Merge branch 'for-linus-4.7' of git://git.kernel.org/pub/scm/linux/kernel/git/mason...

[cascardo/linux.git] / drivers / hv / channel_mgmt.c

diff --git a/drivers/hv/channel_mgmt.c b/drivers/hv/channel_mgmt.c
index 38b682b..b6c1211 100644 (file)
--- a/drivers/hv/channel_mgmt.c
+++ b/drivers/hv/channel_mgmt.c
@@ -597,27 +597,55 @@ static void init_vp_index(struct vmbus_channel *channel, u16 dev_type)
 
 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;
+       int cpu;
+       void *page_addr;
+       struct hv_message *msg;
        struct vmbus_channel_message_header *hdr;
-       bool unloaded = false;
+       u32 message_type;
 
+       /*
+        * CHANNELMSG_UNLOAD_RESPONSE is always delivered to the CPU which was
+        * used for initial contact or to CPU0 depending on host version. When
+        * we're crashing on a different CPU let's hope that IRQ handler on
+        * the cpu which receives CHANNELMSG_UNLOAD_RESPONSE is still
+        * functional and vmbus_unload_response() will complete
+        * vmbus_connection.unload_event. If not, the last thing we can do is
+        * read message pages for all CPUs directly.
+        */
        while (1) {
-               if (READ_ONCE(msg->header.message_type) == HVMSG_NONE) {
-                       mdelay(10);
-                       continue;
-               }
+               if (completion_done(&vmbus_connection.unload_event))
+                       break;
 
-               hdr = (struct vmbus_channel_message_header *)msg->u.payload;
-               if (hdr->msgtype == CHANNELMSG_UNLOAD_RESPONSE)
-                       unloaded = true;
+               for_each_online_cpu(cpu) {
+                       page_addr = hv_context.synic_message_page[cpu];
+                       msg = (struct hv_message *)page_addr +
+                               VMBUS_MESSAGE_SINT;
 
-               vmbus_signal_eom(msg);
+                       message_type = READ_ONCE(msg->header.message_type);
+                       if (message_type == HVMSG_NONE)
+                               continue;
 
-               if (unloaded)
-                       break;
+                       hdr = (struct vmbus_channel_message_header *)
+                               msg->u.payload;
+
+                       if (hdr->msgtype == CHANNELMSG_UNLOAD_RESPONSE)
+                               complete(&vmbus_connection.unload_event);
+
+                       vmbus_signal_eom(msg, message_type);
+               }
+
+               mdelay(10);
+       }
+
+       /*
+        * We're crashing and already got the UNLOAD_RESPONSE, cleanup all
+        * maybe-pending messages on all CPUs to be able to receive new
+        * messages after we reconnect.
+        */
+       for_each_online_cpu(cpu) {
+               page_addr = hv_context.synic_message_page[cpu];
+               msg = (struct hv_message *)page_addr + VMBUS_MESSAGE_SINT;
+               msg->header.message_type = HVMSG_NONE;
        }
 }