Commit 52be9355 authored by Shradha Gupta's avatar Shradha Gupta Committed by Wei Liu
Browse files

Drivers: hv: vm_bus: Handle vmbus rescind calls after vmbus is suspended 



Add a flag to indicate that the vmbus is suspended so we should ignore
any offer message. Add a new work_queue for rescind msg, so we could drain
it along with other offer work_queues upon suspension.
It was observed that in some hibernation related scenario testing, after
vmbus_bus_suspend() we get rescind offer message for the vmbus. This would
lead to processing of a rescind message for a channel that has already been
suspended.

Signed-off-by: default avatarShradha Gupta <shradhagupta@linux.microsoft.com>
Reviewed-by: default avatarMichael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/20220711041147.GA5569@linuxonhyperv3.guj3yctzbm1etfxqx2vob5hsef.xx.internal.cloudapp.net


Signed-off-by: default avatarWei Liu <wei.liu@kernel.org>
parent 32346491

drivers/hv/connection.c

+11 −0
Original line number Diff line number Diff line
@@ -171,6 +171,14 @@ int vmbus_connect(void) 
		goto cleanup;

	}



	vmbus_connection.rescind_work_queue =

		create_workqueue("hv_vmbus_rescind");

	if (!vmbus_connection.rescind_work_queue) {

		ret = -ENOMEM;

		goto cleanup;

	}

	vmbus_connection.ignore_any_offer_msg = false;



	vmbus_connection.handle_primary_chan_wq =

		create_workqueue("hv_pri_chan");

	if (!vmbus_connection.handle_primary_chan_wq) {
@@ -357,6 +365,9 @@ void vmbus_disconnect(void) 
	if (vmbus_connection.handle_primary_chan_wq)

		destroy_workqueue(vmbus_connection.handle_primary_chan_wq);



	if (vmbus_connection.rescind_work_queue)

		destroy_workqueue(vmbus_connection.rescind_work_queue);



	if (vmbus_connection.work_queue)

		destroy_workqueue(vmbus_connection.work_queue);

drivers/hv/hyperv_vmbus.h

+7 −0
Original line number Diff line number Diff line
@@ -261,6 +261,13 @@ struct vmbus_connection { 
	struct workqueue_struct *work_queue;

	struct workqueue_struct *handle_primary_chan_wq;

	struct workqueue_struct *handle_sub_chan_wq;

	struct workqueue_struct *rescind_work_queue;



	/*

	 * On suspension of the vmbus, the accumulated offer messages

	 * must be dropped.

	 */

	bool ignore_any_offer_msg;



	/*

	 * The number of sub-channels and hv_sock channels that should be

drivers/hv/vmbus_drv.c

+19 −8
Original line number Diff line number Diff line
@@ -1160,7 +1160,9 @@ void vmbus_on_msg_dpc(unsigned long data) 
			 * work queue: the RESCIND handler can not start to

			 * run before the OFFER handler finishes.

			 */

			schedule_work(&ctx->work);

			if (vmbus_connection.ignore_any_offer_msg)

				break;

			queue_work(vmbus_connection.rescind_work_queue, &ctx->work);

			break;



		case CHANNELMSG_OFFERCHANNEL:
@@ -1186,6 +1188,8 @@ void vmbus_on_msg_dpc(unsigned long data) 
			 * to the CPUs which will execute the offer & rescind

			 * works by the time these works will start execution.

			 */

			if (vmbus_connection.ignore_any_offer_msg)

				break;

			atomic_inc(&vmbus_connection.offer_in_progress);

			fallthrough;
@@ -2446,15 +2450,20 @@ static int vmbus_acpi_add(struct acpi_device *device) 
#ifdef CONFIG_PM_SLEEP

static int vmbus_bus_suspend(struct device *dev)

{

	struct hv_per_cpu_context *hv_cpu = per_cpu_ptr(

			hv_context.cpu_context, VMBUS_CONNECT_CPU);

	struct vmbus_channel *channel, *sc;



	while (atomic_read(&vmbus_connection.offer_in_progress) != 0) {

		/*

		 * We wait here until the completion of any channel

		 * offers that are currently in progress.

		 */

		usleep_range(1000, 2000);

	}

	tasklet_disable(&hv_cpu->msg_dpc);

	vmbus_connection.ignore_any_offer_msg = true;

	/* The tasklet_enable() takes care of providing a memory barrier */

	tasklet_enable(&hv_cpu->msg_dpc);



	/* Drain all the workqueues as we are in suspend */

	drain_workqueue(vmbus_connection.rescind_work_queue);

	drain_workqueue(vmbus_connection.work_queue);

	drain_workqueue(vmbus_connection.handle_primary_chan_wq);

	drain_workqueue(vmbus_connection.handle_sub_chan_wq);



	mutex_lock(&vmbus_connection.channel_mutex);

	list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) {
@@ -2531,6 +2540,8 @@ static int vmbus_bus_resume(struct device *dev) 
	size_t msgsize;

	int ret;



	vmbus_connection.ignore_any_offer_msg = false;



	/*

	 * We only use the 'vmbus_proto_version', which was in use before

	 * hibernation, to re-negotiate with the host.