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[releases.git] / core / xdp.c
1 // SPDX-License-Identifier: GPL-2.0-only
2 /* net/core/xdp.c
3  *
4  * Copyright (c) 2017 Jesper Dangaard Brouer, Red Hat Inc.
5  */
6 #include <linux/bpf.h>
7 #include <linux/filter.h>
8 #include <linux/types.h>
9 #include <linux/mm.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>
16
17 #include <net/xdp.h>
18 #include <net/xdp_priv.h> /* struct xdp_mem_allocator */
19 #include <trace/events/xdp.h>
20 #include <net/xdp_sock_drv.h>
21
22 #define REG_STATE_NEW           0x0
23 #define REG_STATE_REGISTERED    0x1
24 #define REG_STATE_UNREGISTERED  0x2
25 #define REG_STATE_UNUSED        0x3
26
27 static DEFINE_IDA(mem_id_pool);
28 static DEFINE_MUTEX(mem_id_lock);
29 #define MEM_ID_MAX 0xFFFE
30 #define MEM_ID_MIN 1
31 static int mem_id_next = MEM_ID_MIN;
32
33 static bool mem_id_init; /* false */
34 static struct rhashtable *mem_id_ht;
35
36 static u32 xdp_mem_id_hashfn(const void *data, u32 len, u32 seed)
37 {
38         const u32 *k = data;
39         const u32 key = *k;
40
41         BUILD_BUG_ON(sizeof_field(struct xdp_mem_allocator, mem.id)
42                      != sizeof(u32));
43
44         /* Use cyclic increasing ID as direct hash key */
45         return key;
46 }
47
48 static int xdp_mem_id_cmp(struct rhashtable_compare_arg *arg,
49                           const void *ptr)
50 {
51         const struct xdp_mem_allocator *xa = ptr;
52         u32 mem_id = *(u32 *)arg->key;
53
54         return xa->mem.id != mem_id;
55 }
56
57 static const struct rhashtable_params mem_id_rht_params = {
58         .nelem_hint = 64,
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,
63         .min_size = 8,
64         .automatic_shrinking = true,
65         .hashfn    = xdp_mem_id_hashfn,
66         .obj_cmpfn = xdp_mem_id_cmp,
67 };
68
69 static void __xdp_mem_allocator_rcu_free(struct rcu_head *rcu)
70 {
71         struct xdp_mem_allocator *xa;
72
73         xa = container_of(rcu, struct xdp_mem_allocator, rcu);
74
75         /* Allow this ID to be reused */
76         ida_simple_remove(&mem_id_pool, xa->mem.id);
77
78         kfree(xa);
79 }
80
81 static void mem_xa_remove(struct xdp_mem_allocator *xa)
82 {
83         trace_mem_disconnect(xa);
84
85         if (!rhashtable_remove_fast(mem_id_ht, &xa->node, mem_id_rht_params))
86                 call_rcu(&xa->rcu, __xdp_mem_allocator_rcu_free);
87 }
88
89 static void mem_allocator_disconnect(void *allocator)
90 {
91         struct xdp_mem_allocator *xa;
92         struct rhashtable_iter iter;
93
94         mutex_lock(&mem_id_lock);
95
96         rhashtable_walk_enter(mem_id_ht, &iter);
97         do {
98                 rhashtable_walk_start(&iter);
99
100                 while ((xa = rhashtable_walk_next(&iter)) && !IS_ERR(xa)) {
101                         if (xa->allocator == allocator)
102                                 mem_xa_remove(xa);
103                 }
104
105                 rhashtable_walk_stop(&iter);
106
107         } while (xa == ERR_PTR(-EAGAIN));
108         rhashtable_walk_exit(&iter);
109
110         mutex_unlock(&mem_id_lock);
111 }
112
113 void xdp_unreg_mem_model(struct xdp_mem_info *mem)
114 {
115         struct xdp_mem_allocator *xa;
116         int type = mem->type;
117         int id = mem->id;
118
119         /* Reset mem info to defaults */
120         mem->id = 0;
121         mem->type = 0;
122
123         if (id == 0)
124                 return;
125
126         if (type == MEM_TYPE_PAGE_POOL) {
127                 rcu_read_lock();
128                 xa = rhashtable_lookup(mem_id_ht, &id, mem_id_rht_params);
129                 page_pool_destroy(xa->page_pool);
130                 rcu_read_unlock();
131         }
132 }
133 EXPORT_SYMBOL_GPL(xdp_unreg_mem_model);
134
135 void xdp_rxq_info_unreg_mem_model(struct xdp_rxq_info *xdp_rxq)
136 {
137         if (xdp_rxq->reg_state != REG_STATE_REGISTERED) {
138                 WARN(1, "Missing register, driver bug");
139                 return;
140         }
141
142         xdp_unreg_mem_model(&xdp_rxq->mem);
143 }
144 EXPORT_SYMBOL_GPL(xdp_rxq_info_unreg_mem_model);
145
146 void xdp_rxq_info_unreg(struct xdp_rxq_info *xdp_rxq)
147 {
148         /* Simplify driver cleanup code paths, allow unreg "unused" */
149         if (xdp_rxq->reg_state == REG_STATE_UNUSED)
150                 return;
151
152         xdp_rxq_info_unreg_mem_model(xdp_rxq);
153
154         xdp_rxq->reg_state = REG_STATE_UNREGISTERED;
155         xdp_rxq->dev = NULL;
156 }
157 EXPORT_SYMBOL_GPL(xdp_rxq_info_unreg);
158
159 static void xdp_rxq_info_init(struct xdp_rxq_info *xdp_rxq)
160 {
161         memset(xdp_rxq, 0, sizeof(*xdp_rxq));
162 }
163
164 /* Returns 0 on success, negative on failure */
165 int __xdp_rxq_info_reg(struct xdp_rxq_info *xdp_rxq,
166                        struct net_device *dev, u32 queue_index,
167                        unsigned int napi_id, u32 frag_size)
168 {
169         if (!dev) {
170                 WARN(1, "Missing net_device from driver");
171                 return -ENODEV;
172         }
173
174         if (xdp_rxq->reg_state == REG_STATE_UNUSED) {
175                 WARN(1, "Driver promised not to register this");
176                 return -EINVAL;
177         }
178
179         if (xdp_rxq->reg_state == REG_STATE_REGISTERED) {
180                 WARN(1, "Missing unregister, handled but fix driver");
181                 xdp_rxq_info_unreg(xdp_rxq);
182         }
183
184         /* State either UNREGISTERED or NEW */
185         xdp_rxq_info_init(xdp_rxq);
186         xdp_rxq->dev = dev;
187         xdp_rxq->queue_index = queue_index;
188         xdp_rxq->napi_id = napi_id;
189         xdp_rxq->frag_size = frag_size;
190
191         xdp_rxq->reg_state = REG_STATE_REGISTERED;
192         return 0;
193 }
194 EXPORT_SYMBOL_GPL(__xdp_rxq_info_reg);
195
196 void xdp_rxq_info_unused(struct xdp_rxq_info *xdp_rxq)
197 {
198         xdp_rxq->reg_state = REG_STATE_UNUSED;
199 }
200 EXPORT_SYMBOL_GPL(xdp_rxq_info_unused);
201
202 bool xdp_rxq_info_is_reg(struct xdp_rxq_info *xdp_rxq)
203 {
204         return (xdp_rxq->reg_state == REG_STATE_REGISTERED);
205 }
206 EXPORT_SYMBOL_GPL(xdp_rxq_info_is_reg);
207
208 static int __mem_id_init_hash_table(void)
209 {
210         struct rhashtable *rht;
211         int ret;
212
213         if (unlikely(mem_id_init))
214                 return 0;
215
216         rht = kzalloc(sizeof(*rht), GFP_KERNEL);
217         if (!rht)
218                 return -ENOMEM;
219
220         ret = rhashtable_init(rht, &mem_id_rht_params);
221         if (ret < 0) {
222                 kfree(rht);
223                 return ret;
224         }
225         mem_id_ht = rht;
226         smp_mb(); /* mutex lock should provide enough pairing */
227         mem_id_init = true;
228
229         return 0;
230 }
231
232 /* Allocate a cyclic ID that maps to allocator pointer.
233  * See: https://www.kernel.org/doc/html/latest/core-api/idr.html
234  *
235  * Caller must lock mem_id_lock.
236  */
237 static int __mem_id_cyclic_get(gfp_t gfp)
238 {
239         int retries = 1;
240         int id;
241
242 again:
243         id = ida_simple_get(&mem_id_pool, mem_id_next, MEM_ID_MAX, gfp);
244         if (id < 0) {
245                 if (id == -ENOSPC) {
246                         /* Cyclic allocator, reset next id */
247                         if (retries--) {
248                                 mem_id_next = MEM_ID_MIN;
249                                 goto again;
250                         }
251                 }
252                 return id; /* errno */
253         }
254         mem_id_next = id + 1;
255
256         return id;
257 }
258
259 static bool __is_supported_mem_type(enum xdp_mem_type type)
260 {
261         if (type == MEM_TYPE_PAGE_POOL)
262                 return is_page_pool_compiled_in();
263
264         if (type >= MEM_TYPE_MAX)
265                 return false;
266
267         return true;
268 }
269
270 static struct xdp_mem_allocator *__xdp_reg_mem_model(struct xdp_mem_info *mem,
271                                                      enum xdp_mem_type type,
272                                                      void *allocator)
273 {
274         struct xdp_mem_allocator *xdp_alloc;
275         gfp_t gfp = GFP_KERNEL;
276         int id, errno, ret;
277         void *ptr;
278
279         if (!__is_supported_mem_type(type))
280                 return ERR_PTR(-EOPNOTSUPP);
281
282         mem->type = type;
283
284         if (!allocator) {
285                 if (type == MEM_TYPE_PAGE_POOL)
286                         return ERR_PTR(-EINVAL); /* Setup time check page_pool req */
287                 return NULL;
288         }
289
290         /* Delay init of rhashtable to save memory if feature isn't used */
291         if (!mem_id_init) {
292                 mutex_lock(&mem_id_lock);
293                 ret = __mem_id_init_hash_table();
294                 mutex_unlock(&mem_id_lock);
295                 if (ret < 0) {
296                         WARN_ON(1);
297                         return ERR_PTR(ret);
298                 }
299         }
300
301         xdp_alloc = kzalloc(sizeof(*xdp_alloc), gfp);
302         if (!xdp_alloc)
303                 return ERR_PTR(-ENOMEM);
304
305         mutex_lock(&mem_id_lock);
306         id = __mem_id_cyclic_get(gfp);
307         if (id < 0) {
308                 errno = id;
309                 goto err;
310         }
311         mem->id = id;
312         xdp_alloc->mem = *mem;
313         xdp_alloc->allocator = allocator;
314
315         /* Insert allocator into ID lookup table */
316         ptr = rhashtable_insert_slow(mem_id_ht, &id, &xdp_alloc->node);
317         if (IS_ERR(ptr)) {
318                 ida_simple_remove(&mem_id_pool, mem->id);
319                 mem->id = 0;
320                 errno = PTR_ERR(ptr);
321                 goto err;
322         }
323
324         if (type == MEM_TYPE_PAGE_POOL)
325                 page_pool_use_xdp_mem(allocator, mem_allocator_disconnect, mem);
326
327         mutex_unlock(&mem_id_lock);
328
329         return xdp_alloc;
330 err:
331         mutex_unlock(&mem_id_lock);
332         kfree(xdp_alloc);
333         return ERR_PTR(errno);
334 }
335
336 int xdp_reg_mem_model(struct xdp_mem_info *mem,
337                       enum xdp_mem_type type, void *allocator)
338 {
339         struct xdp_mem_allocator *xdp_alloc;
340
341         xdp_alloc = __xdp_reg_mem_model(mem, type, allocator);
342         if (IS_ERR(xdp_alloc))
343                 return PTR_ERR(xdp_alloc);
344         return 0;
345 }
346 EXPORT_SYMBOL_GPL(xdp_reg_mem_model);
347
348 int xdp_rxq_info_reg_mem_model(struct xdp_rxq_info *xdp_rxq,
349                                enum xdp_mem_type type, void *allocator)
350 {
351         struct xdp_mem_allocator *xdp_alloc;
352
353         if (xdp_rxq->reg_state != REG_STATE_REGISTERED) {
354                 WARN(1, "Missing register, driver bug");
355                 return -EFAULT;
356         }
357
358         xdp_alloc = __xdp_reg_mem_model(&xdp_rxq->mem, type, allocator);
359         if (IS_ERR(xdp_alloc))
360                 return PTR_ERR(xdp_alloc);
361
362         if (trace_mem_connect_enabled() && xdp_alloc)
363                 trace_mem_connect(xdp_alloc, xdp_rxq);
364         return 0;
365 }
366
367 EXPORT_SYMBOL_GPL(xdp_rxq_info_reg_mem_model);
368
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.
374  */
375 void __xdp_return(void *data, struct xdp_mem_info *mem, bool napi_direct,
376                   struct xdp_buff *xdp)
377 {
378         struct page *page;
379
380         switch (mem->type) {
381         case MEM_TYPE_PAGE_POOL:
382                 page = virt_to_head_page(data);
383                 if (napi_direct && xdp_return_frame_no_direct())
384                         napi_direct = false;
385                 /* No need to check ((page->pp_magic & ~0x3UL) == PP_SIGNATURE)
386                  * as mem->type knows this a page_pool page
387                  */
388                 page_pool_put_full_page(page->pp, page, napi_direct);
389                 break;
390         case MEM_TYPE_PAGE_SHARED:
391                 page_frag_free(data);
392                 break;
393         case MEM_TYPE_PAGE_ORDER0:
394                 page = virt_to_page(data); /* Assumes order0 page*/
395                 put_page(page);
396                 break;
397         case MEM_TYPE_XSK_BUFF_POOL:
398                 /* NB! Only valid from an xdp_buff! */
399                 xsk_buff_free(xdp);
400                 break;
401         default:
402                 /* Not possible, checked in xdp_rxq_info_reg_mem_model() */
403                 WARN(1, "Incorrect XDP memory type (%d) usage", mem->type);
404                 break;
405         }
406 }
407
408 void xdp_return_frame(struct xdp_frame *xdpf)
409 {
410         struct skb_shared_info *sinfo;
411         int i;
412
413         if (likely(!xdp_frame_has_frags(xdpf)))
414                 goto out;
415
416         sinfo = xdp_get_shared_info_from_frame(xdpf);
417         for (i = 0; i < sinfo->nr_frags; i++) {
418                 struct page *page = skb_frag_page(&sinfo->frags[i]);
419
420                 __xdp_return(page_address(page), &xdpf->mem, false, NULL);
421         }
422 out:
423         __xdp_return(xdpf->data, &xdpf->mem, false, NULL);
424 }
425 EXPORT_SYMBOL_GPL(xdp_return_frame);
426
427 void xdp_return_frame_rx_napi(struct xdp_frame *xdpf)
428 {
429         struct skb_shared_info *sinfo;
430         int i;
431
432         if (likely(!xdp_frame_has_frags(xdpf)))
433                 goto out;
434
435         sinfo = xdp_get_shared_info_from_frame(xdpf);
436         for (i = 0; i < sinfo->nr_frags; i++) {
437                 struct page *page = skb_frag_page(&sinfo->frags[i]);
438
439                 __xdp_return(page_address(page), &xdpf->mem, true, NULL);
440         }
441 out:
442         __xdp_return(xdpf->data, &xdpf->mem, true, NULL);
443 }
444 EXPORT_SYMBOL_GPL(xdp_return_frame_rx_napi);
445
446 /* XDP bulk APIs introduce a defer/flush mechanism to return
447  * pages belonging to the same xdp_mem_allocator object
448  * (identified via the mem.id field) in bulk to optimize
449  * I-cache and D-cache.
450  * The bulk queue size is set to 16 to be aligned to how
451  * XDP_REDIRECT bulking works. The bulk is flushed when
452  * it is full or when mem.id changes.
453  * xdp_frame_bulk is usually stored/allocated on the function
454  * call-stack to avoid locking penalties.
455  */
456 void xdp_flush_frame_bulk(struct xdp_frame_bulk *bq)
457 {
458         struct xdp_mem_allocator *xa = bq->xa;
459
460         if (unlikely(!xa || !bq->count))
461                 return;
462
463         page_pool_put_page_bulk(xa->page_pool, bq->q, bq->count);
464         /* bq->xa is not cleared to save lookup, if mem.id same in next bulk */
465         bq->count = 0;
466 }
467 EXPORT_SYMBOL_GPL(xdp_flush_frame_bulk);
468
469 /* Must be called with rcu_read_lock held */
470 void xdp_return_frame_bulk(struct xdp_frame *xdpf,
471                            struct xdp_frame_bulk *bq)
472 {
473         struct xdp_mem_info *mem = &xdpf->mem;
474         struct xdp_mem_allocator *xa;
475
476         if (mem->type != MEM_TYPE_PAGE_POOL) {
477                 xdp_return_frame(xdpf);
478                 return;
479         }
480
481         xa = bq->xa;
482         if (unlikely(!xa)) {
483                 xa = rhashtable_lookup(mem_id_ht, &mem->id, mem_id_rht_params);
484                 bq->count = 0;
485                 bq->xa = xa;
486         }
487
488         if (bq->count == XDP_BULK_QUEUE_SIZE)
489                 xdp_flush_frame_bulk(bq);
490
491         if (unlikely(mem->id != xa->mem.id)) {
492                 xdp_flush_frame_bulk(bq);
493                 bq->xa = rhashtable_lookup(mem_id_ht, &mem->id, mem_id_rht_params);
494         }
495
496         if (unlikely(xdp_frame_has_frags(xdpf))) {
497                 struct skb_shared_info *sinfo;
498                 int i;
499
500                 sinfo = xdp_get_shared_info_from_frame(xdpf);
501                 for (i = 0; i < sinfo->nr_frags; i++) {
502                         skb_frag_t *frag = &sinfo->frags[i];
503
504                         bq->q[bq->count++] = skb_frag_address(frag);
505                         if (bq->count == XDP_BULK_QUEUE_SIZE)
506                                 xdp_flush_frame_bulk(bq);
507                 }
508         }
509         bq->q[bq->count++] = xdpf->data;
510 }
511 EXPORT_SYMBOL_GPL(xdp_return_frame_bulk);
512
513 void xdp_return_buff(struct xdp_buff *xdp)
514 {
515         struct skb_shared_info *sinfo;
516         int i;
517
518         if (likely(!xdp_buff_has_frags(xdp)))
519                 goto out;
520
521         sinfo = xdp_get_shared_info_from_buff(xdp);
522         for (i = 0; i < sinfo->nr_frags; i++) {
523                 struct page *page = skb_frag_page(&sinfo->frags[i]);
524
525                 __xdp_return(page_address(page), &xdp->rxq->mem, true, xdp);
526         }
527 out:
528         __xdp_return(xdp->data, &xdp->rxq->mem, true, xdp);
529 }
530 EXPORT_SYMBOL_GPL(xdp_return_buff);
531
532 /* Only called for MEM_TYPE_PAGE_POOL see xdp.h */
533 void __xdp_release_frame(void *data, struct xdp_mem_info *mem)
534 {
535         struct xdp_mem_allocator *xa;
536         struct page *page;
537
538         rcu_read_lock();
539         xa = rhashtable_lookup(mem_id_ht, &mem->id, mem_id_rht_params);
540         page = virt_to_head_page(data);
541         if (xa)
542                 page_pool_release_page(xa->page_pool, page);
543         rcu_read_unlock();
544 }
545 EXPORT_SYMBOL_GPL(__xdp_release_frame);
546
547 void xdp_attachment_setup(struct xdp_attachment_info *info,
548                           struct netdev_bpf *bpf)
549 {
550         if (info->prog)
551                 bpf_prog_put(info->prog);
552         info->prog = bpf->prog;
553         info->flags = bpf->flags;
554 }
555 EXPORT_SYMBOL_GPL(xdp_attachment_setup);
556
557 struct xdp_frame *xdp_convert_zc_to_xdp_frame(struct xdp_buff *xdp)
558 {
559         unsigned int metasize, totsize;
560         void *addr, *data_to_copy;
561         struct xdp_frame *xdpf;
562         struct page *page;
563
564         /* Clone into a MEM_TYPE_PAGE_ORDER0 xdp_frame. */
565         metasize = xdp_data_meta_unsupported(xdp) ? 0 :
566                    xdp->data - xdp->data_meta;
567         totsize = xdp->data_end - xdp->data + metasize;
568
569         if (sizeof(*xdpf) + totsize > PAGE_SIZE)
570                 return NULL;
571
572         page = dev_alloc_page();
573         if (!page)
574                 return NULL;
575
576         addr = page_to_virt(page);
577         xdpf = addr;
578         memset(xdpf, 0, sizeof(*xdpf));
579
580         addr += sizeof(*xdpf);
581         data_to_copy = metasize ? xdp->data_meta : xdp->data;
582         memcpy(addr, data_to_copy, totsize);
583
584         xdpf->data = addr + metasize;
585         xdpf->len = totsize - metasize;
586         xdpf->headroom = 0;
587         xdpf->metasize = metasize;
588         xdpf->frame_sz = PAGE_SIZE;
589         xdpf->mem.type = MEM_TYPE_PAGE_ORDER0;
590
591         xsk_buff_free(xdp);
592         return xdpf;
593 }
594 EXPORT_SYMBOL_GPL(xdp_convert_zc_to_xdp_frame);
595
596 /* Used by XDP_WARN macro, to avoid inlining WARN() in fast-path */
597 void xdp_warn(const char *msg, const char *func, const int line)
598 {
599         WARN(1, "XDP_WARN: %s(line:%d): %s\n", func, line, msg);
600 };
601 EXPORT_SYMBOL_GPL(xdp_warn);
602
603 int xdp_alloc_skb_bulk(void **skbs, int n_skb, gfp_t gfp)
604 {
605         n_skb = kmem_cache_alloc_bulk(skbuff_head_cache, gfp,
606                                       n_skb, skbs);
607         if (unlikely(!n_skb))
608                 return -ENOMEM;
609
610         return 0;
611 }
612 EXPORT_SYMBOL_GPL(xdp_alloc_skb_bulk);
613
614 struct sk_buff *__xdp_build_skb_from_frame(struct xdp_frame *xdpf,
615                                            struct sk_buff *skb,
616                                            struct net_device *dev)
617 {
618         struct skb_shared_info *sinfo = xdp_get_shared_info_from_frame(xdpf);
619         unsigned int headroom, frame_size;
620         void *hard_start;
621         u8 nr_frags;
622
623         /* xdp frags frame */
624         if (unlikely(xdp_frame_has_frags(xdpf)))
625                 nr_frags = sinfo->nr_frags;
626
627         /* Part of headroom was reserved to xdpf */
628         headroom = sizeof(*xdpf) + xdpf->headroom;
629
630         /* Memory size backing xdp_frame data already have reserved
631          * room for build_skb to place skb_shared_info in tailroom.
632          */
633         frame_size = xdpf->frame_sz;
634
635         hard_start = xdpf->data - headroom;
636         skb = build_skb_around(skb, hard_start, frame_size);
637         if (unlikely(!skb))
638                 return NULL;
639
640         skb_reserve(skb, headroom);
641         __skb_put(skb, xdpf->len);
642         if (xdpf->metasize)
643                 skb_metadata_set(skb, xdpf->metasize);
644
645         if (unlikely(xdp_frame_has_frags(xdpf)))
646                 xdp_update_skb_shared_info(skb, nr_frags,
647                                            sinfo->xdp_frags_size,
648                                            nr_frags * xdpf->frame_sz,
649                                            xdp_frame_is_frag_pfmemalloc(xdpf));
650
651         /* Essential SKB info: protocol and skb->dev */
652         skb->protocol = eth_type_trans(skb, dev);
653
654         /* Optional SKB info, currently missing:
655          * - HW checksum info           (skb->ip_summed)
656          * - HW RX hash                 (skb_set_hash)
657          * - RX ring dev queue index    (skb_record_rx_queue)
658          */
659
660         /* Until page_pool get SKB return path, release DMA here */
661         xdp_release_frame(xdpf);
662
663         /* Allow SKB to reuse area used by xdp_frame */
664         xdp_scrub_frame(xdpf);
665
666         return skb;
667 }
668 EXPORT_SYMBOL_GPL(__xdp_build_skb_from_frame);
669
670 struct sk_buff *xdp_build_skb_from_frame(struct xdp_frame *xdpf,
671                                          struct net_device *dev)
672 {
673         struct sk_buff *skb;
674
675         skb = kmem_cache_alloc(skbuff_head_cache, GFP_ATOMIC);
676         if (unlikely(!skb))
677                 return NULL;
678
679         memset(skb, 0, offsetof(struct sk_buff, tail));
680
681         return __xdp_build_skb_from_frame(xdpf, skb, dev);
682 }
683 EXPORT_SYMBOL_GPL(xdp_build_skb_from_frame);
684
685 struct xdp_frame *xdpf_clone(struct xdp_frame *xdpf)
686 {
687         unsigned int headroom, totalsize;
688         struct xdp_frame *nxdpf;
689         struct page *page;
690         void *addr;
691
692         headroom = xdpf->headroom + sizeof(*xdpf);
693         totalsize = headroom + xdpf->len;
694
695         if (unlikely(totalsize > PAGE_SIZE))
696                 return NULL;
697         page = dev_alloc_page();
698         if (!page)
699                 return NULL;
700         addr = page_to_virt(page);
701
702         memcpy(addr, xdpf, totalsize);
703
704         nxdpf = addr;
705         nxdpf->data = addr + headroom;
706         nxdpf->frame_sz = PAGE_SIZE;
707         nxdpf->mem.type = MEM_TYPE_PAGE_ORDER0;
708         nxdpf->mem.id = 0;
709
710         return nxdpf;
711 }