Patch "random: add interrupt callback to VMBus IRQ handler" has been added to the 4.4-stable tree

This is a note to let you know that I've just added the patch titled

random: add interrupt callback to VMBus IRQ handler

to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
random-add-interrupt-callback-to-vmbus-irq-handler.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Stephan Mueller <[email protected]>
Date: Mon, 2 May 2016 02:14:34 -0400
Subject: random: add interrupt callback to VMBus IRQ handler

From: Stephan Mueller <[email protected]>

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.

---
 drivers/char/random.c  |    1 +
 drivers/hv/vmbus_drv.c |    3 +++
 2 files changed, 4 insertions(+)

@@ -948,6 +948,7 @@ void add_interrupt_randomness(int irq, i
 	/* award one bit for the contents of the fast pool */
 	credit_entropy_bits(r, credit + 1);
 }
+EXPORT_SYMBOL_GPL(add_interrupt_randomness);
 
 #ifdef CONFIG_BLOCK
 void add_disk_randomness(struct gendisk *disk)

@@ -41,6 +41,7 @@
 #include <linux/ptrace.h>
 #include <linux/screen_info.h>
 #include <linux/kdebug.h>
+#include <linux/random.h>
 #include "hyperv_vmbus.h"
 
 static struct acpi_device  *hv_acpi_dev;

@@ -826,6 +827,8 @@ static void vmbus_isr(void)
 		else
 			tasklet_schedule(&msg_dpc);
 	}
+
+	add_interrupt_randomness(HYPERVISOR_CALLBACK_VECTOR, 0);
 }
 
 

Patches currently in stable-queue which might be from [email protected] are

queue-4.4/random-add-interrupt-callback-to-vmbus-irq-handler.patch