RDMA/umem: Use umem->owning_mm inside ODP

Since ODP had a single struct mmu_notifier located in the ucontext it
could only handle a single MM at a time, and this prevented it from using
the new owning_mm system.

With the prior rework it is now simple to let ODP track multiple MMs per
ucontext, finish the job so that the per_mm is allocated on a mm by mm
basis, and freed when the last umem is dropped from the ucontext.

As a side effect the new saner locking removes the lockdep splat about
nesting the umem_rwsem between mmu_notifier_unregister and
ib_umem_odp_release.

It also makes ODP work with multiple processes, across, fork, etc.

Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

1 files changed, 2 insertions, 6 deletions

diff --git a/drivers/infiniband/core/uverbs_cmd.c b/drivers/infiniband/core/uverbs_cmd.c
index ce678e1008a4..d77b0b9793c7 100644
--- a/drivers/infiniband/core/uverbs_cmd.c
+++ b/drivers/infiniband/core/uverbs_cmd.c
@@ -124,12 +124,8 @@ ssize_t ib_uverbs_get_context(struct ib_uverbs_file *file,
 	ucontext->cleanup_retryable = false;
 
 #ifdef CONFIG_INFINIBAND_ON_DEMAND_PAGING
-	ucontext->per_mm.umem_tree = RB_ROOT_CACHED;
-	init_rwsem(&ucontext->per_mm.umem_rwsem);
-	ucontext->per_mm.odp_mrs_count = 0;
-	INIT_LIST_HEAD(&ucontext->per_mm.no_private_counters);
-	ucontext->per_mm.context = ucontext;
-
+	mutex_init(&ucontext->per_mm_list_lock);
+	INIT_LIST_HEAD(&ucontext->per_mm_list);
 	if (!(ib_dev->attrs.device_cap_flags & IB_DEVICE_ON_DEMAND_PAGING))
 		ucontext->invalidate_range = NULL;