IB/core: Fix mismatch between locked and pinned pages

commit c4870eb874ac16dccef40e1bc7a002c7e9156adc upstream.

Commit bc3e53f682d9 ("mm: distinguish between mlocked and pinned
pages") introduced a separate counter for pinned pages and used it in
the IB stack.  However, in ib_umem_get() the pinned counter is
incremented, but ib_umem_release() wrongly decrements the locked
counter.  Fix this.

Signed-off-by: Yishai Hadas <yishaih@mellanox.com>
Reviewed-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/infiniband/core/umem.c b/drivers/infiniband/core/umem.c
index 71f0c0f..a841123 100644
--- a/drivers/infiniband/core/umem.c
+++ b/drivers/infiniband/core/umem.c
@@ -269,7 +269,7 @@
 	} else
 		down_write(&mm->mmap_sem);
 
-	current->mm->locked_vm -= diff;
+	current->mm->pinned_vm -= diff;
 	up_write(&mm->mmap_sem);
 	mmput(mm);
 	kfree(umem);