mirror of
https://github.com/edk2-porting/linux-next.git
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c497176cb2
Here the actual receive functions of AF_XDP are implemented, that in a
later commit, will be called from the XDP layers.
There's one set of functions for the XDP_DRV side and another for
XDP_SKB (generic).
A new XDP API, xdp_return_buff, is also introduced.
Adding xdp_return_buff, which is analogous to xdp_return_frame, but
acts upon an struct xdp_buff. The API will be used by AF_XDP in future
commits.
Support for the poll syscall is also implemented.
v2: xskq_validate_id did not update cons_tail.
The entries variable was calculated twice in xskq_nb_avail.
Squashed xdp_return_buff commit.
Signed-off-by: Björn Töpel <bjorn.topel@intel.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
152 lines
3.5 KiB
C
152 lines
3.5 KiB
C
/* SPDX-License-Identifier: GPL-2.0
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* XDP user-space ring structure
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* Copyright(c) 2018 Intel Corporation.
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms and conditions of the GNU General Public License,
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* version 2, as published by the Free Software Foundation.
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*
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* This program is distributed in the hope it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*/
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#ifndef _LINUX_XSK_QUEUE_H
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#define _LINUX_XSK_QUEUE_H
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#include <linux/types.h>
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#include <linux/if_xdp.h>
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#include "xdp_umem_props.h"
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#define RX_BATCH_SIZE 16
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struct xsk_queue {
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struct xdp_umem_props umem_props;
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u32 ring_mask;
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u32 nentries;
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u32 prod_head;
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u32 prod_tail;
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u32 cons_head;
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u32 cons_tail;
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struct xdp_ring *ring;
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u64 invalid_descs;
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};
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/* Common functions operating for both RXTX and umem queues */
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static inline u32 xskq_nb_avail(struct xsk_queue *q, u32 dcnt)
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{
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u32 entries = q->prod_tail - q->cons_tail;
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if (entries == 0) {
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/* Refresh the local pointer */
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q->prod_tail = READ_ONCE(q->ring->producer);
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entries = q->prod_tail - q->cons_tail;
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}
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return (entries > dcnt) ? dcnt : entries;
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}
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static inline u32 xskq_nb_free(struct xsk_queue *q, u32 producer, u32 dcnt)
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{
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u32 free_entries = q->nentries - (producer - q->cons_tail);
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if (free_entries >= dcnt)
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return free_entries;
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/* Refresh the local tail pointer */
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q->cons_tail = READ_ONCE(q->ring->consumer);
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return q->nentries - (producer - q->cons_tail);
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}
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/* UMEM queue */
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static inline bool xskq_is_valid_id(struct xsk_queue *q, u32 idx)
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{
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if (unlikely(idx >= q->umem_props.nframes)) {
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q->invalid_descs++;
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return false;
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}
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return true;
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}
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static inline u32 *xskq_validate_id(struct xsk_queue *q)
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{
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while (q->cons_tail != q->cons_head) {
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struct xdp_umem_ring *ring = (struct xdp_umem_ring *)q->ring;
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unsigned int idx = q->cons_tail & q->ring_mask;
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if (xskq_is_valid_id(q, ring->desc[idx]))
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return &ring->desc[idx];
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q->cons_tail++;
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}
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return NULL;
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}
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static inline u32 *xskq_peek_id(struct xsk_queue *q)
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{
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struct xdp_umem_ring *ring;
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if (q->cons_tail == q->cons_head) {
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WRITE_ONCE(q->ring->consumer, q->cons_tail);
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q->cons_head = q->cons_tail + xskq_nb_avail(q, RX_BATCH_SIZE);
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/* Order consumer and data */
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smp_rmb();
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return xskq_validate_id(q);
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}
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ring = (struct xdp_umem_ring *)q->ring;
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return &ring->desc[q->cons_tail & q->ring_mask];
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}
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static inline void xskq_discard_id(struct xsk_queue *q)
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{
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q->cons_tail++;
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(void)xskq_validate_id(q);
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}
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/* Rx queue */
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static inline int xskq_produce_batch_desc(struct xsk_queue *q,
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u32 id, u32 len, u16 offset)
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{
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struct xdp_rxtx_ring *ring = (struct xdp_rxtx_ring *)q->ring;
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unsigned int idx;
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if (xskq_nb_free(q, q->prod_head, 1) == 0)
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return -ENOSPC;
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idx = (q->prod_head++) & q->ring_mask;
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ring->desc[idx].idx = id;
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ring->desc[idx].len = len;
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ring->desc[idx].offset = offset;
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return 0;
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}
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static inline void xskq_produce_flush_desc(struct xsk_queue *q)
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{
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/* Order producer and data */
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smp_wmb();
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q->prod_tail = q->prod_head,
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WRITE_ONCE(q->ring->producer, q->prod_tail);
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}
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static inline bool xskq_empty_desc(struct xsk_queue *q)
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{
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return (xskq_nb_free(q, q->prod_tail, 1) == q->nentries);
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}
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void xskq_set_umem(struct xsk_queue *q, struct xdp_umem_props *umem_props);
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struct xsk_queue *xskq_create(u32 nentries, bool umem_queue);
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void xskq_destroy(struct xsk_queue *q_ops);
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#endif /* _LINUX_XSK_QUEUE_H */
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