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From: Jesper Dangaard Brouer <brouer@redhat.com>
Date: Thu, 31 May 2018 10:59:47 +0200
Subject: xdp: add flags argument to ndo_xdp_xmit API
Patch-mainline: v4.18-rc1
Git-commit: 42b33468987bac0dd95c30f14820c7abac04a153
References: bsc#1109837

This patch only change the API and reject any use of flags. This is an
intermediate step that allows us to implement the flush flag operation
later, for each individual driver in a separate patch.

The plan is to implement flush operation via XDP_XMIT_FLUSH flag
and then remove XDP_XMIT_FLAGS_NONE when done.

Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/net/ethernet/intel/i40e/i40e_txrx.c   |    6 +++++-
 drivers/net/ethernet/intel/i40e/i40e_txrx.h   |    3 ++-
 drivers/net/ethernet/intel/ixgbe/ixgbe_main.c |    5 ++++-
 drivers/net/tun.c                             |    8 ++++++--
 drivers/net/virtio_net.c                      |    5 ++++-
 include/linux/netdevice.h                     |    7 ++++---
 include/net/xdp.h                             |    5 +++++
 kernel/bpf/devmap.c                           |    2 +-
 net/core/filter.c                             |    2 +-
 9 files changed, 32 insertions(+), 11 deletions(-)

--- a/drivers/net/ethernet/intel/i40e/i40e_txrx.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_txrx.c
@@ -3716,7 +3716,8 @@ netdev_tx_t i40e_lan_xmit_frame(struct s
  * For error cases, a negative errno code is returned and no-frames
  * are transmitted (caller must handle freeing frames).
  **/
-int i40e_xdp_xmit(struct net_device *dev, int n, struct xdp_frame **frames)
+int i40e_xdp_xmit(struct net_device *dev, int n, struct xdp_frame **frames,
+		  u32 flags)
 {
 	struct i40e_netdev_priv *np = netdev_priv(dev);
 	unsigned int queue_index = smp_processor_id();
@@ -3730,6 +3731,9 @@ int i40e_xdp_xmit(struct net_device *dev
 	if (!i40e_enabled_xdp_vsi(vsi) || queue_index >= vsi->num_queue_pairs)
 		return -ENXIO;
 
+	if (unlikely(flags & ~XDP_XMIT_FLAGS_NONE))
+		return -EINVAL;
+
 	for (i = 0; i < n; i++) {
 		struct xdp_frame *xdpf = frames[i];
 		int err;
--- a/drivers/net/ethernet/intel/i40e/i40e_txrx.h
+++ b/drivers/net/ethernet/intel/i40e/i40e_txrx.h
@@ -510,7 +510,8 @@ u32 i40e_get_tx_pending(struct i40e_ring
 void i40e_detect_recover_hung(struct i40e_vsi *vsi);
 int __i40e_maybe_stop_tx(struct i40e_ring *tx_ring, int size);
 bool __i40e_chk_linearize(struct sk_buff *skb);
-int i40e_xdp_xmit(struct net_device *dev, int n, struct xdp_frame **frames);
+int i40e_xdp_xmit(struct net_device *dev, int n, struct xdp_frame **frames,
+		  u32 flags);
 void i40e_xdp_flush(struct net_device *dev);
 
 /**
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
@@ -10049,7 +10049,7 @@ static int ixgbe_xdp(struct net_device *
 }
 
 static int ixgbe_xdp_xmit(struct net_device *dev, int n,
-			  struct xdp_frame **frames)
+			  struct xdp_frame **frames, u32 flags)
 {
 	struct ixgbe_adapter *adapter = netdev_priv(dev);
 	struct ixgbe_ring *ring;
@@ -10059,6 +10059,9 @@ static int ixgbe_xdp_xmit(struct net_dev
 	if (unlikely(test_bit(__IXGBE_DOWN, &adapter->state)))
 		return -ENETDOWN;
 
+	if (unlikely(flags & ~XDP_XMIT_FLAGS_NONE))
+		return -EINVAL;
+
 	/* During program transitions its possible adapter->xdp_prog is assigned
 	 * but ring has not been configured yet. In this case simply abort xmit.
 	 */
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -1288,7 +1288,8 @@ static const struct net_device_ops tun_n
 	.ndo_get_stats64	= tun_net_get_stats64,
 };
 
-static int tun_xdp_xmit(struct net_device *dev, int n, struct xdp_frame **frames)
+static int tun_xdp_xmit(struct net_device *dev, int n,
+			struct xdp_frame **frames, u32 flags)
 {
 	struct tun_struct *tun = netdev_priv(dev);
 	struct tun_file *tfile;
@@ -1297,6 +1298,9 @@ static int tun_xdp_xmit(struct net_devic
 	int cnt = n;
 	int i;
 
+	if (unlikely(flags & ~XDP_XMIT_FLAGS_NONE))
+		return -EINVAL;
+
 	rcu_read_lock();
 
 	numqueues = READ_ONCE(tun->numqueues);
@@ -1335,7 +1339,7 @@ static int tun_xdp_tx(struct net_device
 	if (unlikely(!frame))
 		return -EOVERFLOW;
 
-	return tun_xdp_xmit(dev, 1, &frame);
+	return tun_xdp_xmit(dev, 1, &frame, 0);
 }
 
 static void tun_xdp_flush(struct net_device *dev)
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -474,7 +474,7 @@ static int __virtnet_xdp_tx_xmit(struct
 }
 
 static int virtnet_xdp_xmit(struct net_device *dev,
-			    int n, struct xdp_frame **frames)
+			    int n, struct xdp_frame **frames, u32 flags)
 {
 	struct virtnet_info *vi = netdev_priv(dev);
 	struct receive_queue *rq = vi->rq;
@@ -487,6 +487,9 @@ static int virtnet_xdp_xmit(struct net_d
 	int err;
 	int i;
 
+	if (unlikely(flags & ~XDP_XMIT_FLAGS_NONE))
+		return -EINVAL;
+
 	qp = vi->curr_queue_pairs - vi->xdp_queue_pairs + smp_processor_id();
 	sq = &vi->sq[qp];
 
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -1171,13 +1171,13 @@ struct tlsdev_ops {
  *	This function is used to set or query state related to XDP on the
  *	netdevice and manage BPF offload. See definition of
  *	enum bpf_netdev_command for details.
- * int (*ndo_xdp_xmit)(struct net_device *dev, int n, struct xdp_frame **xdp);
+ * int (*ndo_xdp_xmit)(struct net_device *dev, int n, struct xdp_frame **xdp,
+ *			u32 flags);
  *	This function is used to submit @n XDP packets for transmit on a
  *	netdevice. Returns number of frames successfully transmitted, frames
  *	that got dropped are freed/returned via xdp_return_frame().
  *	Returns negative number, means general error invoking ndo, meaning
  *	no frames were xmit'ed and core-caller will free all frames.
- *	TODO: Consider add flag to allow sending flush operation.
  * void (*ndo_xdp_flush)(struct net_device *dev);
  *	This function is used to inform the driver to flush a particular
  *	xdp tx queue. Must be called on same CPU as xdp_xmit.
@@ -1366,7 +1366,8 @@ struct net_device_ops {
 	int			(*ndo_bpf)(struct net_device *dev,
 					   struct netdev_bpf *bpf);
 	int			(*ndo_xdp_xmit)(struct net_device *dev, int n,
-						struct xdp_frame **xdp);
+						struct xdp_frame **xdp,
+						u32 flags);
 	void			(*ndo_xdp_flush)(struct net_device *dev);
 };
 
--- a/include/net/xdp.h
+++ b/include/net/xdp.h
@@ -40,6 +40,11 @@ enum xdp_mem_type {
 	MEM_TYPE_MAX,
 };
 
+/* XDP flags for ndo_xdp_xmit */
+#define XDP_XMIT_FLAGS_NONE	0U
+#define XDP_XMIT_FLUSH		(1U << 0)	/* doorbell signal consumer */
+#define XDP_XMIT_FLAGS_MASK	XDP_XMIT_FLUSH
+
 struct xdp_mem_info {
 	u32 type; /* enum xdp_mem_type, but known size type */
 	u32 id;
--- a/kernel/bpf/devmap.c
+++ b/kernel/bpf/devmap.c
@@ -232,7 +232,7 @@ static int bq_xmit_all(struct bpf_dtab_n
 		prefetch(xdpf);
 	}
 
-	sent = dev->netdev_ops->ndo_xdp_xmit(dev, bq->count, bq->q);
+	sent = dev->netdev_ops->ndo_xdp_xmit(dev, bq->count, bq->q, 0);
 	if (sent < 0) {
 		err = sent;
 		sent = 0;
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -3036,7 +3036,7 @@ static int __bpf_tx_xdp(struct net_devic
 	if (unlikely(!xdpf))
 		return -EOVERFLOW;
 
-	sent = dev->netdev_ops->ndo_xdp_xmit(dev, 1, &xdpf);
+	sent = dev->netdev_ops->ndo_xdp_xmit(dev, 1, &xdpf, 0);
 	if (sent <= 0)
 		return sent;
 	dev->netdev_ops->ndo_xdp_flush(dev);