1 files changed, 38 insertions, 19 deletions

diff --git a/net/core/dev.c b/net/core/dev.c
index 96cf83da0d66..fca407b4a6ea 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -6852,6 +6852,32 @@ int dev_change_proto_down(struct net_device *dev, bool proto_down)
 }
 EXPORT_SYMBOL(dev_change_proto_down);
 
+bool __dev_xdp_attached(struct net_device *dev, xdp_op_t xdp_op)
+{
+        struct netdev_xdp xdp;
+
+        memset(&xdp, 0, sizeof(xdp));
+        xdp.command = XDP_QUERY_PROG;
+
+        /* Query must always succeed. */
+        WARN_ON(xdp_op(dev, &xdp) < 0);
+        return xdp.prog_attached;
+}
+
+static int dev_xdp_install(struct net_device *dev, xdp_op_t xdp_op,
+                           struct netlink_ext_ack *extack,
+                           struct bpf_prog *prog)
+{
+        struct netdev_xdp xdp;
+
+        memset(&xdp, 0, sizeof(xdp));
+        xdp.command = XDP_SETUP_PROG;
+        xdp.extack = extack;
+        xdp.prog = prog;
+
+        return xdp_op(dev, &xdp);
+}
+
 /**
  *      dev_change_xdp_fd - set or clear a bpf program for a device rx path
  *      @dev: device
@@ -6864,41 +6890,34 @@ EXPORT_SYMBOL(dev_change_proto_down);
 int dev_change_xdp_fd(struct net_device *dev, struct netlink_ext_ack *extack,
                       int fd, u32 flags)
 {
-        int (*xdp_op)(struct net_device *dev, struct netdev_xdp *xdp);
         const struct net_device_ops *ops = dev->netdev_ops;
         struct bpf_prog *prog = NULL;
-        struct netdev_xdp xdp;
+        xdp_op_t xdp_op, xdp_chk;
         int err;
 
         ASSERT_RTNL();
 
-        xdp_op = ops->ndo_xdp;
+        xdp_op = xdp_chk = ops->ndo_xdp;
+        if (!xdp_op && (flags & XDP_FLAGS_DRV_MODE))
+                return -EOPNOTSUPP;
         if (!xdp_op || (flags & XDP_FLAGS_SKB_MODE))
                 xdp_op = generic_xdp_install;
+        if (xdp_op == xdp_chk)
+                xdp_chk = generic_xdp_install;
 
         if (fd >= 0) {
-                if (flags & XDP_FLAGS_UPDATE_IF_NOEXIST) {
-                        memset(&xdp, 0, sizeof(xdp));
-                        xdp.command = XDP_QUERY_PROG;
-
-                        err = xdp_op(dev, &xdp);
-                        if (err < 0)
-                                return err;
-                        if (xdp.prog_attached)
-                                return -EBUSY;
-                }
+                if (xdp_chk && __dev_xdp_attached(dev, xdp_chk))
+                        return -EEXIST;
+                if ((flags & XDP_FLAGS_UPDATE_IF_NOEXIST) &&
+                    __dev_xdp_attached(dev, xdp_op))
+                        return -EBUSY;
 
                 prog = bpf_prog_get_type(fd, BPF_PROG_TYPE_XDP);
                 if (IS_ERR(prog))
                         return PTR_ERR(prog);
         }
 
-        memset(&xdp, 0, sizeof(xdp));
-        xdp.command = XDP_SETUP_PROG;
-        xdp.extack = extack;
-        xdp.prog = prog;
-
-        err = xdp_op(dev, &xdp);
+        err = dev_xdp_install(dev, xdp_op, extack, prog);
         if (err < 0 && prog)
                 bpf_prog_put(prog);