xref: /linux/net/xdp/xsk_buff_pool.c (revision c7decec2f2d2ab0366567f9e30c0e1418cece43f)
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 = kvcalloc(xs->tx->nentries, sizeof(*pool->tx_descs),
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(struct_size(pool, free_heads, entries),	GFP_KERNEL);
63 	if (!pool)
64 		goto out;
65 
66 	pool->heads = kvcalloc(umem->chunks, sizeof(*pool->heads), GFP_KERNEL);
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(sizeof(*dma_map), GFP_KERNEL);
332 	if (!dma_map)
333 		return NULL;
334 
335 	dma_map->dma_pages = kvcalloc(nr_pages, sizeof(*dma_map->dma_pages), GFP_KERNEL);
336 	if (!dma_map->dma_pages) {
337 		kfree(dma_map);
338 		return NULL;
339 	}
340 
341 	dma_map->netdev = netdev;
342 	dma_map->dev = dev;
343 	dma_map->dma_pages_cnt = nr_pages;
344 	refcount_set(&dma_map->users, 1);
345 	list_add(&dma_map->list, &umem->xsk_dma_list);
346 	return dma_map;
347 }
348 
349 static void xp_destroy_dma_map(struct xsk_dma_map *dma_map)
350 {
351 	list_del(&dma_map->list);
352 	kvfree(dma_map->dma_pages);
353 	kfree(dma_map);
354 }
355 
356 static void __xp_dma_unmap(struct xsk_dma_map *dma_map, unsigned long attrs)
357 {
358 	dma_addr_t *dma;
359 	u32 i;
360 
361 	for (i = 0; i < dma_map->dma_pages_cnt; i++) {
362 		dma = &dma_map->dma_pages[i];
363 		if (*dma) {
364 			*dma &= ~XSK_NEXT_PG_CONTIG_MASK;
365 			dma_unmap_page_attrs(dma_map->dev, *dma, PAGE_SIZE,
366 					     DMA_BIDIRECTIONAL, attrs);
367 			*dma = 0;
368 		}
369 	}
370 
371 	xp_destroy_dma_map(dma_map);
372 }
373 
374 void xp_dma_unmap(struct xsk_buff_pool *pool, unsigned long attrs)
375 {
376 	struct xsk_dma_map *dma_map;
377 
378 	if (!pool->dma_pages)
379 		return;
380 
381 	dma_map = xp_find_dma_map(pool);
382 	if (!dma_map) {
383 		WARN(1, "Could not find dma_map for device");
384 		return;
385 	}
386 
387 	if (refcount_dec_and_test(&dma_map->users))
388 		__xp_dma_unmap(dma_map, attrs);
389 
390 	kvfree(pool->dma_pages);
391 	pool->dma_pages = NULL;
392 	pool->dma_pages_cnt = 0;
393 	pool->dev = NULL;
394 }
395 EXPORT_SYMBOL(xp_dma_unmap);
396 
397 static void xp_check_dma_contiguity(struct xsk_dma_map *dma_map)
398 {
399 	u32 i;
400 
401 	for (i = 0; i < dma_map->dma_pages_cnt - 1; i++) {
402 		if (dma_map->dma_pages[i] + PAGE_SIZE == dma_map->dma_pages[i + 1])
403 			dma_map->dma_pages[i] |= XSK_NEXT_PG_CONTIG_MASK;
404 		else
405 			dma_map->dma_pages[i] &= ~XSK_NEXT_PG_CONTIG_MASK;
406 	}
407 }
408 
409 static int xp_init_dma_info(struct xsk_buff_pool *pool, struct xsk_dma_map *dma_map)
410 {
411 	if (!pool->unaligned) {
412 		u32 i;
413 
414 		for (i = 0; i < pool->heads_cnt; i++) {
415 			struct xdp_buff_xsk *xskb = &pool->heads[i];
416 			u64 orig_addr;
417 
418 			orig_addr = xskb->xdp.data_hard_start - pool->addrs - pool->headroom;
419 			xp_init_xskb_dma(xskb, pool, dma_map->dma_pages, orig_addr);
420 		}
421 	}
422 
423 	pool->dma_pages = kvcalloc(dma_map->dma_pages_cnt, sizeof(*pool->dma_pages), GFP_KERNEL);
424 	if (!pool->dma_pages)
425 		return -ENOMEM;
426 
427 	pool->dev = dma_map->dev;
428 	pool->dma_pages_cnt = dma_map->dma_pages_cnt;
429 	memcpy(pool->dma_pages, dma_map->dma_pages,
430 	       pool->dma_pages_cnt * sizeof(*pool->dma_pages));
431 
432 	return 0;
433 }
434 
435 int xp_dma_map(struct xsk_buff_pool *pool, struct device *dev,
436 	       unsigned long attrs, struct page **pages, u32 nr_pages)
437 {
438 	struct xsk_dma_map *dma_map;
439 	dma_addr_t dma;
440 	int err;
441 	u32 i;
442 
443 	dma_map = xp_find_dma_map(pool);
444 	if (dma_map) {
445 		err = xp_init_dma_info(pool, dma_map);
446 		if (err)
447 			return err;
448 
449 		refcount_inc(&dma_map->users);
450 		return 0;
451 	}
452 
453 	dma_map = xp_create_dma_map(dev, pool->netdev, nr_pages, pool->umem);
454 	if (!dma_map)
455 		return -ENOMEM;
456 
457 	for (i = 0; i < dma_map->dma_pages_cnt; i++) {
458 		dma = dma_map_page_attrs(dev, pages[i], 0, PAGE_SIZE,
459 					 DMA_BIDIRECTIONAL, attrs);
460 		if (dma_mapping_error(dev, dma)) {
461 			__xp_dma_unmap(dma_map, attrs);
462 			return -ENOMEM;
463 		}
464 		dma_map->dma_pages[i] = dma;
465 	}
466 
467 	if (pool->unaligned)
468 		xp_check_dma_contiguity(dma_map);
469 
470 	err = xp_init_dma_info(pool, dma_map);
471 	if (err) {
472 		__xp_dma_unmap(dma_map, attrs);
473 		return err;
474 	}
475 
476 	return 0;
477 }
478 EXPORT_SYMBOL(xp_dma_map);
479 
480 static bool xp_addr_crosses_non_contig_pg(struct xsk_buff_pool *pool,
481 					  u64 addr)
482 {
483 	return xp_desc_crosses_non_contig_pg(pool, addr, pool->chunk_size);
484 }
485 
486 static bool xp_check_unaligned(struct xsk_buff_pool *pool, u64 *addr)
487 {
488 	*addr = xp_unaligned_extract_addr(*addr);
489 	if (*addr >= pool->addrs_cnt ||
490 	    *addr + pool->chunk_size > pool->addrs_cnt ||
491 	    xp_addr_crosses_non_contig_pg(pool, *addr))
492 		return false;
493 	return true;
494 }
495 
496 static bool xp_check_aligned(struct xsk_buff_pool *pool, u64 *addr)
497 {
498 	*addr = xp_aligned_extract_addr(pool, *addr);
499 	return *addr < pool->addrs_cnt;
500 }
501 
502 static struct xdp_buff_xsk *xp_get_xskb(struct xsk_buff_pool *pool, u64 addr)
503 {
504 	struct xdp_buff_xsk *xskb;
505 
506 	if (pool->unaligned) {
507 		xskb = pool->free_heads[--pool->free_heads_cnt];
508 		xp_init_xskb_addr(xskb, pool, addr);
509 		if (pool->dma_pages)
510 			xp_init_xskb_dma(xskb, pool, pool->dma_pages, addr);
511 	} else {
512 		xskb = &pool->heads[xp_aligned_extract_idx(pool, addr)];
513 	}
514 
515 	return xskb;
516 }
517 
518 static struct xdp_buff_xsk *__xp_alloc(struct xsk_buff_pool *pool)
519 {
520 	struct xdp_buff_xsk *xskb;
521 	u64 addr;
522 	bool ok;
523 
524 	if (pool->free_heads_cnt == 0)
525 		return NULL;
526 
527 	for (;;) {
528 		if (!xskq_cons_peek_addr_unchecked(pool->fq, &addr)) {
529 			pool->fq->queue_empty_descs++;
530 			return NULL;
531 		}
532 
533 		ok = pool->unaligned ? xp_check_unaligned(pool, &addr) :
534 		     xp_check_aligned(pool, &addr);
535 		if (!ok) {
536 			pool->fq->invalid_descs++;
537 			xskq_cons_release(pool->fq);
538 			continue;
539 		}
540 		break;
541 	}
542 
543 	xskb = xp_get_xskb(pool, addr);
544 
545 	xskq_cons_release(pool->fq);
546 	return xskb;
547 }
548 
549 struct xdp_buff *xp_alloc(struct xsk_buff_pool *pool)
550 {
551 	struct xdp_buff_xsk *xskb;
552 
553 	if (!pool->free_list_cnt) {
554 		xskb = __xp_alloc(pool);
555 		if (!xskb)
556 			return NULL;
557 	} else {
558 		pool->free_list_cnt--;
559 		xskb = list_first_entry(&pool->free_list, struct xdp_buff_xsk,
560 					list_node);
561 		list_del_init(&xskb->list_node);
562 	}
563 
564 	xskb->xdp.data = xskb->xdp.data_hard_start + XDP_PACKET_HEADROOM;
565 	xskb->xdp.data_meta = xskb->xdp.data;
566 	xskb->xdp.flags = 0;
567 
568 	if (pool->dev)
569 		xp_dma_sync_for_device(pool, xskb->dma, pool->frame_len);
570 
571 	return &xskb->xdp;
572 }
573 EXPORT_SYMBOL(xp_alloc);
574 
575 static u32 xp_alloc_new_from_fq(struct xsk_buff_pool *pool, struct xdp_buff **xdp, u32 max)
576 {
577 	u32 i, cached_cons, nb_entries;
578 
579 	if (max > pool->free_heads_cnt)
580 		max = pool->free_heads_cnt;
581 	max = xskq_cons_nb_entries(pool->fq, max);
582 
583 	cached_cons = pool->fq->cached_cons;
584 	nb_entries = max;
585 	i = max;
586 	while (i--) {
587 		struct xdp_buff_xsk *xskb;
588 		u64 addr;
589 		bool ok;
590 
591 		__xskq_cons_read_addr_unchecked(pool->fq, cached_cons++, &addr);
592 
593 		ok = pool->unaligned ? xp_check_unaligned(pool, &addr) :
594 			xp_check_aligned(pool, &addr);
595 		if (unlikely(!ok)) {
596 			pool->fq->invalid_descs++;
597 			nb_entries--;
598 			continue;
599 		}
600 
601 		xskb = xp_get_xskb(pool, addr);
602 
603 		*xdp = &xskb->xdp;
604 		xdp++;
605 	}
606 
607 	xskq_cons_release_n(pool->fq, max);
608 	return nb_entries;
609 }
610 
611 static u32 xp_alloc_reused(struct xsk_buff_pool *pool, struct xdp_buff **xdp, u32 nb_entries)
612 {
613 	struct xdp_buff_xsk *xskb;
614 	u32 i;
615 
616 	nb_entries = min_t(u32, nb_entries, pool->free_list_cnt);
617 
618 	i = nb_entries;
619 	while (i--) {
620 		xskb = list_first_entry(&pool->free_list, struct xdp_buff_xsk, list_node);
621 		list_del_init(&xskb->list_node);
622 
623 		*xdp = &xskb->xdp;
624 		xdp++;
625 	}
626 	pool->free_list_cnt -= nb_entries;
627 
628 	return nb_entries;
629 }
630 
631 static u32 xp_alloc_slow(struct xsk_buff_pool *pool, struct xdp_buff **xdp,
632 			 u32 max)
633 {
634 	int i;
635 
636 	for (i = 0; i < max; i++) {
637 		struct xdp_buff *buff;
638 
639 		buff = xp_alloc(pool);
640 		if (unlikely(!buff))
641 			return i;
642 		*xdp = buff;
643 		xdp++;
644 	}
645 
646 	return max;
647 }
648 
649 u32 xp_alloc_batch(struct xsk_buff_pool *pool, struct xdp_buff **xdp, u32 max)
650 {
651 	u32 nb_entries1 = 0, nb_entries2;
652 
653 	if (unlikely(pool->dev && dma_dev_need_sync(pool->dev)))
654 		return xp_alloc_slow(pool, xdp, max);
655 
656 	if (unlikely(pool->free_list_cnt)) {
657 		nb_entries1 = xp_alloc_reused(pool, xdp, max);
658 		if (nb_entries1 == max)
659 			return nb_entries1;
660 
661 		max -= nb_entries1;
662 		xdp += nb_entries1;
663 	}
664 
665 	nb_entries2 = xp_alloc_new_from_fq(pool, xdp, max);
666 	if (!nb_entries2)
667 		pool->fq->queue_empty_descs++;
668 
669 	return nb_entries1 + nb_entries2;
670 }
671 EXPORT_SYMBOL(xp_alloc_batch);
672 
673 bool xp_can_alloc(struct xsk_buff_pool *pool, u32 count)
674 {
675 	u32 req_count, avail_count;
676 
677 	if (pool->free_list_cnt >= count)
678 		return true;
679 
680 	req_count = count - pool->free_list_cnt;
681 	avail_count = xskq_cons_nb_entries(pool->fq, req_count);
682 	if (!avail_count)
683 		pool->fq->queue_empty_descs++;
684 
685 	return avail_count >= req_count;
686 }
687 EXPORT_SYMBOL(xp_can_alloc);
688 
689 void xp_free(struct xdp_buff_xsk *xskb)
690 {
691 	if (!list_empty(&xskb->list_node))
692 		return;
693 
694 	xskb->pool->free_list_cnt++;
695 	list_add(&xskb->list_node, &xskb->pool->free_list);
696 }
697 EXPORT_SYMBOL(xp_free);
698 
699 static u64 __xp_raw_get_addr(const struct xsk_buff_pool *pool, u64 addr)
700 {
701 	return pool->unaligned ? xp_unaligned_add_offset_to_addr(addr) : addr;
702 }
703 
704 static void *__xp_raw_get_data(const struct xsk_buff_pool *pool, u64 addr)
705 {
706 	return pool->addrs + addr;
707 }
708 
709 void *xp_raw_get_data(struct xsk_buff_pool *pool, u64 addr)
710 {
711 	return __xp_raw_get_data(pool, __xp_raw_get_addr(pool, addr));
712 }
713 EXPORT_SYMBOL(xp_raw_get_data);
714 
715 static dma_addr_t __xp_raw_get_dma(const struct xsk_buff_pool *pool, u64 addr)
716 {
717 	return (pool->dma_pages[addr >> PAGE_SHIFT] &
718 		~XSK_NEXT_PG_CONTIG_MASK) +
719 		(addr & ~PAGE_MASK);
720 }
721 
722 dma_addr_t xp_raw_get_dma(struct xsk_buff_pool *pool, u64 addr)
723 {
724 	return __xp_raw_get_dma(pool, __xp_raw_get_addr(pool, addr));
725 }
726 EXPORT_SYMBOL(xp_raw_get_dma);
727 
728 /**
729  * xp_raw_get_ctx - get &xdp_desc context
730  * @pool: XSk buff pool desc address belongs to
731  * @addr: desc address (from userspace)
732  *
733  * Helper for getting desc's DMA address and metadata pointer, if present.
734  * Saves one call on hotpath, double calculation of the actual address,
735  * and inline checks for metadata presence and sanity.
736  *
737  * Return: new &xdp_desc_ctx struct containing desc's DMA address and metadata
738  * pointer, if it is present and valid (initialized to %NULL otherwise).
739  */
740 struct xdp_desc_ctx xp_raw_get_ctx(const struct xsk_buff_pool *pool, u64 addr)
741 {
742 	struct xdp_desc_ctx ret;
743 
744 	addr = __xp_raw_get_addr(pool, addr);
745 
746 	ret.dma = __xp_raw_get_dma(pool, addr);
747 	ret.meta = __xsk_buff_get_metadata(pool, __xp_raw_get_data(pool, addr));
748 
749 	return ret;
750 }
751 EXPORT_SYMBOL(xp_raw_get_ctx);
752