PCI: hv: Use zero-length array in struct pci_packet

Use zero-length array in struct pci_packet and rename struct pci_message's
field "message_type" to "type".  This makes the code more readable.

No functionality change.

Signed-off-by: Dexuan Cui <decui@microsoft.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: KY Srinivasan <kys@microsoft.com>
CC: Jake Oshins <jakeo@microsoft.com>
CC: Haiyang Zhang <haiyangz@microsoft.com>
CC: Vitaly Kuznetsov <vkuznets@redhat.com>

diff --git a/drivers/pci/host/pci-hyperv.c b/drivers/pci/host/pci-hyperv.c
index a8deeca..6fa40f1 100644 (file)
--- a/drivers/pci/host/pci-hyperv.c
+++ b/drivers/pci/host/pci-hyperv.c
@@ -200,11 +200,11 @@ struct tran_int_desc {
  */
 
 struct pci_message {
-       u32 message_type;
+       u32 type;
 } __packed;
 
 struct pci_child_message {
-       u32 message_type;
+       struct pci_message message_type;
        union win_slot_encoding wslot;
 } __packed;
 
@@ -222,7 +222,8 @@ struct pci_packet {
        void (*completion_func)(void *context, struct pci_response *resp,
                                int resp_packet_size);
        void *compl_ctxt;
-       struct pci_message message;
+
+       struct pci_message message[0];
 };
 
 /*
@@ -314,7 +315,7 @@ struct pci_dev_incoming {
 } __packed;
 
 struct pci_eject_response {
-       u32 message_type;
+       struct pci_message message_type;
        union win_slot_encoding wslot;
        u32 status;
 } __packed;
@@ -694,13 +695,12 @@ static void hv_int_desc_free(struct hv_pci_dev *hpdev,
        struct pci_delete_interrupt *int_pkt;
        struct {
                struct pci_packet pkt;
-               u8 buffer[sizeof(struct pci_delete_interrupt) -
-                         sizeof(struct pci_message)];
+               u8 buffer[sizeof(struct pci_delete_interrupt)];
        } ctxt;
 
        memset(&ctxt, 0, sizeof(ctxt));
        int_pkt = (struct pci_delete_interrupt *)&ctxt.pkt.message;
-       int_pkt->message_type.message_type =
+       int_pkt->message_type.type =
                PCI_DELETE_INTERRUPT_MESSAGE;
        int_pkt->wslot.slot = hpdev->desc.win_slot.slot;
        int_pkt->int_desc = *int_desc;
@@ -847,8 +847,7 @@ static void hv_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
        struct cpumask *affinity;
        struct {
                struct pci_packet pkt;
-               u8 buffer[sizeof(struct pci_create_interrupt) -
-                         sizeof(struct pci_message)];
+               u8 buffer[sizeof(struct pci_create_interrupt)];
        } ctxt;
        int cpu;
        int ret;
@@ -876,7 +875,7 @@ static void hv_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
        ctxt.pkt.completion_func = hv_pci_compose_compl;
        ctxt.pkt.compl_ctxt = ∁
        int_pkt = (struct pci_create_interrupt *)&ctxt.pkt.message;
-       int_pkt->message_type.message_type = PCI_CREATE_INTERRUPT_MESSAGE;
+       int_pkt->message_type.type = PCI_CREATE_INTERRUPT_MESSAGE;
        int_pkt->wslot.slot = hpdev->desc.win_slot.slot;
        int_pkt->int_desc.vector = cfg->vector;
        int_pkt->int_desc.vector_count = 1;
@@ -1289,7 +1288,7 @@ static struct hv_pci_dev *new_pcichild_device(struct hv_pcibus_device *hbus,
        pkt.init_packet.compl_ctxt = &comp_pkt;
        pkt.init_packet.completion_func = q_resource_requirements;
        res_req = (struct pci_child_message *)&pkt.init_packet.message;
-       res_req->message_type = PCI_QUERY_RESOURCE_REQUIREMENTS;
+       res_req->message_type.type = PCI_QUERY_RESOURCE_REQUIREMENTS;
        res_req->wslot.slot = desc->win_slot.slot;
 
        ret = vmbus_sendpacket(hbus->hdev->channel, res_req,
@@ -1557,8 +1556,7 @@ static void hv_eject_device_work(struct work_struct *work)
        int wslot;
        struct {
                struct pci_packet pkt;
-               u8 buffer[sizeof(struct pci_eject_response) -
-                         sizeof(struct pci_message)];
+               u8 buffer[sizeof(struct pci_eject_response)];
        } ctxt;
 
        hpdev = container_of(work, struct hv_pci_dev, wrk);
@@ -1584,7 +1582,7 @@ static void hv_eject_device_work(struct work_struct *work)
 
        memset(&ctxt, 0, sizeof(ctxt));
        ejct_pkt = (struct pci_eject_response *)&ctxt.pkt.message;
-       ejct_pkt->message_type = PCI_EJECTION_COMPLETE;
+       ejct_pkt->message_type.type = PCI_EJECTION_COMPLETE;
        ejct_pkt->wslot.slot = hpdev->desc.win_slot.slot;
        vmbus_sendpacket(hpdev->hbus->hdev->channel, ejct_pkt,
                         sizeof(*ejct_pkt), (unsigned long)&ctxt.pkt,
@@ -1687,7 +1685,7 @@ static void hv_pci_onchannelcallback(void *context)
                case VM_PKT_DATA_INBAND:
 
                        new_message = (struct pci_incoming_message *)buffer;
-                       switch (new_message->message_type.message_type) {
+                       switch (new_message->message_type.type) {
                        case PCI_BUS_RELATIONS:
 
                                bus_rel = (struct pci_bus_relations *)buffer;
@@ -1718,7 +1716,7 @@ static void hv_pci_onchannelcallback(void *context)
                        default:
                                dev_warn(&hbus->hdev->device,
                                        "Unimplemented protocol message %x\n",
-                                       new_message->message_type.message_type);
+                                       new_message->message_type.type);
                                break;
                        }
                        break;
@@ -1771,7 +1769,7 @@ static int hv_pci_protocol_negotiation(struct hv_device *hdev)
        pkt->completion_func = hv_pci_generic_compl;
        pkt->compl_ctxt = &comp_pkt;
        version_req = (struct pci_version_request *)&pkt->message;
-       version_req->message_type.message_type = PCI_QUERY_PROTOCOL_VERSION;
+       version_req->message_type.type = PCI_QUERY_PROTOCOL_VERSION;
        version_req->protocol_version = PCI_PROTOCOL_VERSION_CURRENT;
 
        ret = vmbus_sendpacket(hdev->channel, version_req,
@@ -1972,7 +1970,7 @@ static int hv_pci_enter_d0(struct hv_device *hdev)
        pkt->completion_func = hv_pci_generic_compl;
        pkt->compl_ctxt = &comp_pkt;
        d0_entry = (struct pci_bus_d0_entry *)&pkt->message;
-       d0_entry->message_type.message_type = PCI_BUS_D0ENTRY;
+       d0_entry->message_type.type = PCI_BUS_D0ENTRY;
        d0_entry->mmio_base = hbus->mem_config->start;
 
        ret = vmbus_sendpacket(hdev->channel, d0_entry, sizeof(*d0_entry),
@@ -2018,7 +2016,7 @@ static int hv_pci_query_relations(struct hv_device *hdev)
                return -ENOTEMPTY;
 
        memset(&message, 0, sizeof(message));
-       message.message_type = PCI_QUERY_BUS_RELATIONS;
+       message.type = PCI_QUERY_BUS_RELATIONS;
 
        ret = vmbus_sendpacket(hdev->channel, &message, sizeof(message),
                               0, VM_PKT_DATA_INBAND, 0);
@@ -2071,8 +2069,8 @@ static int hv_send_resources_allocated(struct hv_device *hdev)
                init_completion(&comp_pkt.host_event);
                pkt->completion_func = hv_pci_generic_compl;
                pkt->compl_ctxt = &comp_pkt;
-               pkt->message.message_type = PCI_RESOURCES_ASSIGNED;
                res_assigned = (struct pci_resources_assigned *)&pkt->message;
+               res_assigned->message_type.type = PCI_RESOURCES_ASSIGNED;
                res_assigned->wslot.slot = hpdev->desc.win_slot.slot;
 
                put_pcichild(hpdev, hv_pcidev_ref_by_slot);
@@ -2122,7 +2120,7 @@ static int hv_send_resources_released(struct hv_device *hdev)
                        continue;
 
                memset(&pkt, 0, sizeof(pkt));
-               pkt.message_type = PCI_RESOURCES_RELEASED;
+               pkt.message_type.type = PCI_RESOURCES_RELEASED;
                pkt.wslot.slot = hpdev->desc.win_slot.slot;
 
                put_pcichild(hpdev, hv_pcidev_ref_by_slot);
@@ -2289,7 +2287,7 @@ static int hv_pci_remove(struct hv_device *hdev)
        init_completion(&comp_pkt.host_event);
        pkt.teardown_packet.completion_func = hv_pci_generic_compl;
        pkt.teardown_packet.compl_ctxt = &comp_pkt;
-       pkt.teardown_packet.message.message_type = PCI_BUS_D0EXIT;
+       pkt.teardown_packet.message[0].type = PCI_BUS_D0EXIT;
 
        ret = vmbus_sendpacket(hdev->channel, &pkt.teardown_packet.message,
                               sizeof(struct pci_message),