[3.16 stable PATCH 1/2] virtio-rng: fix stuck of hot-unplugging busy device

From: Amos Kong
Date: Fri Oct 10 2014 - 18:52:03 EST

When we try to hot-remove a busy virtio-rng device from QEMU monitor,
the device can't be hot-removed. Because virtio-rng driver hangs at

This patch exits the waiting by completing have_data completion before
unregistering, resets data_avail to avoid the hwrng core use wrong
buffer bytes.

Signed-off-by: Amos Kong <akong@xxxxxxxxxx>
Reviewed-by: Amit Shah <amit.shah@xxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
(cherry picked from commit 3856e548372513665670ca5db60d9a74b970fe0d)
Signed-off-by: Amos Kong <akong@xxxxxxxxxx>
drivers/char/hw_random/virtio-rng.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/drivers/char/hw_random/virtio-rng.c b/drivers/char/hw_random/virtio-rng.c
index f1aa13b..b50252c 100644
--- a/drivers/char/hw_random/virtio-rng.c
+++ b/drivers/char/hw_random/virtio-rng.c
@@ -137,6 +137,8 @@ static void remove_common(struct virtio_device *vdev)
struct virtrng_info *vi = vdev->priv;

+ vi->data_avail = 0;
+ complete(&vi->have_data);
vi->busy = false;
if (vi->hwrng_register_done)

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