virtio: rng: allow tasks to be killed that are waiting for rng input

Use wait_for_completion_killable() instead of wait_for_completion() when
waiting for the host to send us entropy.  Without this,

  # cat /dev/hwrng
  ^C

just hangs.

Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

1 files changed, 4 insertions, 1 deletions

diff --git a/drivers/char/hw_random/virtio-rng.c b/drivers/char/hw_random/virtio-rng.c
index 723725bbb96b..c8a935034218 100644
--- a/drivers/char/hw_random/virtio-rng.c
+++ b/drivers/char/hw_random/virtio-rng.c
@@ -55,6 +55,7 @@ static void register_buffer(u8 *buf, size_t size)
 
 static int virtio_read(struct hwrng *rng, void *buf, size_t size, bool wait)
 {
+        int ret;
 
         if (!busy) {
                 busy = true;
@@ -65,7 +66,9 @@ static int virtio_read(struct hwrng *rng, void *buf, size_t size, bool wait)
         if (!wait)
                 return 0;
 
-        wait_for_completion(&have_data);
+        ret = wait_for_completion_killable(&have_data);
+        if (ret < 0)
+                return ret;
 
         busy = false;