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authorDexuan Cui <decui@microsoft.com>2015-03-27 19:10:08 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2015-04-03 17:18:01 +0300
commit652594c7dfd9bf6392e3a727bc69d89a2562d953 (patch)
tree6f40c87328a8d8e2880d8a4a6feb3f3fdb1c6caf /drivers/hv/hyperv_vmbus.h
parent01081f5ab9916603555f236b11f76bb00e4e01e9 (diff)
downloadlinux-652594c7dfd9bf6392e3a727bc69d89a2562d953.tar.xz
hv: run non-blocking message handlers in the dispatch tasklet
A work item in vmbus_connection.work_queue can sleep, waiting for a new host message (usually it is some kind of "completion" message). Currently the new message will be handled in the same workqueue, but since work items in the workqueue is serialized, we actually have no chance to handle the new message if the current work item is sleeping -- as as result, the current work item will hang forever. K. Y. has posted the below fix to resolve the issue: Drivers: hv: vmbus: Perform device register in the per-channel work element Actually we can simplify the fix by directly running non-blocking message handlers in the dispatch tasklet (inspired by K. Y.). This patch is the fundamental change. The following 2 patches will simplify the message offering and rescind-offering handling a lot. Signed-off-by: Dexuan Cui <decui@microsoft.com> Cc: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/hv/hyperv_vmbus.h')
-rw-r--r--drivers/hv/hyperv_vmbus.h17
1 files changed, 17 insertions, 0 deletions
diff --git a/drivers/hv/hyperv_vmbus.h b/drivers/hv/hyperv_vmbus.h
index c8e27e0fdc99..f40a5a935ab6 100644
--- a/drivers/hv/hyperv_vmbus.h
+++ b/drivers/hv/hyperv_vmbus.h
@@ -685,6 +685,23 @@ struct vmbus_msginfo {
extern struct vmbus_connection vmbus_connection;
+enum vmbus_message_handler_type {
+ /* The related handler can sleep. */
+ VMHT_BLOCKING = 0,
+
+ /* The related handler must NOT sleep. */
+ VMHT_NON_BLOCKING = 1,
+};
+
+struct vmbus_channel_message_table_entry {
+ enum vmbus_channel_message_type message_type;
+ enum vmbus_message_handler_type handler_type;
+ void (*message_handler)(struct vmbus_channel_message_header *msg);
+};
+
+extern struct vmbus_channel_message_table_entry
+ channel_message_table[CHANNELMSG_COUNT];
+
/* General vmbus interface */
struct hv_device *vmbus_device_create(const uuid_le *type,