static void hv_pci_onchannelcallback()

in controller/pci-hyperv.c [2685:2823]

• 108 lines of code
• 19 McCabe index (conditional complexity)

static void hv_pci_onchannelcallback(void *context)
{
	const int packet_size = 0x100;
	int ret;
	struct hv_pcibus_device *hbus = context;
	u32 bytes_recvd;
	u64 req_id;
	struct vmpacket_descriptor *desc;
	unsigned char *buffer;
	int bufferlen = packet_size;
	struct pci_packet *comp_packet;
	struct pci_response *response;
	struct pci_incoming_message *new_message;
	struct pci_bus_relations *bus_rel;
	struct pci_bus_relations2 *bus_rel2;
	struct pci_dev_inval_block *inval;
	struct pci_dev_incoming *dev_message;
	struct hv_pci_dev *hpdev;

	buffer = kmalloc(bufferlen, GFP_ATOMIC);
	if (!buffer)
		return;

	while (1) {
		ret = vmbus_recvpacket_raw(hbus->hdev->channel, buffer,
					   bufferlen, &bytes_recvd, &req_id);

		if (ret == -ENOBUFS) {
			kfree(buffer);
			/* Handle large packet */
			bufferlen = bytes_recvd;
			buffer = kmalloc(bytes_recvd, GFP_ATOMIC);
			if (!buffer)
				return;
			continue;
		}

		/* Zero length indicates there are no more packets. */
		if (ret || !bytes_recvd)
			break;

		/*
		 * All incoming packets must be at least as large as a
		 * response.
		 */
		if (bytes_recvd <= sizeof(struct pci_response))
			continue;
		desc = (struct vmpacket_descriptor *)buffer;

		switch (desc->type) {
		case VM_PKT_COMP:

			/*
			 * The host is trusted, and thus it's safe to interpret
			 * this transaction ID as a pointer.
			 */
			comp_packet = (struct pci_packet *)req_id;
			response = (struct pci_response *)buffer;
			comp_packet->completion_func(comp_packet->compl_ctxt,
						     response,
						     bytes_recvd);
			break;

		case VM_PKT_DATA_INBAND:

			new_message = (struct pci_incoming_message *)buffer;
			switch (new_message->message_type.type) {
			case PCI_BUS_RELATIONS:

				bus_rel = (struct pci_bus_relations *)buffer;
				if (bytes_recvd <
					struct_size(bus_rel, func,
						    bus_rel->device_count)) {
					dev_err(&hbus->hdev->device,
						"bus relations too small\n");
					break;
				}

				hv_pci_devices_present(hbus, bus_rel);
				break;

			case PCI_BUS_RELATIONS2:

				bus_rel2 = (struct pci_bus_relations2 *)buffer;
				if (bytes_recvd <
					struct_size(bus_rel2, func,
						    bus_rel2->device_count)) {
					dev_err(&hbus->hdev->device,
						"bus relations v2 too small\n");
					break;
				}

				hv_pci_devices_present2(hbus, bus_rel2);
				break;

			case PCI_EJECT:

				dev_message = (struct pci_dev_incoming *)buffer;
				hpdev = get_pcichild_wslot(hbus,
						      dev_message->wslot.slot);
				if (hpdev) {
					hv_pci_eject_device(hpdev);
					put_pcichild(hpdev);
				}
				break;

			case PCI_INVALIDATE_BLOCK:

				inval = (struct pci_dev_inval_block *)buffer;
				hpdev = get_pcichild_wslot(hbus,
							   inval->wslot.slot);
				if (hpdev) {
					if (hpdev->block_invalidate) {
						hpdev->block_invalidate(
						    hpdev->invalidate_context,
						    inval->block_mask);
					}
					put_pcichild(hpdev);
				}
				break;

			default:
				dev_warn(&hbus->hdev->device,
					"Unimplemented protocol message %x\n",
					new_message->message_type.type);
				break;
			}
			break;

		default:
			dev_err(&hbus->hdev->device,
				"unhandled packet type %d, tid %llx len %d\n",
				desc->type, req_id, bytes_recvd);
			break;
		}
	}

	kfree(buffer);
}