3 files changed, 72 insertions, 28 deletions

diff --git a/drivers/char/hw_random/geode-rng.c b/drivers/char/hw_random/geode-rng.c
index 207272979..2f8289865 100644
--- a/drivers/char/hw_random/geode-rng.c
+++ b/drivers/char/hw_random/geode-rng.c
@@ -58,7 +58,8 @@ struct amd_geode_priv {
 
 static int geode_rng_data_read(struct hwrng *rng, u32 *data)
 {
-	void __iomem *mem = (void __iomem *)rng->priv;
+	struct amd_geode_priv *priv = (struct amd_geode_priv *)rng->priv;
+	void __iomem *mem = priv->membase;
 
 	*data = readl(mem + GEODE_RNG_DATA_REG);
 
@@ -67,7 +68,8 @@ static int geode_rng_data_read(struct hwrng *rng, u32 *data)
 
 static int geode_rng_data_present(struct hwrng *rng, int wait)
 {
-	void __iomem *mem = (void __iomem *)rng->priv;
+	struct amd_geode_priv *priv = (struct amd_geode_priv *)rng->priv;
+	void __iomem *mem = priv->membase;
 	int data, i;
 
 	for (i = 0; i < 20; i++) {
diff --git a/drivers/char/hw_random/imx-rngc.c b/drivers/char/hw_random/imx-rngc.c
index dc9b8f377..084f7e425 100644
--- a/drivers/char/hw_random/imx-rngc.c
+++ b/drivers/char/hw_random/imx-rngc.c
@@ -105,7 +105,7 @@ static int imx_rngc_self_test(struct imx_rngc *rngc)
 	cmd = readl(rngc->base + RNGC_COMMAND);
 	writel(cmd | RNGC_CMD_SELF_TEST, rngc->base + RNGC_COMMAND);
 
-	ret = wait_for_completion_timeout(&rngc->rng_op_done, RNGC_TIMEOUT);
+	ret = wait_for_completion_timeout(&rngc->rng_op_done, msecs_to_jiffies(RNGC_TIMEOUT));
 	if (!ret) {
 		imx_rngc_irq_mask_clear(rngc);
 		return -ETIMEDOUT;
@@ -188,9 +188,7 @@ static int imx_rngc_init(struct hwrng *rng)
 		cmd = readl(rngc->base + RNGC_COMMAND);
 		writel(cmd | RNGC_CMD_SEED, rngc->base + RNGC_COMMAND);
 
-		ret = wait_for_completion_timeout(&rngc->rng_op_done,
-				RNGC_TIMEOUT);
-
+		ret = wait_for_completion_timeout(&rngc->rng_op_done, msecs_to_jiffies(RNGC_TIMEOUT));
 		if (!ret) {
 			imx_rngc_irq_mask_clear(rngc);
 			return -ETIMEDOUT;
diff --git a/drivers/char/hw_random/virtio-rng.c b/drivers/char/hw_random/virtio-rng.c
index 7abd604e9..58884d875 100644
--- a/drivers/char/hw_random/virtio-rng.c
+++ b/drivers/char/hw_random/virtio-rng.c
@@ -17,6 +17,7 @@
  *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
  */
 
+#include <asm/barrier.h>
 #include <linux/err.h>
 #include <linux/hw_random.h>
 #include <linux/scatterlist.h>
@@ -30,71 +31,111 @@ static DEFINE_IDA(rng_index_ida);
 struct virtrng_info {
 	struct hwrng hwrng;
 	struct virtqueue *vq;
-	struct completion have_data;
 	char name[25];
-	unsigned int data_avail;
 	int index;
-	bool busy;
 	bool hwrng_register_done;
 	bool hwrng_removed;
+	/* data transfer */
+	struct completion have_data;
+	unsigned int data_avail;
+	unsigned int data_idx;
+	/* minimal size returned by rng_buffer_size() */
+#if SMP_CACHE_BYTES < 32
+	u8 data[32];
+#else
+	u8 data[SMP_CACHE_BYTES];
+#endif
 };
 
 static void random_recv_done(struct virtqueue *vq)
 {
 	struct virtrng_info *vi = vq->vdev->priv;
+	unsigned int len;
 
 	/* We can get spurious callbacks, e.g. shared IRQs + virtio_pci. */
-	if (!virtqueue_get_buf(vi->vq, &vi->data_avail))
+	if (!virtqueue_get_buf(vi->vq, &len))
 		return;
 
+	smp_store_release(&vi->data_avail, len);
 	complete(&vi->have_data);
 }
 
-/* The host will fill any buffer we give it with sweet, sweet randomness. */
-static void register_buffer(struct virtrng_info *vi, u8 *buf, size_t size)
+static void request_entropy(struct virtrng_info *vi)
 {
 	struct scatterlist sg;
 
-	sg_init_one(&sg, buf, size);
+	reinit_completion(&vi->have_data);
+	vi->data_idx = 0;
+
+	sg_init_one(&sg, vi->data, sizeof(vi->data));
 
 	/* There should always be room for one buffer. */
-	virtqueue_add_inbuf(vi->vq, &sg, 1, buf, GFP_KERNEL);
+	virtqueue_add_inbuf(vi->vq, &sg, 1, vi->data, GFP_KERNEL);
 
 	virtqueue_kick(vi->vq);
 }
 
+static unsigned int copy_data(struct virtrng_info *vi, void *buf,
+			      unsigned int size)
+{
+	size = min_t(unsigned int, size, vi->data_avail);
+	memcpy(buf, vi->data + vi->data_idx, size);
+	vi->data_idx += size;
+	vi->data_avail -= size;
+	if (vi->data_avail == 0)
+		request_entropy(vi);
+	return size;
+}
+
 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;
+	unsigned int chunk;
+	size_t read;
 
 	if (vi->hwrng_removed)
 		return -ENODEV;
 
-	if (!vi->busy) {
-		vi->busy = true;
-		reinit_completion(&vi->have_data);
-		register_buffer(vi, buf, size);
+	read = 0;
+
+	/* copy available data */
+	if (smp_load_acquire(&vi->data_avail)) {
+		chunk = copy_data(vi, buf, size);
+		size -= chunk;
+		read += chunk;
 	}
 
 	if (!wait)
-		return 0;
-
-	ret = wait_for_completion_killable(&vi->have_data);
-	if (ret < 0)
-		return ret;
+		return read;
+
+	/* We have already copied available entropy,
+	 * so either size is 0 or data_avail is 0
+	 */
+	while (size != 0) {
+		/* data_avail is 0 but a request is pending */
+		ret = wait_for_completion_killable(&vi->have_data);
+		if (ret < 0)
+			return ret;
+		/* if vi->data_avail is 0, we have been interrupted
+		 * by a cleanup, but buffer stays in the queue
+		 */
+		if (vi->data_avail == 0)
+			return read;
 
-	vi->busy = false;
+		chunk = copy_data(vi, buf + read, size);
+		size -= chunk;
+		read += chunk;
+	}
 
-	return vi->data_avail;
+	return read;
 }
 
 static void virtio_cleanup(struct hwrng *rng)
 {
 	struct virtrng_info *vi = (struct virtrng_info *)rng->priv;
 
-	if (vi->busy)
-		wait_for_completion(&vi->have_data);
+	complete(&vi->have_data);
 }
 
 static int probe_common(struct virtio_device *vdev)
@@ -130,6 +171,9 @@ static int probe_common(struct virtio_device *vdev)
 		goto err_find;
 	}
 
+	/* we always have a pending entropy request */
+	request_entropy(vi);
+
 	return 0;
 
 err_find:
@@ -145,9 +189,9 @@ static void remove_common(struct virtio_device *vdev)
 
 	vi->hwrng_removed = true;
 	vi->data_avail = 0;
+	vi->data_idx = 0;
 	complete(&vi->have_data);
 	vdev->config->reset(vdev);
-	vi->busy = false;
 	if (vi->hwrng_register_done)
 		hwrng_unregister(&vi->hwrng);
 	vdev->config->del_vqs(vdev);