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authorAmit Shah <amit.shah@redhat.com>2014-07-27 07:34:01 +0930
committerRusty Russell <rusty@rustcorp.com.au>2014-07-27 21:07:19 +0930
commit5c06273401f2eb7b290cadbae18ee00f8f65e893 (patch)
tree95635eeb27150d591eff5a5781ad44614fc8a40f /drivers/char
parent6062829fcdcae4518436f51336c0e05bd1f04806 (diff)
virtio: rng: delay hwrng_register() till driver is ready
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_register() 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. Signed-off-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Diffstat (limited to 'drivers/char')
-rw-r--r--drivers/char/hw_random/virtio-rng.c25
1 files changed, 15 insertions, 10 deletions
diff --git a/drivers/char/hw_random/virtio-rng.c b/drivers/char/hw_random/virtio-rng.c
index a1562841f539..d9927eb4fa98 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;
- }
-
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;
+}
+
#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,