RDMA/uverbs: Export XRC domains to user space

Allow user space to create XRC domains.  Because XRCDs are expected to
be shared among multiple processes, we use inodes to identify an XRCD.

Based on patches by Jack Morgenstein <jackm@dev.mellanox.co.il>

Signed-off-by: Sean Hefty <sean.hefty@intel.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
diff --git a/drivers/infiniband/core/uverbs_main.c b/drivers/infiniband/core/uverbs_main.c
index 56898b6..bb9dcea 100644
--- a/drivers/infiniband/core/uverbs_main.c
+++ b/drivers/infiniband/core/uverbs_main.c
@@ -72,6 +72,7 @@
 DEFINE_IDR(ib_uverbs_cq_idr);
 DEFINE_IDR(ib_uverbs_qp_idr);
 DEFINE_IDR(ib_uverbs_srq_idr);
+DEFINE_IDR(ib_uverbs_xrcd_idr);
 
 static DEFINE_SPINLOCK(map_lock);
 static DECLARE_BITMAP(dev_map, IB_UVERBS_MAX_DEVICES);
@@ -107,6 +108,8 @@
 	[IB_USER_VERBS_CMD_MODIFY_SRQ]		= ib_uverbs_modify_srq,
 	[IB_USER_VERBS_CMD_QUERY_SRQ]		= ib_uverbs_query_srq,
 	[IB_USER_VERBS_CMD_DESTROY_SRQ]		= ib_uverbs_destroy_srq,
+	[IB_USER_VERBS_CMD_OPEN_XRCD]		= ib_uverbs_open_xrcd,
+	[IB_USER_VERBS_CMD_CLOSE_XRCD]		= ib_uverbs_close_xrcd,
 };
 
 static void ib_uverbs_add_one(struct ib_device *device);
@@ -241,6 +244,18 @@
 		kfree(uobj);
 	}
 
+	mutex_lock(&file->device->xrcd_tree_mutex);
+	list_for_each_entry_safe(uobj, tmp, &context->xrcd_list, list) {
+		struct ib_xrcd *xrcd = uobj->object;
+		struct ib_uxrcd_object *uxrcd =
+			container_of(uobj, struct ib_uxrcd_object, uobject);
+
+		idr_remove_uobj(&ib_uverbs_xrcd_idr, uobj);
+		ib_uverbs_dealloc_xrcd(file->device, xrcd);
+		kfree(uxrcd);
+	}
+	mutex_unlock(&file->device->xrcd_tree_mutex);
+
 	list_for_each_entry_safe(uobj, tmp, &context->pd_list, list) {
 		struct ib_pd *pd = uobj->object;
 
@@ -741,6 +756,8 @@
 
 	kref_init(&uverbs_dev->ref);
 	init_completion(&uverbs_dev->comp);
+	uverbs_dev->xrcd_tree = RB_ROOT;
+	mutex_init(&uverbs_dev->xrcd_tree_mutex);
 
 	spin_lock(&map_lock);
 	devnum = find_first_zero_bit(dev_map, IB_UVERBS_MAX_DEVICES);