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 _______________________________________________ svn-src-head@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
