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);