2 files changed, 92 insertions, 95 deletions

diff --git a/drivers/char/hw_random/core.c b/drivers/char/hw_random/core.c
index 1573aebd54b5..e989f67bb61f 100644
--- a/drivers/char/hw_random/core.c
+++ b/drivers/char/hw_random/core.c
@@ -52,7 +52,9 @@
 static struct hwrng *current_rng;
 static LIST_HEAD(rng_list);
 static DEFINE_MUTEX(rng_mutex);
-
+static int data_avail;
+static u8 rng_buffer[SMP_CACHE_BYTES < 32 ? 32 : SMP_CACHE_BYTES]
+	__cacheline_aligned;
 
 static inline int hwrng_init(struct hwrng *rng)
 {
@@ -67,19 +69,6 @@ static inline void hwrng_cleanup(struct hwrng *rng)
 		rng->cleanup(rng);
 }
 
-static inline int hwrng_data_present(struct hwrng *rng, int wait)
-{
-	if (!rng->data_present)
-		return 1;
-	return rng->data_present(rng, wait);
-}
-
-static inline int hwrng_data_read(struct hwrng *rng, u32 *data)
-{
-	return rng->data_read(rng, data);
-}
-
-
 static int rng_dev_open(struct inode *inode, struct file *filp)
 {
 	/* enforce read-only access to this chrdev */
@@ -87,58 +76,90 @@ static int rng_dev_open(struct inode *inode, struct file *filp)
 		return -EINVAL;
 	if (filp->f_mode & FMODE_WRITE)
 		return -EINVAL;
-	cycle_kernel_lock();
+	return 0;
+}
+
+static inline int rng_get_data(struct hwrng *rng, u8 *buffer, size_t size,
+			int wait) {
+	int present;
+
+	if (rng->read)
+		return rng->read(rng, (void *)buffer, size, wait);
+
+	if (rng->data_present)
+		present = rng->data_present(rng, wait);
+	else
+		present = 1;
+
+	if (present)
+		return rng->data_read(rng, (u32 *)buffer);
+
 	return 0;
 }
 
 static ssize_t rng_dev_read(struct file *filp, char __user *buf,
 			    size_t size, loff_t *offp)
 {
-	u32 data;
 	ssize_t ret = 0;
 	int err = 0;
-	int bytes_read;
+	int bytes_read, len;
 
 	while (size) {
-		err = -ERESTARTSYS;
-		if (mutex_lock_interruptible(&rng_mutex))
+		if (mutex_lock_interruptible(&rng_mutex)) {
+			err = -ERESTARTSYS;
 			goto out;
+		}
+
 		if (!current_rng) {
-			mutex_unlock(&rng_mutex);
 			err = -ENODEV;
-			goto out;
+			goto out_unlock;
 		}
 
-		bytes_read = 0;
-		if (hwrng_data_present(current_rng,
-				       !(filp->f_flags & O_NONBLOCK)))
-			bytes_read = hwrng_data_read(current_rng, &data);
-		mutex_unlock(&rng_mutex);
-
-		err = -EAGAIN;
-		if (!bytes_read && (filp->f_flags & O_NONBLOCK))
-			goto out;
-		if (bytes_read < 0) {
-			err = bytes_read;
-			goto out;
+		if (!data_avail) {
+			bytes_read = rng_get_data(current_rng, rng_buffer,
+				sizeof(rng_buffer),
+				!(filp->f_flags & O_NONBLOCK));
+			if (bytes_read < 0) {
+				err = bytes_read;
+				goto out_unlock;
+			}
+			data_avail = bytes_read;
 		}
 
-		err = -EFAULT;
-		while (bytes_read && size) {
-			if (put_user((u8)data, buf++))
-				goto out;
-			size--;
-			ret++;
-			bytes_read--;
-			data >>= 8;
+		if (!data_avail) {
+			if (filp->f_flags & O_NONBLOCK) {
+				err = -EAGAIN;
+				goto out_unlock;
+			}
+		} else {
+			len = data_avail;
+			if (len > size)
+				len = size;
+
+			data_avail -= len;
+
+			if (copy_to_user(buf + ret, rng_buffer + data_avail,
+								len)) {
+				err = -EFAULT;
+				goto out_unlock;
+			}
+
+			size -= len;
+			ret += len;
 		}
 
+		mutex_unlock(&rng_mutex);
+
 		if (need_resched())
 			schedule_timeout_interruptible(1);
-		err = -ERESTARTSYS;
-		if (signal_pending(current))
+
+		if (signal_pending(current)) {
+			err = -ERESTARTSYS;
 			goto out;
+		}
 	}
+out_unlock:
+	mutex_unlock(&rng_mutex);
 out:
 	return ret ? : err;
 }
@@ -280,7 +301,7 @@ int hwrng_register(struct hwrng *rng)
 	struct hwrng *old_rng, *tmp;
 
 	if (rng->name == NULL ||
-	    rng->data_read == NULL)
+	    (rng->data_read == NULL && rng->read == NULL))
 		goto out;
 
 	mutex_lock(&rng_mutex);
diff --git a/drivers/char/hw_random/virtio-rng.c b/drivers/char/hw_random/virtio-rng.c
index 915157fcff98..bdaef8e94021 100644
--- a/drivers/char/hw_random/virtio-rng.c
+++ b/drivers/char/hw_random/virtio-rng.c
@@ -16,6 +16,7 @@
  *  along with this program; if not, write to the Free Software
  *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
  */
+
 #include <linux/err.h>
 #include <linux/hw_random.h>
 #include <linux/scatterlist.h>
@@ -23,78 +24,64 @@
 #include <linux/virtio.h>
 #include <linux/virtio_rng.h>
 
-/* The host will fill any buffer we give it with sweet, sweet randomness.  We
- * give it 64 bytes at a time, and the hwrng framework takes it 4 bytes at a
- * time. */
-#define RANDOM_DATA_SIZE 64
-
 static struct virtqueue *vq;
-static u32 *random_data;
-static unsigned int data_left;
+static unsigned int data_avail;
 static DECLARE_COMPLETION(have_data);
+static bool busy;
 
 static void random_recv_done(struct virtqueue *vq)
 {
-	unsigned int len;
-
 	/* We can get spurious callbacks, e.g. shared IRQs + virtio_pci. */
-	if (!vq->vq_ops->get_buf(vq, &len))
+	if (!vq->vq_ops->get_buf(vq, &data_avail))
 		return;
 
-	data_left += len;
 	complete(&have_data);
 }
 
-static void register_buffer(void)
+/* The host will fill any buffer we give it with sweet, sweet randomness. */
+static void register_buffer(u8 *buf, size_t size)
 {
 	struct scatterlist sg;
 
-	sg_init_one(&sg, random_data+data_left, RANDOM_DATA_SIZE-data_left);
+	sg_init_one(&sg, buf, size);
+
 	/* There should always be room for one buffer. */
-	if (vq->vq_ops->add_buf(vq, &sg, 0, 1, random_data) < 0)
+	if (vq->vq_ops->add_buf(vq, &sg, 0, 1, buf) < 0)
 		BUG();
+
 	vq->vq_ops->kick(vq);
 }
 
-/* At least we don't udelay() in a loop like some other drivers. */
-static int virtio_data_present(struct hwrng *rng, int wait)
+static int virtio_read(struct hwrng *rng, void *buf, size_t size, bool wait)
 {
-	if (data_left >= sizeof(u32))
-		return 1;
 
-again:
+	if (!busy) {
+		busy = true;
+		init_completion(&have_data);
+		register_buffer(buf, size);
+	}
+
 	if (!wait)
 		return 0;
 
 	wait_for_completion(&have_data);
 
-	/* Not enough?  Re-register. */
-	if (unlikely(data_left < sizeof(u32))) {
-		register_buffer();
-		goto again;
-	}
+	busy = false;
 
-	return 1;
+	return data_avail;
 }
 
-/* virtio_data_present() must have succeeded before this is called. */
-static int virtio_data_read(struct hwrng *rng, u32 *data)
+static void virtio_cleanup(struct hwrng *rng)
 {
-	BUG_ON(data_left < sizeof(u32));
-	data_left -= sizeof(u32);
-	*data = random_data[data_left / 4];
-
-	if (data_left < sizeof(u32)) {
-		init_completion(&have_data);
-		register_buffer();
-	}
-	return sizeof(*data);
+	if (busy)
+		wait_for_completion(&have_data);
 }
 
+
 static struct hwrng virtio_hwrng = {
-	.name = "virtio",
-	.data_present = virtio_data_present,
-	.data_read = virtio_data_read,
+	.name		= "virtio",
+	.cleanup	= virtio_cleanup,
+	.read		= virtio_read,
 };
 
 static int virtrng_probe(struct virtio_device *vdev)
@@ -112,7 +99,6 @@ static int virtrng_probe(struct virtio_device *vdev)
 		return err;
 	}
 
-	register_buffer();
 	return 0;
 }
 
@@ -138,21 +124,11 @@ static struct virtio_driver virtio_rng = {
 
 static int __init init(void)
 {
-	int err;
-
-	random_data = kmalloc(RANDOM_DATA_SIZE, GFP_KERNEL);
-	if (!random_data)
-		return -ENOMEM;
-
-	err = register_virtio_driver(&virtio_rng);
-	if (err)
-		kfree(random_data);
-	return err;
+	return register_virtio_driver(&virtio_rng);
 }
 
 static void __exit fini(void)
 {
-	kfree(random_data);
 	unregister_virtio_driver(&virtio_rng);
 }
 module_init(init);