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: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 28583aa0c17df6fdbeb4f30625f258dcd69855d0..2c85e5cac2a961860133db4dbc17d8a4c2306b1f 100644 (file)
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -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 {

diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index 986058a57917f5b6ce0394d83206c08e161f4bd9..bbf38befefb28d9153c94b01eaba1f2a6a785279 100644 (file)
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -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);

diff --git a/include/linux/if_tun.h b/include/linux/if_tun.h
index fd00170b494f7efee6f4a58ef19a4da10321564d..3d2996dc7d85cda42c36be2b4ddeb9a55cca3faf 100644 (file)
--- a/include/linux/if_tun.h
+++ b/include/linux/if_tun.h
@@ -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;
 }