xref: /linux/net/xdp/xsk_buff_pool.c (revision bf4afc53b77aeaa48b5409da5c8da6bb4eff7f43)
1 // SPDX-License-Identifier: GPL-2.0
2 
3 #include <linux/netdevice.h>
4 #include <net/netdev_lock.h>
5 #include <net/xsk_buff_pool.h>
6 #include <net/xdp_sock.h>
7 #include <net/xdp_sock_drv.h>
8 
9 #include "xsk_queue.h"
10 #include "xdp_umem.h"
11 #include "xsk.h"
12 
13 void xp_add_xsk(struct xsk_buff_pool *pool, struct xdp_sock *xs)
14 {
15 	if (!xs->tx)
16 		return;
17 
18 	spin_lock(&pool->xsk_tx_list_lock);
19 	list_add_rcu(&xs->tx_list, &pool->xsk_tx_list);
20 	spin_unlock(&pool->xsk_tx_list_lock);
21 }
22 
23 void xp_del_xsk(struct xsk_buff_pool *pool, struct xdp_sock *xs)
24 {
25 	if (!xs->tx)
26 		return;
27 
28 	spin_lock(&pool->xsk_tx_list_lock);
29 	list_del_rcu(&xs->tx_list);
30 	spin_unlock(&pool->xsk_tx_list_lock);
31 }
32 
33 void xp_destroy(struct xsk_buff_pool *pool)
34 {
35 	if (!pool)
36 		return;
37 
38 	kvfree(pool->tx_descs);
39 	kvfree(pool->heads);
40 	kvfree(pool);
41 }
42 
43 int xp_alloc_tx_descs(struct xsk_buff_pool *pool, struct xdp_sock *xs)
44 {
45 	pool->tx_descs = kvzalloc_objs(*pool->tx_descs, xs->tx->nentries,
46 				       GFP_KERNEL);
47 	if (!pool->tx_descs)
48 		return -ENOMEM;
49 
50 	return 0;
51 }
52 
53 struct xsk_buff_pool *xp_create_and_assign_umem(struct xdp_sock *xs,
54 						struct xdp_umem *umem)
55 {
56 	bool unaligned = umem->flags & XDP_UMEM_UNALIGNED_CHUNK_FLAG;
57 	struct xsk_buff_pool *pool;
58 	struct xdp_buff_xsk *xskb;
59 	u32 i, entries;
60 
61 	entries = unaligned ? umem->chunks : 0;
62 	pool = kvzalloc_flex(*pool, free_heads, entries, GFP_KERNEL);
63 	if (!pool)
64 		goto out;
65 
66 	pool->heads = kvzalloc_objs(*pool->heads, umem->chunks);
67 	if (!pool->heads)
68 		goto out;
69 
70 	if (xs->tx)
71 		if (xp_alloc_tx_descs(pool, xs))
72 			goto out;
73 
74 	pool->chunk_mask = ~((u64)umem->chunk_size - 1);
75 	pool->addrs_cnt = umem->size;
76 	pool->heads_cnt = umem->chunks;
77 	pool->free_heads_cnt = umem->chunks;
78 	pool->headroom = umem->headroom;
79 	pool->chunk_size = umem->chunk_size;
80 	pool->chunk_shift = ffs(umem->chunk_size) - 1;
81 	pool->unaligned = unaligned;
82 	pool->frame_len = umem->chunk_size - umem->headroom -
83 		XDP_PACKET_HEADROOM;
84 	pool->umem = umem;
85 	pool->addrs = umem->addrs;
86 	pool->tx_metadata_len = umem->tx_metadata_len;
87 	pool->tx_sw_csum = umem->flags & XDP_UMEM_TX_SW_CSUM;
88 	spin_lock_init(&pool->rx_lock);
89 	INIT_LIST_HEAD(&pool->free_list);
90 	INIT_LIST_HEAD(&pool->xskb_list);
91 	INIT_LIST_HEAD(&pool->xsk_tx_list);
92 	spin_lock_init(&pool->xsk_tx_list_lock);
93 	spin_lock_init(&pool->cq_prod_lock);
94 	spin_lock_init(&xs->cq_tmp->cq_cached_prod_lock);
95 	refcount_set(&pool->users, 1);
96 
97 	pool->fq = xs->fq_tmp;
98 	pool->cq = xs->cq_tmp;
99 
100 	for (i = 0; i < pool->free_heads_cnt; i++) {
101 		xskb = &pool->heads[i];
102 		xskb->pool = pool;
103 		xskb->xdp.frame_sz = umem->chunk_size - umem->headroom;
104 		INIT_LIST_HEAD(&xskb->list_node);
105 		if (pool->unaligned)
106 			pool->free_heads[i] = xskb;
107 		else
108 			xp_init_xskb_addr(xskb, pool, (u64)i * pool->chunk_size);
109 	}
110 
111 	return pool;
112 
113 out:
114 	xp_destroy(pool);
115 	return NULL;
116 }
117 
118 void xp_set_rxq_info(struct xsk_buff_pool *pool, struct xdp_rxq_info *rxq)
119 {
120 	u32 i;
121 
122 	for (i = 0; i < pool->heads_cnt; i++)
123 		pool->heads[i].xdp.rxq = rxq;
124 }
125 EXPORT_SYMBOL(xp_set_rxq_info);
126 
127 void xp_fill_cb(struct xsk_buff_pool *pool, struct xsk_cb_desc *desc)
128 {
129 	u32 i;
130 
131 	for (i = 0; i < pool->heads_cnt; i++) {
132 		struct xdp_buff_xsk *xskb = &pool->heads[i];
133 
134 		memcpy(xskb->cb + desc->off, desc->src, desc->bytes);
135 	}
136 }
137 EXPORT_SYMBOL(xp_fill_cb);
138 
139 static void xp_disable_drv_zc(struct xsk_buff_pool *pool)
140 {
141 	struct netdev_bpf bpf;
142 	int err;
143 
144 	ASSERT_RTNL();
145 
146 	if (pool->umem->zc) {
147 		bpf.command = XDP_SETUP_XSK_POOL;
148 		bpf.xsk.pool = NULL;
149 		bpf.xsk.queue_id = pool->queue_id;
150 
151 		err = pool->netdev->netdev_ops->ndo_bpf(pool->netdev, &bpf);
152 
153 		if (err)
154 			WARN(1, "Failed to disable zero-copy!\n");
155 	}
156 }
157 
158 int xp_assign_dev(struct xsk_buff_pool *pool,
159 		  struct net_device *netdev, u16 queue_id, u16 flags)
160 {
161 	bool force_zc, force_copy;
162 	struct netdev_bpf bpf;
163 	int err = 0;
164 
165 	ASSERT_RTNL();
166 
167 	force_zc = flags & XDP_ZEROCOPY;
168 	force_copy = flags & XDP_COPY;
169 
170 	if (force_zc && force_copy)
171 		return -EINVAL;
172 
173 	if (xsk_get_pool_from_qid(netdev, queue_id))
174 		return -EBUSY;
175 
176 	pool->netdev = netdev;
177 	pool->queue_id = queue_id;
178 	err = xsk_reg_pool_at_qid(netdev, pool, queue_id);
179 	if (err)
180 		return err;
181 
182 	if (flags & XDP_USE_SG)
183 		pool->umem->flags |= XDP_UMEM_SG_FLAG;
184 
185 	if (flags & XDP_USE_NEED_WAKEUP)
186 		pool->uses_need_wakeup = true;
187 	/* Tx needs to be explicitly woken up the first time.  Also
188 	 * for supporting drivers that do not implement this
189 	 * feature. They will always have to call sendto() or poll().
190 	 */
191 	pool->cached_need_wakeup = XDP_WAKEUP_TX;
192 
193 	dev_hold(netdev);
194 
195 	if (force_copy)
196 		/* For copy-mode, we are done. */
197 		return 0;
198 
199 	if ((netdev->xdp_features & NETDEV_XDP_ACT_XSK) != NETDEV_XDP_ACT_XSK) {
200 		err = -EOPNOTSUPP;
201 		goto err_unreg_pool;
202 	}
203 
204 	if (netdev->xdp_zc_max_segs == 1 && (flags & XDP_USE_SG)) {
205 		err = -EOPNOTSUPP;
206 		goto err_unreg_pool;
207 	}
208 
209 	if (dev_get_min_mp_channel_count(netdev)) {
210 		err = -EBUSY;
211 		goto err_unreg_pool;
212 	}
213 
214 	bpf.command = XDP_SETUP_XSK_POOL;
215 	bpf.xsk.pool = pool;
216 	bpf.xsk.queue_id = queue_id;
217 
218 	netdev_ops_assert_locked(netdev);
219 	err = netdev->netdev_ops->ndo_bpf(netdev, &bpf);
220 	if (err)
221 		goto err_unreg_pool;
222 
223 	if (!pool->dma_pages) {
224 		WARN(1, "Driver did not DMA map zero-copy buffers");
225 		err = -EINVAL;
226 		goto err_unreg_xsk;
227 	}
228 	pool->umem->zc = true;
229 	pool->xdp_zc_max_segs = netdev->xdp_zc_max_segs;
230 	return 0;
231 
232 err_unreg_xsk:
233 	xp_disable_drv_zc(pool);
234 err_unreg_pool:
235 	if (!force_zc)
236 		err = 0; /* fallback to copy mode */
237 	if (err) {
238 		xsk_clear_pool_at_qid(netdev, queue_id);
239 		dev_put(netdev);
240 	}
241 	return err;
242 }
243 
244 int xp_assign_dev_shared(struct xsk_buff_pool *pool, struct xdp_sock *umem_xs,
245 			 struct net_device *dev, u16 queue_id)
246 {
247 	u16 flags;
248 	struct xdp_umem *umem = umem_xs->umem;
249 
250 	flags = umem->zc ? XDP_ZEROCOPY : XDP_COPY;
251 	if (umem_xs->pool->uses_need_wakeup)
252 		flags |= XDP_USE_NEED_WAKEUP;
253 
254 	return xp_assign_dev(pool, dev, queue_id, flags);
255 }
256 
257 void xp_clear_dev(struct xsk_buff_pool *pool)
258 {
259 	struct net_device *netdev = pool->netdev;
260 
261 	if (!pool->netdev)
262 		return;
263 
264 	netdev_lock_ops(netdev);
265 	xp_disable_drv_zc(pool);
266 	xsk_clear_pool_at_qid(pool->netdev, pool->queue_id);
267 	pool->netdev = NULL;
268 	netdev_unlock_ops(netdev);
269 	dev_put(netdev);
270 }
271 
272 static void xp_release_deferred(struct work_struct *work)
273 {
274 	struct xsk_buff_pool *pool = container_of(work, struct xsk_buff_pool,
275 						  work);
276 
277 	rtnl_lock();
278 	xp_clear_dev(pool);
279 	rtnl_unlock();
280 
281 	if (pool->fq) {
282 		xskq_destroy(pool->fq);
283 		pool->fq = NULL;
284 	}
285 
286 	if (pool->cq) {
287 		xskq_destroy(pool->cq);
288 		pool->cq = NULL;
289 	}
290 
291 	xdp_put_umem(pool->umem, false);
292 	xp_destroy(pool);
293 }
294 
295 void xp_get_pool(struct xsk_buff_pool *pool)
296 {
297 	refcount_inc(&pool->users);
298 }
299 
300 bool xp_put_pool(struct xsk_buff_pool *pool)
301 {
302 	if (!pool)
303 		return false;
304 
305 	if (refcount_dec_and_test(&pool->users)) {
306 		INIT_WORK(&pool->work, xp_release_deferred);
307 		schedule_work(&pool->work);
308 		return true;
309 	}
310 
311 	return false;
312 }
313 
314 static struct xsk_dma_map *xp_find_dma_map(struct xsk_buff_pool *pool)
315 {
316 	struct xsk_dma_map *dma_map;
317 
318 	list_for_each_entry(dma_map, &pool->umem->xsk_dma_list, list) {
319 		if (dma_map->netdev == pool->netdev)
320 			return dma_map;
321 	}
322 
323 	return NULL;
324 }
325 
326 static struct xsk_dma_map *xp_create_dma_map(struct device *dev, struct net_device *netdev,
327 					     u32 nr_pages, struct xdp_umem *umem)
328 {
329 	struct xsk_dma_map *dma_map;
330 
331 	dma_map = kzalloc_obj(*dma_map);
332 	if (!dma_map)
333 		return NULL;
334 
335 	dma_map->dma_pages = kvzalloc_objs(*dma_map->dma_pages, nr_pages,
336 					   GFP_KERNEL);
337 	if (!dma_map->dma_pages) {
338 		kfree(dma_map);
339 		return NULL;
340 	}
341 
342 	dma_map->netdev = netdev;
343 	dma_map->dev = dev;
344 	dma_map->dma_pages_cnt = nr_pages;
345 	refcount_set(&dma_map->users, 1);
346 	list_add(&dma_map->list, &umem->xsk_dma_list);
347 	return dma_map;
348 }
349 
350 static void xp_destroy_dma_map(struct xsk_dma_map *dma_map)
351 {
352 	list_del(&dma_map->list);
353 	kvfree(dma_map->dma_pages);
354 	kfree(dma_map);
355 }
356 
357 static void __xp_dma_unmap(struct xsk_dma_map *dma_map, unsigned long attrs)
358 {
359 	dma_addr_t *dma;
360 	u32 i;
361 
362 	for (i = 0; i < dma_map->dma_pages_cnt; i++) {
363 		dma = &dma_map->dma_pages[i];
364 		if (*dma) {
365 			*dma &= ~XSK_NEXT_PG_CONTIG_MASK;
366 			dma_unmap_page_attrs(dma_map->dev, *dma, PAGE_SIZE,
367 					     DMA_BIDIRECTIONAL, attrs);
368 			*dma = 0;
369 		}
370 	}
371 
372 	xp_destroy_dma_map(dma_map);
373 }
374 
375 void xp_dma_unmap(struct xsk_buff_pool *pool, unsigned long attrs)
376 {
377 	struct xsk_dma_map *dma_map;
378 
379 	if (!pool->dma_pages)
380 		return;
381 
382 	dma_map = xp_find_dma_map(pool);
383 	if (!dma_map) {
384 		WARN(1, "Could not find dma_map for device");
385 		return;
386 	}
387 
388 	if (refcount_dec_and_test(&dma_map->users))
389 		__xp_dma_unmap(dma_map, attrs);
390 
391 	kvfree(pool->dma_pages);
392 	pool->dma_pages = NULL;
393 	pool->dma_pages_cnt = 0;
394 	pool->dev = NULL;
395 }
396 EXPORT_SYMBOL(xp_dma_unmap);
397 
398 static void xp_check_dma_contiguity(struct xsk_dma_map *dma_map)
399 {
400 	u32 i;
401 
402 	for (i = 0; i < dma_map->dma_pages_cnt - 1; i++) {
403 		if (dma_map->dma_pages[i] + PAGE_SIZE == dma_map->dma_pages[i + 1])
404 			dma_map->dma_pages[i] |= XSK_NEXT_PG_CONTIG_MASK;
405 		else
406 			dma_map->dma_pages[i] &= ~XSK_NEXT_PG_CONTIG_MASK;
407 	}
408 }
409 
410 static int xp_init_dma_info(struct xsk_buff_pool *pool, struct xsk_dma_map *dma_map)
411 {
412 	if (!pool->unaligned) {
413 		u32 i;
414 
415 		for (i = 0; i < pool->heads_cnt; i++) {
416 			struct xdp_buff_xsk *xskb = &pool->heads[i];
417 			u64 orig_addr;
418 
419 			orig_addr = xskb->xdp.data_hard_start - pool->addrs - pool->headroom;
420 			xp_init_xskb_dma(xskb, pool, dma_map->dma_pages, orig_addr);
421 		}
422 	}
423 
424 	pool->dma_pages = kvzalloc_objs(*pool->dma_pages,
425 					dma_map->dma_pages_cnt, GFP_KERNEL);
426 	if (!pool->dma_pages)
427 		return -ENOMEM;
428 
429 	pool->dev = dma_map->dev;
430 	pool->dma_pages_cnt = dma_map->dma_pages_cnt;
431 	memcpy(pool->dma_pages, dma_map->dma_pages,
432 	       pool->dma_pages_cnt * sizeof(*pool->dma_pages));
433 
434 	return 0;
435 }
436 
437 int xp_dma_map(struct xsk_buff_pool *pool, struct device *dev,
438 	       unsigned long attrs, struct page **pages, u32 nr_pages)
439 {
440 	struct xsk_dma_map *dma_map;
441 	dma_addr_t dma;
442 	int err;
443 	u32 i;
444 
445 	dma_map = xp_find_dma_map(pool);
446 	if (dma_map) {
447 		err = xp_init_dma_info(pool, dma_map);
448 		if (err)
449 			return err;
450 
451 		refcount_inc(&dma_map->users);
452 		return 0;
453 	}
454 
455 	dma_map = xp_create_dma_map(dev, pool->netdev, nr_pages, pool->umem);
456 	if (!dma_map)
457 		return -ENOMEM;
458 
459 	for (i = 0; i < dma_map->dma_pages_cnt; i++) {
460 		dma = dma_map_page_attrs(dev, pages[i], 0, PAGE_SIZE,
461 					 DMA_BIDIRECTIONAL, attrs);
462 		if (dma_mapping_error(dev, dma)) {
463 			__xp_dma_unmap(dma_map, attrs);
464 			return -ENOMEM;
465 		}
466 		dma_map->dma_pages[i] = dma;
467 	}
468 
469 	if (pool->unaligned)
470 		xp_check_dma_contiguity(dma_map);
471 
472 	err = xp_init_dma_info(pool, dma_map);
473 	if (err) {
474 		__xp_dma_unmap(dma_map, attrs);
475 		return err;
476 	}
477 
478 	return 0;
479 }
480 EXPORT_SYMBOL(xp_dma_map);
481 
482 static bool xp_addr_crosses_non_contig_pg(struct xsk_buff_pool *pool,
483 					  u64 addr)
484 {
485 	return xp_desc_crosses_non_contig_pg(pool, addr, pool->chunk_size);
486 }
487 
488 static bool xp_check_unaligned(struct xsk_buff_pool *pool, u64 *addr)
489 {
490 	*addr = xp_unaligned_extract_addr(*addr);
491 	if (*addr >= pool->addrs_cnt ||
492 	    *addr + pool->chunk_size > pool->addrs_cnt ||
493 	    xp_addr_crosses_non_contig_pg(pool, *addr))
494 		return false;
495 	return true;
496 }
497 
498 static bool xp_check_aligned(struct xsk_buff_pool *pool, u64 *addr)
499 {
500 	*addr = xp_aligned_extract_addr(pool, *addr);
501 	return *addr < pool->addrs_cnt;
502 }
503 
504 static struct xdp_buff_xsk *xp_get_xskb(struct xsk_buff_pool *pool, u64 addr)
505 {
506 	struct xdp_buff_xsk *xskb;
507 
508 	if (pool->unaligned) {
509 		xskb = pool->free_heads[--pool->free_heads_cnt];
510 		xp_init_xskb_addr(xskb, pool, addr);
511 		if (pool->dma_pages)
512 			xp_init_xskb_dma(xskb, pool, pool->dma_pages, addr);
513 	} else {
514 		xskb = &pool->heads[xp_aligned_extract_idx(pool, addr)];
515 	}
516 
517 	return xskb;
518 }
519 
520 static struct xdp_buff_xsk *__xp_alloc(struct xsk_buff_pool *pool)
521 {
522 	struct xdp_buff_xsk *xskb;
523 	u64 addr;
524 	bool ok;
525 
526 	if (pool->free_heads_cnt == 0)
527 		return NULL;
528 
529 	for (;;) {
530 		if (!xskq_cons_peek_addr_unchecked(pool->fq, &addr)) {
531 			pool->fq->queue_empty_descs++;
532 			return NULL;
533 		}
534 
535 		ok = pool->unaligned ? xp_check_unaligned(pool, &addr) :
536 		     xp_check_aligned(pool, &addr);
537 		if (!ok) {
538 			pool->fq->invalid_descs++;
539 			xskq_cons_release(pool->fq);
540 			continue;
541 		}
542 		break;
543 	}
544 
545 	xskb = xp_get_xskb(pool, addr);
546 
547 	xskq_cons_release(pool->fq);
548 	return xskb;
549 }
550 
551 struct xdp_buff *xp_alloc(struct xsk_buff_pool *pool)
552 {
553 	struct xdp_buff_xsk *xskb;
554 
555 	if (!pool->free_list_cnt) {
556 		xskb = __xp_alloc(pool);
557 		if (!xskb)
558 			return NULL;
559 	} else {
560 		pool->free_list_cnt--;
561 		xskb = list_first_entry(&pool->free_list, struct xdp_buff_xsk,
562 					list_node);
563 		list_del_init(&xskb->list_node);
564 	}
565 
566 	xskb->xdp.data = xskb->xdp.data_hard_start + XDP_PACKET_HEADROOM;
567 	xskb->xdp.data_meta = xskb->xdp.data;
568 	xskb->xdp.flags = 0;
569 
570 	if (pool->dev)
571 		xp_dma_sync_for_device(pool, xskb->dma, pool->frame_len);
572 
573 	return &xskb->xdp;
574 }
575 EXPORT_SYMBOL(xp_alloc);
576 
577 static u32 xp_alloc_new_from_fq(struct xsk_buff_pool *pool, struct xdp_buff **xdp, u32 max)
578 {
579 	u32 i, cached_cons, nb_entries;
580 
581 	if (max > pool->free_heads_cnt)
582 		max = pool->free_heads_cnt;
583 	max = xskq_cons_nb_entries(pool->fq, max);
584 
585 	cached_cons = pool->fq->cached_cons;
586 	nb_entries = max;
587 	i = max;
588 	while (i--) {
589 		struct xdp_buff_xsk *xskb;
590 		u64 addr;
591 		bool ok;
592 
593 		__xskq_cons_read_addr_unchecked(pool->fq, cached_cons++, &addr);
594 
595 		ok = pool->unaligned ? xp_check_unaligned(pool, &addr) :
596 			xp_check_aligned(pool, &addr);
597 		if (unlikely(!ok)) {
598 			pool->fq->invalid_descs++;
599 			nb_entries--;
600 			continue;
601 		}
602 
603 		xskb = xp_get_xskb(pool, addr);
604 
605 		*xdp = &xskb->xdp;
606 		xdp++;
607 	}
608 
609 	xskq_cons_release_n(pool->fq, max);
610 	return nb_entries;
611 }
612 
613 static u32 xp_alloc_reused(struct xsk_buff_pool *pool, struct xdp_buff **xdp, u32 nb_entries)
614 {
615 	struct xdp_buff_xsk *xskb;
616 	u32 i;
617 
618 	nb_entries = min_t(u32, nb_entries, pool->free_list_cnt);
619 
620 	i = nb_entries;
621 	while (i--) {
622 		xskb = list_first_entry(&pool->free_list, struct xdp_buff_xsk, list_node);
623 		list_del_init(&xskb->list_node);
624 
625 		*xdp = &xskb->xdp;
626 		xdp++;
627 	}
628 	pool->free_list_cnt -= nb_entries;
629 
630 	return nb_entries;
631 }
632 
633 static u32 xp_alloc_slow(struct xsk_buff_pool *pool, struct xdp_buff **xdp,
634 			 u32 max)
635 {
636 	int i;
637 
638 	for (i = 0; i < max; i++) {
639 		struct xdp_buff *buff;
640 
641 		buff = xp_alloc(pool);
642 		if (unlikely(!buff))
643 			return i;
644 		*xdp = buff;
645 		xdp++;
646 	}
647 
648 	return max;
649 }
650 
651 u32 xp_alloc_batch(struct xsk_buff_pool *pool, struct xdp_buff **xdp, u32 max)
652 {
653 	u32 nb_entries1 = 0, nb_entries2;
654 
655 	if (unlikely(pool->dev && dma_dev_need_sync(pool->dev)))
656 		return xp_alloc_slow(pool, xdp, max);
657 
658 	if (unlikely(pool->free_list_cnt)) {
659 		nb_entries1 = xp_alloc_reused(pool, xdp, max);
660 		if (nb_entries1 == max)
661 			return nb_entries1;
662 
663 		max -= nb_entries1;
664 		xdp += nb_entries1;
665 	}
666 
667 	nb_entries2 = xp_alloc_new_from_fq(pool, xdp, max);
668 	if (!nb_entries2)
669 		pool->fq->queue_empty_descs++;
670 
671 	return nb_entries1 + nb_entries2;
672 }
673 EXPORT_SYMBOL(xp_alloc_batch);
674 
675 bool xp_can_alloc(struct xsk_buff_pool *pool, u32 count)
676 {
677 	u32 req_count, avail_count;
678 
679 	if (pool->free_list_cnt >= count)
680 		return true;
681 
682 	req_count = count - pool->free_list_cnt;
683 	avail_count = xskq_cons_nb_entries(pool->fq, req_count);
684 	if (!avail_count)
685 		pool->fq->queue_empty_descs++;
686 
687 	return avail_count >= req_count;
688 }
689 EXPORT_SYMBOL(xp_can_alloc);
690 
691 void xp_free(struct xdp_buff_xsk *xskb)
692 {
693 	if (!list_empty(&xskb->list_node))
694 		return;
695 
696 	xskb->pool->free_list_cnt++;
697 	list_add(&xskb->list_node, &xskb->pool->free_list);
698 }
699 EXPORT_SYMBOL(xp_free);
700 
701 static u64 __xp_raw_get_addr(const struct xsk_buff_pool *pool, u64 addr)
702 {
703 	return pool->unaligned ? xp_unaligned_add_offset_to_addr(addr) : addr;
704 }
705 
706 static void *__xp_raw_get_data(const struct xsk_buff_pool *pool, u64 addr)
707 {
708 	return pool->addrs + addr;
709 }
710 
711 void *xp_raw_get_data(struct xsk_buff_pool *pool, u64 addr)
712 {
713 	return __xp_raw_get_data(pool, __xp_raw_get_addr(pool, addr));
714 }
715 EXPORT_SYMBOL(xp_raw_get_data);
716 
717 static dma_addr_t __xp_raw_get_dma(const struct xsk_buff_pool *pool, u64 addr)
718 {
719 	return (pool->dma_pages[addr >> PAGE_SHIFT] &
720 		~XSK_NEXT_PG_CONTIG_MASK) +
721 		(addr & ~PAGE_MASK);
722 }
723 
724 dma_addr_t xp_raw_get_dma(struct xsk_buff_pool *pool, u64 addr)
725 {
726 	return __xp_raw_get_dma(pool, __xp_raw_get_addr(pool, addr));
727 }
728 EXPORT_SYMBOL(xp_raw_get_dma);
729 
730 /**
731  * xp_raw_get_ctx - get &xdp_desc context
732  * @pool: XSk buff pool desc address belongs to
733  * @addr: desc address (from userspace)
734  *
735  * Helper for getting desc's DMA address and metadata pointer, if present.
736  * Saves one call on hotpath, double calculation of the actual address,
737  * and inline checks for metadata presence and sanity.
738  *
739  * Return: new &xdp_desc_ctx struct containing desc's DMA address and metadata
740  * pointer, if it is present and valid (initialized to %NULL otherwise).
741  */
742 struct xdp_desc_ctx xp_raw_get_ctx(const struct xsk_buff_pool *pool, u64 addr)
743 {
744 	struct xdp_desc_ctx ret;
745 
746 	addr = __xp_raw_get_addr(pool, addr);
747 
748 	ret.dma = __xp_raw_get_dma(pool, addr);
749 	ret.meta = __xsk_buff_get_metadata(pool, __xp_raw_get_data(pool, addr));
750 
751 	return ret;
752 }
753 EXPORT_SYMBOL(xp_raw_get_ctx);
754