1 // SPDX-License-Identifier: GPL-2.0-only
4 * Copyright (c) 2017 Jesper Dangaard Brouer, Red Hat Inc.
7 #include <linux/filter.h>
8 #include <linux/types.h>
10 #include <linux/netdevice.h>
11 #include <linux/slab.h>
12 #include <linux/idr.h>
13 #include <linux/rhashtable.h>
14 #include <linux/bug.h>
15 #include <net/page_pool.h>
18 #include <net/xdp_priv.h> /* struct xdp_mem_allocator */
19 #include <trace/events/xdp.h>
20 #include <net/xdp_sock_drv.h>
22 #define REG_STATE_NEW 0x0
23 #define REG_STATE_REGISTERED 0x1
24 #define REG_STATE_UNREGISTERED 0x2
25 #define REG_STATE_UNUSED 0x3
27 static DEFINE_IDA(mem_id_pool);
28 static DEFINE_MUTEX(mem_id_lock);
29 #define MEM_ID_MAX 0xFFFE
31 static int mem_id_next = MEM_ID_MIN;
33 static bool mem_id_init; /* false */
34 static struct rhashtable *mem_id_ht;
36 static u32 xdp_mem_id_hashfn(const void *data, u32 len, u32 seed)
41 BUILD_BUG_ON(sizeof_field(struct xdp_mem_allocator, mem.id)
44 /* Use cyclic increasing ID as direct hash key */
48 static int xdp_mem_id_cmp(struct rhashtable_compare_arg *arg,
51 const struct xdp_mem_allocator *xa = ptr;
52 u32 mem_id = *(u32 *)arg->key;
54 return xa->mem.id != mem_id;
57 static const struct rhashtable_params mem_id_rht_params = {
59 .head_offset = offsetof(struct xdp_mem_allocator, node),
60 .key_offset = offsetof(struct xdp_mem_allocator, mem.id),
61 .key_len = sizeof_field(struct xdp_mem_allocator, mem.id),
62 .max_size = MEM_ID_MAX,
64 .automatic_shrinking = true,
65 .hashfn = xdp_mem_id_hashfn,
66 .obj_cmpfn = xdp_mem_id_cmp,
69 static void __xdp_mem_allocator_rcu_free(struct rcu_head *rcu)
71 struct xdp_mem_allocator *xa;
73 xa = container_of(rcu, struct xdp_mem_allocator, rcu);
75 /* Allow this ID to be reused */
76 ida_simple_remove(&mem_id_pool, xa->mem.id);
81 static void mem_xa_remove(struct xdp_mem_allocator *xa)
83 trace_mem_disconnect(xa);
85 if (!rhashtable_remove_fast(mem_id_ht, &xa->node, mem_id_rht_params))
86 call_rcu(&xa->rcu, __xdp_mem_allocator_rcu_free);
89 static void mem_allocator_disconnect(void *allocator)
91 struct xdp_mem_allocator *xa;
92 struct rhashtable_iter iter;
94 mutex_lock(&mem_id_lock);
96 rhashtable_walk_enter(mem_id_ht, &iter);
98 rhashtable_walk_start(&iter);
100 while ((xa = rhashtable_walk_next(&iter)) && !IS_ERR(xa)) {
101 if (xa->allocator == allocator)
105 rhashtable_walk_stop(&iter);
107 } while (xa == ERR_PTR(-EAGAIN));
108 rhashtable_walk_exit(&iter);
110 mutex_unlock(&mem_id_lock);
113 void xdp_unreg_mem_model(struct xdp_mem_info *mem)
115 struct xdp_mem_allocator *xa;
116 int type = mem->type;
119 /* Reset mem info to defaults */
126 if (type == MEM_TYPE_PAGE_POOL) {
128 xa = rhashtable_lookup(mem_id_ht, &id, mem_id_rht_params);
129 page_pool_destroy(xa->page_pool);
133 EXPORT_SYMBOL_GPL(xdp_unreg_mem_model);
135 void xdp_rxq_info_unreg_mem_model(struct xdp_rxq_info *xdp_rxq)
137 if (xdp_rxq->reg_state != REG_STATE_REGISTERED) {
138 WARN(1, "Missing register, driver bug");
142 xdp_unreg_mem_model(&xdp_rxq->mem);
144 EXPORT_SYMBOL_GPL(xdp_rxq_info_unreg_mem_model);
146 void xdp_rxq_info_unreg(struct xdp_rxq_info *xdp_rxq)
148 /* Simplify driver cleanup code paths, allow unreg "unused" */
149 if (xdp_rxq->reg_state == REG_STATE_UNUSED)
152 WARN(!(xdp_rxq->reg_state == REG_STATE_REGISTERED), "Driver BUG");
154 xdp_rxq_info_unreg_mem_model(xdp_rxq);
156 xdp_rxq->reg_state = REG_STATE_UNREGISTERED;
159 EXPORT_SYMBOL_GPL(xdp_rxq_info_unreg);
161 static void xdp_rxq_info_init(struct xdp_rxq_info *xdp_rxq)
163 memset(xdp_rxq, 0, sizeof(*xdp_rxq));
166 /* Returns 0 on success, negative on failure */
167 int xdp_rxq_info_reg(struct xdp_rxq_info *xdp_rxq,
168 struct net_device *dev, u32 queue_index, unsigned int napi_id)
170 if (xdp_rxq->reg_state == REG_STATE_UNUSED) {
171 WARN(1, "Driver promised not to register this");
175 if (xdp_rxq->reg_state == REG_STATE_REGISTERED) {
176 WARN(1, "Missing unregister, handled but fix driver");
177 xdp_rxq_info_unreg(xdp_rxq);
181 WARN(1, "Missing net_device from driver");
185 /* State either UNREGISTERED or NEW */
186 xdp_rxq_info_init(xdp_rxq);
188 xdp_rxq->queue_index = queue_index;
189 xdp_rxq->napi_id = napi_id;
191 xdp_rxq->reg_state = REG_STATE_REGISTERED;
194 EXPORT_SYMBOL_GPL(xdp_rxq_info_reg);
196 void xdp_rxq_info_unused(struct xdp_rxq_info *xdp_rxq)
198 xdp_rxq->reg_state = REG_STATE_UNUSED;
200 EXPORT_SYMBOL_GPL(xdp_rxq_info_unused);
202 bool xdp_rxq_info_is_reg(struct xdp_rxq_info *xdp_rxq)
204 return (xdp_rxq->reg_state == REG_STATE_REGISTERED);
206 EXPORT_SYMBOL_GPL(xdp_rxq_info_is_reg);
208 static int __mem_id_init_hash_table(void)
210 struct rhashtable *rht;
213 if (unlikely(mem_id_init))
216 rht = kzalloc(sizeof(*rht), GFP_KERNEL);
220 ret = rhashtable_init(rht, &mem_id_rht_params);
226 smp_mb(); /* mutex lock should provide enough pairing */
232 /* Allocate a cyclic ID that maps to allocator pointer.
233 * See: https://www.kernel.org/doc/html/latest/core-api/idr.html
235 * Caller must lock mem_id_lock.
237 static int __mem_id_cyclic_get(gfp_t gfp)
243 id = ida_simple_get(&mem_id_pool, mem_id_next, MEM_ID_MAX, gfp);
246 /* Cyclic allocator, reset next id */
248 mem_id_next = MEM_ID_MIN;
252 return id; /* errno */
254 mem_id_next = id + 1;
259 static bool __is_supported_mem_type(enum xdp_mem_type type)
261 if (type == MEM_TYPE_PAGE_POOL)
262 return is_page_pool_compiled_in();
264 if (type >= MEM_TYPE_MAX)
270 static struct xdp_mem_allocator *__xdp_reg_mem_model(struct xdp_mem_info *mem,
271 enum xdp_mem_type type,
274 struct xdp_mem_allocator *xdp_alloc;
275 gfp_t gfp = GFP_KERNEL;
279 if (!__is_supported_mem_type(type))
280 return ERR_PTR(-EOPNOTSUPP);
285 if (type == MEM_TYPE_PAGE_POOL)
286 return ERR_PTR(-EINVAL); /* Setup time check page_pool req */
290 /* Delay init of rhashtable to save memory if feature isn't used */
292 mutex_lock(&mem_id_lock);
293 ret = __mem_id_init_hash_table();
294 mutex_unlock(&mem_id_lock);
301 xdp_alloc = kzalloc(sizeof(*xdp_alloc), gfp);
303 return ERR_PTR(-ENOMEM);
305 mutex_lock(&mem_id_lock);
306 id = __mem_id_cyclic_get(gfp);
312 xdp_alloc->mem = *mem;
313 xdp_alloc->allocator = allocator;
315 /* Insert allocator into ID lookup table */
316 ptr = rhashtable_insert_slow(mem_id_ht, &id, &xdp_alloc->node);
318 ida_simple_remove(&mem_id_pool, mem->id);
320 errno = PTR_ERR(ptr);
324 if (type == MEM_TYPE_PAGE_POOL)
325 page_pool_use_xdp_mem(allocator, mem_allocator_disconnect);
327 mutex_unlock(&mem_id_lock);
331 mutex_unlock(&mem_id_lock);
333 return ERR_PTR(errno);
336 int xdp_reg_mem_model(struct xdp_mem_info *mem,
337 enum xdp_mem_type type, void *allocator)
339 struct xdp_mem_allocator *xdp_alloc;
341 xdp_alloc = __xdp_reg_mem_model(mem, type, allocator);
342 if (IS_ERR(xdp_alloc))
343 return PTR_ERR(xdp_alloc);
346 EXPORT_SYMBOL_GPL(xdp_reg_mem_model);
348 int xdp_rxq_info_reg_mem_model(struct xdp_rxq_info *xdp_rxq,
349 enum xdp_mem_type type, void *allocator)
351 struct xdp_mem_allocator *xdp_alloc;
353 if (xdp_rxq->reg_state != REG_STATE_REGISTERED) {
354 WARN(1, "Missing register, driver bug");
358 xdp_alloc = __xdp_reg_mem_model(&xdp_rxq->mem, type, allocator);
359 if (IS_ERR(xdp_alloc))
360 return PTR_ERR(xdp_alloc);
362 if (trace_mem_connect_enabled() && xdp_alloc)
363 trace_mem_connect(xdp_alloc, xdp_rxq);
367 EXPORT_SYMBOL_GPL(xdp_rxq_info_reg_mem_model);
369 /* XDP RX runs under NAPI protection, and in different delivery error
370 * scenarios (e.g. queue full), it is possible to return the xdp_frame
371 * while still leveraging this protection. The @napi_direct boolean
372 * is used for those calls sites. Thus, allowing for faster recycling
373 * of xdp_frames/pages in those cases.
375 static void __xdp_return(void *data, struct xdp_mem_info *mem, bool napi_direct,
376 struct xdp_buff *xdp)
378 struct xdp_mem_allocator *xa;
382 case MEM_TYPE_PAGE_POOL:
384 /* mem->id is valid, checked in xdp_rxq_info_reg_mem_model() */
385 xa = rhashtable_lookup(mem_id_ht, &mem->id, mem_id_rht_params);
386 page = virt_to_head_page(data);
387 if (napi_direct && xdp_return_frame_no_direct())
389 page_pool_put_full_page(xa->page_pool, page, napi_direct);
392 case MEM_TYPE_PAGE_SHARED:
393 page_frag_free(data);
395 case MEM_TYPE_PAGE_ORDER0:
396 page = virt_to_page(data); /* Assumes order0 page*/
399 case MEM_TYPE_XSK_BUFF_POOL:
400 /* NB! Only valid from an xdp_buff! */
404 /* Not possible, checked in xdp_rxq_info_reg_mem_model() */
405 WARN(1, "Incorrect XDP memory type (%d) usage", mem->type);
410 void xdp_return_frame(struct xdp_frame *xdpf)
412 __xdp_return(xdpf->data, &xdpf->mem, false, NULL);
414 EXPORT_SYMBOL_GPL(xdp_return_frame);
416 void xdp_return_frame_rx_napi(struct xdp_frame *xdpf)
418 __xdp_return(xdpf->data, &xdpf->mem, true, NULL);
420 EXPORT_SYMBOL_GPL(xdp_return_frame_rx_napi);
422 /* XDP bulk APIs introduce a defer/flush mechanism to return
423 * pages belonging to the same xdp_mem_allocator object
424 * (identified via the mem.id field) in bulk to optimize
425 * I-cache and D-cache.
426 * The bulk queue size is set to 16 to be aligned to how
427 * XDP_REDIRECT bulking works. The bulk is flushed when
428 * it is full or when mem.id changes.
429 * xdp_frame_bulk is usually stored/allocated on the function
430 * call-stack to avoid locking penalties.
432 void xdp_flush_frame_bulk(struct xdp_frame_bulk *bq)
434 struct xdp_mem_allocator *xa = bq->xa;
436 if (unlikely(!xa || !bq->count))
439 page_pool_put_page_bulk(xa->page_pool, bq->q, bq->count);
440 /* bq->xa is not cleared to save lookup, if mem.id same in next bulk */
443 EXPORT_SYMBOL_GPL(xdp_flush_frame_bulk);
445 /* Must be called with rcu_read_lock held */
446 void xdp_return_frame_bulk(struct xdp_frame *xdpf,
447 struct xdp_frame_bulk *bq)
449 struct xdp_mem_info *mem = &xdpf->mem;
450 struct xdp_mem_allocator *xa;
452 if (mem->type != MEM_TYPE_PAGE_POOL) {
453 __xdp_return(xdpf->data, &xdpf->mem, false, NULL);
459 xa = rhashtable_lookup(mem_id_ht, &mem->id, mem_id_rht_params);
464 if (bq->count == XDP_BULK_QUEUE_SIZE)
465 xdp_flush_frame_bulk(bq);
467 if (unlikely(mem->id != xa->mem.id)) {
468 xdp_flush_frame_bulk(bq);
469 bq->xa = rhashtable_lookup(mem_id_ht, &mem->id, mem_id_rht_params);
472 bq->q[bq->count++] = xdpf->data;
474 EXPORT_SYMBOL_GPL(xdp_return_frame_bulk);
476 void xdp_return_buff(struct xdp_buff *xdp)
478 __xdp_return(xdp->data, &xdp->rxq->mem, true, xdp);
481 /* Only called for MEM_TYPE_PAGE_POOL see xdp.h */
482 void __xdp_release_frame(void *data, struct xdp_mem_info *mem)
484 struct xdp_mem_allocator *xa;
488 xa = rhashtable_lookup(mem_id_ht, &mem->id, mem_id_rht_params);
489 page = virt_to_head_page(data);
491 page_pool_release_page(xa->page_pool, page);
494 EXPORT_SYMBOL_GPL(__xdp_release_frame);
496 void xdp_attachment_setup(struct xdp_attachment_info *info,
497 struct netdev_bpf *bpf)
500 bpf_prog_put(info->prog);
501 info->prog = bpf->prog;
502 info->flags = bpf->flags;
504 EXPORT_SYMBOL_GPL(xdp_attachment_setup);
506 struct xdp_frame *xdp_convert_zc_to_xdp_frame(struct xdp_buff *xdp)
508 unsigned int metasize, totsize;
509 void *addr, *data_to_copy;
510 struct xdp_frame *xdpf;
513 /* Clone into a MEM_TYPE_PAGE_ORDER0 xdp_frame. */
514 metasize = xdp_data_meta_unsupported(xdp) ? 0 :
515 xdp->data - xdp->data_meta;
516 totsize = xdp->data_end - xdp->data + metasize;
518 if (sizeof(*xdpf) + totsize > PAGE_SIZE)
521 page = dev_alloc_page();
525 addr = page_to_virt(page);
527 memset(xdpf, 0, sizeof(*xdpf));
529 addr += sizeof(*xdpf);
530 data_to_copy = metasize ? xdp->data_meta : xdp->data;
531 memcpy(addr, data_to_copy, totsize);
533 xdpf->data = addr + metasize;
534 xdpf->len = totsize - metasize;
536 xdpf->metasize = metasize;
537 xdpf->frame_sz = PAGE_SIZE;
538 xdpf->mem.type = MEM_TYPE_PAGE_ORDER0;
543 EXPORT_SYMBOL_GPL(xdp_convert_zc_to_xdp_frame);
545 /* Used by XDP_WARN macro, to avoid inlining WARN() in fast-path */
546 void xdp_warn(const char *msg, const char *func, const int line)
548 WARN(1, "XDP_WARN: %s(line:%d): %s\n", func, line, msg);
550 EXPORT_SYMBOL_GPL(xdp_warn);
552 int xdp_alloc_skb_bulk(void **skbs, int n_skb, gfp_t gfp)
554 n_skb = kmem_cache_alloc_bulk(skbuff_head_cache, gfp,
556 if (unlikely(!n_skb))
561 EXPORT_SYMBOL_GPL(xdp_alloc_skb_bulk);
563 struct sk_buff *__xdp_build_skb_from_frame(struct xdp_frame *xdpf,
565 struct net_device *dev)
567 unsigned int headroom, frame_size;
570 /* Part of headroom was reserved to xdpf */
571 headroom = sizeof(*xdpf) + xdpf->headroom;
573 /* Memory size backing xdp_frame data already have reserved
574 * room for build_skb to place skb_shared_info in tailroom.
576 frame_size = xdpf->frame_sz;
578 hard_start = xdpf->data - headroom;
579 skb = build_skb_around(skb, hard_start, frame_size);
583 skb_reserve(skb, headroom);
584 __skb_put(skb, xdpf->len);
586 skb_metadata_set(skb, xdpf->metasize);
588 /* Essential SKB info: protocol and skb->dev */
589 skb->protocol = eth_type_trans(skb, dev);
591 /* Optional SKB info, currently missing:
592 * - HW checksum info (skb->ip_summed)
593 * - HW RX hash (skb_set_hash)
594 * - RX ring dev queue index (skb_record_rx_queue)
597 /* Until page_pool get SKB return path, release DMA here */
598 xdp_release_frame(xdpf);
600 /* Allow SKB to reuse area used by xdp_frame */
601 xdp_scrub_frame(xdpf);
605 EXPORT_SYMBOL_GPL(__xdp_build_skb_from_frame);
607 struct sk_buff *xdp_build_skb_from_frame(struct xdp_frame *xdpf,
608 struct net_device *dev)
612 skb = kmem_cache_alloc(skbuff_head_cache, GFP_ATOMIC);
616 memset(skb, 0, offsetof(struct sk_buff, tail));
618 return __xdp_build_skb_from_frame(xdpf, skb, dev);
620 EXPORT_SYMBOL_GPL(xdp_build_skb_from_frame);
622 struct xdp_frame *xdpf_clone(struct xdp_frame *xdpf)
624 unsigned int headroom, totalsize;
625 struct xdp_frame *nxdpf;
629 headroom = xdpf->headroom + sizeof(*xdpf);
630 totalsize = headroom + xdpf->len;
632 if (unlikely(totalsize > PAGE_SIZE))
634 page = dev_alloc_page();
637 addr = page_to_virt(page);
639 memcpy(addr, xdpf, totalsize);
642 nxdpf->data = addr + headroom;
643 nxdpf->frame_sz = PAGE_SIZE;
644 nxdpf->mem.type = MEM_TYPE_PAGE_ORDER0;