1/* SPDX-License-Identifier: GPL-2.0-only */
2/* Copyright (C) 2024-2025 Intel Corporation */
3
4#ifndef __LIBETH_TX_H
5#define __LIBETH_TX_H
6
7#include <linux/skbuff.h>
8
9#include <net/libeth/types.h>
10
11/* Tx buffer completion */
12
13/**
14 * enum libeth_sqe_type - type of &libeth_sqe to act on Tx completion
15 * @LIBETH_SQE_EMPTY: unused/empty OR XDP_TX/XSk frame, no action required
16 * @LIBETH_SQE_CTX: context descriptor with empty SQE, no action required
17 * @LIBETH_SQE_SLAB: kmalloc-allocated buffer, unmap and kfree()
18 * @LIBETH_SQE_FRAG: mapped skb frag, only unmap DMA
19 * @LIBETH_SQE_SKB: &sk_buff, unmap and napi_consume_skb(), update stats
20 * @__LIBETH_SQE_XDP_START: separator between skb and XDP types
21 * @LIBETH_SQE_XDP_TX: &skb_shared_info, libeth_xdp_return_buff_bulk(), stats
22 * @LIBETH_SQE_XDP_XMIT: &xdp_frame, unmap and xdp_return_frame_bulk(), stats
23 * @LIBETH_SQE_XDP_XMIT_FRAG: &xdp_frame frag, only unmap DMA
24 * @LIBETH_SQE_XSK_TX: &libeth_xdp_buff on XSk queue, xsk_buff_free(), stats
25 * @LIBETH_SQE_XSK_TX_FRAG: &libeth_xdp_buff frag on XSk queue, xsk_buff_free()
26 */
27enum libeth_sqe_type {
28 LIBETH_SQE_EMPTY = 0U,
29 LIBETH_SQE_CTX,
30 LIBETH_SQE_SLAB,
31 LIBETH_SQE_FRAG,
32 LIBETH_SQE_SKB,
33
34 __LIBETH_SQE_XDP_START,
35 LIBETH_SQE_XDP_TX = __LIBETH_SQE_XDP_START,
36 LIBETH_SQE_XDP_XMIT,
37 LIBETH_SQE_XDP_XMIT_FRAG,
38 LIBETH_SQE_XSK_TX,
39 LIBETH_SQE_XSK_TX_FRAG,
40};
41
42/**
43 * struct libeth_sqe - represents a Send Queue Element / Tx buffer
44 * @type: type of the buffer, see the enum above
45 * @rs_idx: index of the last buffer from the batch this one was sent in
46 * @raw: slab buffer to free via kfree()
47 * @skb: &sk_buff to consume
48 * @sinfo: skb shared info of an XDP_TX frame
49 * @xdpf: XDP frame from ::ndo_xdp_xmit()
50 * @xsk: XSk Rx frame from XDP_TX action
51 * @dma: DMA address to unmap
52 * @len: length of the mapped region to unmap
53 * @nr_frags: number of frags in the frame this buffer belongs to
54 * @packets: number of physical packets sent for this frame
55 * @bytes: number of physical bytes sent for this frame
56 * @priv: driver-private scratchpad
57 */
58struct libeth_sqe {
59 enum libeth_sqe_type type:32;
60 u32 rs_idx;
61
62 union {
63 void *raw;
64 struct sk_buff *skb;
65 struct skb_shared_info *sinfo;
66 struct xdp_frame *xdpf;
67 struct libeth_xdp_buff *xsk;
68 };
69
70 DEFINE_DMA_UNMAP_ADDR(dma);
71 DEFINE_DMA_UNMAP_LEN(len);
72
73 u32 nr_frags;
74 u32 packets;
75 u32 bytes;
76
77 unsigned long priv;
78} __aligned_largest;
79
80/**
81 * LIBETH_SQE_CHECK_PRIV - check the driver's private SQE data
82 * @p: type or name of the object the driver wants to fit into &libeth_sqe
83 *
84 * Make sure the driver's private data fits into libeth_sqe::priv. To be used
85 * right after its declaration.
86 */
87#define LIBETH_SQE_CHECK_PRIV(p) \
88 static_assert(sizeof(p) <= sizeof_field(struct libeth_sqe, priv))
89
90/**
91 * struct libeth_cq_pp - completion queue poll params
92 * @dev: &device to perform DMA unmapping
93 * @bq: XDP frame bulk to combine return operations
94 * @ss: onstack NAPI stats to fill
95 * @xss: onstack XDPSQ NAPI stats to fill
96 * @xdp_tx: number of XDP-not-XSk frames processed
97 * @napi: whether it's called from the NAPI context
98 *
99 * libeth uses this structure to access objects needed for performing full
100 * Tx complete operation without passing lots of arguments and change the
101 * prototypes each time a new one is added.
102 */
103struct libeth_cq_pp {
104 struct device *dev;
105 struct xdp_frame_bulk *bq;
106
107 union {
108 struct libeth_sq_napi_stats *ss;
109 struct libeth_xdpsq_napi_stats *xss;
110 };
111 u32 xdp_tx;
112
113 bool napi;
114};
115
116/**
117 * libeth_tx_complete - perform Tx completion for one SQE
118 * @sqe: SQE to complete
119 * @cp: poll params
120 *
121 * Do Tx complete for all the types of buffers, incl. freeing, unmapping,
122 * updating the stats etc.
123 */
124static inline void libeth_tx_complete(struct libeth_sqe *sqe,
125 const struct libeth_cq_pp *cp)
126{
127 switch (sqe->type) {
128 case LIBETH_SQE_EMPTY:
129 return;
130 case LIBETH_SQE_SKB:
131 case LIBETH_SQE_FRAG:
132 case LIBETH_SQE_SLAB:
133 dma_unmap_page(cp->dev, dma_unmap_addr(sqe, dma),
134 dma_unmap_len(sqe, len), DMA_TO_DEVICE);
135 break;
136 default:
137 break;
138 }
139
140 switch (sqe->type) {
141 case LIBETH_SQE_SKB:
142 cp->ss->packets += sqe->packets;
143 cp->ss->bytes += sqe->bytes;
144
145 napi_consume_skb(skb: sqe->skb, budget: cp->napi);
146 break;
147 case LIBETH_SQE_SLAB:
148 kfree(objp: sqe->raw);
149 break;
150 default:
151 break;
152 }
153
154 sqe->type = LIBETH_SQE_EMPTY;
155}
156
157void libeth_tx_complete_any(struct libeth_sqe *sqe, struct libeth_cq_pp *cp);
158
159#endif /* __LIBETH_TX_H */
160

source code of linux/include/net/libeth/tx.h