Adding upstream version 5.10.209.upstream/5.10.209

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1294 insertions, 0 deletions

diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c
new file mode 100644
index 000000000..d04f91f4d
--- /dev/null
+++ b/net/xdp/xsk.c
@@ -0,0 +1,1294 @@
+// SPDX-License-Identifier: GPL-2.0
+/* XDP sockets
+ *
+ * AF_XDP sockets allows a channel between XDP programs and userspace
+ * applications.
+ * Copyright(c) 2018 Intel Corporation.
+ *
+ * Author(s): Björn Töpel <bjorn.topel@intel.com>
+ *	      Magnus Karlsson <magnus.karlsson@intel.com>
+ */
+
+#define pr_fmt(fmt) "AF_XDP: %s: " fmt, __func__
+
+#include <linux/if_xdp.h>
+#include <linux/init.h>
+#include <linux/sched/mm.h>
+#include <linux/sched/signal.h>
+#include <linux/sched/task.h>
+#include <linux/socket.h>
+#include <linux/file.h>
+#include <linux/uaccess.h>
+#include <linux/net.h>
+#include <linux/netdevice.h>
+#include <linux/rculist.h>
+#include <net/xdp_sock_drv.h>
+#include <net/xdp.h>
+
+#include "xsk_queue.h"
+#include "xdp_umem.h"
+#include "xsk.h"
+
+#define TX_BATCH_SIZE 16
+
+static DEFINE_PER_CPU(struct list_head, xskmap_flush_list);
+
+void xsk_set_rx_need_wakeup(struct xsk_buff_pool *pool)
+{
+	if (pool->cached_need_wakeup & XDP_WAKEUP_RX)
+		return;
+
+	pool->fq->ring->flags |= XDP_RING_NEED_WAKEUP;
+	pool->cached_need_wakeup |= XDP_WAKEUP_RX;
+}
+EXPORT_SYMBOL(xsk_set_rx_need_wakeup);
+
+void xsk_set_tx_need_wakeup(struct xsk_buff_pool *pool)
+{
+	struct xdp_sock *xs;
+
+	if (pool->cached_need_wakeup & XDP_WAKEUP_TX)
+		return;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(xs, &pool->xsk_tx_list, tx_list) {
+		xs->tx->ring->flags |= XDP_RING_NEED_WAKEUP;
+	}
+	rcu_read_unlock();
+
+	pool->cached_need_wakeup |= XDP_WAKEUP_TX;
+}
+EXPORT_SYMBOL(xsk_set_tx_need_wakeup);
+
+void xsk_clear_rx_need_wakeup(struct xsk_buff_pool *pool)
+{
+	if (!(pool->cached_need_wakeup & XDP_WAKEUP_RX))
+		return;
+
+	pool->fq->ring->flags &= ~XDP_RING_NEED_WAKEUP;
+	pool->cached_need_wakeup &= ~XDP_WAKEUP_RX;
+}
+EXPORT_SYMBOL(xsk_clear_rx_need_wakeup);
+
+void xsk_clear_tx_need_wakeup(struct xsk_buff_pool *pool)
+{
+	struct xdp_sock *xs;
+
+	if (!(pool->cached_need_wakeup & XDP_WAKEUP_TX))
+		return;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(xs, &pool->xsk_tx_list, tx_list) {
+		xs->tx->ring->flags &= ~XDP_RING_NEED_WAKEUP;
+	}
+	rcu_read_unlock();
+
+	pool->cached_need_wakeup &= ~XDP_WAKEUP_TX;
+}
+EXPORT_SYMBOL(xsk_clear_tx_need_wakeup);
+
+bool xsk_uses_need_wakeup(struct xsk_buff_pool *pool)
+{
+	return pool->uses_need_wakeup;
+}
+EXPORT_SYMBOL(xsk_uses_need_wakeup);
+
+struct xsk_buff_pool *xsk_get_pool_from_qid(struct net_device *dev,
+					    u16 queue_id)
+{
+	if (queue_id < dev->real_num_rx_queues)
+		return dev->_rx[queue_id].pool;
+	if (queue_id < dev->real_num_tx_queues)
+		return dev->_tx[queue_id].pool;
+
+	return NULL;
+}
+EXPORT_SYMBOL(xsk_get_pool_from_qid);
+
+void xsk_clear_pool_at_qid(struct net_device *dev, u16 queue_id)
+{
+	if (queue_id < dev->num_rx_queues)
+		dev->_rx[queue_id].pool = NULL;
+	if (queue_id < dev->num_tx_queues)
+		dev->_tx[queue_id].pool = NULL;
+}
+
+/* The buffer pool is stored both in the _rx struct and the _tx struct as we do
+ * not know if the device has more tx queues than rx, or the opposite.
+ * This might also change during run time.
+ */
+int xsk_reg_pool_at_qid(struct net_device *dev, struct xsk_buff_pool *pool,
+			u16 queue_id)
+{
+	if (queue_id >= max_t(unsigned int,
+			      dev->real_num_rx_queues,
+			      dev->real_num_tx_queues))
+		return -EINVAL;
+
+	if (queue_id < dev->real_num_rx_queues)
+		dev->_rx[queue_id].pool = pool;
+	if (queue_id < dev->real_num_tx_queues)
+		dev->_tx[queue_id].pool = pool;
+
+	return 0;
+}
+
+void xp_release(struct xdp_buff_xsk *xskb)
+{
+	xskb->pool->free_heads[xskb->pool->free_heads_cnt++] = xskb;
+}
+
+static u64 xp_get_handle(struct xdp_buff_xsk *xskb)
+{
+	u64 offset = xskb->xdp.data - xskb->xdp.data_hard_start;
+
+	offset += xskb->pool->headroom;
+	if (!xskb->pool->unaligned)
+		return xskb->orig_addr + offset;
+	return xskb->orig_addr + (offset << XSK_UNALIGNED_BUF_OFFSET_SHIFT);
+}
+
+static int __xsk_rcv_zc(struct xdp_sock *xs, struct xdp_buff *xdp, u32 len)
+{
+	struct xdp_buff_xsk *xskb = container_of(xdp, struct xdp_buff_xsk, xdp);
+	u64 addr;
+	int err;
+
+	addr = xp_get_handle(xskb);
+	err = xskq_prod_reserve_desc(xs->rx, addr, len);
+	if (err) {
+		xs->rx_queue_full++;
+		return err;
+	}
+
+	xp_release(xskb);
+	return 0;
+}
+
+static void xsk_copy_xdp(struct xdp_buff *to, struct xdp_buff *from, u32 len)
+{
+	void *from_buf, *to_buf;
+	u32 metalen;
+
+	if (unlikely(xdp_data_meta_unsupported(from))) {
+		from_buf = from->data;
+		to_buf = to->data;
+		metalen = 0;
+	} else {
+		from_buf = from->data_meta;
+		metalen = from->data - from->data_meta;
+		to_buf = to->data - metalen;
+	}
+
+	memcpy(to_buf, from_buf, len + metalen);
+}
+
+static int __xsk_rcv(struct xdp_sock *xs, struct xdp_buff *xdp, u32 len,
+		     bool explicit_free)
+{
+	struct xdp_buff *xsk_xdp;
+	int err;
+
+	if (len > xsk_pool_get_rx_frame_size(xs->pool)) {
+		xs->rx_dropped++;
+		return -ENOSPC;
+	}
+
+	xsk_xdp = xsk_buff_alloc(xs->pool);
+	if (!xsk_xdp) {
+		xs->rx_dropped++;
+		return -ENOSPC;
+	}
+
+	xsk_copy_xdp(xsk_xdp, xdp, len);
+	err = __xsk_rcv_zc(xs, xsk_xdp, len);
+	if (err) {
+		xsk_buff_free(xsk_xdp);
+		return err;
+	}
+	if (explicit_free)
+		xdp_return_buff(xdp);
+	return 0;
+}
+
+static bool xsk_tx_writeable(struct xdp_sock *xs)
+{
+	if (xskq_cons_present_entries(xs->tx) > xs->tx->nentries / 2)
+		return false;
+
+	return true;
+}
+
+static bool xsk_is_bound(struct xdp_sock *xs)
+{
+	if (READ_ONCE(xs->state) == XSK_BOUND) {
+		/* Matches smp_wmb() in bind(). */
+		smp_rmb();
+		return true;
+	}
+	return false;
+}
+
+static int xsk_rcv(struct xdp_sock *xs, struct xdp_buff *xdp,
+		   bool explicit_free)
+{
+	u32 len;
+
+	if (!xsk_is_bound(xs))
+		return -EINVAL;
+
+	if (xs->dev != xdp->rxq->dev || xs->queue_id != xdp->rxq->queue_index)
+		return -EINVAL;
+
+	len = xdp->data_end - xdp->data;
+
+	return xdp->rxq->mem.type == MEM_TYPE_XSK_BUFF_POOL ?
+		__xsk_rcv_zc(xs, xdp, len) :
+		__xsk_rcv(xs, xdp, len, explicit_free);
+}
+
+static void xsk_flush(struct xdp_sock *xs)
+{
+	xskq_prod_submit(xs->rx);
+	__xskq_cons_release(xs->pool->fq);
+	sock_def_readable(&xs->sk);
+}
+
+int xsk_generic_rcv(struct xdp_sock *xs, struct xdp_buff *xdp)
+{
+	int err;
+
+	spin_lock_bh(&xs->rx_lock);
+	err = xsk_rcv(xs, xdp, false);
+	xsk_flush(xs);
+	spin_unlock_bh(&xs->rx_lock);
+	return err;
+}
+
+int __xsk_map_redirect(struct xdp_sock *xs, struct xdp_buff *xdp)
+{
+	struct list_head *flush_list = this_cpu_ptr(&xskmap_flush_list);
+	int err;
+
+	err = xsk_rcv(xs, xdp, true);
+	if (err)
+		return err;
+
+	if (!xs->flush_node.prev)
+		list_add(&xs->flush_node, flush_list);
+
+	return 0;
+}
+
+void __xsk_map_flush(void)
+{
+	struct list_head *flush_list = this_cpu_ptr(&xskmap_flush_list);
+	struct xdp_sock *xs, *tmp;
+
+	list_for_each_entry_safe(xs, tmp, flush_list, flush_node) {
+		xsk_flush(xs);
+		__list_del_clearprev(&xs->flush_node);
+	}
+}
+
+void xsk_tx_completed(struct xsk_buff_pool *pool, u32 nb_entries)
+{
+	xskq_prod_submit_n(pool->cq, nb_entries);
+}
+EXPORT_SYMBOL(xsk_tx_completed);
+
+void xsk_tx_release(struct xsk_buff_pool *pool)
+{
+	struct xdp_sock *xs;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(xs, &pool->xsk_tx_list, tx_list) {
+		__xskq_cons_release(xs->tx);
+		if (xsk_tx_writeable(xs))
+			xs->sk.sk_write_space(&xs->sk);
+	}
+	rcu_read_unlock();
+}
+EXPORT_SYMBOL(xsk_tx_release);
+
+bool xsk_tx_peek_desc(struct xsk_buff_pool *pool, struct xdp_desc *desc)
+{
+	struct xdp_sock *xs;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(xs, &pool->xsk_tx_list, tx_list) {
+		if (!xskq_cons_peek_desc(xs->tx, desc, pool)) {
+			xs->tx->queue_empty_descs++;
+			continue;
+		}
+
+		/* This is the backpressure mechanism for the Tx path.
+		 * Reserve space in the completion queue and only proceed
+		 * if there is space in it. This avoids having to implement
+		 * any buffering in the Tx path.
+		 */
+		if (xskq_prod_reserve_addr(pool->cq, desc->addr))
+			goto out;
+
+		xskq_cons_release(xs->tx);
+		rcu_read_unlock();
+		return true;
+	}
+
+out:
+	rcu_read_unlock();
+	return false;
+}
+EXPORT_SYMBOL(xsk_tx_peek_desc);
+
+static int xsk_wakeup(struct xdp_sock *xs, u8 flags)
+{
+	struct net_device *dev = xs->dev;
+	int err;
+
+	rcu_read_lock();
+	err = dev->netdev_ops->ndo_xsk_wakeup(dev, xs->queue_id, flags);
+	rcu_read_unlock();
+
+	return err;
+}
+
+static int xsk_zc_xmit(struct xdp_sock *xs)
+{
+	return xsk_wakeup(xs, XDP_WAKEUP_TX);
+}
+
+static void xsk_destruct_skb(struct sk_buff *skb)
+{
+	u64 addr = (u64)(long)skb_shinfo(skb)->destructor_arg;
+	struct xdp_sock *xs = xdp_sk(skb->sk);
+	unsigned long flags;
+
+	spin_lock_irqsave(&xs->pool->cq_lock, flags);
+	xskq_prod_submit_addr(xs->pool->cq, addr);
+	spin_unlock_irqrestore(&xs->pool->cq_lock, flags);
+
+	sock_wfree(skb);
+}
+
+static int xsk_generic_xmit(struct sock *sk)
+{
+	struct xdp_sock *xs = xdp_sk(sk);
+	u32 max_batch = TX_BATCH_SIZE;
+	bool sent_frame = false;
+	struct xdp_desc desc;
+	struct sk_buff *skb;
+	unsigned long flags;
+	int err = 0;
+	u32 hr, tr;
+
+	mutex_lock(&xs->mutex);
+
+	if (xs->queue_id >= xs->dev->real_num_tx_queues)
+		goto out;
+
+	hr = max(NET_SKB_PAD, L1_CACHE_ALIGN(xs->dev->needed_headroom));
+	tr = xs->dev->needed_tailroom;
+
+	while (xskq_cons_peek_desc(xs->tx, &desc, xs->pool)) {
+		char *buffer;
+		u64 addr;
+		u32 len;
+
+		if (max_batch-- == 0) {
+			err = -EAGAIN;
+			goto out;
+		}
+
+		len = desc.len;
+		skb = sock_alloc_send_skb(sk, hr + len + tr, 1, &err);
+		if (unlikely(!skb))
+			goto out;
+
+		skb_reserve(skb, hr);
+		skb_put(skb, len);
+
+		addr = desc.addr;
+		buffer = xsk_buff_raw_get_data(xs->pool, addr);
+		err = skb_store_bits(skb, 0, buffer, len);
+		/* This is the backpressure mechanism for the Tx path.
+		 * Reserve space in the completion queue and only proceed
+		 * if there is space in it. This avoids having to implement
+		 * any buffering in the Tx path.
+		 */
+		spin_lock_irqsave(&xs->pool->cq_lock, flags);
+		if (unlikely(err) || xskq_prod_reserve(xs->pool->cq)) {
+			spin_unlock_irqrestore(&xs->pool->cq_lock, flags);
+			kfree_skb(skb);
+			goto out;
+		}
+		spin_unlock_irqrestore(&xs->pool->cq_lock, flags);
+
+		skb->dev = xs->dev;
+		skb->priority = sk->sk_priority;
+		skb->mark = sk->sk_mark;
+		skb_shinfo(skb)->destructor_arg = (void *)(long)desc.addr;
+		skb->destructor = xsk_destruct_skb;
+
+		err = __dev_direct_xmit(skb, xs->queue_id);
+		if  (err == NETDEV_TX_BUSY) {
+			/* Tell user-space to retry the send */
+			skb->destructor = sock_wfree;
+			spin_lock_irqsave(&xs->pool->cq_lock, flags);
+			xskq_prod_cancel(xs->pool->cq);
+			spin_unlock_irqrestore(&xs->pool->cq_lock, flags);
+			/* Free skb without triggering the perf drop trace */
+			consume_skb(skb);
+			err = -EAGAIN;
+			goto out;
+		}
+
+		xskq_cons_release(xs->tx);
+		/* Ignore NET_XMIT_CN as packet might have been sent */
+		if (err == NET_XMIT_DROP) {
+			/* SKB completed but not sent */
+			err = -EBUSY;
+			goto out;
+		}
+
+		sent_frame = true;
+	}
+
+	xs->tx->queue_empty_descs++;
+
+out:
+	if (sent_frame)
+		if (xsk_tx_writeable(xs))
+			sk->sk_write_space(sk);
+
+	mutex_unlock(&xs->mutex);
+	return err;
+}
+
+static int __xsk_sendmsg(struct sock *sk)
+{
+	struct xdp_sock *xs = xdp_sk(sk);
+
+	if (unlikely(!(xs->dev->flags & IFF_UP)))
+		return -ENETDOWN;
+	if (unlikely(!xs->tx))
+		return -ENOBUFS;
+
+	return xs->zc ? xsk_zc_xmit(xs) : xsk_generic_xmit(sk);
+}
+
+static int xsk_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len)
+{
+	bool need_wait = !(m->msg_flags & MSG_DONTWAIT);
+	struct sock *sk = sock->sk;
+	struct xdp_sock *xs = xdp_sk(sk);
+
+	if (unlikely(!xsk_is_bound(xs)))
+		return -ENXIO;
+	if (unlikely(need_wait))
+		return -EOPNOTSUPP;
+
+	return __xsk_sendmsg(sk);
+}
+
+static __poll_t xsk_poll(struct file *file, struct socket *sock,
+			     struct poll_table_struct *wait)
+{
+	__poll_t mask = 0;
+	struct sock *sk = sock->sk;
+	struct xdp_sock *xs = xdp_sk(sk);
+	struct xsk_buff_pool *pool;
+
+	sock_poll_wait(file, sock, wait);
+
+	if (unlikely(!xsk_is_bound(xs)))
+		return mask;
+
+	pool = xs->pool;
+
+	if (pool->cached_need_wakeup) {
+		if (xs->zc)
+			xsk_wakeup(xs, pool->cached_need_wakeup);
+		else
+			/* Poll needs to drive Tx also in copy mode */
+			__xsk_sendmsg(sk);
+	}
+
+	if (xs->rx && !xskq_prod_is_empty(xs->rx))
+		mask |= EPOLLIN | EPOLLRDNORM;
+	if (xs->tx && xsk_tx_writeable(xs))
+		mask |= EPOLLOUT | EPOLLWRNORM;
+
+	return mask;
+}
+
+static int xsk_init_queue(u32 entries, struct xsk_queue **queue,
+			  bool umem_queue)
+{
+	struct xsk_queue *q;
+
+	if (entries == 0 || *queue || !is_power_of_2(entries))
+		return -EINVAL;
+
+	q = xskq_create(entries, umem_queue);
+	if (!q)
+		return -ENOMEM;
+
+	/* Make sure queue is ready before it can be seen by others */
+	smp_wmb();
+	WRITE_ONCE(*queue, q);
+	return 0;
+}
+
+static void xsk_unbind_dev(struct xdp_sock *xs)
+{
+	struct net_device *dev = xs->dev;
+
+	if (xs->state != XSK_BOUND)
+		return;
+	WRITE_ONCE(xs->state, XSK_UNBOUND);
+
+	/* Wait for driver to stop using the xdp socket. */
+	xp_del_xsk(xs->pool, xs);
+	xs->dev = NULL;
+	synchronize_net();
+	dev_put(dev);
+}
+
+static struct xsk_map *xsk_get_map_list_entry(struct xdp_sock *xs,
+					      struct xdp_sock ***map_entry)
+{
+	struct xsk_map *map = NULL;
+	struct xsk_map_node *node;
+
+	*map_entry = NULL;
+
+	spin_lock_bh(&xs->map_list_lock);
+	node = list_first_entry_or_null(&xs->map_list, struct xsk_map_node,
+					node);
+	if (node) {
+		WARN_ON(xsk_map_inc(node->map));
+		map = node->map;
+		*map_entry = node->map_entry;
+	}
+	spin_unlock_bh(&xs->map_list_lock);
+	return map;
+}
+
+static void xsk_delete_from_maps(struct xdp_sock *xs)
+{
+	/* This function removes the current XDP socket from all the
+	 * maps it resides in. We need to take extra care here, due to
+	 * the two locks involved. Each map has a lock synchronizing
+	 * updates to the entries, and each socket has a lock that
+	 * synchronizes access to the list of maps (map_list). For
+	 * deadlock avoidance the locks need to be taken in the order
+	 * "map lock"->"socket map list lock". We start off by
+	 * accessing the socket map list, and take a reference to the
+	 * map to guarantee existence between the
+	 * xsk_get_map_list_entry() and xsk_map_try_sock_delete()
+	 * calls. Then we ask the map to remove the socket, which
+	 * tries to remove the socket from the map. Note that there
+	 * might be updates to the map between
+	 * xsk_get_map_list_entry() and xsk_map_try_sock_delete().
+	 */
+	struct xdp_sock **map_entry = NULL;
+	struct xsk_map *map;
+
+	while ((map = xsk_get_map_list_entry(xs, &map_entry))) {
+		xsk_map_try_sock_delete(map, xs, map_entry);
+		xsk_map_put(map);
+	}
+}
+
+static int xsk_release(struct socket *sock)
+{
+	struct sock *sk = sock->sk;
+	struct xdp_sock *xs = xdp_sk(sk);
+	struct net *net;
+
+	if (!sk)
+		return 0;
+
+	net = sock_net(sk);
+
+	mutex_lock(&net->xdp.lock);
+	sk_del_node_init_rcu(sk);
+	mutex_unlock(&net->xdp.lock);
+
+	local_bh_disable();
+	sock_prot_inuse_add(net, sk->sk_prot, -1);
+	local_bh_enable();
+
+	xsk_delete_from_maps(xs);
+	mutex_lock(&xs->mutex);
+	xsk_unbind_dev(xs);
+	mutex_unlock(&xs->mutex);
+
+	xskq_destroy(xs->rx);
+	xskq_destroy(xs->tx);
+	xskq_destroy(xs->fq_tmp);
+	xskq_destroy(xs->cq_tmp);
+
+	sock_orphan(sk);
+	sock->sk = NULL;
+
+	sk_refcnt_debug_release(sk);
+	sock_put(sk);
+
+	return 0;
+}
+
+static struct socket *xsk_lookup_xsk_from_fd(int fd)
+{
+	struct socket *sock;
+	int err;
+
+	sock = sockfd_lookup(fd, &err);
+	if (!sock)
+		return ERR_PTR(-ENOTSOCK);
+
+	if (sock->sk->sk_family != PF_XDP) {
+		sockfd_put(sock);
+		return ERR_PTR(-ENOPROTOOPT);
+	}
+
+	return sock;
+}
+
+static bool xsk_validate_queues(struct xdp_sock *xs)
+{
+	return xs->fq_tmp && xs->cq_tmp;
+}
+
+static int xsk_bind(struct socket *sock, struct sockaddr *addr, int addr_len)
+{
+	struct sockaddr_xdp *sxdp = (struct sockaddr_xdp *)addr;
+	struct sock *sk = sock->sk;
+	struct xdp_sock *xs = xdp_sk(sk);
+	struct net_device *dev;
+	int bound_dev_if;
+	u32 flags, qid;
+	int err = 0;
+
+	if (addr_len < sizeof(struct sockaddr_xdp))
+		return -EINVAL;
+	if (sxdp->sxdp_family != AF_XDP)
+		return -EINVAL;
+
+	flags = sxdp->sxdp_flags;
+	if (flags & ~(XDP_SHARED_UMEM | XDP_COPY | XDP_ZEROCOPY |
+		      XDP_USE_NEED_WAKEUP))
+		return -EINVAL;
+
+	bound_dev_if = READ_ONCE(sk->sk_bound_dev_if);
+	if (bound_dev_if && bound_dev_if != sxdp->sxdp_ifindex)
+		return -EINVAL;
+
+	rtnl_lock();
+	mutex_lock(&xs->mutex);
+	if (xs->state != XSK_READY) {
+		err = -EBUSY;
+		goto out_release;
+	}
+
+	dev = dev_get_by_index(sock_net(sk), sxdp->sxdp_ifindex);
+	if (!dev) {
+		err = -ENODEV;
+		goto out_release;
+	}
+
+	if (!xs->rx && !xs->tx) {
+		err = -EINVAL;
+		goto out_unlock;
+	}
+
+	qid = sxdp->sxdp_queue_id;
+
+	if (flags & XDP_SHARED_UMEM) {
+		struct xdp_sock *umem_xs;
+		struct socket *sock;
+
+		if ((flags & XDP_COPY) || (flags & XDP_ZEROCOPY) ||
+		    (flags & XDP_USE_NEED_WAKEUP)) {
+			/* Cannot specify flags for shared sockets. */
+			err = -EINVAL;
+			goto out_unlock;
+		}
+
+		if (xs->umem) {
+			/* We have already our own. */
+			err = -EINVAL;
+			goto out_unlock;
+		}
+
+		sock = xsk_lookup_xsk_from_fd(sxdp->sxdp_shared_umem_fd);
+		if (IS_ERR(sock)) {
+			err = PTR_ERR(sock);
+			goto out_unlock;
+		}
+
+		umem_xs = xdp_sk(sock->sk);
+		if (!xsk_is_bound(umem_xs)) {
+			err = -EBADF;
+			sockfd_put(sock);
+			goto out_unlock;
+		}
+
+		if (umem_xs->queue_id != qid || umem_xs->dev != dev) {
+			/* Share the umem with another socket on another qid
+			 * and/or device.
+			 */
+			xs->pool = xp_create_and_assign_umem(xs,
+							     umem_xs->umem);
+			if (!xs->pool) {
+				err = -ENOMEM;
+				sockfd_put(sock);
+				goto out_unlock;
+			}
+
+			err = xp_assign_dev_shared(xs->pool, umem_xs, dev,
+						   qid);
+			if (err) {
+				xp_destroy(xs->pool);
+				xs->pool = NULL;
+				sockfd_put(sock);
+				goto out_unlock;
+			}
+		} else {
+			/* Share the buffer pool with the other socket. */
+			if (xs->fq_tmp || xs->cq_tmp) {
+				/* Do not allow setting your own fq or cq. */
+				err = -EINVAL;
+				sockfd_put(sock);
+				goto out_unlock;
+			}
+
+			xp_get_pool(umem_xs->pool);
+			xs->pool = umem_xs->pool;
+		}
+
+		xdp_get_umem(umem_xs->umem);
+		WRITE_ONCE(xs->umem, umem_xs->umem);
+		sockfd_put(sock);
+	} else if (!xs->umem || !xsk_validate_queues(xs)) {
+		err = -EINVAL;
+		goto out_unlock;
+	} else {
+		/* This xsk has its own umem. */
+		xs->pool = xp_create_and_assign_umem(xs, xs->umem);
+		if (!xs->pool) {
+			err = -ENOMEM;
+			goto out_unlock;
+		}
+
+		err = xp_assign_dev(xs->pool, dev, qid, flags);
+		if (err) {
+			xp_destroy(xs->pool);
+			xs->pool = NULL;
+			goto out_unlock;
+		}
+	}
+
+	/* FQ and CQ are now owned by the buffer pool and cleaned up with it. */
+	xs->fq_tmp = NULL;
+	xs->cq_tmp = NULL;
+
+	xs->dev = dev;
+	xs->zc = xs->umem->zc;
+	xs->queue_id = qid;
+	xp_add_xsk(xs->pool, xs);
+
+out_unlock:
+	if (err) {
+		dev_put(dev);
+	} else {
+		/* Matches smp_rmb() in bind() for shared umem
+		 * sockets, and xsk_is_bound().
+		 */
+		smp_wmb();
+		WRITE_ONCE(xs->state, XSK_BOUND);
+	}
+out_release:
+	mutex_unlock(&xs->mutex);
+	rtnl_unlock();
+	return err;
+}
+
+struct xdp_umem_reg_v1 {
+	__u64 addr; /* Start of packet data area */
+	__u64 len; /* Length of packet data area */
+	__u32 chunk_size;
+	__u32 headroom;
+};
+
+static int xsk_setsockopt(struct socket *sock, int level, int optname,
+			  sockptr_t optval, unsigned int optlen)
+{
+	struct sock *sk = sock->sk;
+	struct xdp_sock *xs = xdp_sk(sk);
+	int err;
+
+	if (level != SOL_XDP)
+		return -ENOPROTOOPT;
+
+	switch (optname) {
+	case XDP_RX_RING:
+	case XDP_TX_RING:
+	{
+		struct xsk_queue **q;
+		int entries;
+
+		if (optlen < sizeof(entries))
+			return -EINVAL;
+		if (copy_from_sockptr(&entries, optval, sizeof(entries)))
+			return -EFAULT;
+
+		mutex_lock(&xs->mutex);
+		if (xs->state != XSK_READY) {
+			mutex_unlock(&xs->mutex);
+			return -EBUSY;
+		}
+		q = (optname == XDP_TX_RING) ? &xs->tx : &xs->rx;
+		err = xsk_init_queue(entries, q, false);
+		if (!err && optname == XDP_TX_RING)
+			/* Tx needs to be explicitly woken up the first time */
+			xs->tx->ring->flags |= XDP_RING_NEED_WAKEUP;
+		mutex_unlock(&xs->mutex);
+		return err;
+	}
+	case XDP_UMEM_REG:
+	{
+		size_t mr_size = sizeof(struct xdp_umem_reg);
+		struct xdp_umem_reg mr = {};
+		struct xdp_umem *umem;
+
+		if (optlen < sizeof(struct xdp_umem_reg_v1))
+			return -EINVAL;
+		else if (optlen < sizeof(mr))
+			mr_size = sizeof(struct xdp_umem_reg_v1);
+
+		if (copy_from_sockptr(&mr, optval, mr_size))
+			return -EFAULT;
+
+		mutex_lock(&xs->mutex);
+		if (xs->state != XSK_READY || xs->umem) {
+			mutex_unlock(&xs->mutex);
+			return -EBUSY;
+		}
+
+		umem = xdp_umem_create(&mr);
+		if (IS_ERR(umem)) {
+			mutex_unlock(&xs->mutex);
+			return PTR_ERR(umem);
+		}
+
+		/* Make sure umem is ready before it can be seen by others */
+		smp_wmb();
+		WRITE_ONCE(xs->umem, umem);
+		mutex_unlock(&xs->mutex);
+		return 0;
+	}
+	case XDP_UMEM_FILL_RING:
+	case XDP_UMEM_COMPLETION_RING:
+	{
+		struct xsk_queue **q;
+		int entries;
+
+		if (copy_from_sockptr(&entries, optval, sizeof(entries)))
+			return -EFAULT;
+
+		mutex_lock(&xs->mutex);
+		if (xs->state != XSK_READY) {
+			mutex_unlock(&xs->mutex);
+			return -EBUSY;
+		}
+
+		q = (optname == XDP_UMEM_FILL_RING) ? &xs->fq_tmp :
+			&xs->cq_tmp;
+		err = xsk_init_queue(entries, q, true);
+		mutex_unlock(&xs->mutex);
+		return err;
+	}
+	default:
+		break;
+	}
+
+	return -ENOPROTOOPT;
+}
+
+static void xsk_enter_rxtx_offsets(struct xdp_ring_offset_v1 *ring)
+{
+	ring->producer = offsetof(struct xdp_rxtx_ring, ptrs.producer);
+	ring->consumer = offsetof(struct xdp_rxtx_ring, ptrs.consumer);
+	ring->desc = offsetof(struct xdp_rxtx_ring, desc);
+}
+
+static void xsk_enter_umem_offsets(struct xdp_ring_offset_v1 *ring)
+{
+	ring->producer = offsetof(struct xdp_umem_ring, ptrs.producer);
+	ring->consumer = offsetof(struct xdp_umem_ring, ptrs.consumer);
+	ring->desc = offsetof(struct xdp_umem_ring, desc);
+}
+
+struct xdp_statistics_v1 {
+	__u64 rx_dropped;
+	__u64 rx_invalid_descs;
+	__u64 tx_invalid_descs;
+};
+
+static int xsk_getsockopt(struct socket *sock, int level, int optname,
+			  char __user *optval, int __user *optlen)
+{
+	struct sock *sk = sock->sk;
+	struct xdp_sock *xs = xdp_sk(sk);
+	int len;
+
+	if (level != SOL_XDP)
+		return -ENOPROTOOPT;
+
+	if (get_user(len, optlen))
+		return -EFAULT;
+	if (len < 0)
+		return -EINVAL;
+
+	switch (optname) {
+	case XDP_STATISTICS:
+	{
+		struct xdp_statistics stats = {};
+		bool extra_stats = true;
+		size_t stats_size;
+
+		if (len < sizeof(struct xdp_statistics_v1)) {
+			return -EINVAL;
+		} else if (len < sizeof(stats)) {
+			extra_stats = false;
+			stats_size = sizeof(struct xdp_statistics_v1);
+		} else {
+			stats_size = sizeof(stats);
+		}
+
+		mutex_lock(&xs->mutex);
+		stats.rx_dropped = xs->rx_dropped;
+		if (extra_stats) {
+			stats.rx_ring_full = xs->rx_queue_full;
+			stats.rx_fill_ring_empty_descs =
+				xs->pool ? xskq_nb_queue_empty_descs(xs->pool->fq) : 0;
+			stats.tx_ring_empty_descs = xskq_nb_queue_empty_descs(xs->tx);
+		} else {
+			stats.rx_dropped += xs->rx_queue_full;
+		}
+		stats.rx_invalid_descs = xskq_nb_invalid_descs(xs->rx);
+		stats.tx_invalid_descs = xskq_nb_invalid_descs(xs->tx);
+		mutex_unlock(&xs->mutex);
+
+		if (copy_to_user(optval, &stats, stats_size))
+			return -EFAULT;
+		if (put_user(stats_size, optlen))
+			return -EFAULT;
+
+		return 0;
+	}
+	case XDP_MMAP_OFFSETS:
+	{
+		struct xdp_mmap_offsets off;
+		struct xdp_mmap_offsets_v1 off_v1;
+		bool flags_supported = true;
+		void *to_copy;
+
+		if (len < sizeof(off_v1))
+			return -EINVAL;
+		else if (len < sizeof(off))
+			flags_supported = false;
+
+		if (flags_supported) {
+			/* xdp_ring_offset is identical to xdp_ring_offset_v1
+			 * except for the flags field added to the end.
+			 */
+			xsk_enter_rxtx_offsets((struct xdp_ring_offset_v1 *)
+					       &off.rx);
+			xsk_enter_rxtx_offsets((struct xdp_ring_offset_v1 *)
+					       &off.tx);
+			xsk_enter_umem_offsets((struct xdp_ring_offset_v1 *)
+					       &off.fr);
+			xsk_enter_umem_offsets((struct xdp_ring_offset_v1 *)
+					       &off.cr);
+			off.rx.flags = offsetof(struct xdp_rxtx_ring,
+						ptrs.flags);
+			off.tx.flags = offsetof(struct xdp_rxtx_ring,
+						ptrs.flags);
+			off.fr.flags = offsetof(struct xdp_umem_ring,
+						ptrs.flags);
+			off.cr.flags = offsetof(struct xdp_umem_ring,
+						ptrs.flags);
+
+			len = sizeof(off);
+			to_copy = &off;
+		} else {
+			xsk_enter_rxtx_offsets(&off_v1.rx);
+			xsk_enter_rxtx_offsets(&off_v1.tx);
+			xsk_enter_umem_offsets(&off_v1.fr);
+			xsk_enter_umem_offsets(&off_v1.cr);
+
+			len = sizeof(off_v1);
+			to_copy = &off_v1;
+		}
+
+		if (copy_to_user(optval, to_copy, len))
+			return -EFAULT;
+		if (put_user(len, optlen))
+			return -EFAULT;
+
+		return 0;
+	}
+	case XDP_OPTIONS:
+	{
+		struct xdp_options opts = {};
+
+		if (len < sizeof(opts))
+			return -EINVAL;
+
+		mutex_lock(&xs->mutex);
+		if (xs->zc)
+			opts.flags |= XDP_OPTIONS_ZEROCOPY;
+		mutex_unlock(&xs->mutex);
+
+		len = sizeof(opts);
+		if (copy_to_user(optval, &opts, len))
+			return -EFAULT;
+		if (put_user(len, optlen))
+			return -EFAULT;
+
+		return 0;
+	}
+	default:
+		break;
+	}
+
+	return -EOPNOTSUPP;
+}
+
+static int xsk_mmap(struct file *file, struct socket *sock,
+		    struct vm_area_struct *vma)
+{
+	loff_t offset = (loff_t)vma->vm_pgoff << PAGE_SHIFT;
+	unsigned long size = vma->vm_end - vma->vm_start;
+	struct xdp_sock *xs = xdp_sk(sock->sk);
+	struct xsk_queue *q = NULL;
+	unsigned long pfn;
+	struct page *qpg;
+
+	if (READ_ONCE(xs->state) != XSK_READY)
+		return -EBUSY;
+
+	if (offset == XDP_PGOFF_RX_RING) {
+		q = READ_ONCE(xs->rx);
+	} else if (offset == XDP_PGOFF_TX_RING) {
+		q = READ_ONCE(xs->tx);
+	} else {
+		/* Matches the smp_wmb() in XDP_UMEM_REG */
+		smp_rmb();
+		if (offset == XDP_UMEM_PGOFF_FILL_RING)
+			q = READ_ONCE(xs->fq_tmp);
+		else if (offset == XDP_UMEM_PGOFF_COMPLETION_RING)
+			q = READ_ONCE(xs->cq_tmp);
+	}
+
+	if (!q)
+		return -EINVAL;
+
+	/* Matches the smp_wmb() in xsk_init_queue */
+	smp_rmb();
+	qpg = virt_to_head_page(q->ring);
+	if (size > page_size(qpg))
+		return -EINVAL;
+
+	pfn = virt_to_phys(q->ring) >> PAGE_SHIFT;
+	return remap_pfn_range(vma, vma->vm_start, pfn,
+			       size, vma->vm_page_prot);
+}
+
+static int xsk_notifier(struct notifier_block *this,
+			unsigned long msg, void *ptr)
+{
+	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
+	struct net *net = dev_net(dev);
+	struct sock *sk;
+
+	switch (msg) {
+	case NETDEV_UNREGISTER:
+		mutex_lock(&net->xdp.lock);
+		sk_for_each(sk, &net->xdp.list) {
+			struct xdp_sock *xs = xdp_sk(sk);
+
+			mutex_lock(&xs->mutex);
+			if (xs->dev == dev) {
+				sk->sk_err = ENETDOWN;
+				if (!sock_flag(sk, SOCK_DEAD))
+					sk->sk_error_report(sk);
+
+				xsk_unbind_dev(xs);
+
+				/* Clear device references. */
+				xp_clear_dev(xs->pool);
+			}
+			mutex_unlock(&xs->mutex);
+		}
+		mutex_unlock(&net->xdp.lock);
+		break;
+	}
+	return NOTIFY_DONE;
+}
+
+static struct proto xsk_proto = {
+	.name =		"XDP",
+	.owner =	THIS_MODULE,
+	.obj_size =	sizeof(struct xdp_sock),
+};
+
+static const struct proto_ops xsk_proto_ops = {
+	.family		= PF_XDP,
+	.owner		= THIS_MODULE,
+	.release	= xsk_release,
+	.bind		= xsk_bind,
+	.connect	= sock_no_connect,
+	.socketpair	= sock_no_socketpair,
+	.accept		= sock_no_accept,
+	.getname	= sock_no_getname,
+	.poll		= xsk_poll,
+	.ioctl		= sock_no_ioctl,
+	.listen		= sock_no_listen,
+	.shutdown	= sock_no_shutdown,
+	.setsockopt	= xsk_setsockopt,
+	.getsockopt	= xsk_getsockopt,
+	.sendmsg	= xsk_sendmsg,
+	.recvmsg	= sock_no_recvmsg,
+	.mmap		= xsk_mmap,
+	.sendpage	= sock_no_sendpage,
+};
+
+static void xsk_destruct(struct sock *sk)
+{
+	struct xdp_sock *xs = xdp_sk(sk);
+
+	if (!sock_flag(sk, SOCK_DEAD))
+		return;
+
+	if (!xp_put_pool(xs->pool))
+		xdp_put_umem(xs->umem, !xs->pool);
+
+	sk_refcnt_debug_dec(sk);
+}
+
+static int xsk_create(struct net *net, struct socket *sock, int protocol,
+		      int kern)
+{
+	struct xdp_sock *xs;
+	struct sock *sk;
+
+	if (!ns_capable(net->user_ns, CAP_NET_RAW))
+		return -EPERM;
+	if (sock->type != SOCK_RAW)
+		return -ESOCKTNOSUPPORT;
+
+	if (protocol)
+		return -EPROTONOSUPPORT;
+
+	sock->state = SS_UNCONNECTED;
+
+	sk = sk_alloc(net, PF_XDP, GFP_KERNEL, &xsk_proto, kern);
+	if (!sk)
+		return -ENOBUFS;
+
+	sock->ops = &xsk_proto_ops;
+
+	sock_init_data(sock, sk);
+
+	sk->sk_family = PF_XDP;
+
+	sk->sk_destruct = xsk_destruct;
+	sk_refcnt_debug_inc(sk);
+
+	sock_set_flag(sk, SOCK_RCU_FREE);
+
+	xs = xdp_sk(sk);
+	xs->state = XSK_READY;
+	mutex_init(&xs->mutex);
+	spin_lock_init(&xs->rx_lock);
+
+	INIT_LIST_HEAD(&xs->map_list);
+	spin_lock_init(&xs->map_list_lock);
+
+	mutex_lock(&net->xdp.lock);
+	sk_add_node_rcu(sk, &net->xdp.list);
+	mutex_unlock(&net->xdp.lock);
+
+	local_bh_disable();
+	sock_prot_inuse_add(net, &xsk_proto, 1);
+	local_bh_enable();
+
+	return 0;
+}
+
+static const struct net_proto_family xsk_family_ops = {
+	.family = PF_XDP,
+	.create = xsk_create,
+	.owner	= THIS_MODULE,
+};
+
+static struct notifier_block xsk_netdev_notifier = {
+	.notifier_call	= xsk_notifier,
+};
+
+static int __net_init xsk_net_init(struct net *net)
+{
+	mutex_init(&net->xdp.lock);
+	INIT_HLIST_HEAD(&net->xdp.list);
+	return 0;
+}
+
+static void __net_exit xsk_net_exit(struct net *net)
+{
+	WARN_ON_ONCE(!hlist_empty(&net->xdp.list));
+}
+
+static struct pernet_operations xsk_net_ops = {
+	.init = xsk_net_init,
+	.exit = xsk_net_exit,
+};
+
+static int __init xsk_init(void)
+{
+	int err, cpu;
+
+	err = proto_register(&xsk_proto, 0 /* no slab */);
+	if (err)
+		goto out;
+
+	err = sock_register(&xsk_family_ops);
+	if (err)
+		goto out_proto;
+
+	err = register_pernet_subsys(&xsk_net_ops);
+	if (err)
+		goto out_sk;
+
+	err = register_netdevice_notifier(&xsk_netdev_notifier);
+	if (err)
+		goto out_pernet;
+
+	for_each_possible_cpu(cpu)
+		INIT_LIST_HEAD(&per_cpu(xskmap_flush_list, cpu));
+	return 0;
+
+out_pernet:
+	unregister_pernet_subsys(&xsk_net_ops);
+out_sk:
+	sock_unregister(PF_XDP);
+out_proto:
+	proto_unregister(&xsk_proto);
+out:
+	return err;
+}
+
+fs_initcall(xsk_init);