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 645d356545d1325369785271480c1358d36dd963..692482b7c2fbc9c21960b5c6bcae47600534a2dc 100644 (file)
--- 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 233da0b9f4b9aed3d5fa1124cbac1c994e7634d4..1f2fff71dbe3144a1fc6fe172a21b617d0fbf139 100644 (file)
--- 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
  *