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authorLinus Torvalds <torvalds@linux-foundation.org>2014-07-18 20:25:54 -1000
committerLinus Torvalds <torvalds@linux-foundation.org>2014-07-18 20:25:54 -1000
commit4e106275290bdb015bc16dc48e55d78cc480e7c7 (patch)
tree0fe35ef231b8219883230e6a39a193ea57ac5418
parentf83971912231fe5390d2357442b6c25bb8076d9b (diff)
parente052dbf554610e2104c5a7518c4d8374bed701bb (diff)
downloadlinux-stericsson-4e106275290bdb015bc16dc48e55d78cc480e7c7.tar.gz
Merge git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6
Pull crypto fixes from Herbert Xu: "This push fixes a boot hang in virt guests when the virtio RNG is enabled" * git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6: hwrng: virtio - ensure reads happen after successful probe hwrng: fetch randomness only after device init
-rw-r--r--drivers/char/hw_random/core.c47
-rw-r--r--drivers/char/hw_random/virtio-rng.c10
2 files changed, 49 insertions, 8 deletions
diff --git a/drivers/char/hw_random/core.c b/drivers/char/hw_random/core.c
index 334601cc81cf..c4419ea1ab07 100644
--- a/drivers/char/hw_random/core.c
+++ b/drivers/char/hw_random/core.c
@@ -55,16 +55,41 @@ static DEFINE_MUTEX(rng_mutex);
static int data_avail;
static u8 *rng_buffer;
+static inline int rng_get_data(struct hwrng *rng, u8 *buffer, size_t size,
+ int wait);
+
static size_t rng_buffer_size(void)
{
return SMP_CACHE_BYTES < 32 ? 32 : SMP_CACHE_BYTES;
}
+static void add_early_randomness(struct hwrng *rng)
+{
+ unsigned char bytes[16];
+ int bytes_read;
+
+ /*
+ * Currently only virtio-rng cannot return data during device
+ * probe, and that's handled in virtio-rng.c itself. If there
+ * are more such devices, this call to rng_get_data can be
+ * made conditional here instead of doing it per-device.
+ */
+ bytes_read = rng_get_data(rng, bytes, sizeof(bytes), 1);
+ if (bytes_read > 0)
+ add_device_randomness(bytes, bytes_read);
+}
+
static inline int hwrng_init(struct hwrng *rng)
{
- if (!rng->init)
- return 0;
- return rng->init(rng);
+ if (rng->init) {
+ int ret;
+
+ ret = rng->init(rng);
+ if (ret)
+ return ret;
+ }
+ add_early_randomness(rng);
+ return 0;
}
static inline void hwrng_cleanup(struct hwrng *rng)
@@ -304,8 +329,6 @@ int hwrng_register(struct hwrng *rng)
{
int err = -EINVAL;
struct hwrng *old_rng, *tmp;
- unsigned char bytes[16];
- int bytes_read;
if (rng->name == NULL ||
(rng->data_read == NULL && rng->read == NULL))
@@ -347,9 +370,17 @@ int hwrng_register(struct hwrng *rng)
INIT_LIST_HEAD(&rng->list);
list_add_tail(&rng->list, &rng_list);
- bytes_read = rng_get_data(rng, bytes, sizeof(bytes), 1);
- if (bytes_read > 0)
- add_device_randomness(bytes, bytes_read);
+ if (old_rng && !rng->init) {
+ /*
+ * Use a new device's input to add some randomness to
+ * the system. If this rng device isn't going to be
+ * used right away, its init function hasn't been
+ * called yet; so only use the randomness from devices
+ * that don't need an init callback.
+ */
+ add_early_randomness(rng);
+ }
+
out_unlock:
mutex_unlock(&rng_mutex);
out:
diff --git a/drivers/char/hw_random/virtio-rng.c b/drivers/char/hw_random/virtio-rng.c
index f3e71501de54..e9b15bc18b4d 100644
--- a/drivers/char/hw_random/virtio-rng.c
+++ b/drivers/char/hw_random/virtio-rng.c
@@ -38,6 +38,8 @@ struct virtrng_info {
int index;
};
+static bool probe_done;
+
static void random_recv_done(struct virtqueue *vq)
{
struct virtrng_info *vi = vq->vdev->priv;
@@ -67,6 +69,13 @@ 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;
+ /*
+ * Don't ask host for data till we're setup. This call can
+ * happen during hwrng_register(), after commit d9e7972619.
+ */
+ if (unlikely(!probe_done))
+ return 0;
+
if (!vi->busy) {
vi->busy = true;
init_completion(&vi->have_data);
@@ -137,6 +146,7 @@ static int probe_common(struct virtio_device *vdev)
return err;
}
+ probe_done = true;
return 0;
}