RDMA/cxgb3: Doorbell overflow avoidance and recovery

[safe/jmp/linux-2.6] / drivers / infiniband / hw / cxgb3 / iwch.c

diff --git a/drivers/infiniband/hw/cxgb3/iwch.c b/drivers/infiniband/hw/cxgb3/iwch.c
index b0ea010..d992543 100644 (file)
--- a/drivers/infiniband/hw/cxgb3/iwch.c
+++ b/drivers/infiniband/hw/cxgb3/iwch.c
@@ -65,6 +65,46 @@ struct cxgb3_client t3c_client = {
 static LIST_HEAD(dev_list);
 static DEFINE_MUTEX(dev_mutex);
 
+static int disable_qp_db(int id, void *p, void *data)
+{
+       struct iwch_qp *qhp = p;
+
+       cxio_disable_wq_db(&qhp->wq);
+       return 0;
+}
+
+static int enable_qp_db(int id, void *p, void *data)
+{
+       struct iwch_qp *qhp = p;
+
+       if (data)
+               ring_doorbell(qhp->rhp->rdev.ctrl_qp.doorbell, qhp->wq.qpid);
+       cxio_enable_wq_db(&qhp->wq);
+       return 0;
+}
+
+static void disable_dbs(struct iwch_dev *rnicp)
+{
+       spin_lock_irq(&rnicp->lock);
+       idr_for_each(&rnicp->qpidr, disable_qp_db, NULL);
+       spin_unlock_irq(&rnicp->lock);
+}
+
+static void enable_dbs(struct iwch_dev *rnicp, int ring_db)
+{
+       spin_lock_irq(&rnicp->lock);
+       idr_for_each(&rnicp->qpidr, enable_qp_db,
+                    (void *)(unsigned long)ring_db);
+       spin_unlock_irq(&rnicp->lock);
+}
+
+static void iwch_db_drop_task(struct work_struct *work)
+{
+       struct iwch_dev *rnicp = container_of(work, struct iwch_dev,
+                                             db_drop_task.work);
+       enable_dbs(rnicp, 1);
+}
+
 static void rnic_init(struct iwch_dev *rnicp)
 {
        PDBG("%s iwch_dev %p\n", __func__,  rnicp);
@@ -72,6 +112,7 @@ static void rnic_init(struct iwch_dev *rnicp)
        idr_init(&rnicp->qpidr);
        idr_init(&rnicp->mmidr);
        spin_lock_init(&rnicp->lock);
+       INIT_DELAYED_WORK(&rnicp->db_drop_task, iwch_db_drop_task);
 
        rnicp->attr.max_qps = T3_MAX_NUM_QP - 32;
        rnicp->attr.max_wrs = T3_MAX_QP_DEPTH;
@@ -147,6 +188,7 @@ static void close_rnic_dev(struct t3cdev *tdev)
        mutex_lock(&dev_mutex);
        list_for_each_entry_safe(dev, tmp, &dev_list, entry) {
                if (dev->rdev.t3cdev_p == tdev) {
+                       cancel_delayed_work_sync(&dev->db_drop_task);
                        list_del(&dev->entry);
                        iwch_unregister_device(dev);
                        cxio_rdev_close(&dev->rdev);
@@ -165,7 +207,8 @@ static void iwch_event_handler(struct t3cdev *tdev, u32 evt, u32 port_id)
        struct cxio_rdev *rdev = tdev->ulp;
        struct iwch_dev *rnicp;
        struct ib_event event;
-       u32    portnum = port_id + 1;
+       u32 portnum = port_id + 1;
+       int dispatch = 0;
 
        if (!rdev)
                return;
@@ -174,21 +217,49 @@ static void iwch_event_handler(struct t3cdev *tdev, u32 evt, u32 port_id)
        case OFFLOAD_STATUS_DOWN: {
                rdev->flags = CXIO_ERROR_FATAL;
                event.event  = IB_EVENT_DEVICE_FATAL;
+               dispatch = 1;
                break;
                }
        case OFFLOAD_PORT_DOWN: {
                event.event  = IB_EVENT_PORT_ERR;
+               dispatch = 1;
                break;
                }
        case OFFLOAD_PORT_UP: {
                event.event  = IB_EVENT_PORT_ACTIVE;
+               dispatch = 1;
+               break;
+               }
+       case OFFLOAD_DB_FULL: {
+               disable_dbs(rnicp);
+               break;
+               }
+       case OFFLOAD_DB_EMPTY: {
+               enable_dbs(rnicp, 1);
+               break;
+               }
+       case OFFLOAD_DB_DROP: {
+               unsigned long delay = 1000;
+               unsigned short r;
+
+               disable_dbs(rnicp);
+               get_random_bytes(&r, 2);
+               delay += r & 1023;
+
+               /*
+                * delay is between 1000-2023 usecs.
+                */
+               schedule_delayed_work(&rnicp->db_drop_task,
+                       usecs_to_jiffies(delay));
                break;
                }
        }
 
-       event.device = &rnicp->ibdev;
-       event.element.port_num = portnum;
-       ib_dispatch_event(&event);
+       if (dispatch) {
+               event.device = &rnicp->ibdev;
+               event.element.port_num = portnum;
+               ib_dispatch_event(&event);
+       }
 
        return;
 }