Commit 24ea5012 authored by Maciej Fijalkowski's avatar Maciej Fijalkowski Committed by Alexei Starovoitov
Browse files

xsk: support mbuf on ZC RX 



Given that skb_shared_info relies on skb_frag_t, in order to support
xskb chaining, introduce xdp_buff_xsk::xskb_list_node and
xsk_buff_pool::xskb_list.

This is needed so ZC drivers can add frags as xskb nodes which will make
it possible to handle it both when producing AF_XDP Rx descriptors as
well as freeing/recycling all the frags that a single frame carries.

Speaking of latter, update xsk_buff_free() to take care of list nodes.
For the former (adding as frags), introduce xsk_buff_add_frag() for ZC
drivers usage that is going to be used to add a frag to xskb list from
pool.

xsk_buff_get_frag() will be utilized by XDP_TX and, on contrary, will
return xdp_buff.

One of the previous patches added a wrapper for ZC Rx so implement xskb
list walk and production of Rx descriptors there.

On bind() path, bail out if socket wants to use ZC multi-buffer but
underlying netdev does not support it.

Signed-off-by: default avatarMaciej Fijalkowski <maciej.fijalkowski@intel.com>
Link: https://lore.kernel.org/r/20230719132421.584801-12-maciej.fijalkowski@intel.com


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 13ce2daa

include/net/xdp_sock_drv.h

+44 −0
Original line number Diff line number Diff line
@@ -108,10 +108,45 @@ static inline bool xsk_buff_can_alloc(struct xsk_buff_pool *pool, u32 count) 
static inline void xsk_buff_free(struct xdp_buff *xdp)

{

	struct xdp_buff_xsk *xskb = container_of(xdp, struct xdp_buff_xsk, xdp);

	struct list_head *xskb_list = &xskb->pool->xskb_list;

	struct xdp_buff_xsk *pos, *tmp;



	if (likely(!xdp_buff_has_frags(xdp)))

		goto out;



	list_for_each_entry_safe(pos, tmp, xskb_list, xskb_list_node) {

		list_del(&pos->xskb_list_node);

		xp_free(pos);

	}



	xdp_get_shared_info_from_buff(xdp)->nr_frags = 0;

out:

	xp_free(xskb);

}



static inline void xsk_buff_add_frag(struct xdp_buff *xdp)

{

	struct xdp_buff_xsk *frag = container_of(xdp, struct xdp_buff_xsk, xdp);



	list_add_tail(&frag->xskb_list_node, &frag->pool->xskb_list);

}



static inline struct xdp_buff *xsk_buff_get_frag(struct xdp_buff *first)

{

	struct xdp_buff_xsk *xskb = container_of(first, struct xdp_buff_xsk, xdp);

	struct xdp_buff *ret = NULL;

	struct xdp_buff_xsk *frag;



	frag = list_first_entry_or_null(&xskb->pool->xskb_list,

					struct xdp_buff_xsk, xskb_list_node);

	if (frag) {

		list_del(&frag->xskb_list_node);

		ret = &frag->xdp;

	}



	return ret;

}



static inline void xsk_buff_set_size(struct xdp_buff *xdp, u32 size)

{

	xdp->data = xdp->data_hard_start + XDP_PACKET_HEADROOM;
@@ -265,6 +300,15 @@ static inline void xsk_buff_free(struct xdp_buff *xdp) 
{

}



static inline void xsk_buff_add_frag(struct xdp_buff *xdp)

{

}



static inline struct xdp_buff *xsk_buff_get_frag(struct xdp_buff *first)

{

	return NULL;

}



static inline void xsk_buff_set_size(struct xdp_buff *xdp, u32 size)

{

}

include/net/xsk_buff_pool.h

+2 −0
Original line number Diff line number Diff line
@@ -29,6 +29,7 @@ struct xdp_buff_xsk { 
	struct xsk_buff_pool *pool;

	u64 orig_addr;

	struct list_head free_list_node;

	struct list_head xskb_list_node;

};



#define XSK_CHECK_PRIV_TYPE(t) BUILD_BUG_ON(sizeof(t) > offsetofend(struct xdp_buff_xsk, cb))
@@ -54,6 +55,7 @@ struct xsk_buff_pool { 
	struct xdp_umem *umem;

	struct work_struct work;

	struct list_head free_list;

	struct list_head xskb_list;

	u32 heads_cnt;

	u16 queue_id;

net/xdp/xsk.c

+25 −1
Original line number Diff line number Diff line
@@ -155,8 +155,32 @@ static int __xsk_rcv_zc(struct xdp_sock *xs, struct xdp_buff_xsk *xskb, u32 len, 
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);

	u32 frags = xdp_buff_has_frags(xdp);

	struct xdp_buff_xsk *pos, *tmp;

	struct list_head *xskb_list;

	u32 contd = 0;

	int err;



	if (frags)

		contd = XDP_PKT_CONTD;



	err = __xsk_rcv_zc(xs, xskb, len, contd);

	if (err || likely(!frags))

		goto out;



	xskb_list = &xskb->pool->xskb_list;

	list_for_each_entry_safe(pos, tmp, xskb_list, xskb_list_node) {

		if (list_is_singular(xskb_list))

			contd = 0;

		len = pos->xdp.data_end - pos->xdp.data;

		err = __xsk_rcv_zc(xs, pos, len, contd);

		if (err)

			return err;

		list_del(&pos->xskb_list_node);

	}



	return __xsk_rcv_zc(xs, xskb, len, 0);

out:

	return err;

}



static void *xsk_copy_xdp_start(struct xdp_buff *from)

net/xdp/xsk_buff_pool.c

+7 −0
Original line number Diff line number Diff line
@@ -86,6 +86,7 @@ struct xsk_buff_pool *xp_create_and_assign_umem(struct xdp_sock *xs, 
	pool->umem = umem;

	pool->addrs = umem->addrs;

	INIT_LIST_HEAD(&pool->free_list);

	INIT_LIST_HEAD(&pool->xskb_list);

	INIT_LIST_HEAD(&pool->xsk_tx_list);

	spin_lock_init(&pool->xsk_tx_list_lock);

	spin_lock_init(&pool->cq_lock);
@@ -99,6 +100,7 @@ struct xsk_buff_pool *xp_create_and_assign_umem(struct xdp_sock *xs, 
		xskb->pool = pool;

		xskb->xdp.frame_sz = umem->chunk_size - umem->headroom;

		INIT_LIST_HEAD(&xskb->free_list_node);

		INIT_LIST_HEAD(&xskb->xskb_list_node);

		if (pool->unaligned)

			pool->free_heads[i] = xskb;

		else
@@ -187,6 +189,11 @@ int xp_assign_dev(struct xsk_buff_pool *pool, 
		goto err_unreg_pool;

	}



	if (netdev->xdp_zc_max_segs == 1 && (flags & XDP_USE_SG)) {

		err = -EOPNOTSUPP;

		goto err_unreg_pool;

	}



	bpf.command = XDP_SETUP_XSK_POOL;

	bpf.xsk.pool = pool;

	bpf.xsk.queue_id = queue_id;