linux-kernel - [RFC PATCH 3/3] Revert "virtio: rng: ensure reads happen after successful probe"

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Date:	Mon, 14 Jul 2014 10:05:21 +0530
From:	Amit Shah <amit.shah@...hat.com>
To:	linux-kernel@...r.kernel.org
Cc:	Virtualization List <virtualization@...ts.linux-foundation.org>,
	Rusty Russell <rusty@...tcorp.com.au>,
	herbert@...dor.apana.org.au, keescook@...omium.org,
	jason@...edaemon.net, Amit Shah <amit.shah@...hat.com>
Subject: [RFC PATCH 3/3] Revert "virtio: rng: ensure reads happen after successful probe"

This reverts commit ceb5d72a2e27e95bc9570ce259c45b35f0e23462.

This commit was added for -stable so systems with virtio-rng don't
freeze at boot-time.

With the addition of the previous commits that delay the request for
initial randomness after probe() is successful, this is no longer
needed.

CC: Kees Cook <keescook@...omium.org>
CC: Jason Cooper <jason@...edaemon.net>
CC: Herbert Xu <herbert@...dor.apana.org.au>
Signed-off-by: Amit Shah <amit.shah@...hat.com>
---
 drivers/char/hw_random/core.c       |  6 ------
 drivers/char/hw_random/virtio-rng.c | 10 ----------
 2 files changed, 16 deletions(-)

diff --git a/drivers/char/hw_random/core.c b/drivers/char/hw_random/core.c
index 2a765fd..148d9be 100644
--- a/drivers/char/hw_random/core.c
+++ b/drivers/char/hw_random/core.c
@@ -68,12 +68,6 @@ static void get_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);
diff --git a/drivers/char/hw_random/virtio-rng.c b/drivers/char/hw_random/virtio-rng.c
index f53f1e8..f7d1573 100644
--- a/drivers/char/hw_random/virtio-rng.c
+++ b/drivers/char/hw_random/virtio-rng.c
@@ -37,8 +37,6 @@ struct virtrng_info {
 	int index;
 };
 
-static bool probe_done;
-
 static void random_recv_done(struct virtqueue *vq)
 {
 	struct virtrng_info *vi = vq->vdev->priv;
@@ -68,13 +66,6 @@ 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);
@@ -146,7 +137,6 @@ static int probe_common(struct virtio_device *vdev)
 		return err;
 	}
 
-	probe_done = true;
 	return 0;
 }
 
-- 
1.9.3

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