IB/hfi1: Protect the interval RB tree when cleaning up

[mirror_ubuntu-artful-kernel.git] / drivers / staging / rdma / hfi1 / mmu_rb.c

diff --git a/drivers/staging/rdma/hfi1/mmu_rb.c b/drivers/staging/rdma/hfi1/mmu_rb.c
index b3f0682a36c95ffdd15f1b4d5d2f8cfb2e2afac3..72b6d70ae2b57c5436984a17689bf61199881202 100644 (file)
--- a/drivers/staging/rdma/hfi1/mmu_rb.c
+++ b/drivers/staging/rdma/hfi1/mmu_rb.c
@@ -126,10 +126,15 @@ void hfi1_mmu_rb_unregister(struct rb_root *root)
        if (!handler)
                return;
 
+       /* Unregister first so we don't get any more notifications. */
+       if (current->mm)
+               mmu_notifier_unregister(&handler->mn, current->mm);
+
        spin_lock_irqsave(&mmu_rb_lock, flags);
        list_del(&handler->list);
        spin_unlock_irqrestore(&mmu_rb_lock, flags);
 
+       spin_lock_irqsave(&handler->lock, flags);
        if (!RB_EMPTY_ROOT(root)) {
                struct rb_node *node;
                struct mmu_rb_node *rbnode;
@@ -141,9 +146,8 @@ void hfi1_mmu_rb_unregister(struct rb_root *root)
                                handler->ops->remove(root, rbnode, NULL);
                }
        }
+       spin_unlock_irqrestore(&handler->lock, flags);
 
-       if (current->mm)
-               mmu_notifier_unregister(&handler->mn, current->mm);
        kfree(handler);
 }