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>
diff --git a/drivers/hv/channel_mgmt.c b/drivers/hv/channel_mgmt.c
index bb39705..287f07b 100644
--- a/drivers/hv/channel_mgmt.c
+++ b/drivers/hv/channel_mgmt.c
@@ -33,11 +33,6 @@
#include "hyperv_vmbus.h"
-struct vmbus_channel_message_table_entry {
- enum vmbus_channel_message_type message_type;
- void (*message_handler)(struct vmbus_channel_message_header *msg);
-};
-
struct vmbus_rescind_work {
struct work_struct work;
struct vmbus_channel *channel;
@@ -827,25 +822,25 @@
}
/* Channel message dispatch table */
-static struct vmbus_channel_message_table_entry
+struct vmbus_channel_message_table_entry
channel_message_table[CHANNELMSG_COUNT] = {
- {CHANNELMSG_INVALID, NULL},
- {CHANNELMSG_OFFERCHANNEL, vmbus_onoffer},
- {CHANNELMSG_RESCIND_CHANNELOFFER, vmbus_onoffer_rescind},
- {CHANNELMSG_REQUESTOFFERS, NULL},
- {CHANNELMSG_ALLOFFERS_DELIVERED, vmbus_onoffers_delivered},
- {CHANNELMSG_OPENCHANNEL, NULL},
- {CHANNELMSG_OPENCHANNEL_RESULT, vmbus_onopen_result},
- {CHANNELMSG_CLOSECHANNEL, NULL},
- {CHANNELMSG_GPADL_HEADER, NULL},
- {CHANNELMSG_GPADL_BODY, NULL},
- {CHANNELMSG_GPADL_CREATED, vmbus_ongpadl_created},
- {CHANNELMSG_GPADL_TEARDOWN, NULL},
- {CHANNELMSG_GPADL_TORNDOWN, vmbus_ongpadl_torndown},
- {CHANNELMSG_RELID_RELEASED, NULL},
- {CHANNELMSG_INITIATE_CONTACT, NULL},
- {CHANNELMSG_VERSION_RESPONSE, vmbus_onversion_response},
- {CHANNELMSG_UNLOAD, NULL},
+ {CHANNELMSG_INVALID, 0, NULL},
+ {CHANNELMSG_OFFERCHANNEL, 0, vmbus_onoffer},
+ {CHANNELMSG_RESCIND_CHANNELOFFER, 0, vmbus_onoffer_rescind},
+ {CHANNELMSG_REQUESTOFFERS, 0, NULL},
+ {CHANNELMSG_ALLOFFERS_DELIVERED, 1, vmbus_onoffers_delivered},
+ {CHANNELMSG_OPENCHANNEL, 0, NULL},
+ {CHANNELMSG_OPENCHANNEL_RESULT, 1, vmbus_onopen_result},
+ {CHANNELMSG_CLOSECHANNEL, 0, NULL},
+ {CHANNELMSG_GPADL_HEADER, 0, NULL},
+ {CHANNELMSG_GPADL_BODY, 0, NULL},
+ {CHANNELMSG_GPADL_CREATED, 1, vmbus_ongpadl_created},
+ {CHANNELMSG_GPADL_TEARDOWN, 0, NULL},
+ {CHANNELMSG_GPADL_TORNDOWN, 1, vmbus_ongpadl_torndown},
+ {CHANNELMSG_RELID_RELEASED, 0, NULL},
+ {CHANNELMSG_INITIATE_CONTACT, 0, NULL},
+ {CHANNELMSG_VERSION_RESPONSE, 1, vmbus_onversion_response},
+ {CHANNELMSG_UNLOAD, 0, NULL},
};
/*
