Merge branch 'misc' into release

[safe/jmp/linux-2.6] / drivers / char / hw_random / virtio-rng.c

diff --git a/drivers/char/hw_random/virtio-rng.c b/drivers/char/hw_random/virtio-rng.c
index 32216b6..64fe0a7 100644 (file)
--- 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)
@@ -112,11 +99,10 @@ static int virtrng_probe(struct virtio_device *vdev)
                return err;
        }
 
-       register_buffer();
        return 0;
 }
 
-static void virtrng_remove(struct virtio_device *vdev)
+static void __devexit virtrng_remove(struct virtio_device *vdev)
 {
        vdev->config->reset(vdev);
        hwrng_unregister(&virtio_hwrng);
@@ -128,7 +114,7 @@ static struct virtio_device_id id_table[] = {
        { 0 },
 };
 
-static struct virtio_driver virtio_rng = {
+static struct virtio_driver virtio_rng_driver = {
        .driver.name =  KBUILD_MODNAME,
        .driver.owner = THIS_MODULE,
        .id_table =     id_table,
@@ -138,22 +124,12 @@ 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_driver);
 }
 
 static void __exit fini(void)
 {
-       kfree(random_data);
-       unregister_virtio_driver(&virtio_rng);
+       unregister_virtio_driver(&virtio_rng_driver);
 }
 module_init(init);
 module_exit(fini);