nvme-fc: add a dev_loss_tmo field to the remoteport

Add a dev_loss_tmo value, paralleling the SCSI FC transport, for device
connectivity loss.

The transport initializes the value in the nvme_fc_register_remoteport()
call. If the value is not set, a default of 60s is set.

Add a new routine to the api, nvme_fc_set_remoteport_devloss() routine,
which allows the lldd to dynamically update the value on an existing
remoteport.

Signed-off-by: James Smart <james.smart@broadcom.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

2 files changed, 40 insertions, 2 deletions

diff --git a/drivers/nvme/host/fc.c b/drivers/nvme/host/fc.c
index e37c69f7921d..25479d3031fa 100644
--- a/drivers/nvme/host/fc.c
+++ b/drivers/nvme/host/fc.c
@@ -45,6 +45,8 @@ enum nvme_fc_queue_flags {
 
 #define NVMEFC_QUEUE_DELAY      3               /* ms units */
 
+#define NVME_FC_DEFAULT_DEV_LOSS_TMO    60      /* seconds */
+
 struct nvme_fc_queue {
         struct nvme_fc_ctrl     *ctrl;
         struct device           *dev;
@@ -585,6 +587,11 @@ nvme_fc_register_remoteport(struct nvme_fc_local_port *localport,
         newrec->remoteport.port_id = pinfo->port_id;
         newrec->remoteport.port_state = FC_OBJSTATE_ONLINE;
         newrec->remoteport.port_num = idx;
+        /* a registration value of dev_loss_tmo=0 results in the default */
+        if (pinfo->dev_loss_tmo)
+                newrec->remoteport.dev_loss_tmo = pinfo->dev_loss_tmo;
+        else
+                newrec->remoteport.dev_loss_tmo = NVME_FC_DEFAULT_DEV_LOSS_TMO;
 
         spin_lock_irqsave(&nvme_fc_lock, flags);
         list_add_tail(&newrec->endp_list, &lport->endp_list);
@@ -688,6 +695,30 @@ nvme_fc_rescan_remoteport(struct nvme_fc_remote_port *remoteport)
 }
 EXPORT_SYMBOL_GPL(nvme_fc_rescan_remoteport);
 
+int
+nvme_fc_set_remoteport_devloss(struct nvme_fc_remote_port *portptr,
+                        u32 dev_loss_tmo)
+{
+        struct nvme_fc_rport *rport = remoteport_to_rport(portptr);
+        struct nvme_fc_ctrl *ctrl;
+        unsigned long flags;
+
+        spin_lock_irqsave(&rport->lock, flags);
+
+        if (portptr->port_state != FC_OBJSTATE_ONLINE) {
+                spin_unlock_irqrestore(&rport->lock, flags);
+                return -EINVAL;
+        }
+
+        /* a dev_loss_tmo of 0 (immediate) is allowed to be set */
+        rport->remoteport.dev_loss_tmo = dev_loss_tmo;
+
+        spin_unlock_irqrestore(&rport->lock, flags);
+
+        return 0;
+}
+EXPORT_SYMBOL_GPL(nvme_fc_set_remoteport_devloss);
+
 
 /* *********************** FC-NVME DMA Handling **************************** */
 
diff --git a/include/linux/nvme-fc-driver.h b/include/linux/nvme-fc-driver.h
index 2be4db353937..496ff759f84c 100644
--- a/include/linux/nvme-fc-driver.h
+++ b/include/linux/nvme-fc-driver.h
@@ -40,6 +40,8 @@
  * @node_name: FC WWNN for the port
  * @port_name: FC WWPN for the port
  * @port_role: What NVME roles are supported (see FC_PORT_ROLE_xxx)
+ * @dev_loss_tmo: maximum delay for reconnects to an association on
+ *             this device. Used only on a remoteport.
  *
  * Initialization values for dynamic port fields:
  * @port_id:      FC N_Port_ID currently assigned the port. Upper 8 bits must
@@ -50,6 +52,7 @@ struct nvme_fc_port_info {
         u64                     port_name;
         u32                     port_role;
         u32                     port_id;
+        u32                     dev_loss_tmo;
 };
 
 
@@ -200,6 +203,9 @@ enum nvme_fc_obj_state {
  *             The length of the buffer corresponds to the local_priv_sz
  *             value specified in the nvme_fc_port_template supplied by
  *             the LLDD.
+ * @dev_loss_tmo: maximum delay for reconnects to an association on
+ *             this device. To modify, lldd must call
+ *             nvme_fc_set_remoteport_devloss().
  *
  * Fields with dynamic values. Values may change base on link state. LLDD
  * may reference fields directly to change them. Initialized by the
@@ -257,10 +263,9 @@ struct nvme_fc_remote_port {
         u32 port_role;
         u64 node_name;
         u64 port_name;
-
         struct nvme_fc_local_port *localport;
-
         void *private;
+        u32 dev_loss_tmo;
 
         /* dynamic fields */
         u32 port_id;
@@ -446,6 +451,8 @@ int nvme_fc_unregister_remoteport(struct nvme_fc_remote_port *remoteport);
 
 void nvme_fc_rescan_remoteport(struct nvme_fc_remote_port *remoteport);
 
+int nvme_fc_set_remoteport_devloss(struct nvme_fc_remote_port *remoteport,
+                        u32 dev_loss_tmo);
 
 
 /*