net: xen-netback: use API provided by xenbus module to map rings

The xenbus module provides xenbus_map_ring_valloc() and
xenbus_map_ring_vfree().  Use these to map the Tx and Rx ring pages
granted by the frontend.

Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Acked-by: David S. Miller <davem@davemloft.net>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

2 files changed, 22 insertions, 69 deletions

diff --git a/drivers/net/xen-netback/common.h b/drivers/net/xen-netback/common.h
index 161f207786a4..94b79c3338c4 100644
--- a/drivers/net/xen-netback/common.h
+++ b/drivers/net/xen-netback/common.h
@@ -58,10 +58,6 @@ struct xenvif {
         u8               fe_dev_addr[6];
 
         /* Physical parameters of the comms window. */
-        grant_handle_t   tx_shmem_handle;
-        grant_ref_t      tx_shmem_ref;
-        grant_handle_t   rx_shmem_handle;
-        grant_ref_t      rx_shmem_ref;
         unsigned int     irq;
 
         /* List of frontends to notify after a batch of frames sent. */
@@ -70,8 +66,6 @@ struct xenvif {
         /* The shared rings and indexes. */
         struct xen_netif_tx_back_ring tx;
         struct xen_netif_rx_back_ring rx;
-        struct vm_struct *tx_comms_area;
-        struct vm_struct *rx_comms_area;
 
         /* Frontend feature information. */
         u8 can_sg:1;
@@ -106,6 +100,11 @@ struct xenvif {
         wait_queue_head_t waiting_to_free;
 };
 
+static inline struct xenbus_device *xenvif_to_xenbus_device(struct xenvif *vif)
+{
+        return to_xenbus_device(vif->dev->dev.parent);
+}
+
 #define XEN_NETIF_TX_RING_SIZE __CONST_RING_SIZE(xen_netif_tx, PAGE_SIZE)
 #define XEN_NETIF_RX_RING_SIZE __CONST_RING_SIZE(xen_netif_rx, PAGE_SIZE)
 
diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c
index fd00f25d9850..3af2924fe058 100644
--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -1577,88 +1577,42 @@ static int xen_netbk_kthread(void *data)
 
 void xen_netbk_unmap_frontend_rings(struct xenvif *vif)
 {
-        struct gnttab_unmap_grant_ref op;
-
-        if (vif->tx.sring) {
-                gnttab_set_unmap_op(&op, (unsigned long)vif->tx_comms_area->addr,
-                                    GNTMAP_host_map, vif->tx_shmem_handle);
-
-                if (HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, &op, 1))
-                        BUG();
-        }
-
-        if (vif->rx.sring) {
-                gnttab_set_unmap_op(&op, (unsigned long)vif->rx_comms_area->addr,
-                                    GNTMAP_host_map, vif->rx_shmem_handle);
-
-                if (HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, &op, 1))
-                        BUG();
-        }
-        if (vif->rx_comms_area)
-                free_vm_area(vif->rx_comms_area);
-        if (vif->tx_comms_area)
-                free_vm_area(vif->tx_comms_area);
+        if (vif->tx.sring)
+                xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(vif),
+                                        vif->tx.sring);
+        if (vif->rx.sring)
+                xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(vif),
+                                        vif->rx.sring);
 }
 
 int xen_netbk_map_frontend_rings(struct xenvif *vif,
                                  grant_ref_t tx_ring_ref,
                                  grant_ref_t rx_ring_ref)
 {
-        struct gnttab_map_grant_ref op;
+        void *addr;
         struct xen_netif_tx_sring *txs;
         struct xen_netif_rx_sring *rxs;
 
         int err = -ENOMEM;
 
-        vif->tx_comms_area = alloc_vm_area(PAGE_SIZE);
-        if (vif->tx_comms_area == NULL)
+        err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(vif),
+                                     tx_ring_ref, &addr);
+        if (err)
                 goto err;
 
-        vif->rx_comms_area = alloc_vm_area(PAGE_SIZE);
-        if (vif->rx_comms_area == NULL)
-                goto err;
-
-        gnttab_set_map_op(&op, (unsigned long)vif->tx_comms_area->addr,
-                          GNTMAP_host_map, tx_ring_ref, vif->domid);
-
-        if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1))
-                BUG();
-
-        if (op.status) {
-                netdev_warn(vif->dev,
-                            "failed to map tx ring. err=%d status=%d\n",
-                            err, op.status);
-                err = op.status;
-                goto err;
-        }
-
-        vif->tx_shmem_ref    = tx_ring_ref;
-        vif->tx_shmem_handle = op.handle;
-
-        txs = (struct xen_netif_tx_sring *)vif->tx_comms_area->addr;
+        txs = (struct xen_netif_tx_sring *)addr;
         BACK_RING_INIT(&vif->tx, txs, PAGE_SIZE);
 
-        gnttab_set_map_op(&op, (unsigned long)vif->rx_comms_area->addr,
-                          GNTMAP_host_map, rx_ring_ref, vif->domid);
-
-        if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1))
-                BUG();
-
-        if (op.status) {
-                netdev_warn(vif->dev,
-                            "failed to map rx ring. err=%d status=%d\n",
-                            err, op.status);
-                err = op.status;
+        err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(vif),
+                                     rx_ring_ref, &addr);
+        if (err)
                 goto err;
-        }
-
-        vif->rx_shmem_ref     = rx_ring_ref;
-        vif->rx_shmem_handle  = op.handle;
-        vif->rx_req_cons_peek = 0;
 
-        rxs = (struct xen_netif_rx_sring *)vif->rx_comms_area->addr;
+        rxs = (struct xen_netif_rx_sring *)addr;
         BACK_RING_INIT(&vif->rx, rxs, PAGE_SIZE);
 
+        vif->rx_req_cons_peek = 0;
+
         return 0;
 
 err: