1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Devmem TCP 4 * 5 * Authors: Mina Almasry <almasrymina@google.com> 6 * Willem de Bruijn <willemdebruijn.kernel@gmail.com> 7 * Kaiyuan Zhang <kaiyuanz@google.com 8 */ 9 10 #include <linux/dma-buf.h> 11 #include <linux/genalloc.h> 12 #include <linux/mm.h> 13 #include <linux/netdevice.h> 14 #include <linux/types.h> 15 #include <net/netdev_queues.h> 16 #include <net/netdev_rx_queue.h> 17 #include <net/page_pool/helpers.h> 18 #include <net/page_pool/memory_provider.h> 19 #include <trace/events/page_pool.h> 20 21 #include "devmem.h" 22 #include "mp_dmabuf_devmem.h" 23 #include "page_pool_priv.h" 24 25 /* Device memory support */ 26 27 static DEFINE_XARRAY_FLAGS(net_devmem_dmabuf_bindings, XA_FLAGS_ALLOC1); 28 29 static const struct memory_provider_ops dmabuf_devmem_ops; 30 31 bool net_is_devmem_iov(struct net_iov *niov) 32 { 33 return niov->pp->mp_ops == &dmabuf_devmem_ops; 34 } 35 36 static void net_devmem_dmabuf_free_chunk_owner(struct gen_pool *genpool, 37 struct gen_pool_chunk *chunk, 38 void *not_used) 39 { 40 struct dmabuf_genpool_chunk_owner *owner = chunk->owner; 41 42 kvfree(owner->area.niovs); 43 kfree(owner); 44 } 45 46 static dma_addr_t net_devmem_get_dma_addr(const struct net_iov *niov) 47 { 48 struct dmabuf_genpool_chunk_owner *owner; 49 50 owner = net_devmem_iov_to_chunk_owner(niov); 51 return owner->base_dma_addr + 52 ((dma_addr_t)net_iov_idx(niov) << PAGE_SHIFT); 53 } 54 55 void __net_devmem_dmabuf_binding_free(struct net_devmem_dmabuf_binding *binding) 56 { 57 size_t size, avail; 58 59 gen_pool_for_each_chunk(binding->chunk_pool, 60 net_devmem_dmabuf_free_chunk_owner, NULL); 61 62 size = gen_pool_size(binding->chunk_pool); 63 avail = gen_pool_avail(binding->chunk_pool); 64 65 if (!WARN(size != avail, "can't destroy genpool. size=%zu, avail=%zu", 66 size, avail)) 67 gen_pool_destroy(binding->chunk_pool); 68 69 dma_buf_unmap_attachment_unlocked(binding->attachment, binding->sgt, 70 DMA_FROM_DEVICE); 71 dma_buf_detach(binding->dmabuf, binding->attachment); 72 dma_buf_put(binding->dmabuf); 73 xa_destroy(&binding->bound_rxqs); 74 kfree(binding); 75 } 76 77 struct net_iov * 78 net_devmem_alloc_dmabuf(struct net_devmem_dmabuf_binding *binding) 79 { 80 struct dmabuf_genpool_chunk_owner *owner; 81 unsigned long dma_addr; 82 struct net_iov *niov; 83 ssize_t offset; 84 ssize_t index; 85 86 dma_addr = gen_pool_alloc_owner(binding->chunk_pool, PAGE_SIZE, 87 (void **)&owner); 88 if (!dma_addr) 89 return NULL; 90 91 offset = dma_addr - owner->base_dma_addr; 92 index = offset / PAGE_SIZE; 93 niov = &owner->area.niovs[index]; 94 95 niov->pp_magic = 0; 96 niov->pp = NULL; 97 atomic_long_set(&niov->pp_ref_count, 0); 98 99 return niov; 100 } 101 102 void net_devmem_free_dmabuf(struct net_iov *niov) 103 { 104 struct net_devmem_dmabuf_binding *binding = net_devmem_iov_binding(niov); 105 unsigned long dma_addr = net_devmem_get_dma_addr(niov); 106 107 if (WARN_ON(!gen_pool_has_addr(binding->chunk_pool, dma_addr, 108 PAGE_SIZE))) 109 return; 110 111 gen_pool_free(binding->chunk_pool, dma_addr, PAGE_SIZE); 112 } 113 114 void net_devmem_unbind_dmabuf(struct net_devmem_dmabuf_binding *binding) 115 { 116 struct netdev_rx_queue *rxq; 117 unsigned long xa_idx; 118 unsigned int rxq_idx; 119 120 if (binding->list.next) 121 list_del(&binding->list); 122 123 xa_for_each(&binding->bound_rxqs, xa_idx, rxq) { 124 const struct pp_memory_provider_params mp_params = { 125 .mp_priv = binding, 126 .mp_ops = &dmabuf_devmem_ops, 127 }; 128 129 rxq_idx = get_netdev_rx_queue_index(rxq); 130 131 __net_mp_close_rxq(binding->dev, rxq_idx, &mp_params); 132 } 133 134 xa_erase(&net_devmem_dmabuf_bindings, binding->id); 135 136 net_devmem_dmabuf_binding_put(binding); 137 } 138 139 int net_devmem_bind_dmabuf_to_queue(struct net_device *dev, u32 rxq_idx, 140 struct net_devmem_dmabuf_binding *binding, 141 struct netlink_ext_ack *extack) 142 { 143 struct pp_memory_provider_params mp_params = { 144 .mp_priv = binding, 145 .mp_ops = &dmabuf_devmem_ops, 146 }; 147 struct netdev_rx_queue *rxq; 148 u32 xa_idx; 149 int err; 150 151 err = __net_mp_open_rxq(dev, rxq_idx, &mp_params, extack); 152 if (err) 153 return err; 154 155 rxq = __netif_get_rx_queue(dev, rxq_idx); 156 err = xa_alloc(&binding->bound_rxqs, &xa_idx, rxq, xa_limit_32b, 157 GFP_KERNEL); 158 if (err) 159 goto err_close_rxq; 160 161 return 0; 162 163 err_close_rxq: 164 __net_mp_close_rxq(dev, rxq_idx, &mp_params); 165 return err; 166 } 167 168 struct net_devmem_dmabuf_binding * 169 net_devmem_bind_dmabuf(struct net_device *dev, unsigned int dmabuf_fd, 170 struct netlink_ext_ack *extack) 171 { 172 struct net_devmem_dmabuf_binding *binding; 173 static u32 id_alloc_next; 174 struct scatterlist *sg; 175 struct dma_buf *dmabuf; 176 unsigned int sg_idx, i; 177 unsigned long virtual; 178 int err; 179 180 dmabuf = dma_buf_get(dmabuf_fd); 181 if (IS_ERR(dmabuf)) 182 return ERR_CAST(dmabuf); 183 184 binding = kzalloc_node(sizeof(*binding), GFP_KERNEL, 185 dev_to_node(&dev->dev)); 186 if (!binding) { 187 err = -ENOMEM; 188 goto err_put_dmabuf; 189 } 190 191 binding->dev = dev; 192 193 err = xa_alloc_cyclic(&net_devmem_dmabuf_bindings, &binding->id, 194 binding, xa_limit_32b, &id_alloc_next, 195 GFP_KERNEL); 196 if (err < 0) 197 goto err_free_binding; 198 199 xa_init_flags(&binding->bound_rxqs, XA_FLAGS_ALLOC); 200 201 refcount_set(&binding->ref, 1); 202 203 binding->dmabuf = dmabuf; 204 205 binding->attachment = dma_buf_attach(binding->dmabuf, dev->dev.parent); 206 if (IS_ERR(binding->attachment)) { 207 err = PTR_ERR(binding->attachment); 208 NL_SET_ERR_MSG(extack, "Failed to bind dmabuf to device"); 209 goto err_free_id; 210 } 211 212 binding->sgt = dma_buf_map_attachment_unlocked(binding->attachment, 213 DMA_FROM_DEVICE); 214 if (IS_ERR(binding->sgt)) { 215 err = PTR_ERR(binding->sgt); 216 NL_SET_ERR_MSG(extack, "Failed to map dmabuf attachment"); 217 goto err_detach; 218 } 219 220 /* For simplicity we expect to make PAGE_SIZE allocations, but the 221 * binding can be much more flexible than that. We may be able to 222 * allocate MTU sized chunks here. Leave that for future work... 223 */ 224 binding->chunk_pool = 225 gen_pool_create(PAGE_SHIFT, dev_to_node(&dev->dev)); 226 if (!binding->chunk_pool) { 227 err = -ENOMEM; 228 goto err_unmap; 229 } 230 231 virtual = 0; 232 for_each_sgtable_dma_sg(binding->sgt, sg, sg_idx) { 233 dma_addr_t dma_addr = sg_dma_address(sg); 234 struct dmabuf_genpool_chunk_owner *owner; 235 size_t len = sg_dma_len(sg); 236 struct net_iov *niov; 237 238 owner = kzalloc_node(sizeof(*owner), GFP_KERNEL, 239 dev_to_node(&dev->dev)); 240 if (!owner) { 241 err = -ENOMEM; 242 goto err_free_chunks; 243 } 244 245 owner->area.base_virtual = virtual; 246 owner->base_dma_addr = dma_addr; 247 owner->area.num_niovs = len / PAGE_SIZE; 248 owner->binding = binding; 249 250 err = gen_pool_add_owner(binding->chunk_pool, dma_addr, 251 dma_addr, len, dev_to_node(&dev->dev), 252 owner); 253 if (err) { 254 kfree(owner); 255 err = -EINVAL; 256 goto err_free_chunks; 257 } 258 259 owner->area.niovs = kvmalloc_array(owner->area.num_niovs, 260 sizeof(*owner->area.niovs), 261 GFP_KERNEL); 262 if (!owner->area.niovs) { 263 err = -ENOMEM; 264 goto err_free_chunks; 265 } 266 267 for (i = 0; i < owner->area.num_niovs; i++) { 268 niov = &owner->area.niovs[i]; 269 niov->owner = &owner->area; 270 page_pool_set_dma_addr_netmem(net_iov_to_netmem(niov), 271 net_devmem_get_dma_addr(niov)); 272 } 273 274 virtual += len; 275 } 276 277 return binding; 278 279 err_free_chunks: 280 gen_pool_for_each_chunk(binding->chunk_pool, 281 net_devmem_dmabuf_free_chunk_owner, NULL); 282 gen_pool_destroy(binding->chunk_pool); 283 err_unmap: 284 dma_buf_unmap_attachment_unlocked(binding->attachment, binding->sgt, 285 DMA_FROM_DEVICE); 286 err_detach: 287 dma_buf_detach(dmabuf, binding->attachment); 288 err_free_id: 289 xa_erase(&net_devmem_dmabuf_bindings, binding->id); 290 err_free_binding: 291 kfree(binding); 292 err_put_dmabuf: 293 dma_buf_put(dmabuf); 294 return ERR_PTR(err); 295 } 296 297 /*** "Dmabuf devmem memory provider" ***/ 298 299 int mp_dmabuf_devmem_init(struct page_pool *pool) 300 { 301 struct net_devmem_dmabuf_binding *binding = pool->mp_priv; 302 303 if (!binding) 304 return -EINVAL; 305 306 /* dma-buf dma addresses do not need and should not be used with 307 * dma_sync_for_cpu/device. Force disable dma_sync. 308 */ 309 pool->dma_sync = false; 310 pool->dma_sync_for_cpu = false; 311 312 if (pool->p.order != 0) 313 return -E2BIG; 314 315 net_devmem_dmabuf_binding_get(binding); 316 return 0; 317 } 318 319 netmem_ref mp_dmabuf_devmem_alloc_netmems(struct page_pool *pool, gfp_t gfp) 320 { 321 struct net_devmem_dmabuf_binding *binding = pool->mp_priv; 322 struct net_iov *niov; 323 netmem_ref netmem; 324 325 niov = net_devmem_alloc_dmabuf(binding); 326 if (!niov) 327 return 0; 328 329 netmem = net_iov_to_netmem(niov); 330 331 page_pool_set_pp_info(pool, netmem); 332 333 pool->pages_state_hold_cnt++; 334 trace_page_pool_state_hold(pool, netmem, pool->pages_state_hold_cnt); 335 return netmem; 336 } 337 338 void mp_dmabuf_devmem_destroy(struct page_pool *pool) 339 { 340 struct net_devmem_dmabuf_binding *binding = pool->mp_priv; 341 342 net_devmem_dmabuf_binding_put(binding); 343 } 344 345 bool mp_dmabuf_devmem_release_page(struct page_pool *pool, netmem_ref netmem) 346 { 347 long refcount = atomic_long_read(netmem_get_pp_ref_count_ref(netmem)); 348 349 if (WARN_ON_ONCE(!netmem_is_net_iov(netmem))) 350 return false; 351 352 if (WARN_ON_ONCE(refcount != 1)) 353 return false; 354 355 page_pool_clear_pp_info(netmem); 356 357 net_devmem_free_dmabuf(netmem_to_net_iov(netmem)); 358 359 /* We don't want the page pool put_page()ing our net_iovs. */ 360 return false; 361 } 362 363 static int mp_dmabuf_devmem_nl_fill(void *mp_priv, struct sk_buff *rsp, 364 struct netdev_rx_queue *rxq) 365 { 366 const struct net_devmem_dmabuf_binding *binding = mp_priv; 367 int type = rxq ? NETDEV_A_QUEUE_DMABUF : NETDEV_A_PAGE_POOL_DMABUF; 368 369 return nla_put_u32(rsp, type, binding->id); 370 } 371 372 static void mp_dmabuf_devmem_uninstall(void *mp_priv, 373 struct netdev_rx_queue *rxq) 374 { 375 struct net_devmem_dmabuf_binding *binding = mp_priv; 376 struct netdev_rx_queue *bound_rxq; 377 unsigned long xa_idx; 378 379 xa_for_each(&binding->bound_rxqs, xa_idx, bound_rxq) { 380 if (bound_rxq == rxq) { 381 xa_erase(&binding->bound_rxqs, xa_idx); 382 break; 383 } 384 } 385 } 386 387 static const struct memory_provider_ops dmabuf_devmem_ops = { 388 .init = mp_dmabuf_devmem_init, 389 .destroy = mp_dmabuf_devmem_destroy, 390 .alloc_netmems = mp_dmabuf_devmem_alloc_netmems, 391 .release_netmem = mp_dmabuf_devmem_release_page, 392 .nl_fill = mp_dmabuf_devmem_nl_fill, 393 .uninstall = mp_dmabuf_devmem_uninstall, 394 }; 395