From 2f7c68cb55ecb7331f2381deb497c27155f32faf Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Wed, 03 Jan 2024 09:43:39 +0000
Subject: [PATCH] update kernel to 5.10.198
---
kernel/drivers/char/hw_random/virtio-rng.c | 86 ++++++++++++++++++++++++++++++++----------
1 files changed, 65 insertions(+), 21 deletions(-)
diff --git a/kernel/drivers/char/hw_random/virtio-rng.c b/kernel/drivers/char/hw_random/virtio-rng.c
index a90001e..3a194eb 100644
--- a/kernel/drivers/char/hw_random/virtio-rng.c
+++ b/kernel/drivers/char/hw_random/virtio-rng.c
@@ -4,6 +4,7 @@
* Copyright (C) 2007, 2008 Rusty Russell IBM Corporation
*/
+#include <asm/barrier.h>
#include <linux/err.h>
#include <linux/hw_random.h>
#include <linux/scatterlist.h>
@@ -18,71 +19,111 @@
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;
+ return read;
- ret = wait_for_completion_killable(&vi->have_data);
- if (ret < 0)
- return ret;
+ /* 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)
@@ -118,6 +159,9 @@
goto err_find;
}
+ /* we always have a pending entropy request */
+ request_entropy(vi);
+
return 0;
err_find:
@@ -133,9 +177,9 @@
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);
--
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