[PATCH 4.2.y-ckt 152/305] virtio: fix memory leak of virtio ida cache layers

[Kamal Mostafa]

4.2.8-ckt2 -stable review patch.  If anyone has any objections, please let me know.

---8<------------------------------------------------------------

From: Suman Anna <s-anna@xxxxxx>

commit c13f99b7e945dad5273a8b7ee230f4d1f22d3354 upstream.

The virtio core uses a static ida named virtio_index_ida for
assigning index numbers to virtio devices during registration.
The ida core may allocate some internal idr cache layers and
an ida bitmap upon any ida allocation, and all these layers are
truely freed only upon the ida destruction. The virtio_index_ida
is not destroyed at present, leading to a memory leak when using
the virtio core as a module and atleast one virtio device is
registered and unregistered.

Fix this by invoking ida_destroy() in the virtio core module
exit.

Signed-off-by: Suman Anna <s-anna@xxxxxx>
Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
Signed-off-by: Kamal Mostafa <kamal@xxxxxxxxxxxxx>
---
 drivers/virtio/virtio.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c
index b1877d7..7062bb0 100644
--- a/drivers/virtio/virtio.c
+++ b/drivers/virtio/virtio.c
@@ -412,6 +412,7 @@ static int virtio_init(void)
 static void __exit virtio_exit(void)
 {
 	bus_unregister(&virtio_bus);
+	ida_destroy(&virtio_index_ida);
 }
 core_initcall(virtio_init);
 module_exit(virtio_exit);
-- 
1.9.1