Upgrade to 4.4.50-rt62

[kvmfornfv.git] / kernel / drivers / hv / channel_mgmt.c

diff --git a/kernel/drivers/hv/channel_mgmt.c b/kernel/drivers/hv/channel_mgmt.c
index 652afd1..37238df 100644 (file)
--- a/kernel/drivers/hv/channel_mgmt.c
+++ b/kernel/drivers/hv/channel_mgmt.c
@@ -28,6 +28,7 @@
 #include <linux/list.h>
 #include <linux/module.h>
 #include <linux/completion.h>
+#include <linux/delay.h>
 #include <linux/hyperv.h>
 
 #include "hyperv_vmbus.h"
@@ -191,6 +192,8 @@ void hv_process_channel_removal(struct vmbus_channel *channel, u32 relid)
        if (channel == NULL)
                return;
 
+       BUG_ON(!channel->rescind);
+
        if (channel->target_cpu != get_cpu()) {
                put_cpu();
                smp_call_function_single(channel->target_cpu,
@@ -230,9 +233,7 @@ void vmbus_free_channels(void)
 
        list_for_each_entry_safe(channel, tmp, &vmbus_connection.chn_list,
                listentry) {
-               /* if we don't set rescind to true, vmbus_close_internal()
-                * won't invoke hv_process_channel_removal().
-                */
+               /* hv_process_channel_removal() needs this */
                channel->rescind = true;
 
                vmbus_device_unregister(channel->device_obj);
@@ -459,6 +460,17 @@ static void init_vp_index(struct vmbus_channel *channel, const uuid_le *type_gui
                    cpumask_of_node(primary->numa_node));
 
        cur_cpu = -1;
+
+       /*
+        * Normally Hyper-V host doesn't create more subchannels than there
+        * are VCPUs on the node but it is possible when not all present VCPUs
+        * on the node are initialized by guest. Clear the alloced_cpus_in_node
+        * to start over.
+        */
+       if (cpumask_equal(&primary->alloced_cpus_in_node,
+                         cpumask_of_node(primary->numa_node)))
+               cpumask_clear(&primary->alloced_cpus_in_node);
+
        while (true) {
                cur_cpu = cpumask_next(cur_cpu, &available_mask);
                if (cur_cpu >= nr_cpu_ids) {
@@ -488,6 +500,40 @@ static void init_vp_index(struct vmbus_channel *channel, const uuid_le *type_gui
        channel->target_vp = hv_context.vp_index[cur_cpu];
 }
 
+static void vmbus_wait_for_unload(void)
+{
+       int cpu = smp_processor_id();
+       void *page_addr = hv_context.synic_message_page[cpu];
+       struct hv_message *msg = (struct hv_message *)page_addr +
+                                 VMBUS_MESSAGE_SINT;
+       struct vmbus_channel_message_header *hdr;
+       bool unloaded = false;
+
+       while (1) {
+               if (msg->header.message_type == HVMSG_NONE) {
+                       mdelay(10);
+                       continue;
+               }
+
+               hdr = (struct vmbus_channel_message_header *)msg->u.payload;
+               if (hdr->msgtype == CHANNELMSG_UNLOAD_RESPONSE)
+                       unloaded = true;
+
+               msg->header.message_type = HVMSG_NONE;
+               /*
+                * header.message_type needs to be written before we do
+                * wrmsrl() below.
+                */
+               mb();
+
+               if (msg->header.message_flags.msg_pending)
+                       wrmsrl(HV_X64_MSR_EOM, 0);
+
+               if (unloaded)
+                       break;
+       }
+}
+
 /*
  * vmbus_unload_response - Handler for the unload response.
  */
@@ -513,7 +559,14 @@ void vmbus_initiate_unload(void)
        hdr.msgtype = CHANNELMSG_UNLOAD;
        vmbus_post_msg(&hdr, sizeof(struct vmbus_channel_message_header));
 
-       wait_for_completion(&vmbus_connection.unload_event);
+       /*
+        * vmbus_initiate_unload() is also called on crash and the crash can be
+        * happening in an interrupt context, where scheduling is impossible.
+        */
+       if (!in_interrupt())
+               wait_for_completion(&vmbus_connection.unload_event);
+       else
+               vmbus_wait_for_unload();
 }
 
 /*