iw_cxgb4: block module unload until all ep resources are released

Otherwise an endpoint can be still closing down causing a touch
after free crash.  Also WARN_ON if ulps have failed to destroy
various resources during device removal.

Fixes: ad61a4c7 ("iw_cxgb4: don't block in destroy_qp awaiting the last deref")
Reviewed-by: Sagi Grimberg <sagi@grimbrg.me>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>

drivers/infiniband/hw/cxgb4/cm.c

@@ -314,6 +314,8 @@ static void remove_ep_tid(struct c4iw_ep *ep)
 
 	spin_lock_irqsave(&ep->com.dev->lock, flags);
 	_remove_handle(ep->com.dev, &ep->com.dev->hwtid_idr, ep->hwtid, 0);
+	if (idr_is_empty(&ep->com.dev->hwtid_idr))
+		wake_up(&ep->com.dev->wait);
 	spin_unlock_irqrestore(&ep->com.dev->lock, flags);
 }
 

drivers/infiniband/hw/cxgb4/device.c

@@ -872,9 +872,13 @@ static void c4iw_rdev_close(struct c4iw_rdev *rdev)
 static void c4iw_dealloc(struct uld_ctx *ctx)
 {
 	c4iw_rdev_close(&ctx->dev->rdev);
+	WARN_ON_ONCE(!idr_is_empty(&ctx->dev->cqidr));
 	idr_destroy(&ctx->dev->cqidr);
+	WARN_ON_ONCE(!idr_is_empty(&ctx->dev->qpidr));
 	idr_destroy(&ctx->dev->qpidr);
+	WARN_ON_ONCE(!idr_is_empty(&ctx->dev->mmidr));
 	idr_destroy(&ctx->dev->mmidr);
+	wait_event(ctx->dev->wait, idr_is_empty(&ctx->dev->hwtid_idr));
 	idr_destroy(&ctx->dev->hwtid_idr);
 	idr_destroy(&ctx->dev->stid_idr);
 	idr_destroy(&ctx->dev->atid_idr);
@@ -992,6 +996,7 @@ static struct c4iw_dev *c4iw_alloc(const struct cxgb4_lld_info *infop)
 	mutex_init(&devp->rdev.stats.lock);
 	mutex_init(&devp->db_mutex);
 	INIT_LIST_HEAD(&devp->db_fc_list);
+	init_waitqueue_head(&devp->wait);
 	devp->avail_ird = devp->rdev.lldi.max_ird_adapter;
 
 	if (c4iw_debugfs_root) {

drivers/infiniband/hw/cxgb4/iw_cxgb4.h

@@ -263,6 +263,7 @@ struct c4iw_dev {
 	struct idr stid_idr;
 	struct list_head db_fc_list;
 	u32 avail_ird;
+	wait_queue_head_t wait;
 };
 
 static inline struct c4iw_dev *to_c4iw_dev(struct ib_device *ibdev)