Hi Jim,
On 3 November 2017 at 15:27, Jim Quigley <Jim.Quigley@xxxxxxxxxx> wrote:
> The patch for
>
> commit: 5c06273401f2eb7b290cadbae18ee00f8f65e893
> Author: Amit Shah <amit.shah@xxxxxxxxxx>
> Date: Sun Jul 27 07:34:01 2014 +0930
>
> virtio: rng: delay hwrng_register() till driver is ready
>
> moved the call to hwrng_register() out of the probe routine into the scan
> routine. We need to call hwrng_register() after a suspend/restore cycle
> to re-register the device, but the scan function is not invoked for the
> restore. Add the call to hwrng_register() to virtio_restore().
>
> Reviewed-by: Liam Merwick <Liam.Merwick@xxxxxxxxxx>
> Signed-off-by: Jim Quigley <Jim.Quigley@xxxxxxxxxx>
> ---
> drivers/char/hw_random/virtio-rng.c | 21 ++++++++++++++++++++-
> 1 file changed, 20 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/char/hw_random/virtio-rng.c b/drivers/char/hw_random/virtio-rng.c
> index 3fa2f8a..b89df66 100644
> --- a/drivers/char/hw_random/virtio-rng.c
> +++ b/drivers/char/hw_random/virtio-rng.c
> @@ -184,7 +184,26 @@ static int virtrng_freeze(struct virtio_device *vdev)
>
> static int virtrng_restore(struct virtio_device *vdev)
> {
> - return probe_common(vdev);
> + int err;
> +
> + err = probe_common(vdev);
> + if (!err) {
> + struct virtrng_info *vi = vdev->priv;
> +
> + /*
> + * Set hwrng_removed to ensure that virtio_read()
> + * does not block waiting for data before the
> + * registration is complete.
> + */
> + vi->hwrng_removed = true;
> + err = hwrng_register(&vi->hwrng);
> + if (!err) {
> + vi->hwrng_register_done = true;
> + vi->hwrng_removed = false;
> + }
> + }
> +
> + return err;
> }
> #endif
>
> --
> 1.8.3.1
>
This patch makes me wonder why hwrng_unregister is required in
virtrng_freeze. Looks strange and unusual. May be that is not required
and it can be removed. If it is required can you please add a comment
on why it is required?
Thanks,
PrasannaKumar
