#include <linux/err.h>
#include <linux/slab.h>
#include <linux/string.h>
+#include <linux/delay.h>
#include <scsi/scsi.h>
+#include <scsi/scsi_cmnd.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_host.h>
#include <scsi/scsi_transport.h>
#include <scsi/scsi_transport_srp.h>
+#include "scsi_priv.h"
#include "scsi_transport_srp_internal.h"
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 3
+#define SRP_RPORT_ATTRS 8
struct srp_internal {
struct scsi_transport_template t;
#define dev_to_rport(d) container_of(d, struct srp_rport, dev)
#define transport_class_to_srp_rport(dev) dev_to_rport((dev)->parent)
+static inline struct Scsi_Host *rport_to_shost(struct srp_rport *r)
+{
+ return dev_to_shost(r->dev.parent);
+}
+
+/**
+ * srp_tmo_valid() - check timeout combination validity
+ *
+ * The combination of the timeout parameters must be such that SCSI commands
+ * 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 all three parameters to be disabled simultaneously.
+ */
+int srp_tmo_valid(int reconnect_delay, int fast_io_fail_tmo, int dev_loss_tmo)
+{
+ 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;
+ if (dev_loss_tmo >= LONG_MAX / HZ)
+ return -EINVAL;
+ if (fast_io_fail_tmo >= 0 && dev_loss_tmo >= 0 &&
+ fast_io_fail_tmo >= dev_loss_tmo)
+ return -EINVAL;
+ return 0;
+}
+EXPORT_SYMBOL_GPL(srp_tmo_valid);
static int srp_host_setup(struct transport_container *tc, struct device *dev,
struct device *cdev)
static DEVICE_ATTR(delete, S_IWUSR, NULL, store_srp_rport_delete);
+static ssize_t show_srp_rport_state(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ static const char *const state_name[] = {
+ [SRP_RPORT_RUNNING] = "running",
+ [SRP_RPORT_BLOCKED] = "blocked",
+ [SRP_RPORT_FAIL_FAST] = "fail-fast",
+ [SRP_RPORT_LOST] = "lost",
+ };
+ struct srp_rport *rport = transport_class_to_srp_rport(dev);
+ enum srp_rport_state state = rport->state;
+
+ return sprintf(buf, "%s\n",
+ (unsigned)state < ARRAY_SIZE(state_name) ?
+ state_name[state] : "???");
+}
+
+static DEVICE_ATTR(state, S_IRUGO, show_srp_rport_state, NULL);
+
+static ssize_t srp_show_tmo(char *buf, int tmo)
+{
+ return tmo >= 0 ? sprintf(buf, "%d\n", tmo) : sprintf(buf, "off\n");
+}
+
+static int srp_parse_tmo(int *tmo, const char *buf)
+{
+ int res = 0;
+
+ if (strncmp(buf, "off", 3) != 0)
+ res = kstrtoint(buf, 0, tmo);
+ else
+ *tmo = -1;
+
+ 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)
+{
+ struct srp_rport *rport = transport_class_to_srp_rport(dev);
+
+ return srp_show_tmo(buf, rport->fast_io_fail_tmo);
+}
+
+static ssize_t store_srp_rport_fast_io_fail_tmo(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct srp_rport *rport = transport_class_to_srp_rport(dev);
+ int res;
+ int fast_io_fail_tmo;
+
+ res = srp_parse_tmo(&fast_io_fail_tmo, buf);
+ if (res)
+ goto out;
+ 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;
+ res = count;
+
+out:
+ return res;
+}
+
+static DEVICE_ATTR(fast_io_fail_tmo, S_IRUGO | S_IWUSR,
+ show_srp_rport_fast_io_fail_tmo,
+ store_srp_rport_fast_io_fail_tmo);
+
+static ssize_t show_srp_rport_dev_loss_tmo(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->dev_loss_tmo);
+}
+
+static ssize_t store_srp_rport_dev_loss_tmo(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct srp_rport *rport = transport_class_to_srp_rport(dev);
+ int res;
+ int dev_loss_tmo;
+
+ res = srp_parse_tmo(&dev_loss_tmo, buf);
+ if (res)
+ goto out;
+ 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;
+ res = count;
+
+out:
+ return res;
+}
+
+static DEVICE_ATTR(dev_loss_tmo, S_IRUGO | S_IWUSR,
+ show_srp_rport_dev_loss_tmo,
+ store_srp_rport_dev_loss_tmo);
+
+static int srp_rport_set_state(struct srp_rport *rport,
+ enum srp_rport_state new_state)
+{
+ enum srp_rport_state old_state = rport->state;
+
+ lockdep_assert_held(&rport->mutex);
+
+ switch (new_state) {
+ case SRP_RPORT_RUNNING:
+ switch (old_state) {
+ case SRP_RPORT_LOST:
+ goto invalid;
+ default:
+ break;
+ }
+ break;
+ case SRP_RPORT_BLOCKED:
+ switch (old_state) {
+ case SRP_RPORT_RUNNING:
+ break;
+ default:
+ goto invalid;
+ }
+ break;
+ case SRP_RPORT_FAIL_FAST:
+ switch (old_state) {
+ case SRP_RPORT_LOST:
+ goto invalid;
+ default:
+ break;
+ }
+ break;
+ case SRP_RPORT_LOST:
+ break;
+ }
+ rport->state = new_state;
+ return 0;
+
+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);
+ struct srp_internal *i;
+
+ lockdep_assert_held(&rport->mutex);
+
+ if (srp_rport_set_state(rport, SRP_RPORT_FAIL_FAST))
+ return;
+ scsi_target_unblock(rport->dev.parent, SDEV_TRANSPORT_OFFLINE);
+
+ /* Involve the LLD if possible to terminate all I/O on the rport. */
+ i = to_srp_internal(shost->transportt);
+ if (i->f->terminate_rport_io)
+ i->f->terminate_rport_io(rport);
+}
+
+/**
+ * rport_fast_io_fail_timedout() - fast I/O failure timeout handler
+ */
+static void rport_fast_io_fail_timedout(struct work_struct *work)
+{
+ struct srp_rport *rport = container_of(to_delayed_work(work),
+ struct srp_rport, fast_io_fail_work);
+ struct Scsi_Host *shost = rport_to_shost(rport);
+
+ pr_info("fast_io_fail_tmo expired for SRP %s / %s.\n",
+ dev_name(&rport->dev), dev_name(&shost->shost_gendev));
+
+ mutex_lock(&rport->mutex);
+ if (rport->state == SRP_RPORT_BLOCKED)
+ __rport_fail_io_fast(rport);
+ mutex_unlock(&rport->mutex);
+}
+
+/**
+ * rport_dev_loss_timedout() - device loss timeout handler
+ */
+static void rport_dev_loss_timedout(struct work_struct *work)
+{
+ struct srp_rport *rport = container_of(to_delayed_work(work),
+ struct srp_rport, dev_loss_work);
+ struct Scsi_Host *shost = rport_to_shost(rport);
+ struct srp_internal *i = to_srp_internal(shost->transportt);
+
+ pr_info("dev_loss_tmo expired for SRP %s / %s.\n",
+ dev_name(&rport->dev), dev_name(&shost->shost_gendev));
+
+ mutex_lock(&rport->mutex);
+ WARN_ON(srp_rport_set_state(rport, SRP_RPORT_LOST) != 0);
+ scsi_target_unblock(rport->dev.parent, SDEV_TRANSPORT_OFFLINE);
+ mutex_unlock(&rport->mutex);
+
+ i->f->rport_delete(rport);
+}
+
+static void __srp_start_tl_fail_timers(struct srp_rport *rport)
+{
+ struct Scsi_Host *shost = rport_to_shost(rport);
+ 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",
+ dev_name(&shost->shost_gendev),
+ rport->state);
+ scsi_target_block(&shost->shost_gendev);
+ queue_delayed_work(system_long_wq,
+ &rport->fast_io_fail_work,
+ 1UL * fast_io_fail_tmo * HZ);
+ }
+ if (dev_loss_tmo >= 0)
+ queue_delayed_work(system_long_wq,
+ &rport->dev_loss_work,
+ 1UL * dev_loss_tmo * HZ);
+ } else {
+ pr_debug("%s has already been deleted\n",
+ dev_name(&shost->shost_gendev));
+ srp_rport_set_state(rport, SRP_RPORT_FAIL_FAST);
+ scsi_target_unblock(&shost->shost_gendev,
+ SDEV_TRANSPORT_OFFLINE);
+ }
+}
+
+/**
+ * srp_start_tl_fail_timers() - start the transport layer failure timers
+ *
+ * Start the transport layer fast I/O failure and device loss timers. Do not
+ * modify a timer that was already started.
+ */
+void srp_start_tl_fail_timers(struct srp_rport *rport)
+{
+ mutex_lock(&rport->mutex);
+ __srp_start_tl_fail_timers(rport);
+ mutex_unlock(&rport->mutex);
+}
+EXPORT_SYMBOL(srp_start_tl_fail_timers);
+
+/**
+ * scsi_request_fn_active() - number of kernel threads inside scsi_request_fn()
+ */
+static int scsi_request_fn_active(struct Scsi_Host *shost)
+{
+ struct scsi_device *sdev;
+ struct request_queue *q;
+ int request_fn_active = 0;
+
+ shost_for_each_device(sdev, shost) {
+ q = sdev->request_queue;
+
+ spin_lock_irq(q->queue_lock);
+ request_fn_active += q->request_fn_active;
+ spin_unlock_irq(q->queue_lock);
+ }
+
+ return request_fn_active;
+}
+
+/**
+ * srp_reconnect_rport() - reconnect to an SRP target port
+ *
+ * Blocks SCSI command queueing before invoking reconnect() such that
+ * queuecommand() won't be invoked concurrently with reconnect() from outside
+ * the SCSI EH. This is important since a reconnect() implementation may
+ * reallocate resources needed by queuecommand().
+ *
+ * Notes:
+ * - This function neither waits until outstanding requests have finished nor
+ * tries to abort these. It is the responsibility of the reconnect()
+ * function to finish outstanding commands before reconnecting to the target
+ * port.
+ * - It is the responsibility of the caller to ensure that the resources
+ * reallocated by the reconnect() function won't be used while this function
+ * is in progress. One possible strategy is to invoke this function from
+ * the context of the SCSI EH thread only. Another possible strategy is to
+ * lock the rport mutex inside each SCSI LLD callback that can be invoked by
+ * the SCSI EH (the scsi_host_template.eh_*() functions and also the
+ * scsi_host_template.queuecommand() function).
+ */
+int srp_reconnect_rport(struct srp_rport *rport)
+{
+ struct Scsi_Host *shost = rport_to_shost(rport);
+ struct srp_internal *i = to_srp_internal(shost->transportt);
+ struct scsi_device *sdev;
+ int res;
+
+ pr_debug("SCSI host %s\n", dev_name(&shost->shost_gendev));
+
+ res = mutex_lock_interruptible(&rport->mutex);
+ if (res)
+ goto out;
+ scsi_target_block(&shost->shost_gendev);
+ while (scsi_request_fn_active(shost))
+ msleep(20);
+ res = i->f->reconnect(rport);
+ pr_debug("%s (state %d): transport.reconnect() returned %d\n",
+ dev_name(&shost->shost_gendev), rport->state, res);
+ if (res == 0) {
+ 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);
+ /*
+ * If the SCSI error handler has offlined one or more devices,
+ * invoking scsi_target_unblock() won't change the state of
+ * these devices into running so do that explicitly.
+ */
+ spin_lock_irq(shost->host_lock);
+ __shost_for_each_device(sdev, shost)
+ if (sdev->sdev_state == SDEV_OFFLINE)
+ sdev->sdev_state = SDEV_RUNNING;
+ spin_unlock_irq(shost->host_lock);
+ } else if (rport->state == SRP_RPORT_RUNNING) {
+ /*
+ * srp_reconnect_rport() was invoked with fast_io_fail
+ * off. Mark the port as failed and start the TL failure
+ * timers if these had not yet been started.
+ */
+ __rport_fail_io_fast(rport);
+ scsi_target_unblock(&shost->shost_gendev,
+ SDEV_TRANSPORT_OFFLINE);
+ __srp_start_tl_fail_timers(rport);
+ } else if (rport->state != SRP_RPORT_BLOCKED) {
+ scsi_target_unblock(&shost->shost_gendev,
+ SDEV_TRANSPORT_OFFLINE);
+ }
+ mutex_unlock(&rport->mutex);
+
+out:
+ return res;
+}
+EXPORT_SYMBOL(srp_reconnect_rport);
+
+/**
+ * srp_timed_out() - SRP transport intercept of the SCSI timeout EH
+ *
+ * If a timeout occurs while an rport is in the blocked state, ask the SCSI
+ * EH to continue waiting (BLK_EH_RESET_TIMER). Otherwise let the SCSI core
+ * handle the timeout (BLK_EH_NOT_HANDLED).
+ *
+ * Note: This function is called from soft-IRQ context and with the request
+ * queue lock held.
+ */
+static enum blk_eh_timer_return srp_timed_out(struct scsi_cmnd *scmd)
+{
+ struct scsi_device *sdev = scmd->device;
+ struct Scsi_Host *shost = sdev->host;
+ struct srp_internal *i = to_srp_internal(shost->transportt);
+
+ pr_debug("timeout for sdev %s\n", dev_name(&sdev->sdev_gendev));
+ return i->f->reset_timer_if_blocked && scsi_device_blocked(sdev) ?
+ BLK_EH_RESET_TIMER : BLK_EH_NOT_HANDLED;
+}
+
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);
+
put_device(dev->parent);
kfree(rport);
}
return &i->t.host_attrs.ac == cont;
}
+/**
+ * srp_rport_get() - increment rport reference count
+ */
+void srp_rport_get(struct srp_rport *rport)
+{
+ get_device(&rport->dev);
+}
+EXPORT_SYMBOL(srp_rport_get);
+
+/**
+ * srp_rport_put() - decrement rport reference count
+ */
+void srp_rport_put(struct srp_rport *rport)
+{
+ put_device(&rport->dev);
+}
+EXPORT_SYMBOL(srp_rport_put);
+
/**
* srp_rport_add - add a SRP remote port to the device hierarchy
* @shost: scsi host the remote port is connected to.
{
struct srp_rport *rport;
struct device *parent = &shost->shost_gendev;
+ struct srp_internal *i = to_srp_internal(shost->transportt);
int id, ret;
rport = kzalloc(sizeof(*rport), GFP_KERNEL);
if (!rport)
return ERR_PTR(-ENOMEM);
+ mutex_init(&rport->mutex);
+
device_initialize(&rport->dev);
rport->dev.parent = get_device(parent);
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;
+ INIT_DELAYED_WORK(&rport->fast_io_fail_work,
+ rport_fast_io_fail_timedout);
+ INIT_DELAYED_WORK(&rport->dev_loss_work, rport_dev_loss_timedout);
+
id = atomic_inc_return(&to_srp_host_attrs(shost)->next_port_id);
dev_set_name(&rport->dev, "port-%d:%d", shost->host_no, id);
transport_remove_device(dev);
device_del(dev);
transport_destroy_device(dev);
+
+ mutex_lock(&rport->mutex);
+ if (rport->state == SRP_RPORT_BLOCKED)
+ __rport_fail_io_fast(rport);
+ rport->deleted = true;
+ mutex_unlock(&rport->mutex);
+
put_device(dev);
}
EXPORT_SYMBOL_GPL(srp_rport_del);
if (!i)
return NULL;
+ i->t.eh_timed_out = srp_timed_out;
+
i->t.tsk_mgmt_response = srp_tsk_mgmt_response;
i->t.it_nexus_response = srp_it_nexus_response;
count = 0;
i->rport_attrs[count++] = &dev_attr_port_id;
i->rport_attrs[count++] = &dev_attr_roles;
+ if (ft->has_rport_state) {
+ i->rport_attrs[count++] = &dev_attr_state;
+ 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;
projects / firefly-linux-kernel-4.4.55.git / blobdiff