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path: root/drivers/net/xen-netback/interface.c
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Diffstat (limited to 'drivers/net/xen-netback/interface.c')
-rw-r--r--drivers/net/xen-netback/interface.c10
1 files changed, 9 insertions, 1 deletions
diff --git a/drivers/net/xen-netback/interface.c b/drivers/net/xen-netback/interface.c
index f15ba3de6195..0c8a02a1ead7 100644
--- a/drivers/net/xen-netback/interface.c
+++ b/drivers/net/xen-netback/interface.c
@@ -585,6 +585,7 @@ int xenvif_connect_ctrl(struct xenvif *vif, grant_ref_t ring_ref,
struct net_device *dev = vif->dev;
void *addr;
struct xen_netif_ctrl_sring *shared;
+ RING_IDX rsp_prod, req_prod;
int err;
err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(vif),
@@ -593,7 +594,14 @@ int xenvif_connect_ctrl(struct xenvif *vif, grant_ref_t ring_ref,
goto err;
shared = (struct xen_netif_ctrl_sring *)addr;
- BACK_RING_INIT(&vif->ctrl, shared, XEN_PAGE_SIZE);
+ rsp_prod = READ_ONCE(shared->rsp_prod);
+ req_prod = READ_ONCE(shared->req_prod);
+
+ BACK_RING_ATTACH(&vif->ctrl, shared, rsp_prod, XEN_PAGE_SIZE);
+
+ err = -EIO;
+ if (req_prod - rsp_prod > RING_SIZE(&vif->ctrl))
+ goto err_unmap;
err = bind_interdomain_evtchn_to_irq(vif->domid, evtchn);
if (err < 0)