diff options
| -rw-r--r-- | drivers/char/hw_random/virtio-rng.c | 24 |
1 files changed, 16 insertions, 8 deletions
diff --git a/drivers/char/hw_random/virtio-rng.c b/drivers/char/hw_random/virtio-rng.c index f2041fede82..32216b62324 100644 --- a/drivers/char/hw_random/virtio-rng.c +++ b/drivers/char/hw_random/virtio-rng.c @@ -35,13 +35,13 @@ static DECLARE_COMPLETION(have_data); static void random_recv_done(struct virtqueue *vq) { - int len; + unsigned int len; /* We can get spurious callbacks, e.g. shared IRQs + virtio_pci. */ if (!vq->vq_ops->get_buf(vq, &len)) return; - data_left = len / sizeof(random_data[0]); + data_left += len; complete(&have_data); } @@ -49,7 +49,7 @@ static void register_buffer(void) { struct scatterlist sg; - sg_init_one(&sg, random_data, RANDOM_DATA_SIZE); + sg_init_one(&sg, random_data+data_left, RANDOM_DATA_SIZE-data_left); /* There should always be room for one buffer. */ if (vq->vq_ops->add_buf(vq, &sg, 0, 1, random_data) != 0) BUG(); @@ -59,24 +59,32 @@ static void register_buffer(void) /* At least we don't udelay() in a loop like some other drivers. */ static int virtio_data_present(struct hwrng *rng, int wait) { - if (data_left) + if (data_left >= sizeof(u32)) return 1; +again: if (!wait) return 0; wait_for_completion(&have_data); + + /* Not enough? Re-register. */ + if (unlikely(data_left < sizeof(u32))) { + register_buffer(); + goto again; + } + return 1; } /* virtio_data_present() must have succeeded before this is called. */ static int virtio_data_read(struct hwrng *rng, u32 *data) { - BUG_ON(!data_left); - - *data = random_data[--data_left]; + BUG_ON(data_left < sizeof(u32)); + data_left -= sizeof(u32); + *data = random_data[data_left / 4]; - if (!data_left) { + if (data_left < sizeof(u32)) { init_completion(&have_data); register_buffer(); } |