[Xen-devel] [PATCH 3/6] net: xen-netback: use API provided by xenbus module to map rings

[David Vrabel <david.vrabel@xxxxxxxxxx>]

From: David Vrabel <david.vrabel@xxxxxxxxxx>

The xenbus module provides xenbus_map_ring_page() and
xenbus_map_ring_page().  Use these to map the ring pages granted by
the frontend.

Signed-off-by: David Vrabel <david.vrabel@xxxxxxxxxx>
Cc: Ian Campbell <ian.campbell@xxxxxxxxxx>
---
 drivers/net/xen-netback/common.h  |   13 +++---
 drivers/net/xen-netback/netback.c |   79 +++++++-----------------------------
 2 files changed, 23 insertions(+), 69 deletions(-)

diff --git a/drivers/net/xen-netback/common.h b/drivers/net/xen-netback/common.h
index 161f207..05e0a8e 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 +66,8 @@ 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;
+       struct page *tx_ring_page;
+       struct page *rx_ring_page;
 
        /* Frontend feature information. */
        u8 can_sg:1;
@@ -106,6 +102,11 @@ 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 fd00f25..2a017b28 100644
--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -1577,88 +1577,41 @@ 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_page(xenvif_to_xenbus_device(vif),
+                                      vif->tx_ring_page);
+       if (vif->rx.sring)
+               xenbus_unmap_ring_page(xenvif_to_xenbus_device(vif),
+                                      vif->rx_ring_page);
 }
 
 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;
        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_page(xenvif_to_xenbus_device(vif),
+                                  tx_ring_ref, &vif->tx_ring_page);
+       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 = page_address(vif->tx_ring_page);
        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_page(xenvif_to_xenbus_device(vif),
+                                  rx_ring_ref, &vif->rx_ring_page);
+       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 = page_address(vif->rx_ring_page);
        BACK_RING_INIT(&vif->rx, rxs, PAGE_SIZE);
 
+       vif->rx_req_cons_peek = 0;
+
        return 0;
 
 err:
-- 
1.7.2.5


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