xen-netback: add control ring boilerplate

[cascardo/linux.git] / drivers / net / xen-netback / netback.c

diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c
index 4412a57..ff22b6d 100644 (file)
--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -1926,7 +1926,7 @@ static inline bool tx_dealloc_work_todo(struct xenvif_queue *queue)
        return queue->dealloc_cons != queue->dealloc_prod;
 }
 
-void xenvif_unmap_frontend_rings(struct xenvif_queue *queue)
+void xenvif_unmap_frontend_data_rings(struct xenvif_queue *queue)
 {
        if (queue->tx.sring)
                xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(queue->vif),
@@ -1936,9 +1936,9 @@ void xenvif_unmap_frontend_rings(struct xenvif_queue *queue)
                                        queue->rx.sring);
 }
 
-int xenvif_map_frontend_rings(struct xenvif_queue *queue,
-                             grant_ref_t tx_ring_ref,
-                             grant_ref_t rx_ring_ref)
+int xenvif_map_frontend_data_rings(struct xenvif_queue *queue,
+                                  grant_ref_t tx_ring_ref,
+                                  grant_ref_t rx_ring_ref)
 {
        void *addr;
        struct xen_netif_tx_sring *txs;
@@ -1965,7 +1965,7 @@ int xenvif_map_frontend_rings(struct xenvif_queue *queue,
        return 0;
 
 err:
-       xenvif_unmap_frontend_rings(queue);
+       xenvif_unmap_frontend_data_rings(queue);
        return err;
 }
 
@@ -2164,6 +2164,95 @@ int xenvif_dealloc_kthread(void *data)
        return 0;
 }
 
+static void make_ctrl_response(struct xenvif *vif,
+                              const struct xen_netif_ctrl_request *req,
+                              u32 status, u32 data)
+{
+       RING_IDX idx = vif->ctrl.rsp_prod_pvt;
+       struct xen_netif_ctrl_response rsp = {
+               .id = req->id,
+               .type = req->type,
+               .status = status,
+               .data = data,
+       };
+
+       *RING_GET_RESPONSE(&vif->ctrl, idx) = rsp;
+       vif->ctrl.rsp_prod_pvt = ++idx;
+}
+
+static void push_ctrl_response(struct xenvif *vif)
+{
+       int notify;
+
+       RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&vif->ctrl, notify);
+       if (notify)
+               notify_remote_via_irq(vif->ctrl_irq);
+}
+
+static void process_ctrl_request(struct xenvif *vif,
+                                const struct xen_netif_ctrl_request *req)
+{
+       make_ctrl_response(vif, req, XEN_NETIF_CTRL_STATUS_NOT_SUPPORTED,
+                          0);
+       push_ctrl_response(vif);
+}
+
+static void xenvif_ctrl_action(struct xenvif *vif)
+{
+       for (;;) {
+               RING_IDX req_prod, req_cons;
+
+               req_prod = vif->ctrl.sring->req_prod;
+               req_cons = vif->ctrl.req_cons;
+
+               /* Make sure we can see requests before we process them. */
+               rmb();
+
+               if (req_cons == req_prod)
+                       break;
+
+               while (req_cons != req_prod) {
+                       struct xen_netif_ctrl_request req;
+
+                       RING_COPY_REQUEST(&vif->ctrl, req_cons, &req);
+                       req_cons++;
+
+                       process_ctrl_request(vif, &req);
+               }
+
+               vif->ctrl.req_cons = req_cons;
+               vif->ctrl.sring->req_event = req_cons + 1;
+       }
+}
+
+static bool xenvif_ctrl_work_todo(struct xenvif *vif)
+{
+       if (likely(RING_HAS_UNCONSUMED_REQUESTS(&vif->ctrl)))
+               return 1;
+
+       return 0;
+}
+
+int xenvif_ctrl_kthread(void *data)
+{
+       struct xenvif *vif = data;
+
+       for (;;) {
+               wait_event_interruptible(vif->ctrl_wq,
+                                        xenvif_ctrl_work_todo(vif) ||
+                                        kthread_should_stop());
+               if (kthread_should_stop())
+                       break;
+
+               while (xenvif_ctrl_work_todo(vif))
+                       xenvif_ctrl_action(vif);
+
+               cond_resched();
+       }
+
+       return 0;
+}
+
 static int __init netback_init(void)
 {
        int rc = 0;