svn commit: r292861 - head/sys/dev/hyperv/vmbus
Xin LI
delphij at FreeBSD.org
Tue Dec 29 08:19:45 UTC 2015
Author: delphij
Date: Tue Dec 29 08:19:43 2015
New Revision: 292861
URL: https://svnweb.freebsd.org/changeset/base/292861
Log:
hyperv: vmbus: run non-blocking message handlers in vmbus_msg_swintr()
We'll remove the per-channel control_work_queue because it can't properly
do serialization of message handling, e.g., when there are 2 NIC devices,
vmbus_channel_on_offer() -> hv_queue_work_item() has a race condition:
for an SMP VM, vmbus_channel_process_offer() can run concurrently on
different CPUs and if the second NIC's
vmbus_channel_process_offer() -> hv_vmbus_child_device_register() runs
first, the second NIC's name will be hn0 and the first NIC's name will
be hn1!
We can fix the race condition by removing the per-channel control_work_queue
and run all the message handlers in the global
hv_vmbus_g_connection.work_queue -- we'll do this in the next patch.
With the coming next patch, we have to run the non-blocking handlers
directly in the kernel thread vmbus_msg_swintr(), because the special
handling of sub-channel: when a sub-channel (e.g., of the storvsc driver)
is received and being handled in vmbus_channel_on_offer() running on the
global hv_vmbus_g_connection.work_queue, vmbus_channel_process_offer()
invokes channel->sc_creation_callback, i.e., storvsc_handle_sc_creation,
and the callback will invoke hv_vmbus_channel_open() -> hv_vmbus_post_message
and expect a further reply from the host, but the handling of the further
messag can't be done because the current message's handling hasn't finished
yet; as result, hv_vmbus_channel_open() -> sema_timedwait() will time out
and th device can't work.
Also renamed the handler type from hv_pfn_channel_msg_handler to
vmbus_msg_handler: the 'pfn' and 'channel' in the old name make no sense.
Submitted by: Dexuan Cui <decui microsoft com>
Reviewed by: royger
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D4596
Modified:
head/sys/dev/hyperv/vmbus/hv_channel_mgmt.c
head/sys/dev/hyperv/vmbus/hv_vmbus_drv_freebsd.c
head/sys/dev/hyperv/vmbus/hv_vmbus_priv.h
Modified: head/sys/dev/hyperv/vmbus/hv_channel_mgmt.c
==============================================================================
--- head/sys/dev/hyperv/vmbus/hv_channel_mgmt.c Tue Dec 29 08:19:06 2015 (r292860)
+++ head/sys/dev/hyperv/vmbus/hv_channel_mgmt.c Tue Dec 29 08:19:43 2015 (r292861)
@@ -31,13 +31,6 @@
#include "hv_vmbus_priv.h"
-typedef void (*hv_pfn_channel_msg_handler)(hv_vmbus_channel_msg_header* msg);
-
-typedef struct hv_vmbus_channel_msg_table_entry {
- hv_vmbus_channel_msg_type messageType;
- hv_pfn_channel_msg_handler messageHandler;
-} hv_vmbus_channel_msg_table_entry;
-
/*
* Internal functions
*/
@@ -55,29 +48,40 @@ static void vmbus_channel_on_version_res
*/
hv_vmbus_channel_msg_table_entry
g_channel_message_table[HV_CHANNEL_MESSAGE_COUNT] = {
- { HV_CHANNEL_MESSAGE_INVALID, NULL },
- { HV_CHANNEL_MESSAGE_OFFER_CHANNEL, vmbus_channel_on_offer },
+ { HV_CHANNEL_MESSAGE_INVALID,
+ 0, NULL },
+ { HV_CHANNEL_MESSAGE_OFFER_CHANNEL,
+ 0, vmbus_channel_on_offer },
{ HV_CHANNEL_MESSAGE_RESCIND_CHANNEL_OFFER,
- vmbus_channel_on_offer_rescind },
- { HV_CHANNEL_MESSAGE_REQUEST_OFFERS, NULL },
+ 0, vmbus_channel_on_offer_rescind },
+ { HV_CHANNEL_MESSAGE_REQUEST_OFFERS,
+ 0, NULL },
{ HV_CHANNEL_MESSAGE_ALL_OFFERS_DELIVERED,
- vmbus_channel_on_offers_delivered },
- { HV_CHANNEL_MESSAGE_OPEN_CHANNEL, NULL },
+ 1, vmbus_channel_on_offers_delivered },
+ { HV_CHANNEL_MESSAGE_OPEN_CHANNEL,
+ 0, NULL },
{ HV_CHANNEL_MESSAGE_OPEN_CHANNEL_RESULT,
- vmbus_channel_on_open_result },
- { HV_CHANNEL_MESSAGE_CLOSE_CHANNEL, NULL },
- { HV_CHANNEL_MESSAGEL_GPADL_HEADER, NULL },
- { HV_CHANNEL_MESSAGE_GPADL_BODY, NULL },
+ 1, vmbus_channel_on_open_result },
+ { HV_CHANNEL_MESSAGE_CLOSE_CHANNEL,
+ 0, NULL },
+ { HV_CHANNEL_MESSAGEL_GPADL_HEADER,
+ 0, NULL },
+ { HV_CHANNEL_MESSAGE_GPADL_BODY,
+ 0, NULL },
{ HV_CHANNEL_MESSAGE_GPADL_CREATED,
- vmbus_channel_on_gpadl_created },
- { HV_CHANNEL_MESSAGE_GPADL_TEARDOWN, NULL },
+ 1, vmbus_channel_on_gpadl_created },
+ { HV_CHANNEL_MESSAGE_GPADL_TEARDOWN,
+ 0, NULL },
{ HV_CHANNEL_MESSAGE_GPADL_TORNDOWN,
- vmbus_channel_on_gpadl_torndown },
- { HV_CHANNEL_MESSAGE_REL_ID_RELEASED, NULL },
- { HV_CHANNEL_MESSAGE_INITIATED_CONTACT, NULL },
+ 1, vmbus_channel_on_gpadl_torndown },
+ { HV_CHANNEL_MESSAGE_REL_ID_RELEASED,
+ 0, NULL },
+ { HV_CHANNEL_MESSAGE_INITIATED_CONTACT,
+ 0, NULL },
{ HV_CHANNEL_MESSAGE_VERSION_RESPONSE,
- vmbus_channel_on_version_response },
- { HV_CHANNEL_MESSAGE_UNLOAD, NULL }
+ 1, vmbus_channel_on_version_response },
+ { HV_CHANNEL_MESSAGE_UNLOAD,
+ 0, NULL }
};
Modified: head/sys/dev/hyperv/vmbus/hv_vmbus_drv_freebsd.c
==============================================================================
--- head/sys/dev/hyperv/vmbus/hv_vmbus_drv_freebsd.c Tue Dec 29 08:19:06 2015 (r292860)
+++ head/sys/dev/hyperv/vmbus/hv_vmbus_drv_freebsd.c Tue Dec 29 08:19:43 2015 (r292861)
@@ -76,8 +76,12 @@ vmbus_msg_swintr(void *arg)
{
int cpu;
void* page_addr;
+ hv_vmbus_channel_msg_header *hdr;
+ hv_vmbus_channel_msg_table_entry *entry;
+ hv_vmbus_channel_msg_type msg_type;
hv_vmbus_message* msg;
hv_vmbus_message* copied;
+ static bool warned = false;
cpu = (int)(long)arg;
KASSERT(cpu <= mp_maxid, ("VMBUS: vmbus_msg_swintr: "
@@ -87,9 +91,24 @@ vmbus_msg_swintr(void *arg)
msg = (hv_vmbus_message*) page_addr + HV_VMBUS_MESSAGE_SINT;
for (;;) {
- if (msg->header.message_type == HV_MESSAGE_TYPE_NONE) {
+ if (msg->header.message_type == HV_MESSAGE_TYPE_NONE)
break; /* no message */
- } else {
+
+ hdr = (hv_vmbus_channel_msg_header *)msg->u.payload;
+ msg_type = hdr->message_type;
+
+ if (msg_type >= HV_CHANNEL_MESSAGE_COUNT && !warned) {
+ warned = true;
+ printf("VMBUS: unknown message type = %d\n", msg_type);
+ goto handled;
+ }
+
+ entry = &g_channel_message_table[msg_type];
+
+ if (entry->handler_no_sleep)
+ entry->messageHandler(hdr);
+ else {
+
copied = malloc(sizeof(hv_vmbus_message),
M_DEVBUF, M_NOWAIT);
KASSERT(copied != NULL,
@@ -97,11 +116,13 @@ vmbus_msg_swintr(void *arg)
" hv_vmbus_message!"));
if (copied == NULL)
continue;
+
memcpy(copied, msg, sizeof(hv_vmbus_message));
hv_queue_work_item(hv_vmbus_g_connection.work_queue,
- hv_vmbus_on_channel_message, copied);
- }
-
+ hv_vmbus_on_channel_message,
+ copied);
+ }
+handled:
msg->header.message_type = HV_MESSAGE_TYPE_NONE;
/*
Modified: head/sys/dev/hyperv/vmbus/hv_vmbus_priv.h
==============================================================================
--- head/sys/dev/hyperv/vmbus/hv_vmbus_priv.h Tue Dec 29 08:19:06 2015 (r292860)
+++ head/sys/dev/hyperv/vmbus/hv_vmbus_priv.h Tue Dec 29 08:19:43 2015 (r292861)
@@ -586,6 +586,16 @@ typedef enum {
extern hv_vmbus_context hv_vmbus_g_context;
extern hv_vmbus_connection hv_vmbus_g_connection;
+typedef void (*vmbus_msg_handler)(hv_vmbus_channel_msg_header *msg);
+
+typedef struct hv_vmbus_channel_msg_table_entry {
+ hv_vmbus_channel_msg_type messageType;
+
+ bool handler_no_sleep; /* true: the handler doesn't sleep */
+ vmbus_msg_handler messageHandler;
+} hv_vmbus_channel_msg_table_entry;
+
+extern hv_vmbus_channel_msg_table_entry g_channel_message_table[];
/*
* Private, VM Bus functions
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