev_loss_tmo;
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@ -312,6 +366,29 @@ static int srp_rport_set_state(struct srp_rport *rport,
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return -EINVAL;
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}
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/**
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* srp_reconnect_work() - reconnect and schedule a new attempt if necessary
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*/
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static void srp_reconnect_work(struct work_struct *work)
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{
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struct srp_rport *rport = container_of(to_delayed_work(work),
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struct srp_rport, reconnect_work);
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struct Scsi_Host *shost = rport_to_shost(rport);
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int delay, res;
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res = srp_reconnect_rport(rport);
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if (res != 0) {
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shost_printk(KERN_ERR, shost,
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"reconnect attempt %d failed (%d)\n",
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++rport->failed_reconnects, res);
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delay = rport->reconnect_delay *
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min(100, max(1, rport->failed_reconnects - 10));
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if (delay > 0)
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queue_delayed_work(system_long_wq,
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&rport->reconnect_work, delay * HZ);
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}
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}
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static void __rport_fail_io_fast(struct srp_rport *rport)
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{
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struct Scsi_Host *shost = rport_to_shost(rport);
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@ -371,16 +448,21 @@ static void rport_dev_loss_timedout(struct work_struct *work)
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static void __srp_start_tl_fail_timers(struct srp_rport *rport)
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{
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struct Scsi_Host *shost = rport_to_shost(rport);
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int fast_io_fail_tmo, dev_loss_tmo;
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int delay, fast_io_fail_tmo, dev_loss_tmo;
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lockdep_assert_held(&rport->mutex);
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if (!rport->deleted) {
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delay = rport->reconnect_delay;
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fast_io_fail_tmo = rport->fast_io_fail_tmo;
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dev_loss_tmo = rport->dev_loss_tmo;
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pr_debug("%s current state: %d\n",
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dev_name(&shost->shost_gendev), rport->state);
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if (delay > 0)
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queue_delayed_work(system_long_wq,
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&rport->reconnect_work,
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1UL * delay * HZ);
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if (fast_io_fail_tmo >= 0 &&
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srp_rport_set_state(rport, SRP_RPORT_BLOCKED) == 0) {
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pr_debug("%s new state: %d\n",
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@ -481,6 +563,7 @@ int srp_reconnect_rport(struct srp_rport *rport)
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cancel_delayed_work(&rport->fast_io_fail_work);
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cancel_delayed_work(&rport->dev_loss_work);
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rport->failed_reconnects = 0;
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srp_rport_set_state(rport, SRP_RPORT_RUNNING);
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scsi_target_unblock(&shost->shost_gendev, SDEV_RUNNING);
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/*
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@ -539,6 +622,7 @@ static void srp_rport_release(struct device *dev)
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{
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struct srp_rport *rport = dev_to_rport(dev);
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cancel_delayed_work_sync(&rport->reconnect_work);
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cancel_delayed_work_sync(&rport->fast_io_fail_work);
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cancel_delayed_work_sync(&rport->dev_loss_work);
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@ -635,6 +719,10 @@ struct srp_rport *srp_rport_add(struct Scsi_Host *shost,
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memcpy(rport->port_id, ids->port_id, sizeof(rport->port_id));
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rport->roles = ids->roles;
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if (i->f->reconnect)
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rport->reconnect_delay = i->f->reconnect_delay ?
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*i->f->reconnect_delay : 10;
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INIT_DELAYED_WORK(&rport->reconnect_work, srp_reconnect_work);
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rport->fast_io_fail_tmo = i->f->fast_io_fail_tmo ?
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*i->f->fast_io_fail_tmo : 15;
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rport->dev_loss_tmo = i->f->dev_loss_tmo ? *i->f->dev_loss_tmo : 60;
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@ -773,6 +861,10 @@ srp_attach_transport(struct srp_function_template *ft)
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i->rport_attrs[count++] = &dev_attr_fast_io_fail_tmo;
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i->rport_attrs[count++] = &dev_attr_dev_loss_tmo;
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}
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if (ft->reconnect) {
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i->rport_attrs[count++] = &dev_attr_reconnect_delay;
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i->rport_attrs[count++] = &dev_attr_failed_reconnects;
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}
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if (ft->rport_delete)
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i->rport_attrs[count++] = &dev_attr_delete;
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i->rport_attrs[count++] = NULL;
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@ -31,7 +31,8 @@ enum srp_rport_state {
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/**
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* struct srp_rport
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* @lld_data: LLD private data.
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* @mutex: Protects against concurrent rport fast_io_fail / dev_loss_tmo.
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* @mutex: Protects against concurrent rport reconnect / fast_io_fail /
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* dev_loss_tmo activity.
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*/
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struct srp_rport {
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/* for initiator and target drivers */
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@ -48,6 +49,9 @@ struct srp_rport {
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struct mutex mutex;
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enum srp_rport_state state;
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bool deleted;
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int reconnect_delay;
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int failed_reconnects;
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struct delayed_work reconnect_work;
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int fast_io_fail_tmo;
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int dev_loss_tmo;
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struct delayed_work fast_io_fail_work;
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@ -60,6 +64,7 @@ struct srp_rport {
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* dev_loss_tmo sysfs attribute for an rport.
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* @reset_timer_if_blocked: Whether or srp_timed_out() should reset the command
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* timer if the device on which it has been queued is blocked.
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* @reconnect_delay: If not NULL, points to the default reconnect_delay value.
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* @fast_io_fail_tmo: If not NULL, points to the default fast_io_fail_tmo value.
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* @dev_loss_tmo: If not NULL, points to the default dev_loss_tmo value.
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* @reconnect: Callback function for reconnecting to the target. See also
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@ -71,6 +76,7 @@ struct srp_function_template {
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/* for initiator drivers */
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bool has_rport_state;
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bool reset_timer_if_blocked;
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int *reconnect_delay;
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int *fast_io_fail_tmo;
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int *dev_loss_tmo;
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int (*reconnect)(struct srp_rport *rport);
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@ -90,7 +96,8 @@ extern void srp_rport_put(struct srp_rport *rport);
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extern struct srp_rport *srp_rport_add(struct Scsi_Host *,
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struct srp_rport_identifiers *);
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extern void srp_rport_del(struct srp_rport *);
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extern int srp_tmo_valid(int fast_io_fail_tmo, int dev_loss_tmo);
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extern int srp_tmo_valid(int reconnect_delay, int fast_io_fail_tmo,
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int dev_loss_tmo);
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extern int srp_reconnect_rport(struct srp_rport *rport);
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extern void srp_start_tl_fail_timers(struct srp_rport *rport);
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extern void srp_remove_host(struct Scsi_Host *);
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