IB/core: Add support for idr types

The new ioctl infrastructure supports driver specific objects.
Each such object type has a hot unplug function, allocation size and
an order of destruction.

When a ucontext is created, a new list is created in this ib_ucontext.
This list contains all objects created under this ib_ucontext.
When a ib_ucontext is destroyed, we traverse this list several time
destroying the various objects by the order mentioned in the object
type description. If few object types have the same destruction order,
they are destroyed in an order opposite to their creation.

Adding an object is done in two parts.
First, an object is allocated and added to idr tree. Then, the
command's handlers (in downstream patches) could work on this object
and fill in its required details.
After a successful command, the commit part is called and the user
objects become ucontext visible. If the handler failed, alloc_abort
should be called.

Removing an uboject is done by calling lookup_get with the write flag
and finalizing it with destroy_commit. A major change from the previous
code is that we actually destroy the kernel object itself in
destroy_commit (rather than just the uobject).

We should make sure idr (per-uverbs-file) and list (per-ucontext) could
be accessed concurrently without corrupting them.

Signed-off-by: Matan Barak <matanb@mellanox.com>
Reviewed-by: Yishai Hadas <yishaih@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

1 files changed, 21 insertions, 0 deletions

diff --git a/include/rdma/ib_verbs.h b/include/rdma/ib_verbs.h
index 319e69106a26..d3efd22943e9 100644
--- a/include/rdma/ib_verbs.h
+++ b/include/rdma/ib_verbs.h
@@ -1357,6 +1357,17 @@ struct ib_fmr_attr {
 
 struct ib_umem;
 
+enum rdma_remove_reason {
+	/* Userspace requested uobject deletion. Call could fail */
+	RDMA_REMOVE_DESTROY,
+	/* Context deletion. This call should delete the actual object itself */
+	RDMA_REMOVE_CLOSE,
+	/* Driver is being hot-unplugged. This call should delete the actual object itself */
+	RDMA_REMOVE_DRIVER_REMOVE,
+	/* Context is being cleaned-up, but commit was just completed */
+	RDMA_REMOVE_DURING_CLEANUP,
+};
+
 struct ib_rdmacg_object {
 #ifdef CONFIG_CGROUP_RDMA
 	struct rdma_cgroup	*cg;		/* owner rdma cgroup */
@@ -1379,6 +1390,13 @@ struct ib_ucontext {
 	struct list_head	rwq_ind_tbl_list;
 	int			closing;
 
+	/* locking the uobjects_list */
+	struct mutex		uobjects_lock;
+	struct list_head	uobjects;
+	/* protects cleanup process from other actions */
+	struct rw_semaphore	cleanup_rwsem;
+	enum rdma_remove_reason cleanup_reason;
+
 	struct pid             *tgid;
 #ifdef CONFIG_INFINIBAND_ON_DEMAND_PAGING
 	struct rb_root      umem_tree;
@@ -1409,8 +1427,11 @@ struct ib_uobject {
 	int			id;		/* index into kernel idr */
 	struct kref		ref;
 	struct rw_semaphore	mutex;		/* protects .live */
+	atomic_t		usecnt;		/* protects exclusive access */
 	struct rcu_head		rcu;		/* kfree_rcu() overhead */
 	int			live;
+
+	const struct uverbs_obj_type *type;
 };
 
 struct ib_udata {