[PATCH v2 0/4] hwrng: virtio - add an internal buffer

[Laurent Vivier]

hwrng core uses two buffers that can be mixed in the virtio-rng queue.

This series fixes the problem by adding an internal buffer in virtio-rng.

Once the internal buffer is added, we can fix two other problems:

- to be able to release the driver without waiting the device releases the
  buffer

- actually returns some data when wait=0 as we can have some already
  available data

It also tries to improve the performance by always having a buffer in
the queue of the device.

v2:
fixes issue reported by syzbot+b86736b5935e0d25b446@xxxxxxxxxxxxxxxxxxxxxxxxx
by reseting data_idx to 0 when the buffer is submitted not when it is
received as the consumer checks for data_avail, not only for the completion.

Laurent Vivier (4):
  hwrng: virtio - add an internal buffer
  hwrng: virtio - don't wait on cleanup
  hwrng: virtio - don't waste entropy
  hwrng: virtio - always add a pending request

 drivers/char/hw_random/virtio-rng.c | 86 ++++++++++++++++++++++-------
 1 file changed, 65 insertions(+), 21 deletions(-)

-- 
2.31.1