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 	unsigned long flags;
16 
17 	if (!xs->tx)
18 		return;
19 
20 	spin_lock_irqsave(&pool->xsk_tx_list_lock, flags);
21 	list_add_rcu(&xs->tx_list, &pool->xsk_tx_list);
22 	spin_unlock_irqrestore(&pool->xsk_tx_list_lock, flags);
23 }
24 
25 void xp_del_xsk(struct xsk_buff_pool *pool, struct xdp_sock *xs)
26 {
27 	unsigned long flags;
28 
29 	if (!xs->tx)
30 		return;
31 
32 	spin_lock_irqsave(&pool->xsk_tx_list_lock, flags);
33 	list_del_rcu(&xs->tx_list);
34 	spin_unlock_irqrestore(&pool->xsk_tx_list_lock, flags);
35 }
36 
37 void xp_destroy(struct xsk_buff_pool *pool)
38 {
39 	if (!pool)
40 		return;
41 
42 	kvfree(pool->tx_descs);
43 	kvfree(pool->heads);
44 	kvfree(pool);
45 }
46 
47 int xp_alloc_tx_descs(struct xsk_buff_pool *pool, struct xdp_sock *xs)
48 {
49 	pool->tx_descs = kvcalloc(xs->tx->nentries, sizeof(*pool->tx_descs),
50 				  GFP_KERNEL);
51 	if (!pool->tx_descs)
52 		return -ENOMEM;
53 
54 	return 0;
55 }
56 
57 struct xsk_buff_pool *xp_create_and_assign_umem(struct xdp_sock *xs,
58 						struct xdp_umem *umem)
59 {
60 	bool unaligned = umem->flags & XDP_UMEM_UNALIGNED_CHUNK_FLAG;
61 	struct xsk_buff_pool *pool;
62 	struct xdp_buff_xsk *xskb;
63 	u32 i, entries;
64 
65 	entries = unaligned ? umem->chunks : 0;
66 	pool = kvzalloc(struct_size(pool, free_heads, entries),	GFP_KERNEL);
67 	if (!pool)
68 		goto out;
69 
70 	pool->heads = kvcalloc(umem->chunks, sizeof(*pool->heads), GFP_KERNEL);
71 	if (!pool->heads)
72 		goto out;
73 
74 	if (xs->tx)
75 		if (xp_alloc_tx_descs(pool, xs))
76 			goto out;
77 
78 	pool->chunk_mask = ~((u64)umem->chunk_size - 1);
79 	pool->addrs_cnt = umem->size;
80 	pool->heads_cnt = umem->chunks;
81 	pool->free_heads_cnt = umem->chunks;
82 	pool->headroom = umem->headroom;
83 	pool->chunk_size = umem->chunk_size;
84 	pool->chunk_shift = ffs(umem->chunk_size) - 1;
85 	pool->unaligned = unaligned;
86 	pool->frame_len = umem->chunk_size - umem->headroom -
87 		XDP_PACKET_HEADROOM;
88 	pool->umem = umem;
89 	pool->addrs = umem->addrs;
90 	pool->tx_metadata_len = umem->tx_metadata_len;
91 	pool->tx_sw_csum = umem->flags & XDP_UMEM_TX_SW_CSUM;
92 	spin_lock_init(&pool->rx_lock);
93 	INIT_LIST_HEAD(&pool->free_list);
94 	INIT_LIST_HEAD(&pool->xskb_list);
95 	INIT_LIST_HEAD(&pool->xsk_tx_list);
96 	spin_lock_init(&pool->xsk_tx_list_lock);
97 	spin_lock_init(&pool->cq_lock);
98 	refcount_set(&pool->users, 1);
99 
100 	pool->fq = xs->fq_tmp;
101 	pool->cq = xs->cq_tmp;
102 
103 	for (i = 0; i < pool->free_heads_cnt; i++) {
104 		xskb = &pool->heads[i];
105 		xskb->pool = pool;
106 		xskb->xdp.frame_sz = umem->chunk_size - umem->headroom;
107 		INIT_LIST_HEAD(&xskb->list_node);
108 		if (pool->unaligned)
109 			pool->free_heads[i] = xskb;
110 		else
111 			xp_init_xskb_addr(xskb, pool, (u64)i * pool->chunk_size);
112 	}
113 
114 	return pool;
115 
116 out:
117 	xp_destroy(pool);
118 	return NULL;
119 }
120 
121 void xp_set_rxq_info(struct xsk_buff_pool *pool, struct xdp_rxq_info *rxq)
122 {
123 	u32 i;
124 
125 	for (i = 0; i < pool->heads_cnt; i++)
126 		pool->heads[i].xdp.rxq = rxq;
127 }
128 EXPORT_SYMBOL(xp_set_rxq_info);
129 
130 void xp_fill_cb(struct xsk_buff_pool *pool, struct xsk_cb_desc *desc)
131 {
132 	u32 i;
133 
134 	for (i = 0; i < pool->heads_cnt; i++) {
135 		struct xdp_buff_xsk *xskb = &pool->heads[i];
136 
137 		memcpy(xskb->cb + desc->off, desc->src, desc->bytes);
138 	}
139 }
140 EXPORT_SYMBOL(xp_fill_cb);
141 
142 static void xp_disable_drv_zc(struct xsk_buff_pool *pool)
143 {
144 	struct netdev_bpf bpf;
145 	int err;
146 
147 	ASSERT_RTNL();
148 
149 	if (pool->umem->zc) {
150 		bpf.command = XDP_SETUP_XSK_POOL;
151 		bpf.xsk.pool = NULL;
152 		bpf.xsk.queue_id = pool->queue_id;
153 
154 		err = pool->netdev->netdev_ops->ndo_bpf(pool->netdev, &bpf);
155 
156 		if (err)
157 			WARN(1, "Failed to disable zero-copy!\n");
158 	}
159 }
160 
161 #define NETDEV_XDP_ACT_ZC	(NETDEV_XDP_ACT_BASIC |		\
162 				 NETDEV_XDP_ACT_REDIRECT |	\
163 				 NETDEV_XDP_ACT_XSK_ZEROCOPY)
164 
165 int xp_assign_dev(struct xsk_buff_pool *pool,
166 		  struct net_device *netdev, u16 queue_id, u16 flags)
167 {
168 	bool force_zc, force_copy;
169 	struct netdev_bpf bpf;
170 	int err = 0;
171 
172 	ASSERT_RTNL();
173 
174 	force_zc = flags & XDP_ZEROCOPY;
175 	force_copy = flags & XDP_COPY;
176 
177 	if (force_zc && force_copy)
178 		return -EINVAL;
179 
180 	if (xsk_get_pool_from_qid(netdev, queue_id))
181 		return -EBUSY;
182 
183 	pool->netdev = netdev;
184 	pool->queue_id = queue_id;
185 	err = xsk_reg_pool_at_qid(netdev, pool, queue_id);
186 	if (err)
187 		return err;
188 
189 	if (flags & XDP_USE_SG)
190 		pool->umem->flags |= XDP_UMEM_SG_FLAG;
191 
192 	if (flags & XDP_USE_NEED_WAKEUP)
193 		pool->uses_need_wakeup = true;
194 	/* Tx needs to be explicitly woken up the first time.  Also
195 	 * for supporting drivers that do not implement this
196 	 * feature. They will always have to call sendto() or poll().
197 	 */
198 	pool->cached_need_wakeup = XDP_WAKEUP_TX;
199 
200 	dev_hold(netdev);
201 
202 	if (force_copy)
203 		/* For copy-mode, we are done. */
204 		return 0;
205 
206 	if ((netdev->xdp_features & NETDEV_XDP_ACT_ZC) != NETDEV_XDP_ACT_ZC) {
207 		err = -EOPNOTSUPP;
208 		goto err_unreg_pool;
209 	}
210 
211 	if (netdev->xdp_zc_max_segs == 1 && (flags & XDP_USE_SG)) {
212 		err = -EOPNOTSUPP;
213 		goto err_unreg_pool;
214 	}
215 
216 	if (dev_get_min_mp_channel_count(netdev)) {
217 		err = -EBUSY;
218 		goto err_unreg_pool;
219 	}
220 
221 	bpf.command = XDP_SETUP_XSK_POOL;
222 	bpf.xsk.pool = pool;
223 	bpf.xsk.queue_id = queue_id;
224 
225 	netdev_ops_assert_locked(netdev);
226 	err = netdev->netdev_ops->ndo_bpf(netdev, &bpf);
227 	if (err)
228 		goto err_unreg_pool;
229 
230 	if (!pool->dma_pages) {
231 		WARN(1, "Driver did not DMA map zero-copy buffers");
232 		err = -EINVAL;
233 		goto err_unreg_xsk;
234 	}
235 	pool->umem->zc = true;
236 	pool->xdp_zc_max_segs = netdev->xdp_zc_max_segs;
237 	return 0;
238 
239 err_unreg_xsk:
240 	xp_disable_drv_zc(pool);
241 err_unreg_pool:
242 	if (!force_zc)
243 		err = 0; /* fallback to copy mode */
244 	if (err) {
245 		xsk_clear_pool_at_qid(netdev, queue_id);
246 		dev_put(netdev);
247 	}
248 	return err;
249 }
250 
251 int xp_assign_dev_shared(struct xsk_buff_pool *pool, struct xdp_sock *umem_xs,
252 			 struct net_device *dev, u16 queue_id)
253 {
254 	u16 flags;
255 	struct xdp_umem *umem = umem_xs->umem;
256 
257 	/* One fill and completion ring required for each queue id. */
258 	if (!pool->fq || !pool->cq)
259 		return -EINVAL;
260 
261 	flags = umem->zc ? XDP_ZEROCOPY : XDP_COPY;
262 	if (umem_xs->pool->uses_need_wakeup)
263 		flags |= XDP_USE_NEED_WAKEUP;
264 
265 	return xp_assign_dev(pool, dev, queue_id, flags);
266 }
267 
268 void xp_clear_dev(struct xsk_buff_pool *pool)
269 {
270 	struct net_device *netdev = pool->netdev;
271 
272 	if (!pool->netdev)
273 		return;
274 
275 	netdev_lock_ops(netdev);
276 	xp_disable_drv_zc(pool);
277 	xsk_clear_pool_at_qid(pool->netdev, pool->queue_id);
278 	pool->netdev = NULL;
279 	netdev_unlock_ops(netdev);
280 	dev_put(netdev);
281 }
282 
283 static void xp_release_deferred(struct work_struct *work)
284 {
285 	struct xsk_buff_pool *pool = container_of(work, struct xsk_buff_pool,
286 						  work);
287 
288 	rtnl_lock();
289 	xp_clear_dev(pool);
290 	rtnl_unlock();
291 
292 	if (pool->fq) {
293 		xskq_destroy(pool->fq);
294 		pool->fq = NULL;
295 	}
296 
297 	if (pool->cq) {
298 		xskq_destroy(pool->cq);
299 		pool->cq = NULL;
300 	}
301 
302 	xdp_put_umem(pool->umem, false);
303 	xp_destroy(pool);
304 }
305 
306 void xp_get_pool(struct xsk_buff_pool *pool)
307 {
308 	refcount_inc(&pool->users);
309 }
310 
311 bool xp_put_pool(struct xsk_buff_pool *pool)
312 {
313 	if (!pool)
314 		return false;
315 
316 	if (refcount_dec_and_test(&pool->users)) {
317 		INIT_WORK(&pool->work, xp_release_deferred);
318 		schedule_work(&pool->work);
319 		return true;
320 	}
321 
322 	return false;
323 }
324 
325 static struct xsk_dma_map *xp_find_dma_map(struct xsk_buff_pool *pool)
326 {
327 	struct xsk_dma_map *dma_map;
328 
329 	list_for_each_entry(dma_map, &pool->umem->xsk_dma_list, list) {
330 		if (dma_map->netdev == pool->netdev)
331 			return dma_map;
332 	}
333 
334 	return NULL;
335 }
336 
337 static struct xsk_dma_map *xp_create_dma_map(struct device *dev, struct net_device *netdev,
338 					     u32 nr_pages, struct xdp_umem *umem)
339 {
340 	struct xsk_dma_map *dma_map;
341 
342 	dma_map = kzalloc(sizeof(*dma_map), GFP_KERNEL);
343 	if (!dma_map)
344 		return NULL;
345 
346 	dma_map->dma_pages = kvcalloc(nr_pages, sizeof(*dma_map->dma_pages), GFP_KERNEL);
347 	if (!dma_map->dma_pages) {
348 		kfree(dma_map);
349 		return NULL;
350 	}
351 
352 	dma_map->netdev = netdev;
353 	dma_map->dev = dev;
354 	dma_map->dma_pages_cnt = nr_pages;
355 	refcount_set(&dma_map->users, 1);
356 	list_add(&dma_map->list, &umem->xsk_dma_list);
357 	return dma_map;
358 }
359 
360 static void xp_destroy_dma_map(struct xsk_dma_map *dma_map)
361 {
362 	list_del(&dma_map->list);
363 	kvfree(dma_map->dma_pages);
364 	kfree(dma_map);
365 }
366 
367 static void __xp_dma_unmap(struct xsk_dma_map *dma_map, unsigned long attrs)
368 {
369 	dma_addr_t *dma;
370 	u32 i;
371 
372 	for (i = 0; i < dma_map->dma_pages_cnt; i++) {
373 		dma = &dma_map->dma_pages[i];
374 		if (*dma) {
375 			*dma &= ~XSK_NEXT_PG_CONTIG_MASK;
376 			dma_unmap_page_attrs(dma_map->dev, *dma, PAGE_SIZE,
377 					     DMA_BIDIRECTIONAL, attrs);
378 			*dma = 0;
379 		}
380 	}
381 
382 	xp_destroy_dma_map(dma_map);
383 }
384 
385 void xp_dma_unmap(struct xsk_buff_pool *pool, unsigned long attrs)
386 {
387 	struct xsk_dma_map *dma_map;
388 
389 	if (!pool->dma_pages)
390 		return;
391 
392 	dma_map = xp_find_dma_map(pool);
393 	if (!dma_map) {
394 		WARN(1, "Could not find dma_map for device");
395 		return;
396 	}
397 
398 	if (refcount_dec_and_test(&dma_map->users))
399 		__xp_dma_unmap(dma_map, attrs);
400 
401 	kvfree(pool->dma_pages);
402 	pool->dma_pages = NULL;
403 	pool->dma_pages_cnt = 0;
404 	pool->dev = NULL;
405 }
406 EXPORT_SYMBOL(xp_dma_unmap);
407 
408 static void xp_check_dma_contiguity(struct xsk_dma_map *dma_map)
409 {
410 	u32 i;
411 
412 	for (i = 0; i < dma_map->dma_pages_cnt - 1; i++) {
413 		if (dma_map->dma_pages[i] + PAGE_SIZE == dma_map->dma_pages[i + 1])
414 			dma_map->dma_pages[i] |= XSK_NEXT_PG_CONTIG_MASK;
415 		else
416 			dma_map->dma_pages[i] &= ~XSK_NEXT_PG_CONTIG_MASK;
417 	}
418 }
419 
420 static int xp_init_dma_info(struct xsk_buff_pool *pool, struct xsk_dma_map *dma_map)
421 {
422 	if (!pool->unaligned) {
423 		u32 i;
424 
425 		for (i = 0; i < pool->heads_cnt; i++) {
426 			struct xdp_buff_xsk *xskb = &pool->heads[i];
427 			u64 orig_addr;
428 
429 			orig_addr = xskb->xdp.data_hard_start - pool->addrs - pool->headroom;
430 			xp_init_xskb_dma(xskb, pool, dma_map->dma_pages, orig_addr);
431 		}
432 	}
433 
434 	pool->dma_pages = kvcalloc(dma_map->dma_pages_cnt, sizeof(*pool->dma_pages), GFP_KERNEL);
435 	if (!pool->dma_pages)
436 		return -ENOMEM;
437 
438 	pool->dev = dma_map->dev;
439 	pool->dma_pages_cnt = dma_map->dma_pages_cnt;
440 	memcpy(pool->dma_pages, dma_map->dma_pages,
441 	       pool->dma_pages_cnt * sizeof(*pool->dma_pages));
442 
443 	return 0;
444 }
445 
446 int xp_dma_map(struct xsk_buff_pool *pool, struct device *dev,
447 	       unsigned long attrs, struct page **pages, u32 nr_pages)
448 {
449 	struct xsk_dma_map *dma_map;
450 	dma_addr_t dma;
451 	int err;
452 	u32 i;
453 
454 	dma_map = xp_find_dma_map(pool);
455 	if (dma_map) {
456 		err = xp_init_dma_info(pool, dma_map);
457 		if (err)
458 			return err;
459 
460 		refcount_inc(&dma_map->users);
461 		return 0;
462 	}
463 
464 	dma_map = xp_create_dma_map(dev, pool->netdev, nr_pages, pool->umem);
465 	if (!dma_map)
466 		return -ENOMEM;
467 
468 	for (i = 0; i < dma_map->dma_pages_cnt; i++) {
469 		dma = dma_map_page_attrs(dev, pages[i], 0, PAGE_SIZE,
470 					 DMA_BIDIRECTIONAL, attrs);
471 		if (dma_mapping_error(dev, dma)) {
472 			__xp_dma_unmap(dma_map, attrs);
473 			return -ENOMEM;
474 		}
475 		dma_map->dma_pages[i] = dma;
476 	}
477 
478 	if (pool->unaligned)
479 		xp_check_dma_contiguity(dma_map);
480 
481 	err = xp_init_dma_info(pool, dma_map);
482 	if (err) {
483 		__xp_dma_unmap(dma_map, attrs);
484 		return err;
485 	}
486 
487 	return 0;
488 }
489 EXPORT_SYMBOL(xp_dma_map);
490 
491 static bool xp_addr_crosses_non_contig_pg(struct xsk_buff_pool *pool,
492 					  u64 addr)
493 {
494 	return xp_desc_crosses_non_contig_pg(pool, addr, pool->chunk_size);
495 }
496 
497 static bool xp_check_unaligned(struct xsk_buff_pool *pool, u64 *addr)
498 {
499 	*addr = xp_unaligned_extract_addr(*addr);
500 	if (*addr >= pool->addrs_cnt ||
501 	    *addr + pool->chunk_size > pool->addrs_cnt ||
502 	    xp_addr_crosses_non_contig_pg(pool, *addr))
503 		return false;
504 	return true;
505 }
506 
507 static bool xp_check_aligned(struct xsk_buff_pool *pool, u64 *addr)
508 {
509 	*addr = xp_aligned_extract_addr(pool, *addr);
510 	return *addr < pool->addrs_cnt;
511 }
512 
513 static struct xdp_buff_xsk *xp_get_xskb(struct xsk_buff_pool *pool, u64 addr)
514 {
515 	struct xdp_buff_xsk *xskb;
516 
517 	if (pool->unaligned) {
518 		xskb = pool->free_heads[--pool->free_heads_cnt];
519 		xp_init_xskb_addr(xskb, pool, addr);
520 		if (pool->dma_pages)
521 			xp_init_xskb_dma(xskb, pool, pool->dma_pages, addr);
522 	} else {
523 		xskb = &pool->heads[xp_aligned_extract_idx(pool, addr)];
524 	}
525 
526 	return xskb;
527 }
528 
529 static struct xdp_buff_xsk *__xp_alloc(struct xsk_buff_pool *pool)
530 {
531 	struct xdp_buff_xsk *xskb;
532 	u64 addr;
533 	bool ok;
534 
535 	if (pool->free_heads_cnt == 0)
536 		return NULL;
537 
538 	for (;;) {
539 		if (!xskq_cons_peek_addr_unchecked(pool->fq, &addr)) {
540 			pool->fq->queue_empty_descs++;
541 			return NULL;
542 		}
543 
544 		ok = pool->unaligned ? xp_check_unaligned(pool, &addr) :
545 		     xp_check_aligned(pool, &addr);
546 		if (!ok) {
547 			pool->fq->invalid_descs++;
548 			xskq_cons_release(pool->fq);
549 			continue;
550 		}
551 		break;
552 	}
553 
554 	xskb = xp_get_xskb(pool, addr);
555 
556 	xskq_cons_release(pool->fq);
557 	return xskb;
558 }
559 
560 struct xdp_buff *xp_alloc(struct xsk_buff_pool *pool)
561 {
562 	struct xdp_buff_xsk *xskb;
563 
564 	if (!pool->free_list_cnt) {
565 		xskb = __xp_alloc(pool);
566 		if (!xskb)
567 			return NULL;
568 	} else {
569 		pool->free_list_cnt--;
570 		xskb = list_first_entry(&pool->free_list, struct xdp_buff_xsk,
571 					list_node);
572 		list_del_init(&xskb->list_node);
573 	}
574 
575 	xskb->xdp.data = xskb->xdp.data_hard_start + XDP_PACKET_HEADROOM;
576 	xskb->xdp.data_meta = xskb->xdp.data;
577 	xskb->xdp.flags = 0;
578 
579 	if (pool->dev)
580 		xp_dma_sync_for_device(pool, xskb->dma, pool->frame_len);
581 
582 	return &xskb->xdp;
583 }
584 EXPORT_SYMBOL(xp_alloc);
585 
586 static u32 xp_alloc_new_from_fq(struct xsk_buff_pool *pool, struct xdp_buff **xdp, u32 max)
587 {
588 	u32 i, cached_cons, nb_entries;
589 
590 	if (max > pool->free_heads_cnt)
591 		max = pool->free_heads_cnt;
592 	max = xskq_cons_nb_entries(pool->fq, max);
593 
594 	cached_cons = pool->fq->cached_cons;
595 	nb_entries = max;
596 	i = max;
597 	while (i--) {
598 		struct xdp_buff_xsk *xskb;
599 		u64 addr;
600 		bool ok;
601 
602 		__xskq_cons_read_addr_unchecked(pool->fq, cached_cons++, &addr);
603 
604 		ok = pool->unaligned ? xp_check_unaligned(pool, &addr) :
605 			xp_check_aligned(pool, &addr);
606 		if (unlikely(!ok)) {
607 			pool->fq->invalid_descs++;
608 			nb_entries--;
609 			continue;
610 		}
611 
612 		xskb = xp_get_xskb(pool, addr);
613 
614 		*xdp = &xskb->xdp;
615 		xdp++;
616 	}
617 
618 	xskq_cons_release_n(pool->fq, max);
619 	return nb_entries;
620 }
621 
622 static u32 xp_alloc_reused(struct xsk_buff_pool *pool, struct xdp_buff **xdp, u32 nb_entries)
623 {
624 	struct xdp_buff_xsk *xskb;
625 	u32 i;
626 
627 	nb_entries = min_t(u32, nb_entries, pool->free_list_cnt);
628 
629 	i = nb_entries;
630 	while (i--) {
631 		xskb = list_first_entry(&pool->free_list, struct xdp_buff_xsk, list_node);
632 		list_del_init(&xskb->list_node);
633 
634 		*xdp = &xskb->xdp;
635 		xdp++;
636 	}
637 	pool->free_list_cnt -= nb_entries;
638 
639 	return nb_entries;
640 }
641 
642 static u32 xp_alloc_slow(struct xsk_buff_pool *pool, struct xdp_buff **xdp,
643 			 u32 max)
644 {
645 	int i;
646 
647 	for (i = 0; i < max; i++) {
648 		struct xdp_buff *buff;
649 
650 		buff = xp_alloc(pool);
651 		if (unlikely(!buff))
652 			return i;
653 		*xdp = buff;
654 		xdp++;
655 	}
656 
657 	return max;
658 }
659 
660 u32 xp_alloc_batch(struct xsk_buff_pool *pool, struct xdp_buff **xdp, u32 max)
661 {
662 	u32 nb_entries1 = 0, nb_entries2;
663 
664 	if (unlikely(pool->dev && dma_dev_need_sync(pool->dev)))
665 		return xp_alloc_slow(pool, xdp, max);
666 
667 	if (unlikely(pool->free_list_cnt)) {
668 		nb_entries1 = xp_alloc_reused(pool, xdp, max);
669 		if (nb_entries1 == max)
670 			return nb_entries1;
671 
672 		max -= nb_entries1;
673 		xdp += nb_entries1;
674 	}
675 
676 	nb_entries2 = xp_alloc_new_from_fq(pool, xdp, max);
677 	if (!nb_entries2)
678 		pool->fq->queue_empty_descs++;
679 
680 	return nb_entries1 + nb_entries2;
681 }
682 EXPORT_SYMBOL(xp_alloc_batch);
683 
684 bool xp_can_alloc(struct xsk_buff_pool *pool, u32 count)
685 {
686 	u32 req_count, avail_count;
687 
688 	if (pool->free_list_cnt >= count)
689 		return true;
690 
691 	req_count = count - pool->free_list_cnt;
692 	avail_count = xskq_cons_nb_entries(pool->fq, req_count);
693 	if (!avail_count)
694 		pool->fq->queue_empty_descs++;
695 
696 	return avail_count >= req_count;
697 }
698 EXPORT_SYMBOL(xp_can_alloc);
699 
700 void xp_free(struct xdp_buff_xsk *xskb)
701 {
702 	if (!list_empty(&xskb->list_node))
703 		return;
704 
705 	xskb->pool->free_list_cnt++;
706 	list_add(&xskb->list_node, &xskb->pool->free_list);
707 }
708 EXPORT_SYMBOL(xp_free);
709 
710 static u64 __xp_raw_get_addr(const struct xsk_buff_pool *pool, u64 addr)
711 {
712 	return pool->unaligned ? xp_unaligned_add_offset_to_addr(addr) : addr;
713 }
714 
715 static void *__xp_raw_get_data(const struct xsk_buff_pool *pool, u64 addr)
716 {
717 	return pool->addrs + addr;
718 }
719 
720 void *xp_raw_get_data(struct xsk_buff_pool *pool, u64 addr)
721 {
722 	return __xp_raw_get_data(pool, __xp_raw_get_addr(pool, addr));
723 }
724 EXPORT_SYMBOL(xp_raw_get_data);
725 
726 static dma_addr_t __xp_raw_get_dma(const struct xsk_buff_pool *pool, u64 addr)
727 {
728 	return (pool->dma_pages[addr >> PAGE_SHIFT] &
729 		~XSK_NEXT_PG_CONTIG_MASK) +
730 		(addr & ~PAGE_MASK);
731 }
732 
733 dma_addr_t xp_raw_get_dma(struct xsk_buff_pool *pool, u64 addr)
734 {
735 	return __xp_raw_get_dma(pool, __xp_raw_get_addr(pool, addr));
736 }
737 EXPORT_SYMBOL(xp_raw_get_dma);
738 
739 /**
740  * xp_raw_get_ctx - get &xdp_desc context
741  * @pool: XSk buff pool desc address belongs to
742  * @addr: desc address (from userspace)
743  *
744  * Helper for getting desc's DMA address and metadata pointer, if present.
745  * Saves one call on hotpath, double calculation of the actual address,
746  * and inline checks for metadata presence and sanity.
747  *
748  * Return: new &xdp_desc_ctx struct containing desc's DMA address and metadata
749  * pointer, if it is present and valid (initialized to %NULL otherwise).
750  */
751 struct xdp_desc_ctx xp_raw_get_ctx(const struct xsk_buff_pool *pool, u64 addr)
752 {
753 	struct xdp_desc_ctx ret;
754 
755 	addr = __xp_raw_get_addr(pool, addr);
756 
757 	ret.dma = __xp_raw_get_dma(pool, addr);
758 	ret.meta = __xsk_buff_get_metadata(pool, __xp_raw_get_data(pool, addr));
759 
760 	return ret;
761 }
762 EXPORT_SYMBOL(xp_raw_get_ctx);
763