1 files changed, 41 insertions, 29 deletions

diff --git a/net/xdp/xdp_umem.c b/net/xdp/xdp_umem.c
index f47abb46c587..911ca6d3cb5a 100644
--- a/net/xdp/xdp_umem.c
+++ b/net/xdp/xdp_umem.c
@@ -11,6 +11,8 @@
 #include <linux/slab.h>
 #include <linux/bpf.h>
 #include <linux/mm.h>
+#include <linux/netdevice.h>
+#include <linux/rtnetlink.h>
 
 #include "xdp_umem.h"
 #include "xsk_queue.h"
@@ -40,6 +42,21 @@ void xdp_del_sk_umem(struct xdp_umem *umem, struct xdp_sock *xs)
 	}
 }
 
+int xdp_umem_query(struct net_device *dev, u16 queue_id)
+{
+	struct netdev_bpf bpf;
+
+	ASSERT_RTNL();
+
+	memset(&bpf, 0, sizeof(bpf));
+	bpf.command = XDP_QUERY_XSK_UMEM;
+	bpf.xsk.queue_id = queue_id;
+
+	if (!dev->netdev_ops->ndo_bpf)
+		return 0;
+	return dev->netdev_ops->ndo_bpf(dev, &bpf) ?: !!bpf.xsk.umem;
+}
+
 int xdp_umem_assign_dev(struct xdp_umem *umem, struct net_device *dev,
 			u32 queue_id, u16 flags)
 {
@@ -56,41 +73,36 @@ int xdp_umem_assign_dev(struct xdp_umem *umem, struct net_device *dev,
 	if (force_copy)
 		return 0;
 
-	dev_hold(dev);
-
-	if (dev->netdev_ops->ndo_bpf && dev->netdev_ops->ndo_xsk_async_xmit) {
-		bpf.command = XDP_QUERY_XSK_UMEM;
+	if (!dev->netdev_ops->ndo_bpf || !dev->netdev_ops->ndo_xsk_async_xmit)
+		return force_zc ? -ENOTSUPP : 0; /* fail or fallback */
 
-		rtnl_lock();
-		err = dev->netdev_ops->ndo_bpf(dev, &bpf);
-		rtnl_unlock();
+	bpf.command = XDP_QUERY_XSK_UMEM;
 
-		if (err) {
-			dev_put(dev);
-			return force_zc ? -ENOTSUPP : 0;
-		}
-
-		bpf.command = XDP_SETUP_XSK_UMEM;
-		bpf.xsk.umem = umem;
-		bpf.xsk.queue_id = queue_id;
+	rtnl_lock();
+	err = xdp_umem_query(dev, queue_id);
+	if (err) {
+		err = err < 0 ? -ENOTSUPP : -EBUSY;
+		goto err_rtnl_unlock;
+	}
 
-		rtnl_lock();
-		err = dev->netdev_ops->ndo_bpf(dev, &bpf);
-		rtnl_unlock();
+	bpf.command = XDP_SETUP_XSK_UMEM;
+	bpf.xsk.umem = umem;
+	bpf.xsk.queue_id = queue_id;
 
-		if (err) {
-			dev_put(dev);
-			return force_zc ? err : 0; /* fail or fallback */
-		}
+	err = dev->netdev_ops->ndo_bpf(dev, &bpf);
+	if (err)
+		goto err_rtnl_unlock;
+	rtnl_unlock();
 
-		umem->dev = dev;
-		umem->queue_id = queue_id;
-		umem->zc = true;
-		return 0;
-	}
+	dev_hold(dev);
+	umem->dev = dev;
+	umem->queue_id = queue_id;
+	umem->zc = true;
+	return 0;
 
-	dev_put(dev);
-	return force_zc ? -ENOTSUPP : 0; /* fail or fallback */
+err_rtnl_unlock:
+	rtnl_unlock();
+	return force_zc ? err : 0; /* fail or fallback */
 }
 
 static void xdp_umem_clear_dev(struct xdp_umem *umem)