scsi_transport_srp: Fix kernel-doc warnings
[firefly-linux-kernel-4.4.55.git] / drivers / scsi / scsi_transport_srp.c
index 2700a5a09bd45a103b857b2f6a81da42834e4d28..d47ffc8d3e431dc2524e30c378cd2fabb6406b74 100644 (file)
@@ -64,10 +64,14 @@ static inline struct Scsi_Host *rport_to_shost(struct srp_rport *r)
 
 /**
  * srp_tmo_valid() - check timeout combination validity
+ * @reconnect_delay: Reconnect delay in seconds.
+ * @fast_io_fail_tmo: Fast I/O fail timeout in seconds.
+ * @dev_loss_tmo: Device loss timeout in seconds.
  *
  * 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
+ * timeout to exceed SCSI_DEVICE_BLOCK_MAX_TIMEOUT nor allow dev_loss_tmo to
+ * exceed that limit if failing I/O fast has been disabled. Furthermore, these
  * parameters must be such that multipath can detect failed paths timely.
  * Hence do not allow all three parameters to be disabled simultaneously.
  */
@@ -79,6 +83,9 @@ int srp_tmo_valid(int reconnect_delay, int fast_io_fail_tmo, int dev_loss_tmo)
                return -EINVAL;
        if (fast_io_fail_tmo > SCSI_DEVICE_BLOCK_MAX_TIMEOUT)
                return -EINVAL;
+       if (fast_io_fail_tmo < 0 &&
+           dev_loss_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 &&
@@ -368,6 +375,7 @@ invalid:
 
 /**
  * srp_reconnect_work() - reconnect and schedule a new attempt if necessary
+ * @work: Work structure used for scheduling this operation.
  */
 static void srp_reconnect_work(struct work_struct *work)
 {
@@ -408,6 +416,7 @@ static void __rport_fail_io_fast(struct srp_rport *rport)
 
 /**
  * rport_fast_io_fail_timedout() - fast I/O failure timeout handler
+ * @work: Work structure used for scheduling this operation.
  */
 static void rport_fast_io_fail_timedout(struct work_struct *work)
 {
@@ -426,6 +435,7 @@ static void rport_fast_io_fail_timedout(struct work_struct *work)
 
 /**
  * rport_dev_loss_timedout() - device loss timeout handler
+ * @work: Work structure used for scheduling this operation.
  */
 static void rport_dev_loss_timedout(struct work_struct *work)
 {
@@ -452,42 +462,35 @@ static void __srp_start_tl_fail_timers(struct srp_rport *rport)
 
        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);
+       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);
+       if (rport->state == SRP_RPORT_LOST)
+               return;
+       if (delay > 0)
+               queue_delayed_work(system_long_wq, &rport->reconnect_work,
+                                  1UL * delay * HZ);
+       if (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);
+               if (fast_io_fail_tmo >= 0)
                        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
+ * @rport: SRP target port.
  *
  * Start the transport layer fast I/O failure and device loss timers. Do not
  * modify a timer that was already started.
@@ -502,6 +505,7 @@ EXPORT_SYMBOL(srp_start_tl_fail_timers);
 
 /**
  * scsi_request_fn_active() - number of kernel threads inside scsi_request_fn()
+ * @shost: SCSI host for which to count the number of scsi_request_fn() callers.
  */
 static int scsi_request_fn_active(struct Scsi_Host *shost)
 {
@@ -522,6 +526,7 @@ static int scsi_request_fn_active(struct Scsi_Host *shost)
 
 /**
  * srp_reconnect_rport() - reconnect to an SRP target port
+ * @rport: SRP target port.
  *
  * Blocks SCSI command queueing before invoking reconnect() such that
  * queuecommand() won't be invoked concurrently with reconnect() from outside
@@ -556,7 +561,7 @@ int srp_reconnect_rport(struct srp_rport *rport)
        scsi_target_block(&shost->shost_gendev);
        while (scsi_request_fn_active(shost))
                msleep(20);
-       res = i->f->reconnect(rport);
+       res = rport->state != SRP_RPORT_LOST ? i->f->reconnect(rport) : -ENODEV;
        pr_debug("%s (state %d): transport.reconnect() returned %d\n",
                 dev_name(&shost->shost_gendev), rport->state, res);
        if (res == 0) {
@@ -578,9 +583,9 @@ int srp_reconnect_rport(struct srp_rport *rport)
                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.
+                * srp_reconnect_rport() has been invoked with fast_io_fail
+                * and dev_loss 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,
@@ -599,6 +604,7 @@ EXPORT_SYMBOL(srp_reconnect_rport);
 
 /**
  * srp_timed_out() - SRP transport intercept of the SCSI timeout EH
+ * @scmd: SCSI command.
  *
  * 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
@@ -622,10 +628,6 @@ 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);
 }
@@ -674,6 +676,7 @@ static int srp_host_match(struct attribute_container *cont, struct device *dev)
 
 /**
  * srp_rport_get() - increment rport reference count
+ * @rport: SRP target port.
  */
 void srp_rport_get(struct srp_rport *rport)
 {
@@ -683,6 +686,7 @@ EXPORT_SYMBOL(srp_rport_get);
 
 /**
  * srp_rport_put() - decrement rport reference count
+ * @rport: SRP target port.
  */
 void srp_rport_put(struct srp_rport *rport)
 {
@@ -780,12 +784,6 @@ void srp_rport_del(struct srp_rport *rport)
        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);
@@ -810,6 +808,27 @@ void srp_remove_host(struct Scsi_Host *shost)
 }
 EXPORT_SYMBOL_GPL(srp_remove_host);
 
+/**
+ * srp_stop_rport_timers - stop the transport layer recovery timers
+ *
+ * Must be called after srp_remove_host() and scsi_remove_host(). The caller
+ * must hold a reference on the rport (rport->dev) and on the SCSI host
+ * (rport->dev.parent).
+ */
+void srp_stop_rport_timers(struct srp_rport *rport)
+{
+       mutex_lock(&rport->mutex);
+       if (rport->state == SRP_RPORT_BLOCKED)
+               __rport_fail_io_fast(rport);
+       srp_rport_set_state(rport, SRP_RPORT_LOST);
+       mutex_unlock(&rport->mutex);
+
+       cancel_delayed_work_sync(&rport->reconnect_work);
+       cancel_delayed_work_sync(&rport->fast_io_fail_work);
+       cancel_delayed_work_sync(&rport->dev_loss_work);
+}
+EXPORT_SYMBOL_GPL(srp_stop_rport_timers);
+
 static int srp_tsk_mgmt_response(struct Scsi_Host *shost, u64 nexus, u64 tm_id,
                                 int result)
 {