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Commit 4e106275 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 

Pull crypto fixes from Herbert Xu:
 "This push fixes a boot hang in virt guests when the virtio RNG is
  enabled"

* git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6:
  hwrng: virtio - ensure reads happen after successful probe
  hwrng: fetch randomness only after device init
parents f8397191 e052dbf5

drivers/char/hw_random/core.c

+39 −8
Original line number Diff line number Diff line
@@ -55,16 +55,41 @@ static DEFINE_MUTEX(rng_mutex); 
static int data_avail;

static u8 *rng_buffer;



static inline int rng_get_data(struct hwrng *rng, u8 *buffer, size_t size,

			       int wait);



static size_t rng_buffer_size(void)

{

	return SMP_CACHE_BYTES < 32 ? 32 : SMP_CACHE_BYTES;

}



static void add_early_randomness(struct hwrng *rng)

{

	unsigned char bytes[16];

	int bytes_read;



	/*

	 * Currently only virtio-rng cannot return data during device

	 * probe, and that's handled in virtio-rng.c itself.  If there

	 * are more such devices, this call to rng_get_data can be

	 * made conditional here instead of doing it per-device.

	 */

	bytes_read = rng_get_data(rng, bytes, sizeof(bytes), 1);

	if (bytes_read > 0)

		add_device_randomness(bytes, bytes_read);

}



static inline int hwrng_init(struct hwrng *rng)

{

	if (!rng->init)

	if (rng->init) {

		int ret;



		ret =  rng->init(rng);

		if (ret)

			return ret;

	}

	add_early_randomness(rng);

	return 0;

	return rng->init(rng);

}



static inline void hwrng_cleanup(struct hwrng *rng)
@@ -304,8 +329,6 @@ int hwrng_register(struct hwrng *rng) 
{

	int err = -EINVAL;

	struct hwrng *old_rng, *tmp;

	unsigned char bytes[16];

	int bytes_read;



	if (rng->name == NULL ||

	    (rng->data_read == NULL && rng->read == NULL))
@@ -347,9 +370,17 @@ int hwrng_register(struct hwrng *rng) 
	INIT_LIST_HEAD(&rng->list);

	list_add_tail(&rng->list, &rng_list);



	bytes_read = rng_get_data(rng, bytes, sizeof(bytes), 1);

	if (bytes_read > 0)

		add_device_randomness(bytes, bytes_read);

	if (old_rng && !rng->init) {

		/*

		 * Use a new device's input to add some randomness to

		 * the system.  If this rng device isn't going to be

		 * used right away, its init function hasn't been

		 * called yet; so only use the randomness from devices

		 * that don't need an init callback.

		 */

		add_early_randomness(rng);

	}



out_unlock:

	mutex_unlock(&rng_mutex);

out:

drivers/char/hw_random/virtio-rng.c

+10 −0
Original line number Diff line number Diff line
@@ -38,6 +38,8 @@ struct virtrng_info { 
	int index;

};



static bool probe_done;



static void random_recv_done(struct virtqueue *vq)

{

	struct virtrng_info *vi = vq->vdev->priv;
@@ -67,6 +69,13 @@ static int virtio_read(struct hwrng *rng, void *buf, size_t size, bool wait) 
	int ret;

	struct virtrng_info *vi = (struct virtrng_info *)rng->priv;



	/*

	 * Don't ask host for data till we're setup.  This call can

	 * happen during hwrng_register(), after commit d9e7972619.

	 */

	if (unlikely(!probe_done))

		return 0;



	if (!vi->busy) {

		vi->busy = true;

		init_completion(&vi->have_data);
@@ -137,6 +146,7 @@ static int probe_common(struct virtio_device *vdev) 
		return err;

	}



	probe_done = true;

	return 0;

}