GNU Linux-libre 5.19-rc6-gnu
[releases.git] / net / xdp / xsk_buff_pool.c
1 // SPDX-License-Identifier: GPL-2.0
2
3 #include <net/xsk_buff_pool.h>
4 #include <net/xdp_sock.h>
5 #include <net/xdp_sock_drv.h>
6
7 #include "xsk_queue.h"
8 #include "xdp_umem.h"
9 #include "xsk.h"
10
11 void xp_add_xsk(struct xsk_buff_pool *pool, struct xdp_sock *xs)
12 {
13         unsigned long flags;
14
15         if (!xs->tx)
16                 return;
17
18         spin_lock_irqsave(&pool->xsk_tx_list_lock, flags);
19         list_add_rcu(&xs->tx_list, &pool->xsk_tx_list);
20         spin_unlock_irqrestore(&pool->xsk_tx_list_lock, flags);
21 }
22
23 void xp_del_xsk(struct xsk_buff_pool *pool, struct xdp_sock *xs)
24 {
25         unsigned long flags;
26
27         if (!xs->tx)
28                 return;
29
30         spin_lock_irqsave(&pool->xsk_tx_list_lock, flags);
31         list_del_rcu(&xs->tx_list);
32         spin_unlock_irqrestore(&pool->xsk_tx_list_lock, flags);
33 }
34
35 void xp_destroy(struct xsk_buff_pool *pool)
36 {
37         if (!pool)
38                 return;
39
40         kvfree(pool->tx_descs);
41         kvfree(pool->heads);
42         kvfree(pool);
43 }
44
45 int xp_alloc_tx_descs(struct xsk_buff_pool *pool, struct xdp_sock *xs)
46 {
47         pool->tx_descs = kvcalloc(xs->tx->nentries, sizeof(*pool->tx_descs),
48                                   GFP_KERNEL);
49         if (!pool->tx_descs)
50                 return -ENOMEM;
51
52         return 0;
53 }
54
55 struct xsk_buff_pool *xp_create_and_assign_umem(struct xdp_sock *xs,
56                                                 struct xdp_umem *umem)
57 {
58         bool unaligned = umem->flags & XDP_UMEM_UNALIGNED_CHUNK_FLAG;
59         struct xsk_buff_pool *pool;
60         struct xdp_buff_xsk *xskb;
61         u32 i, entries;
62
63         entries = unaligned ? umem->chunks : 0;
64         pool = kvzalloc(struct_size(pool, free_heads, entries), GFP_KERNEL);
65         if (!pool)
66                 goto out;
67
68         pool->heads = kvcalloc(umem->chunks, sizeof(*pool->heads), GFP_KERNEL);
69         if (!pool->heads)
70                 goto out;
71
72         if (xs->tx)
73                 if (xp_alloc_tx_descs(pool, xs))
74                         goto out;
75
76         pool->chunk_mask = ~((u64)umem->chunk_size - 1);
77         pool->addrs_cnt = umem->size;
78         pool->heads_cnt = umem->chunks;
79         pool->free_heads_cnt = umem->chunks;
80         pool->headroom = umem->headroom;
81         pool->chunk_size = umem->chunk_size;
82         pool->chunk_shift = ffs(umem->chunk_size) - 1;
83         pool->unaligned = unaligned;
84         pool->frame_len = umem->chunk_size - umem->headroom -
85                 XDP_PACKET_HEADROOM;
86         pool->umem = umem;
87         pool->addrs = umem->addrs;
88         INIT_LIST_HEAD(&pool->free_list);
89         INIT_LIST_HEAD(&pool->xsk_tx_list);
90         spin_lock_init(&pool->xsk_tx_list_lock);
91         spin_lock_init(&pool->cq_lock);
92         refcount_set(&pool->users, 1);
93
94         pool->fq = xs->fq_tmp;
95         pool->cq = xs->cq_tmp;
96
97         for (i = 0; i < pool->free_heads_cnt; i++) {
98                 xskb = &pool->heads[i];
99                 xskb->pool = pool;
100                 xskb->xdp.frame_sz = umem->chunk_size - umem->headroom;
101                 INIT_LIST_HEAD(&xskb->free_list_node);
102                 if (pool->unaligned)
103                         pool->free_heads[i] = xskb;
104                 else
105                         xp_init_xskb_addr(xskb, pool, i * pool->chunk_size);
106         }
107
108         return pool;
109
110 out:
111         xp_destroy(pool);
112         return NULL;
113 }
114
115 void xp_set_rxq_info(struct xsk_buff_pool *pool, struct xdp_rxq_info *rxq)
116 {
117         u32 i;
118
119         for (i = 0; i < pool->heads_cnt; i++)
120                 pool->heads[i].xdp.rxq = rxq;
121 }
122 EXPORT_SYMBOL(xp_set_rxq_info);
123
124 static void xp_disable_drv_zc(struct xsk_buff_pool *pool)
125 {
126         struct netdev_bpf bpf;
127         int err;
128
129         ASSERT_RTNL();
130
131         if (pool->umem->zc) {
132                 bpf.command = XDP_SETUP_XSK_POOL;
133                 bpf.xsk.pool = NULL;
134                 bpf.xsk.queue_id = pool->queue_id;
135
136                 err = pool->netdev->netdev_ops->ndo_bpf(pool->netdev, &bpf);
137
138                 if (err)
139                         WARN(1, "Failed to disable zero-copy!\n");
140         }
141 }
142
143 int xp_assign_dev(struct xsk_buff_pool *pool,
144                   struct net_device *netdev, u16 queue_id, u16 flags)
145 {
146         bool force_zc, force_copy;
147         struct netdev_bpf bpf;
148         int err = 0;
149
150         ASSERT_RTNL();
151
152         force_zc = flags & XDP_ZEROCOPY;
153         force_copy = flags & XDP_COPY;
154
155         if (force_zc && force_copy)
156                 return -EINVAL;
157
158         if (xsk_get_pool_from_qid(netdev, queue_id))
159                 return -EBUSY;
160
161         pool->netdev = netdev;
162         pool->queue_id = queue_id;
163         err = xsk_reg_pool_at_qid(netdev, pool, queue_id);
164         if (err)
165                 return err;
166
167         if (flags & XDP_USE_NEED_WAKEUP)
168                 pool->uses_need_wakeup = true;
169         /* Tx needs to be explicitly woken up the first time.  Also
170          * for supporting drivers that do not implement this
171          * feature. They will always have to call sendto() or poll().
172          */
173         pool->cached_need_wakeup = XDP_WAKEUP_TX;
174
175         dev_hold(netdev);
176
177         if (force_copy)
178                 /* For copy-mode, we are done. */
179                 return 0;
180
181         if (!netdev->netdev_ops->ndo_bpf ||
182             !netdev->netdev_ops->ndo_xsk_wakeup) {
183                 err = -EOPNOTSUPP;
184                 goto err_unreg_pool;
185         }
186
187         bpf.command = XDP_SETUP_XSK_POOL;
188         bpf.xsk.pool = pool;
189         bpf.xsk.queue_id = queue_id;
190
191         err = netdev->netdev_ops->ndo_bpf(netdev, &bpf);
192         if (err)
193                 goto err_unreg_pool;
194
195         if (!pool->dma_pages) {
196                 WARN(1, "Driver did not DMA map zero-copy buffers");
197                 err = -EINVAL;
198                 goto err_unreg_xsk;
199         }
200         pool->umem->zc = true;
201         return 0;
202
203 err_unreg_xsk:
204         xp_disable_drv_zc(pool);
205 err_unreg_pool:
206         if (!force_zc)
207                 err = 0; /* fallback to copy mode */
208         if (err) {
209                 xsk_clear_pool_at_qid(netdev, queue_id);
210                 dev_put(netdev);
211         }
212         return err;
213 }
214
215 int xp_assign_dev_shared(struct xsk_buff_pool *pool, struct xdp_umem *umem,
216                          struct net_device *dev, u16 queue_id)
217 {
218         u16 flags;
219
220         /* One fill and completion ring required for each queue id. */
221         if (!pool->fq || !pool->cq)
222                 return -EINVAL;
223
224         flags = umem->zc ? XDP_ZEROCOPY : XDP_COPY;
225         if (pool->uses_need_wakeup)
226                 flags |= XDP_USE_NEED_WAKEUP;
227
228         return xp_assign_dev(pool, dev, queue_id, flags);
229 }
230
231 void xp_clear_dev(struct xsk_buff_pool *pool)
232 {
233         if (!pool->netdev)
234                 return;
235
236         xp_disable_drv_zc(pool);
237         xsk_clear_pool_at_qid(pool->netdev, pool->queue_id);
238         dev_put(pool->netdev);
239         pool->netdev = NULL;
240 }
241
242 static void xp_release_deferred(struct work_struct *work)
243 {
244         struct xsk_buff_pool *pool = container_of(work, struct xsk_buff_pool,
245                                                   work);
246
247         rtnl_lock();
248         xp_clear_dev(pool);
249         rtnl_unlock();
250
251         if (pool->fq) {
252                 xskq_destroy(pool->fq);
253                 pool->fq = NULL;
254         }
255
256         if (pool->cq) {
257                 xskq_destroy(pool->cq);
258                 pool->cq = NULL;
259         }
260
261         xdp_put_umem(pool->umem, false);
262         xp_destroy(pool);
263 }
264
265 void xp_get_pool(struct xsk_buff_pool *pool)
266 {
267         refcount_inc(&pool->users);
268 }
269
270 bool xp_put_pool(struct xsk_buff_pool *pool)
271 {
272         if (!pool)
273                 return false;
274
275         if (refcount_dec_and_test(&pool->users)) {
276                 INIT_WORK(&pool->work, xp_release_deferred);
277                 schedule_work(&pool->work);
278                 return true;
279         }
280
281         return false;
282 }
283
284 static struct xsk_dma_map *xp_find_dma_map(struct xsk_buff_pool *pool)
285 {
286         struct xsk_dma_map *dma_map;
287
288         list_for_each_entry(dma_map, &pool->umem->xsk_dma_list, list) {
289                 if (dma_map->netdev == pool->netdev)
290                         return dma_map;
291         }
292
293         return NULL;
294 }
295
296 static struct xsk_dma_map *xp_create_dma_map(struct device *dev, struct net_device *netdev,
297                                              u32 nr_pages, struct xdp_umem *umem)
298 {
299         struct xsk_dma_map *dma_map;
300
301         dma_map = kzalloc(sizeof(*dma_map), GFP_KERNEL);
302         if (!dma_map)
303                 return NULL;
304
305         dma_map->dma_pages = kvcalloc(nr_pages, sizeof(*dma_map->dma_pages), GFP_KERNEL);
306         if (!dma_map->dma_pages) {
307                 kfree(dma_map);
308                 return NULL;
309         }
310
311         dma_map->netdev = netdev;
312         dma_map->dev = dev;
313         dma_map->dma_need_sync = false;
314         dma_map->dma_pages_cnt = nr_pages;
315         refcount_set(&dma_map->users, 1);
316         list_add(&dma_map->list, &umem->xsk_dma_list);
317         return dma_map;
318 }
319
320 static void xp_destroy_dma_map(struct xsk_dma_map *dma_map)
321 {
322         list_del(&dma_map->list);
323         kvfree(dma_map->dma_pages);
324         kfree(dma_map);
325 }
326
327 static void __xp_dma_unmap(struct xsk_dma_map *dma_map, unsigned long attrs)
328 {
329         dma_addr_t *dma;
330         u32 i;
331
332         for (i = 0; i < dma_map->dma_pages_cnt; i++) {
333                 dma = &dma_map->dma_pages[i];
334                 if (*dma) {
335                         *dma &= ~XSK_NEXT_PG_CONTIG_MASK;
336                         dma_unmap_page_attrs(dma_map->dev, *dma, PAGE_SIZE,
337                                              DMA_BIDIRECTIONAL, attrs);
338                         *dma = 0;
339                 }
340         }
341
342         xp_destroy_dma_map(dma_map);
343 }
344
345 void xp_dma_unmap(struct xsk_buff_pool *pool, unsigned long attrs)
346 {
347         struct xsk_dma_map *dma_map;
348
349         if (pool->dma_pages_cnt == 0)
350                 return;
351
352         dma_map = xp_find_dma_map(pool);
353         if (!dma_map) {
354                 WARN(1, "Could not find dma_map for device");
355                 return;
356         }
357
358         if (!refcount_dec_and_test(&dma_map->users))
359                 return;
360
361         __xp_dma_unmap(dma_map, attrs);
362         kvfree(pool->dma_pages);
363         pool->dma_pages_cnt = 0;
364         pool->dev = NULL;
365 }
366 EXPORT_SYMBOL(xp_dma_unmap);
367
368 static void xp_check_dma_contiguity(struct xsk_dma_map *dma_map)
369 {
370         u32 i;
371
372         for (i = 0; i < dma_map->dma_pages_cnt - 1; i++) {
373                 if (dma_map->dma_pages[i] + PAGE_SIZE == dma_map->dma_pages[i + 1])
374                         dma_map->dma_pages[i] |= XSK_NEXT_PG_CONTIG_MASK;
375                 else
376                         dma_map->dma_pages[i] &= ~XSK_NEXT_PG_CONTIG_MASK;
377         }
378 }
379
380 static int xp_init_dma_info(struct xsk_buff_pool *pool, struct xsk_dma_map *dma_map)
381 {
382         pool->dma_pages = kvcalloc(dma_map->dma_pages_cnt, sizeof(*pool->dma_pages), GFP_KERNEL);
383         if (!pool->dma_pages)
384                 return -ENOMEM;
385
386         pool->dev = dma_map->dev;
387         pool->dma_pages_cnt = dma_map->dma_pages_cnt;
388         pool->dma_need_sync = dma_map->dma_need_sync;
389         memcpy(pool->dma_pages, dma_map->dma_pages,
390                pool->dma_pages_cnt * sizeof(*pool->dma_pages));
391
392         return 0;
393 }
394
395 int xp_dma_map(struct xsk_buff_pool *pool, struct device *dev,
396                unsigned long attrs, struct page **pages, u32 nr_pages)
397 {
398         struct xsk_dma_map *dma_map;
399         dma_addr_t dma;
400         int err;
401         u32 i;
402
403         dma_map = xp_find_dma_map(pool);
404         if (dma_map) {
405                 err = xp_init_dma_info(pool, dma_map);
406                 if (err)
407                         return err;
408
409                 refcount_inc(&dma_map->users);
410                 return 0;
411         }
412
413         dma_map = xp_create_dma_map(dev, pool->netdev, nr_pages, pool->umem);
414         if (!dma_map)
415                 return -ENOMEM;
416
417         for (i = 0; i < dma_map->dma_pages_cnt; i++) {
418                 dma = dma_map_page_attrs(dev, pages[i], 0, PAGE_SIZE,
419                                          DMA_BIDIRECTIONAL, attrs);
420                 if (dma_mapping_error(dev, dma)) {
421                         __xp_dma_unmap(dma_map, attrs);
422                         return -ENOMEM;
423                 }
424                 if (dma_need_sync(dev, dma))
425                         dma_map->dma_need_sync = true;
426                 dma_map->dma_pages[i] = dma;
427         }
428
429         if (pool->unaligned)
430                 xp_check_dma_contiguity(dma_map);
431         else
432                 for (i = 0; i < pool->heads_cnt; i++) {
433                         struct xdp_buff_xsk *xskb = &pool->heads[i];
434
435                         xp_init_xskb_dma(xskb, pool, dma_map->dma_pages, xskb->orig_addr);
436                 }
437
438         err = xp_init_dma_info(pool, dma_map);
439         if (err) {
440                 __xp_dma_unmap(dma_map, attrs);
441                 return err;
442         }
443
444         return 0;
445 }
446 EXPORT_SYMBOL(xp_dma_map);
447
448 static bool xp_addr_crosses_non_contig_pg(struct xsk_buff_pool *pool,
449                                           u64 addr)
450 {
451         return xp_desc_crosses_non_contig_pg(pool, addr, pool->chunk_size);
452 }
453
454 static bool xp_check_unaligned(struct xsk_buff_pool *pool, u64 *addr)
455 {
456         *addr = xp_unaligned_extract_addr(*addr);
457         if (*addr >= pool->addrs_cnt ||
458             *addr + pool->chunk_size > pool->addrs_cnt ||
459             xp_addr_crosses_non_contig_pg(pool, *addr))
460                 return false;
461         return true;
462 }
463
464 static bool xp_check_aligned(struct xsk_buff_pool *pool, u64 *addr)
465 {
466         *addr = xp_aligned_extract_addr(pool, *addr);
467         return *addr < pool->addrs_cnt;
468 }
469
470 static struct xdp_buff_xsk *__xp_alloc(struct xsk_buff_pool *pool)
471 {
472         struct xdp_buff_xsk *xskb;
473         u64 addr;
474         bool ok;
475
476         if (pool->free_heads_cnt == 0)
477                 return NULL;
478
479         for (;;) {
480                 if (!xskq_cons_peek_addr_unchecked(pool->fq, &addr)) {
481                         pool->fq->queue_empty_descs++;
482                         return NULL;
483                 }
484
485                 ok = pool->unaligned ? xp_check_unaligned(pool, &addr) :
486                      xp_check_aligned(pool, &addr);
487                 if (!ok) {
488                         pool->fq->invalid_descs++;
489                         xskq_cons_release(pool->fq);
490                         continue;
491                 }
492                 break;
493         }
494
495         if (pool->unaligned) {
496                 xskb = pool->free_heads[--pool->free_heads_cnt];
497                 xp_init_xskb_addr(xskb, pool, addr);
498                 if (pool->dma_pages_cnt)
499                         xp_init_xskb_dma(xskb, pool, pool->dma_pages, addr);
500         } else {
501                 xskb = &pool->heads[xp_aligned_extract_idx(pool, addr)];
502         }
503
504         xskq_cons_release(pool->fq);
505         return xskb;
506 }
507
508 struct xdp_buff *xp_alloc(struct xsk_buff_pool *pool)
509 {
510         struct xdp_buff_xsk *xskb;
511
512         if (!pool->free_list_cnt) {
513                 xskb = __xp_alloc(pool);
514                 if (!xskb)
515                         return NULL;
516         } else {
517                 pool->free_list_cnt--;
518                 xskb = list_first_entry(&pool->free_list, struct xdp_buff_xsk,
519                                         free_list_node);
520                 list_del_init(&xskb->free_list_node);
521         }
522
523         xskb->xdp.data = xskb->xdp.data_hard_start + XDP_PACKET_HEADROOM;
524         xskb->xdp.data_meta = xskb->xdp.data;
525
526         if (pool->dma_need_sync) {
527                 dma_sync_single_range_for_device(pool->dev, xskb->dma, 0,
528                                                  pool->frame_len,
529                                                  DMA_BIDIRECTIONAL);
530         }
531         return &xskb->xdp;
532 }
533 EXPORT_SYMBOL(xp_alloc);
534
535 static u32 xp_alloc_new_from_fq(struct xsk_buff_pool *pool, struct xdp_buff **xdp, u32 max)
536 {
537         u32 i, cached_cons, nb_entries;
538
539         if (max > pool->free_heads_cnt)
540                 max = pool->free_heads_cnt;
541         max = xskq_cons_nb_entries(pool->fq, max);
542
543         cached_cons = pool->fq->cached_cons;
544         nb_entries = max;
545         i = max;
546         while (i--) {
547                 struct xdp_buff_xsk *xskb;
548                 u64 addr;
549                 bool ok;
550
551                 __xskq_cons_read_addr_unchecked(pool->fq, cached_cons++, &addr);
552
553                 ok = pool->unaligned ? xp_check_unaligned(pool, &addr) :
554                         xp_check_aligned(pool, &addr);
555                 if (unlikely(!ok)) {
556                         pool->fq->invalid_descs++;
557                         nb_entries--;
558                         continue;
559                 }
560
561                 if (pool->unaligned) {
562                         xskb = pool->free_heads[--pool->free_heads_cnt];
563                         xp_init_xskb_addr(xskb, pool, addr);
564                         if (pool->dma_pages_cnt)
565                                 xp_init_xskb_dma(xskb, pool, pool->dma_pages, addr);
566                 } else {
567                         xskb = &pool->heads[xp_aligned_extract_idx(pool, addr)];
568                 }
569
570                 *xdp = &xskb->xdp;
571                 xdp++;
572         }
573
574         xskq_cons_release_n(pool->fq, max);
575         return nb_entries;
576 }
577
578 static u32 xp_alloc_reused(struct xsk_buff_pool *pool, struct xdp_buff **xdp, u32 nb_entries)
579 {
580         struct xdp_buff_xsk *xskb;
581         u32 i;
582
583         nb_entries = min_t(u32, nb_entries, pool->free_list_cnt);
584
585         i = nb_entries;
586         while (i--) {
587                 xskb = list_first_entry(&pool->free_list, struct xdp_buff_xsk, free_list_node);
588                 list_del_init(&xskb->free_list_node);
589
590                 *xdp = &xskb->xdp;
591                 xdp++;
592         }
593         pool->free_list_cnt -= nb_entries;
594
595         return nb_entries;
596 }
597
598 u32 xp_alloc_batch(struct xsk_buff_pool *pool, struct xdp_buff **xdp, u32 max)
599 {
600         u32 nb_entries1 = 0, nb_entries2;
601
602         if (unlikely(pool->dma_need_sync)) {
603                 struct xdp_buff *buff;
604
605                 /* Slow path */
606                 buff = xp_alloc(pool);
607                 if (buff)
608                         *xdp = buff;
609                 return !!buff;
610         }
611
612         if (unlikely(pool->free_list_cnt)) {
613                 nb_entries1 = xp_alloc_reused(pool, xdp, max);
614                 if (nb_entries1 == max)
615                         return nb_entries1;
616
617                 max -= nb_entries1;
618                 xdp += nb_entries1;
619         }
620
621         nb_entries2 = xp_alloc_new_from_fq(pool, xdp, max);
622         if (!nb_entries2)
623                 pool->fq->queue_empty_descs++;
624
625         return nb_entries1 + nb_entries2;
626 }
627 EXPORT_SYMBOL(xp_alloc_batch);
628
629 bool xp_can_alloc(struct xsk_buff_pool *pool, u32 count)
630 {
631         if (pool->free_list_cnt >= count)
632                 return true;
633         return xskq_cons_has_entries(pool->fq, count - pool->free_list_cnt);
634 }
635 EXPORT_SYMBOL(xp_can_alloc);
636
637 void xp_free(struct xdp_buff_xsk *xskb)
638 {
639         if (!list_empty(&xskb->free_list_node))
640                 return;
641
642         xskb->pool->free_list_cnt++;
643         list_add(&xskb->free_list_node, &xskb->pool->free_list);
644 }
645 EXPORT_SYMBOL(xp_free);
646
647 void *xp_raw_get_data(struct xsk_buff_pool *pool, u64 addr)
648 {
649         addr = pool->unaligned ? xp_unaligned_add_offset_to_addr(addr) : addr;
650         return pool->addrs + addr;
651 }
652 EXPORT_SYMBOL(xp_raw_get_data);
653
654 dma_addr_t xp_raw_get_dma(struct xsk_buff_pool *pool, u64 addr)
655 {
656         addr = pool->unaligned ? xp_unaligned_add_offset_to_addr(addr) : addr;
657         return (pool->dma_pages[addr >> PAGE_SHIFT] &
658                 ~XSK_NEXT_PG_CONTIG_MASK) +
659                 (addr & ~PAGE_MASK);
660 }
661 EXPORT_SYMBOL(xp_raw_get_dma);
662
663 void xp_dma_sync_for_cpu_slow(struct xdp_buff_xsk *xskb)
664 {
665         dma_sync_single_range_for_cpu(xskb->pool->dev, xskb->dma, 0,
666                                       xskb->pool->frame_len, DMA_BIDIRECTIONAL);
667 }
668 EXPORT_SYMBOL(xp_dma_sync_for_cpu_slow);
669
670 void xp_dma_sync_for_device_slow(struct xsk_buff_pool *pool, dma_addr_t dma,
671                                  size_t size)
672 {
673         dma_sync_single_range_for_device(pool->dev, dma, 0,
674                                          size, DMA_BIDIRECTIONAL);
675 }
676 EXPORT_SYMBOL(xp_dma_sync_for_device_slow);