From: Dexuan Cui <decui@xxxxxxxxxxxxx> Sent: Monday, August 19, 2019 6:52 PM > > Fake RESCIND_CHANNEL messages to clean up hv_sock channels by force for > hibernation. There is no better method to clean up the channels since > some of the channels may still be referenced by the userspace apps when > hiberantin is triggered: in this case, the "rescind" fields of the s/hiberantin/hibernation/ > channels are set, and the apps will thoroughly destroy the channels > after hibernation. > > Signed-off-by: Dexuan Cui <decui@xxxxxxxxxxxxx> > --- > drivers/hv/vmbus_drv.c | 55 > ++++++++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 55 insertions(+) > > diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c > index ce9974b..2bea669 100644 > --- a/drivers/hv/vmbus_drv.c > +++ b/drivers/hv/vmbus_drv.c > @@ -24,6 +24,7 @@ > #include <linux/sched/task_stack.h> > > #include <asm/mshyperv.h> > +#include <linux/delay.h> > #include <linux/notifier.h> > #include <linux/ptrace.h> > #include <linux/screen_info.h> > @@ -1069,6 +1070,41 @@ void vmbus_on_msg_dpc(unsigned long data) > vmbus_signal_eom(msg, message_type); > } > > +/* > + * Fake RESCIND_CHANNEL messages to clean up hv_sock channels by force for > + * hibernation, because hv_sock connections can not persist across hibernation. > + */ > +static void vmbus_force_channel_rescinded(struct vmbus_channel *channel) > +{ > + struct onmessage_work_context *ctx; > + struct vmbus_channel_rescind_offer *rescind; > + > + WARN_ON(!is_hvsock_channel(channel)); > + > + /* > + * sizeof(*ctx) is small and the allocation should really not fail, > + * otherwise the state of the hv_sock connections ends up in limbo. > + */ > + ctx = kzalloc(sizeof(*ctx), GFP_KERNEL | __GFP_NOFAIL); > + > + /* > + * So far, these are not really used by Linux. Just set them to the > + * reasonable values conforming to the definitions of the fields. > + */ > + ctx->msg.header.message_type = 1; > + ctx->msg.header.payload_size = sizeof(*rescind); > + > + /* These values are actually used by Linux. */ > + rescind = (struct vmbus_channel_rescind_offer *)ctx->msg.u.payload; > + rescind->header.msgtype = CHANNELMSG_RESCIND_CHANNELOFFER; > + rescind->child_relid = channel->offermsg.child_relid; > + > + INIT_WORK(&ctx->work, vmbus_onmessage_work); > + > + queue_work_on(vmbus_connection.connect_cpu, > + vmbus_connection.work_queue, > + &ctx->work); > +} > > /* > * Direct callback for channels using other deferred processing > @@ -2091,6 +2127,25 @@ static int vmbus_acpi_add(struct acpi_device *device) > > static int vmbus_bus_suspend(struct device *dev) > { > + struct vmbus_channel *channel; > + > + while (atomic_read(&vmbus_connection.offer_in_progress) != 0) { > + /* > + * We wait here until any channel offer is currently > + * being processed. > + */ The wording of the comment is a bit off. Maybe /* * We wait here until the completion of any channel * offers that are currently in progress. */ > + msleep(1); > + } > + > + mutex_lock(&vmbus_connection.channel_mutex); > + list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) { > + if (!is_hvsock_channel(channel)) > + continue; > + > + vmbus_force_channel_rescinded(channel); > + } > + mutex_unlock(&vmbus_connection.channel_mutex); > + > vmbus_initiate_unload(false); > > vmbus_connection.conn_state = DISCONNECTED; > -- > 1.8.3.1 Modulo the nits: Reviewed-by: Michael Kelley <mikelley@xxxxxxxxxxxxx>