1 // SPDX-License-Identifier: GPL-2.0-only 2 /* Copyright (C) 2024-2025 Intel Corporation */ 3 4 #define DEFAULT_SYMBOL_NAMESPACE "LIBETH" 5 6 #include <linux/export.h> 7 8 #include <net/libeth/rx.h> 9 10 /* Rx buffer management */ 11 12 /** 13 * libeth_rx_hw_len_mtu - get the actual buffer size to be passed to HW 14 * @pp: &page_pool_params of the netdev to calculate the size for 15 * @max_len: maximum buffer size for a single descriptor 16 * 17 * Return: HW-writeable length per one buffer to pass it to the HW accounting: 18 * MTU the @dev has, HW required alignment, minimum and maximum allowed values, 19 * and system's page size. 20 */ 21 static u32 libeth_rx_hw_len_mtu(const struct page_pool_params *pp, u32 max_len) 22 { 23 u32 len; 24 25 len = READ_ONCE(pp->netdev->mtu) + LIBETH_RX_LL_LEN; 26 len = ALIGN(len, LIBETH_RX_BUF_STRIDE); 27 len = min3(len, ALIGN_DOWN(max_len ? : U32_MAX, LIBETH_RX_BUF_STRIDE), 28 pp->max_len); 29 30 return len; 31 } 32 33 /** 34 * libeth_rx_hw_len_truesize - get the short buffer size to be passed to HW 35 * @pp: &page_pool_params of the netdev to calculate the size for 36 * @max_len: maximum buffer size for a single descriptor 37 * @truesize: desired truesize for the buffers 38 * 39 * Return: HW-writeable length per one buffer to pass it to the HW ignoring the 40 * MTU and closest to the passed truesize. Can be used for "short" buffer 41 * queues to fragment pages more efficiently. 42 */ 43 static u32 libeth_rx_hw_len_truesize(const struct page_pool_params *pp, 44 u32 max_len, u32 truesize) 45 { 46 u32 min, len; 47 48 min = SKB_HEAD_ALIGN(pp->offset + LIBETH_RX_BUF_STRIDE); 49 truesize = clamp(roundup_pow_of_two(truesize), roundup_pow_of_two(min), 50 PAGE_SIZE << LIBETH_RX_PAGE_ORDER); 51 52 len = SKB_WITH_OVERHEAD(truesize - pp->offset); 53 len = ALIGN_DOWN(len, LIBETH_RX_BUF_STRIDE) ? : LIBETH_RX_BUF_STRIDE; 54 len = min3(len, ALIGN_DOWN(max_len ? : U32_MAX, LIBETH_RX_BUF_STRIDE), 55 pp->max_len); 56 57 return len; 58 } 59 60 /** 61 * libeth_rx_page_pool_params - calculate params with the stack overhead 62 * @fq: buffer queue to calculate the size for 63 * @pp: &page_pool_params of the netdev 64 * 65 * Set the PP params to will all needed stack overhead (headroom, tailroom) and 66 * both the HW buffer length and the truesize for all types of buffers. For 67 * "short" buffers, truesize never exceeds the "wanted" one; for the rest, 68 * it can be up to the page size. 69 * 70 * Return: true on success, false on invalid input params. 71 */ 72 static bool libeth_rx_page_pool_params(struct libeth_fq *fq, 73 struct page_pool_params *pp) 74 { 75 pp->offset = LIBETH_SKB_HEADROOM; 76 /* HW-writeable / syncable length per one page */ 77 pp->max_len = LIBETH_RX_PAGE_LEN(pp->offset); 78 79 /* HW-writeable length per buffer */ 80 switch (fq->type) { 81 case LIBETH_FQE_MTU: 82 fq->buf_len = libeth_rx_hw_len_mtu(pp, fq->buf_len); 83 break; 84 case LIBETH_FQE_SHORT: 85 fq->buf_len = libeth_rx_hw_len_truesize(pp, fq->buf_len, 86 fq->truesize); 87 break; 88 case LIBETH_FQE_HDR: 89 fq->buf_len = ALIGN(LIBETH_MAX_HEAD, LIBETH_RX_BUF_STRIDE); 90 break; 91 default: 92 return false; 93 } 94 95 /* Buffer size to allocate */ 96 fq->truesize = roundup_pow_of_two(SKB_HEAD_ALIGN(pp->offset + 97 fq->buf_len)); 98 99 return true; 100 } 101 102 /** 103 * libeth_rx_page_pool_params_zc - calculate params without the stack overhead 104 * @fq: buffer queue to calculate the size for 105 * @pp: &page_pool_params of the netdev 106 * 107 * Set the PP params to exclude the stack overhead and both the buffer length 108 * and the truesize, which are equal for the data buffers. Note that this 109 * requires separate header buffers to be always active and account the 110 * overhead. 111 * With the MTU == ``PAGE_SIZE``, this allows the kernel to enable the zerocopy 112 * mode. 113 * 114 * Return: true on success, false on invalid input params. 115 */ 116 static bool libeth_rx_page_pool_params_zc(struct libeth_fq *fq, 117 struct page_pool_params *pp) 118 { 119 u32 mtu, max; 120 121 pp->offset = 0; 122 pp->max_len = PAGE_SIZE << LIBETH_RX_PAGE_ORDER; 123 124 switch (fq->type) { 125 case LIBETH_FQE_MTU: 126 mtu = READ_ONCE(pp->netdev->mtu); 127 break; 128 case LIBETH_FQE_SHORT: 129 mtu = fq->truesize; 130 break; 131 default: 132 return false; 133 } 134 135 mtu = roundup_pow_of_two(mtu); 136 max = min(rounddown_pow_of_two(fq->buf_len ? : U32_MAX), 137 pp->max_len); 138 139 fq->buf_len = clamp(mtu, LIBETH_RX_BUF_STRIDE, max); 140 fq->truesize = fq->buf_len; 141 142 return true; 143 } 144 145 /** 146 * libeth_rx_fq_create - create a PP with the default libeth settings 147 * @fq: buffer queue struct to fill 148 * @napi: &napi_struct covering this PP (no usage outside its poll loops) 149 * 150 * Return: %0 on success, -%errno on failure. 151 */ 152 int libeth_rx_fq_create(struct libeth_fq *fq, struct napi_struct *napi) 153 { 154 struct page_pool_params pp = { 155 .flags = PP_FLAG_DMA_MAP | PP_FLAG_DMA_SYNC_DEV, 156 .order = LIBETH_RX_PAGE_ORDER, 157 .pool_size = fq->count, 158 .nid = fq->nid, 159 .dev = napi->dev->dev.parent, 160 .netdev = napi->dev, 161 .napi = napi, 162 .dma_dir = DMA_FROM_DEVICE, 163 }; 164 struct libeth_fqe *fqes; 165 struct page_pool *pool; 166 bool ret; 167 168 if (!fq->hsplit) 169 ret = libeth_rx_page_pool_params(fq, &pp); 170 else 171 ret = libeth_rx_page_pool_params_zc(fq, &pp); 172 if (!ret) 173 return -EINVAL; 174 175 pool = page_pool_create(&pp); 176 if (IS_ERR(pool)) 177 return PTR_ERR(pool); 178 179 fqes = kvcalloc_node(fq->count, sizeof(*fqes), GFP_KERNEL, fq->nid); 180 if (!fqes) 181 goto err_buf; 182 183 fq->fqes = fqes; 184 fq->pp = pool; 185 186 return 0; 187 188 err_buf: 189 page_pool_destroy(pool); 190 191 return -ENOMEM; 192 } 193 EXPORT_SYMBOL_GPL(libeth_rx_fq_create); 194 195 /** 196 * libeth_rx_fq_destroy - destroy a &page_pool created by libeth 197 * @fq: buffer queue to process 198 */ 199 void libeth_rx_fq_destroy(struct libeth_fq *fq) 200 { 201 kvfree(fq->fqes); 202 page_pool_destroy(fq->pp); 203 } 204 EXPORT_SYMBOL_GPL(libeth_rx_fq_destroy); 205 206 /** 207 * libeth_rx_recycle_slow - recycle a libeth page from the NAPI context 208 * @page: page to recycle 209 * 210 * To be used on exceptions or rare cases not requiring fast inline recycling. 211 */ 212 void libeth_rx_recycle_slow(struct page *page) 213 { 214 page_pool_recycle_direct(page->pp, page); 215 } 216 EXPORT_SYMBOL_GPL(libeth_rx_recycle_slow); 217 218 /* Converting abstract packet type numbers into a software structure with 219 * the packet parameters to do O(1) lookup on Rx. 220 */ 221 222 static const u16 libeth_rx_pt_xdp_oip[] = { 223 [LIBETH_RX_PT_OUTER_L2] = XDP_RSS_TYPE_NONE, 224 [LIBETH_RX_PT_OUTER_IPV4] = XDP_RSS_L3_IPV4, 225 [LIBETH_RX_PT_OUTER_IPV6] = XDP_RSS_L3_IPV6, 226 }; 227 228 static const u16 libeth_rx_pt_xdp_iprot[] = { 229 [LIBETH_RX_PT_INNER_NONE] = XDP_RSS_TYPE_NONE, 230 [LIBETH_RX_PT_INNER_UDP] = XDP_RSS_L4_UDP, 231 [LIBETH_RX_PT_INNER_TCP] = XDP_RSS_L4_TCP, 232 [LIBETH_RX_PT_INNER_SCTP] = XDP_RSS_L4_SCTP, 233 [LIBETH_RX_PT_INNER_ICMP] = XDP_RSS_L4_ICMP, 234 [LIBETH_RX_PT_INNER_TIMESYNC] = XDP_RSS_TYPE_NONE, 235 }; 236 237 static const u16 libeth_rx_pt_xdp_pl[] = { 238 [LIBETH_RX_PT_PAYLOAD_NONE] = XDP_RSS_TYPE_NONE, 239 [LIBETH_RX_PT_PAYLOAD_L2] = XDP_RSS_TYPE_NONE, 240 [LIBETH_RX_PT_PAYLOAD_L3] = XDP_RSS_TYPE_NONE, 241 [LIBETH_RX_PT_PAYLOAD_L4] = XDP_RSS_L4, 242 }; 243 244 /** 245 * libeth_rx_pt_gen_hash_type - generate an XDP RSS hash type for a PT 246 * @pt: PT structure to evaluate 247 * 248 * Generates ```hash_type``` field with XDP RSS type values from the parsed 249 * packet parameters if they're obtained dynamically at runtime. 250 */ 251 void libeth_rx_pt_gen_hash_type(struct libeth_rx_pt *pt) 252 { 253 pt->hash_type = 0; 254 pt->hash_type |= libeth_rx_pt_xdp_oip[pt->outer_ip]; 255 pt->hash_type |= libeth_rx_pt_xdp_iprot[pt->inner_prot]; 256 pt->hash_type |= libeth_rx_pt_xdp_pl[pt->payload_layer]; 257 } 258 EXPORT_SYMBOL_GPL(libeth_rx_pt_gen_hash_type); 259 260 /* Module */ 261 262 MODULE_DESCRIPTION("Common Ethernet library"); 263 MODULE_LICENSE("GPL"); 264