Commit 63a64a56 authored by Tirthendu Sarkar's avatar Tirthendu Sarkar Committed by Alexei Starovoitov
Browse files

xsk: prepare 'options' in xdp_desc for multi-buffer use 



Use the 'options' field in xdp_desc as a packet continuity marker. Since
'options' field was unused till now and was expected to be set to 0, the
'eop' descriptor will have it set to 0, while the non-eop descriptors
will have to set it to 1. This ensures legacy applications continue to
work without needing any change for single-buffer packets.

Add helper functions and extend xskq_prod_reserve_desc() to use the
'options' field.

Signed-off-by: default avatarTirthendu Sarkar <tirthendu.sarkar@intel.com>
Link: https://lore.kernel.org/r/20230719132421.584801-2-maciej.fijalkowski@intel.com


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 492e797f

include/uapi/linux/if_xdp.h

+7 −0
Original line number Diff line number Diff line
@@ -108,4 +108,11 @@ struct xdp_desc { 


/* UMEM descriptor is __u64 */



/* Flag indicating that the packet continues with the buffer pointed out by the

 * next frame in the ring. The end of the packet is signalled by setting this

 * bit to zero. For single buffer packets, every descriptor has 'options' set

 * to 0 and this maintains backward compatibility.

 */

#define XDP_PKT_CONTD (1 << 0)



#endif /* _LINUX_IF_XDP_H */

net/xdp/xsk.c

+4 −4
Original line number Diff line number Diff line
@@ -135,14 +135,14 @@ int xsk_reg_pool_at_qid(struct net_device *dev, struct xsk_buff_pool *pool, 
	return 0;

}



static int __xsk_rcv_zc(struct xdp_sock *xs, struct xdp_buff *xdp, u32 len)

static int __xsk_rcv_zc(struct xdp_sock *xs, struct xdp_buff *xdp, u32 len, u32 flags)

{

	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);

	err = xskq_prod_reserve_desc(xs->rx, addr, len, flags);

	if (err) {

		xs->rx_queue_full++;

		return err;
@@ -189,7 +189,7 @@ static int __xsk_rcv(struct xdp_sock *xs, struct xdp_buff *xdp) 
	}



	xsk_copy_xdp(xsk_xdp, xdp, len);

	err = __xsk_rcv_zc(xs, xsk_xdp, len);

	err = __xsk_rcv_zc(xs, xsk_xdp, len, 0);

	if (err) {

		xsk_buff_free(xsk_xdp);

		return err;
@@ -259,7 +259,7 @@ static int xsk_rcv(struct xdp_sock *xs, struct xdp_buff *xdp) 


	if (xdp->rxq->mem.type == MEM_TYPE_XSK_BUFF_POOL) {

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

		return __xsk_rcv_zc(xs, xdp, len);

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

	}



	err = __xsk_rcv(xs, xdp);

net/xdp/xsk_queue.h

+9 −3
Original line number Diff line number Diff line
@@ -130,6 +130,11 @@ static inline bool xskq_cons_read_addr_unchecked(struct xsk_queue *q, u64 *addr) 
	return false;

}



static inline bool xp_unused_options_set(u32 options)

{

	return options & ~XDP_PKT_CONTD;

}



static inline bool xp_aligned_validate_desc(struct xsk_buff_pool *pool,

					    struct xdp_desc *desc)

{
@@ -141,7 +146,7 @@ static inline bool xp_aligned_validate_desc(struct xsk_buff_pool *pool, 
	if (desc->addr >= pool->addrs_cnt)

		return false;



	if (desc->options)

	if (xp_unused_options_set(desc->options))

		return false;

	return true;

}
@@ -158,7 +163,7 @@ static inline bool xp_unaligned_validate_desc(struct xsk_buff_pool *pool, 
	    xp_desc_crosses_non_contig_pg(pool, addr, desc->len))

		return false;



	if (desc->options)

	if (xp_unused_options_set(desc->options))

		return false;

	return true;

}
@@ -360,7 +365,7 @@ static inline void xskq_prod_write_addr_batch(struct xsk_queue *q, struct xdp_de 
}



static inline int xskq_prod_reserve_desc(struct xsk_queue *q,

					 u64 addr, u32 len)

					 u64 addr, u32 len, u32 flags)

{

	struct xdp_rxtx_ring *ring = (struct xdp_rxtx_ring *)q->ring;

	u32 idx;
@@ -372,6 +377,7 @@ static inline int xskq_prod_reserve_desc(struct xsk_queue *q, 
	idx = q->cached_prod++ & q->ring_mask;

	ring->desc[idx].addr = addr;

	ring->desc[idx].len = len;

	ring->desc[idx].options = flags;



	return 0;

}