On 2018年09月07日 00:56, Michael S. Tsirkin wrote:

On Thu, Sep 06, 2018 at 12:05:16PM +0800, Jason Wang wrote:

quoted

This patch introduces a new sock flag - SOCK_XDP. This will be used
for notifying the upper layer that XDP program is attached on the
lower socket, and requires for extra headroom.

TUN will be the first user.

Signed-off-by: Jason Wang <jasowang@redhat.com>

In fact vhost is the 1st user, right? So this can be
pushed out to become patch 10/11.

Better with an independent patch, since patch 10/11 can work without XDP.

Thanks

quoted

---
  drivers/net/tun.c  | 19 +++++++++++++++++++
  include/net/sock.h |  1 +
  2 files changed, 20 insertions(+)

diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index ebd07ad82431..2c548bd20393 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c

@@ -869,6 +869,9 @@ static int tun_attach(struct tun_struct *tun, struct file *file,
  		tun_napi_init(tun, tfile, napi);
  	}
  
+	if (rtnl_dereference(tun->xdp_prog))
+		sock_set_flag(&tfile->sk, SOCK_XDP);
+
  	tun_set_real_num_queues(tun);
  
  	/* device is allowed to go away first, so no need to hold extra

@@ -1241,13 +1244,29 @@ static int tun_xdp_set(struct net_device *dev, struct bpf_prog *prog,
  		       struct netlink_ext_ack *extack)
  {
  	struct tun_struct *tun = netdev_priv(dev);
+	struct tun_file *tfile;
  	struct bpf_prog *old_prog;
+	int i;
  
  	old_prog = rtnl_dereference(tun->xdp_prog);
  	rcu_assign_pointer(tun->xdp_prog, prog);
  	if (old_prog)
  		bpf_prog_put(old_prog);
  
+	for (i = 0; i < tun->numqueues; i++) {
+		tfile = rtnl_dereference(tun->tfiles[i]);
+		if (prog)
+			sock_set_flag(&tfile->sk, SOCK_XDP);
+		else
+			sock_reset_flag(&tfile->sk, SOCK_XDP);
+	}
+	list_for_each_entry(tfile, &tun->disabled, next) {
+		if (prog)
+			sock_set_flag(&tfile->sk, SOCK_XDP);
+		else
+			sock_reset_flag(&tfile->sk, SOCK_XDP);
+	}
+
  	return 0;
  }
  

diff --git a/include/net/sock.h b/include/net/sock.h
index 433f45fc2d68..38cae35f6e16 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h

@@ -800,6 +800,7 @@ enum sock_flags {
  	SOCK_SELECT_ERR_QUEUE, /* Wake select on error queue */
  	SOCK_RCU_FREE, /* wait rcu grace period in sk_destruct() */
  	SOCK_TXTIME,
+	SOCK_XDP, /* XDP is attached */
  };
  
  #define SK_FLAGS_TIMESTAMP ((1UL << SOCK_TIMESTAMP) | (1UL << SOCK_TIMESTAMPING_RX_SOFTWARE))

-- 
2.17.1

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