On Mon, Jul 21, 2014 at 05:15:51PM +0530, Amit Shah wrote: > Instead of calling hwrng_register() in the probe routing, call it in the > scan routine. This ensures that when hwrng_register() is successful, > and it requests a few random bytes to seed the kernel's pool at init, > we're ready to service that request. > > This will also enable us to remove the workaround added previously to > check whether probe was completed, and only then ask for data from the > host. The revert follows in the next commit. > > There's a slight behaviour change here on unsuccessful hwrng_register(). > Previously, when hwrng_unregister() failed, the probe() routine would > fail, and the vqs would be torn down, and driver would be marked not > initialized. Now, the vqs will remain initialized, driver would be > marked initialized as well, but won't be available in the list of RNGs > available to hwrng core. To fix the failures, the procedure remains the > same, i.e. unload and re-load the module, and hope things succeed the > next time around.
I'm not too comfortable with this. I'll try to take a closer look tonight, but in the meantime... > Signed-off-by: Amit Shah <[email protected]> > --- > drivers/char/hw_random/virtio-rng.c | 25 +++++++++++++++---------- > 1 file changed, 15 insertions(+), 10 deletions(-) > > diff --git a/drivers/char/hw_random/virtio-rng.c > b/drivers/char/hw_random/virtio-rng.c > index a156284..d9927eb 100644 > --- a/drivers/char/hw_random/virtio-rng.c > +++ b/drivers/char/hw_random/virtio-rng.c > @@ -35,6 +35,7 @@ struct virtrng_info { > unsigned int data_avail; > int index; > bool busy; > + bool hwrng_register_done; > }; > > static bool probe_done; > @@ -136,15 +137,6 @@ static int probe_common(struct virtio_device *vdev) > return err; > } > > - err = hwrng_register(&vi->hwrng); > - if (err) { > - vdev->config->del_vqs(vdev); > - vi->vq = NULL; > - kfree(vi); > - ida_simple_remove(&rng_index_ida, index); > - return err; > - } > - This needs to stay. register, and failure to do so, should occur in the probe routine. > probe_done = true; > return 0; > } > @@ -152,9 +144,11 @@ static int probe_common(struct virtio_device *vdev) > static void remove_common(struct virtio_device *vdev) > { > struct virtrng_info *vi = vdev->priv; > + > vdev->config->reset(vdev); > vi->busy = false; > - hwrng_unregister(&vi->hwrng); > + if (vi->hwrng_register_done) > + hwrng_unregister(&vi->hwrng); > vdev->config->del_vqs(vdev); > ida_simple_remove(&rng_index_ida, vi->index); > kfree(vi); > @@ -170,6 +164,16 @@ static void virtrng_remove(struct virtio_device *vdev) > remove_common(vdev); > } > > +static void virtrng_scan(struct virtio_device *vdev) > +{ > + struct virtrng_info *vi = vdev->priv; > + int err; > + > + err = hwrng_register(&vi->hwrng); > + if (!err) > + vi->hwrng_register_done = true; Instead, perhaps we should just feed the entropy pool from here? We would still need to prevent the core from doing so. Perhaps back to the flag idea? thx, Jason. > +} > + > #ifdef CONFIG_PM_SLEEP > static int virtrng_freeze(struct virtio_device *vdev) > { > @@ -194,6 +198,7 @@ static struct virtio_driver virtio_rng_driver = { > .id_table = id_table, > .probe = virtrng_probe, > .remove = virtrng_remove, > + .scan = virtrng_scan, > #ifdef CONFIG_PM_SLEEP > .freeze = virtrng_freeze, > .restore = virtrng_restore, > -- > 1.9.3 > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
