From: Stephan Mueller <smueller@chronox.de>
Date: Mon, 2 May 2016 06:14:34 +0000 (-0400)
Subject: random: add interrupt callback to VMBus IRQ handler
X-Git-Tag: v3.16.39~337
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=56713fd74e07f55635bae1a7e186cf5485e7daf5;p=thirdparty%2Fkernel%2Fstable.git

random: add interrupt callback to VMBus IRQ handler

commit 4b44f2d18a330565227a7348844493c59366171e upstream.

The Hyper-V Linux Integration Services use the VMBus implementation for
communication with the Hypervisor. VMBus registers its own interrupt
handler that completely bypasses the common Linux interrupt handling.
This implies that the interrupt entropy collector is not triggered.

This patch adds the interrupt entropy collection callback into the VMBus
interrupt handler function.

Signed-off-by: Stephan Mueller <stephan.mueller@atsec.com>
Signed-off-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---

diff --git a/drivers/char/random.c b/drivers/char/random.c
index 645d356545d13..692482b7c2fbc 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -956,6 +956,7 @@ static void _xfer_secondary_pool(struct entropy_store *r, size_t nbytes)
 	mix_pool_bytes(r, tmp, bytes, NULL);
 	credit_entropy_bits(r, bytes*8);
 }
+EXPORT_SYMBOL_GPL(add_interrupt_randomness);
 
 /*
  * Used as a workqueue function so that when the input pool is getting
diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index 233da0b9f4b9a..1f2fff71dbe31 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -33,6 +33,7 @@
 #include <linux/hyperv.h>
 #include <linux/kernel_stat.h>
 #include <linux/cpu.h>
+#include <linux/random.h>
 #include <asm/hyperv.h>
 #include <asm/hypervisor.h>
 #include <asm/mshyperv.h>
@@ -795,6 +796,8 @@ int __vmbus_driver_register(struct hv_driver *hv_driver, struct module *owner, c
 EXPORT_SYMBOL_GPL(__vmbus_driver_register);
 
 /**
+
+	add_interrupt_randomness(HYPERVISOR_CALLBACK_VECTOR, 0);
  * vmbus_driver_unregister() - Unregister a vmbus's driver
  * @drv: Pointer to driver structure you want to un-register
  *