Commit 1ffcbc85 authored by Jesper Dangaard Brouer's avatar Jesper Dangaard Brouer Committed by David S. Miller
Browse files

tun: convert to use generic xdp_frame and xdp_return_frame API 



The tuntap driver invented it's own driver specific way of queuing
XDP packets, by storing the xdp_buff information in the top of
the XDP frame data.

Convert it over to use the more generic xdp_frame structure.  The
main problem with the in-driver method is that the xdp_rxq_info pointer
cannot be trused/used when dequeueing the frame.

V3: Remove check based on feedback from Jason

Signed-off-by: default avatarJesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent c0048cff

drivers/net/tun.c

+20 −23
Original line number Diff line number Diff line
@@ -248,11 +248,11 @@ struct veth { 
	__be16 h_vlan_TCI;

};



bool tun_is_xdp_buff(void *ptr)

bool tun_is_xdp_frame(void *ptr)

{

	return (unsigned long)ptr & TUN_XDP_FLAG;

}

EXPORT_SYMBOL(tun_is_xdp_buff);

EXPORT_SYMBOL(tun_is_xdp_frame);



void *tun_xdp_to_ptr(void *ptr)

{
@@ -660,10 +660,10 @@ void tun_ptr_free(void *ptr) 
{

	if (!ptr)

		return;

	if (tun_is_xdp_buff(ptr)) {

		struct xdp_buff *xdp = tun_ptr_to_xdp(ptr);

	if (tun_is_xdp_frame(ptr)) {

		struct xdp_frame *xdpf = tun_ptr_to_xdp(ptr);



		put_page(virt_to_head_page(xdp->data));

		xdp_return_frame(xdpf->data, &xdpf->mem);

	} else {

		__skb_array_destroy_skb(ptr);

	}
@@ -1298,17 +1298,14 @@ static const struct net_device_ops tun_netdev_ops = { 
static int tun_xdp_xmit(struct net_device *dev, struct xdp_buff *xdp)

{

	struct tun_struct *tun = netdev_priv(dev);

	struct xdp_buff *buff = xdp->data_hard_start;

	int headroom = xdp->data - xdp->data_hard_start;

	struct xdp_frame *frame;

	struct tun_file *tfile;

	u32 numqueues;

	int ret = 0;



	/* Assure headroom is available and buff is properly aligned */

	if (unlikely(headroom < sizeof(*xdp) || tun_is_xdp_buff(xdp)))

		return -ENOSPC;



	*buff = *xdp;

	frame = convert_to_xdp_frame(xdp);

	if (unlikely(!frame))

		return -EOVERFLOW;



	rcu_read_lock();
@@ -1323,7 +1320,7 @@ static int tun_xdp_xmit(struct net_device *dev, struct xdp_buff *xdp) 
	/* Encode the XDP flag into lowest bit for consumer to differ

	 * XDP buffer from sk_buff.

	 */

	if (ptr_ring_produce(&tfile->tx_ring, tun_xdp_to_ptr(buff))) {

	if (ptr_ring_produce(&tfile->tx_ring, tun_xdp_to_ptr(frame))) {

		this_cpu_inc(tun->pcpu_stats->tx_dropped);

		ret = -ENOSPC;

	}
@@ -2001,11 +1998,11 @@ static ssize_t tun_chr_write_iter(struct kiocb *iocb, struct iov_iter *from) 


static ssize_t tun_put_user_xdp(struct tun_struct *tun,

				struct tun_file *tfile,

				struct xdp_buff *xdp,

				struct xdp_frame *xdp_frame,

				struct iov_iter *iter)

{

	int vnet_hdr_sz = 0;

	size_t size = xdp->data_end - xdp->data;

	size_t size = xdp_frame->len;

	struct tun_pcpu_stats *stats;

	size_t ret;
@@ -2021,7 +2018,7 @@ static ssize_t tun_put_user_xdp(struct tun_struct *tun, 
		iov_iter_advance(iter, vnet_hdr_sz - sizeof(gso));

	}



	ret = copy_to_iter(xdp->data, size, iter) + vnet_hdr_sz;

	ret = copy_to_iter(xdp_frame->data, size, iter) + vnet_hdr_sz;



	stats = get_cpu_ptr(tun->pcpu_stats);

	u64_stats_update_begin(&stats->syncp);
@@ -2189,11 +2186,11 @@ static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile, 
			return err;

	}



	if (tun_is_xdp_buff(ptr)) {

		struct xdp_buff *xdp = tun_ptr_to_xdp(ptr);

	if (tun_is_xdp_frame(ptr)) {

		struct xdp_frame *xdpf = tun_ptr_to_xdp(ptr);



		ret = tun_put_user_xdp(tun, tfile, xdp, to);

		put_page(virt_to_head_page(xdp->data));

		ret = tun_put_user_xdp(tun, tfile, xdpf, to);

		xdp_return_frame(xdpf->data, &xdpf->mem);

	} else {

		struct sk_buff *skb = ptr;
@@ -2432,10 +2429,10 @@ out_free: 
static int tun_ptr_peek_len(void *ptr)

{

	if (likely(ptr)) {

		if (tun_is_xdp_buff(ptr)) {

			struct xdp_buff *xdp = tun_ptr_to_xdp(ptr);

		if (tun_is_xdp_frame(ptr)) {

			struct xdp_frame *xdpf = tun_ptr_to_xdp(ptr);



			return xdp->data_end - xdp->data;

			return xdpf->len;

		}

		return __skb_array_len_with_tag(ptr);

	} else {

drivers/vhost/net.c

+4 −3
Original line number Diff line number Diff line
@@ -32,6 +32,7 @@ 
#include <linux/skbuff.h>



#include <net/sock.h>

#include <net/xdp.h>



#include "vhost.h"
@@ -181,10 +182,10 @@ static void vhost_net_buf_unproduce(struct vhost_net_virtqueue *nvq) 


static int vhost_net_buf_peek_len(void *ptr)

{

	if (tun_is_xdp_buff(ptr)) {

		struct xdp_buff *xdp = tun_ptr_to_xdp(ptr);

	if (tun_is_xdp_frame(ptr)) {

		struct xdp_frame *xdpf = tun_ptr_to_xdp(ptr);



		return xdp->data_end - xdp->data;

		return xdpf->len;

	}



	return __skb_array_len_with_tag(ptr);

include/linux/if_tun.h

+2 −2
Original line number Diff line number Diff line
@@ -22,7 +22,7 @@ 
#if defined(CONFIG_TUN) || defined(CONFIG_TUN_MODULE)

struct socket *tun_get_socket(struct file *);

struct ptr_ring *tun_get_tx_ring(struct file *file);

bool tun_is_xdp_buff(void *ptr);

bool tun_is_xdp_frame(void *ptr);

void *tun_xdp_to_ptr(void *ptr);

void *tun_ptr_to_xdp(void *ptr);

void tun_ptr_free(void *ptr);
@@ -39,7 +39,7 @@ static inline struct ptr_ring *tun_get_tx_ring(struct file *f) 
{

	return ERR_PTR(-EINVAL);

}

static inline bool tun_is_xdp_buff(void *ptr)

static inline bool tun_is_xdp_frame(void *ptr)

{

	return false;

}

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