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1/* SPDX-License-Identifier: GPL-2.0
2 *
3 * page_pool.c
4 * Author: Jesper Dangaard Brouer <netoptimizer@brouer.com>
5 * Copyright (C) 2016 Red Hat, Inc.
6 */
7
8#include <linux/types.h>
9#include <linux/kernel.h>
10#include <linux/slab.h>
11#include <linux/device.h>
12
13#include <net/page_pool.h>
14#include <net/xdp.h>
15
16#include <linux/dma-direction.h>
17#include <linux/dma-mapping.h>
18#include <linux/page-flags.h>
19#include <linux/mm.h> /* for put_page() */
20#include <linux/poison.h>
21#include <linux/ethtool.h>
22
23#include <trace/events/page_pool.h>
24
25#define DEFER_TIME (msecs_to_jiffies(1000))
26#define DEFER_WARN_INTERVAL (60 * HZ)
27
28#define BIAS_MAX LONG_MAX
29
30#ifdef CONFIG_PAGE_POOL_STATS
31/* alloc_stat_inc is intended to be used in softirq context */
32#define alloc_stat_inc(pool, __stat) (pool->alloc_stats.__stat++)
33/* recycle_stat_inc is safe to use when preemption is possible. */
34#define recycle_stat_inc(pool, __stat) \
35 do { \
36 struct page_pool_recycle_stats __percpu *s = pool->recycle_stats; \
37 this_cpu_inc(s->__stat); \
38 } while (0)
39
40#define recycle_stat_add(pool, __stat, val) \
41 do { \
42 struct page_pool_recycle_stats __percpu *s = pool->recycle_stats; \
43 this_cpu_add(s->__stat, val); \
44 } while (0)
45
46static const char pp_stats[][ETH_GSTRING_LEN] = {
47 "rx_pp_alloc_fast",
48 "rx_pp_alloc_slow",
49 "rx_pp_alloc_slow_ho",
50 "rx_pp_alloc_empty",
51 "rx_pp_alloc_refill",
52 "rx_pp_alloc_waive",
53 "rx_pp_recycle_cached",
54 "rx_pp_recycle_cache_full",
55 "rx_pp_recycle_ring",
56 "rx_pp_recycle_ring_full",
57 "rx_pp_recycle_released_ref",
58};
59
60bool page_pool_get_stats(struct page_pool *pool,
61 struct page_pool_stats *stats)
62{
63 int cpu = 0;
64
65 if (!stats)
66 return false;
67
68 /* The caller is responsible to initialize stats. */
69 stats->alloc_stats.fast += pool->alloc_stats.fast;
70 stats->alloc_stats.slow += pool->alloc_stats.slow;
71 stats->alloc_stats.slow_high_order += pool->alloc_stats.slow_high_order;
72 stats->alloc_stats.empty += pool->alloc_stats.empty;
73 stats->alloc_stats.refill += pool->alloc_stats.refill;
74 stats->alloc_stats.waive += pool->alloc_stats.waive;
75
76 for_each_possible_cpu(cpu) {
77 const struct page_pool_recycle_stats *pcpu =
78 per_cpu_ptr(pool->recycle_stats, cpu);
79
80 stats->recycle_stats.cached += pcpu->cached;
81 stats->recycle_stats.cache_full += pcpu->cache_full;
82 stats->recycle_stats.ring += pcpu->ring;
83 stats->recycle_stats.ring_full += pcpu->ring_full;
84 stats->recycle_stats.released_refcnt += pcpu->released_refcnt;
85 }
86
87 return true;
88}
89EXPORT_SYMBOL(page_pool_get_stats);
90
91u8 *page_pool_ethtool_stats_get_strings(u8 *data)
92{
93 int i;
94
95 for (i = 0; i < ARRAY_SIZE(pp_stats); i++) {
96 memcpy(data, pp_stats[i], ETH_GSTRING_LEN);
97 data += ETH_GSTRING_LEN;
98 }
99
100 return data;
101}
102EXPORT_SYMBOL(page_pool_ethtool_stats_get_strings);
103
104int page_pool_ethtool_stats_get_count(void)
105{
106 return ARRAY_SIZE(pp_stats);
107}
108EXPORT_SYMBOL(page_pool_ethtool_stats_get_count);
109
110u64 *page_pool_ethtool_stats_get(u64 *data, void *stats)
111{
112 struct page_pool_stats *pool_stats = stats;
113
114 *data++ = pool_stats->alloc_stats.fast;
115 *data++ = pool_stats->alloc_stats.slow;
116 *data++ = pool_stats->alloc_stats.slow_high_order;
117 *data++ = pool_stats->alloc_stats.empty;
118 *data++ = pool_stats->alloc_stats.refill;
119 *data++ = pool_stats->alloc_stats.waive;
120 *data++ = pool_stats->recycle_stats.cached;
121 *data++ = pool_stats->recycle_stats.cache_full;
122 *data++ = pool_stats->recycle_stats.ring;
123 *data++ = pool_stats->recycle_stats.ring_full;
124 *data++ = pool_stats->recycle_stats.released_refcnt;
125
126 return data;
127}
128EXPORT_SYMBOL(page_pool_ethtool_stats_get);
129
130#else
131#define alloc_stat_inc(pool, __stat)
132#define recycle_stat_inc(pool, __stat)
133#define recycle_stat_add(pool, __stat, val)
134#endif
135
136static int page_pool_init(struct page_pool *pool,
137 const struct page_pool_params *params)
138{
139 unsigned int ring_qsize = 1024; /* Default */
140
141 memcpy(&pool->p, params, sizeof(pool->p));
142
143 /* Validate only known flags were used */
144 if (pool->p.flags & ~(PP_FLAG_ALL))
145 return -EINVAL;
146
147 if (pool->p.pool_size)
148 ring_qsize = pool->p.pool_size;
149
150 /* Sanity limit mem that can be pinned down */
151 if (ring_qsize > 32768)
152 return -E2BIG;
153
154 /* DMA direction is either DMA_FROM_DEVICE or DMA_BIDIRECTIONAL.
155 * DMA_BIDIRECTIONAL is for allowing page used for DMA sending,
156 * which is the XDP_TX use-case.
157 */
158 if (pool->p.flags & PP_FLAG_DMA_MAP) {
159 if ((pool->p.dma_dir != DMA_FROM_DEVICE) &&
160 (pool->p.dma_dir != DMA_BIDIRECTIONAL))
161 return -EINVAL;
162 }
163
164 if (pool->p.flags & PP_FLAG_DMA_SYNC_DEV) {
165 /* In order to request DMA-sync-for-device the page
166 * needs to be mapped
167 */
168 if (!(pool->p.flags & PP_FLAG_DMA_MAP))
169 return -EINVAL;
170
171 if (!pool->p.max_len)
172 return -EINVAL;
173
174 /* pool->p.offset has to be set according to the address
175 * offset used by the DMA engine to start copying rx data
176 */
177 }
178
179 if (PAGE_POOL_DMA_USE_PP_FRAG_COUNT &&
180 pool->p.flags & PP_FLAG_PAGE_FRAG)
181 return -EINVAL;
182
183#ifdef CONFIG_PAGE_POOL_STATS
184 pool->recycle_stats = alloc_percpu(struct page_pool_recycle_stats);
185 if (!pool->recycle_stats)
186 return -ENOMEM;
187#endif
188
189 if (ptr_ring_init(&pool->ring, ring_qsize, GFP_KERNEL) < 0)
190 return -ENOMEM;
191
192 atomic_set(&pool->pages_state_release_cnt, 0);
193
194 /* Driver calling page_pool_create() also call page_pool_destroy() */
195 refcount_set(&pool->user_cnt, 1);
196
197 if (pool->p.flags & PP_FLAG_DMA_MAP)
198 get_device(pool->p.dev);
199
200 return 0;
201}
202
203struct page_pool *page_pool_create(const struct page_pool_params *params)
204{
205 struct page_pool *pool;
206 int err;
207
208 pool = kzalloc_node(sizeof(*pool), GFP_KERNEL, params->nid);
209 if (!pool)
210 return ERR_PTR(-ENOMEM);
211
212 err = page_pool_init(pool, params);
213 if (err < 0) {
214 pr_warn("%s() gave up with errno %d\n", __func__, err);
215 kfree(pool);
216 return ERR_PTR(err);
217 }
218
219 return pool;
220}
221EXPORT_SYMBOL(page_pool_create);
222
223static void page_pool_return_page(struct page_pool *pool, struct page *page);
224
225noinline
226static struct page *page_pool_refill_alloc_cache(struct page_pool *pool)
227{
228 struct ptr_ring *r = &pool->ring;
229 struct page *page;
230 int pref_nid; /* preferred NUMA node */
231
232 /* Quicker fallback, avoid locks when ring is empty */
233 if (__ptr_ring_empty(r)) {
234 alloc_stat_inc(pool, empty);
235 return NULL;
236 }
237
238 /* Softirq guarantee CPU and thus NUMA node is stable. This,
239 * assumes CPU refilling driver RX-ring will also run RX-NAPI.
240 */
241#ifdef CONFIG_NUMA
242 pref_nid = (pool->p.nid == NUMA_NO_NODE) ? numa_mem_id() : pool->p.nid;
243#else
244 /* Ignore pool->p.nid setting if !CONFIG_NUMA, helps compiler */
245 pref_nid = numa_mem_id(); /* will be zero like page_to_nid() */
246#endif
247
248 /* Refill alloc array, but only if NUMA match */
249 do {
250 page = __ptr_ring_consume(r);
251 if (unlikely(!page))
252 break;
253
254 if (likely(page_to_nid(page) == pref_nid)) {
255 pool->alloc.cache[pool->alloc.count++] = page;
256 } else {
257 /* NUMA mismatch;
258 * (1) release 1 page to page-allocator and
259 * (2) break out to fallthrough to alloc_pages_node.
260 * This limit stress on page buddy alloactor.
261 */
262 page_pool_return_page(pool, page);
263 alloc_stat_inc(pool, waive);
264 page = NULL;
265 break;
266 }
267 } while (pool->alloc.count < PP_ALLOC_CACHE_REFILL);
268
269 /* Return last page */
270 if (likely(pool->alloc.count > 0)) {
271 page = pool->alloc.cache[--pool->alloc.count];
272 alloc_stat_inc(pool, refill);
273 }
274
275 return page;
276}
277
278/* fast path */
279static struct page *__page_pool_get_cached(struct page_pool *pool)
280{
281 struct page *page;
282
283 /* Caller MUST guarantee safe non-concurrent access, e.g. softirq */
284 if (likely(pool->alloc.count)) {
285 /* Fast-path */
286 page = pool->alloc.cache[--pool->alloc.count];
287 alloc_stat_inc(pool, fast);
288 } else {
289 page = page_pool_refill_alloc_cache(pool);
290 }
291
292 return page;
293}
294
295static void page_pool_dma_sync_for_device(struct page_pool *pool,
296 struct page *page,
297 unsigned int dma_sync_size)
298{
299 dma_addr_t dma_addr = page_pool_get_dma_addr(page);
300
301 dma_sync_size = min(dma_sync_size, pool->p.max_len);
302 dma_sync_single_range_for_device(pool->p.dev, dma_addr,
303 pool->p.offset, dma_sync_size,
304 pool->p.dma_dir);
305}
306
307static bool page_pool_dma_map(struct page_pool *pool, struct page *page)
308{
309 dma_addr_t dma;
310
311 /* Setup DMA mapping: use 'struct page' area for storing DMA-addr
312 * since dma_addr_t can be either 32 or 64 bits and does not always fit
313 * into page private data (i.e 32bit cpu with 64bit DMA caps)
314 * This mapping is kept for lifetime of page, until leaving pool.
315 */
316 dma = dma_map_page_attrs(pool->p.dev, page, 0,
317 (PAGE_SIZE << pool->p.order),
318 pool->p.dma_dir, DMA_ATTR_SKIP_CPU_SYNC);
319 if (dma_mapping_error(pool->p.dev, dma))
320 return false;
321
322 page_pool_set_dma_addr(page, dma);
323
324 if (pool->p.flags & PP_FLAG_DMA_SYNC_DEV)
325 page_pool_dma_sync_for_device(pool, page, pool->p.max_len);
326
327 return true;
328}
329
330static void page_pool_set_pp_info(struct page_pool *pool,
331 struct page *page)
332{
333 page->pp = pool;
334 page->pp_magic |= PP_SIGNATURE;
335 if (pool->p.init_callback)
336 pool->p.init_callback(page, pool->p.init_arg);
337}
338
339static void page_pool_clear_pp_info(struct page *page)
340{
341 page->pp_magic = 0;
342 page->pp = NULL;
343}
344
345static struct page *__page_pool_alloc_page_order(struct page_pool *pool,
346 gfp_t gfp)
347{
348 struct page *page;
349
350 gfp |= __GFP_COMP;
351 page = alloc_pages_node(pool->p.nid, gfp, pool->p.order);
352 if (unlikely(!page))
353 return NULL;
354
355 if ((pool->p.flags & PP_FLAG_DMA_MAP) &&
356 unlikely(!page_pool_dma_map(pool, page))) {
357 put_page(page);
358 return NULL;
359 }
360
361 alloc_stat_inc(pool, slow_high_order);
362 page_pool_set_pp_info(pool, page);
363
364 /* Track how many pages are held 'in-flight' */
365 pool->pages_state_hold_cnt++;
366 trace_page_pool_state_hold(pool, page, pool->pages_state_hold_cnt);
367 return page;
368}
369
370/* slow path */
371noinline
372static struct page *__page_pool_alloc_pages_slow(struct page_pool *pool,
373 gfp_t gfp)
374{
375 const int bulk = PP_ALLOC_CACHE_REFILL;
376 unsigned int pp_flags = pool->p.flags;
377 unsigned int pp_order = pool->p.order;
378 struct page *page;
379 int i, nr_pages;
380
381 /* Don't support bulk alloc for high-order pages */
382 if (unlikely(pp_order))
383 return __page_pool_alloc_page_order(pool, gfp);
384
385 /* Unnecessary as alloc cache is empty, but guarantees zero count */
386 if (unlikely(pool->alloc.count > 0))
387 return pool->alloc.cache[--pool->alloc.count];
388
389 /* Mark empty alloc.cache slots "empty" for alloc_pages_bulk_array */
390 memset(&pool->alloc.cache, 0, sizeof(void *) * bulk);
391
392 nr_pages = alloc_pages_bulk_array_node(gfp, pool->p.nid, bulk,
393 pool->alloc.cache);
394 if (unlikely(!nr_pages))
395 return NULL;
396
397 /* Pages have been filled into alloc.cache array, but count is zero and
398 * page element have not been (possibly) DMA mapped.
399 */
400 for (i = 0; i < nr_pages; i++) {
401 page = pool->alloc.cache[i];
402 if ((pp_flags & PP_FLAG_DMA_MAP) &&
403 unlikely(!page_pool_dma_map(pool, page))) {
404 put_page(page);
405 continue;
406 }
407
408 page_pool_set_pp_info(pool, page);
409 pool->alloc.cache[pool->alloc.count++] = page;
410 /* Track how many pages are held 'in-flight' */
411 pool->pages_state_hold_cnt++;
412 trace_page_pool_state_hold(pool, page,
413 pool->pages_state_hold_cnt);
414 }
415
416 /* Return last page */
417 if (likely(pool->alloc.count > 0)) {
418 page = pool->alloc.cache[--pool->alloc.count];
419 alloc_stat_inc(pool, slow);
420 } else {
421 page = NULL;
422 }
423
424 /* When page just alloc'ed is should/must have refcnt 1. */
425 return page;
426}
427
428/* For using page_pool replace: alloc_pages() API calls, but provide
429 * synchronization guarantee for allocation side.
430 */
431struct page *page_pool_alloc_pages(struct page_pool *pool, gfp_t gfp)
432{
433 struct page *page;
434
435 /* Fast-path: Get a page from cache */
436 page = __page_pool_get_cached(pool);
437 if (page)
438 return page;
439
440 /* Slow-path: cache empty, do real allocation */
441 page = __page_pool_alloc_pages_slow(pool, gfp);
442 return page;
443}
444EXPORT_SYMBOL(page_pool_alloc_pages);
445
446/* Calculate distance between two u32 values, valid if distance is below 2^(31)
447 * https://en.wikipedia.org/wiki/Serial_number_arithmetic#General_Solution
448 */
449#define _distance(a, b) (s32)((a) - (b))
450
451static s32 page_pool_inflight(struct page_pool *pool)
452{
453 u32 release_cnt = atomic_read(&pool->pages_state_release_cnt);
454 u32 hold_cnt = READ_ONCE(pool->pages_state_hold_cnt);
455 s32 inflight;
456
457 inflight = _distance(hold_cnt, release_cnt);
458
459 trace_page_pool_release(pool, inflight, hold_cnt, release_cnt);
460 WARN(inflight < 0, "Negative(%d) inflight packet-pages", inflight);
461
462 return inflight;
463}
464
465/* Disconnects a page (from a page_pool). API users can have a need
466 * to disconnect a page (from a page_pool), to allow it to be used as
467 * a regular page (that will eventually be returned to the normal
468 * page-allocator via put_page).
469 */
470void page_pool_release_page(struct page_pool *pool, struct page *page)
471{
472 dma_addr_t dma;
473 int count;
474
475 if (!(pool->p.flags & PP_FLAG_DMA_MAP))
476 /* Always account for inflight pages, even if we didn't
477 * map them
478 */
479 goto skip_dma_unmap;
480
481 dma = page_pool_get_dma_addr(page);
482
483 /* When page is unmapped, it cannot be returned to our pool */
484 dma_unmap_page_attrs(pool->p.dev, dma,
485 PAGE_SIZE << pool->p.order, pool->p.dma_dir,
486 DMA_ATTR_SKIP_CPU_SYNC);
487 page_pool_set_dma_addr(page, 0);
488skip_dma_unmap:
489 page_pool_clear_pp_info(page);
490
491 /* This may be the last page returned, releasing the pool, so
492 * it is not safe to reference pool afterwards.
493 */
494 count = atomic_inc_return_relaxed(&pool->pages_state_release_cnt);
495 trace_page_pool_state_release(pool, page, count);
496}
497EXPORT_SYMBOL(page_pool_release_page);
498
499/* Return a page to the page allocator, cleaning up our state */
500static void page_pool_return_page(struct page_pool *pool, struct page *page)
501{
502 page_pool_release_page(pool, page);
503
504 put_page(page);
505 /* An optimization would be to call __free_pages(page, pool->p.order)
506 * knowing page is not part of page-cache (thus avoiding a
507 * __page_cache_release() call).
508 */
509}
510
511static bool page_pool_recycle_in_ring(struct page_pool *pool, struct page *page)
512{
513 int ret;
514 /* BH protection not needed if current is serving softirq */
515 if (in_serving_softirq())
516 ret = ptr_ring_produce(&pool->ring, page);
517 else
518 ret = ptr_ring_produce_bh(&pool->ring, page);
519
520 if (!ret) {
521 recycle_stat_inc(pool, ring);
522 return true;
523 }
524
525 return false;
526}
527
528/* Only allow direct recycling in special circumstances, into the
529 * alloc side cache. E.g. during RX-NAPI processing for XDP_DROP use-case.
530 *
531 * Caller must provide appropriate safe context.
532 */
533static bool page_pool_recycle_in_cache(struct page *page,
534 struct page_pool *pool)
535{
536 if (unlikely(pool->alloc.count == PP_ALLOC_CACHE_SIZE)) {
537 recycle_stat_inc(pool, cache_full);
538 return false;
539 }
540
541 /* Caller MUST have verified/know (page_ref_count(page) == 1) */
542 pool->alloc.cache[pool->alloc.count++] = page;
543 recycle_stat_inc(pool, cached);
544 return true;
545}
546
547/* If the page refcnt == 1, this will try to recycle the page.
548 * if PP_FLAG_DMA_SYNC_DEV is set, we'll try to sync the DMA area for
549 * the configured size min(dma_sync_size, pool->max_len).
550 * If the page refcnt != 1, then the page will be returned to memory
551 * subsystem.
552 */
553static __always_inline struct page *
554__page_pool_put_page(struct page_pool *pool, struct page *page,
555 unsigned int dma_sync_size, bool allow_direct)
556{
557 /* This allocator is optimized for the XDP mode that uses
558 * one-frame-per-page, but have fallbacks that act like the
559 * regular page allocator APIs.
560 *
561 * refcnt == 1 means page_pool owns page, and can recycle it.
562 *
563 * page is NOT reusable when allocated when system is under
564 * some pressure. (page_is_pfmemalloc)
565 */
566 if (likely(page_ref_count(page) == 1 && !page_is_pfmemalloc(page))) {
567 /* Read barrier done in page_ref_count / READ_ONCE */
568
569 if (pool->p.flags & PP_FLAG_DMA_SYNC_DEV)
570 page_pool_dma_sync_for_device(pool, page,
571 dma_sync_size);
572
573 if (allow_direct && in_serving_softirq() &&
574 page_pool_recycle_in_cache(page, pool))
575 return NULL;
576
577 /* Page found as candidate for recycling */
578 return page;
579 }
580 /* Fallback/non-XDP mode: API user have elevated refcnt.
581 *
582 * Many drivers split up the page into fragments, and some
583 * want to keep doing this to save memory and do refcnt based
584 * recycling. Support this use case too, to ease drivers
585 * switching between XDP/non-XDP.
586 *
587 * In-case page_pool maintains the DMA mapping, API user must
588 * call page_pool_put_page once. In this elevated refcnt
589 * case, the DMA is unmapped/released, as driver is likely
590 * doing refcnt based recycle tricks, meaning another process
591 * will be invoking put_page.
592 */
593 recycle_stat_inc(pool, released_refcnt);
594 /* Do not replace this with page_pool_return_page() */
595 page_pool_release_page(pool, page);
596 put_page(page);
597
598 return NULL;
599}
600
601void page_pool_put_defragged_page(struct page_pool *pool, struct page *page,
602 unsigned int dma_sync_size, bool allow_direct)
603{
604 page = __page_pool_put_page(pool, page, dma_sync_size, allow_direct);
605 if (page && !page_pool_recycle_in_ring(pool, page)) {
606 /* Cache full, fallback to free pages */
607 recycle_stat_inc(pool, ring_full);
608 page_pool_return_page(pool, page);
609 }
610}
611EXPORT_SYMBOL(page_pool_put_defragged_page);
612
613/* Caller must not use data area after call, as this function overwrites it */
614void page_pool_put_page_bulk(struct page_pool *pool, void **data,
615 int count)
616{
617 int i, bulk_len = 0;
618
619 for (i = 0; i < count; i++) {
620 struct page *page = virt_to_head_page(data[i]);
621
622 /* It is not the last user for the page frag case */
623 if (!page_pool_is_last_frag(pool, page))
624 continue;
625
626 page = __page_pool_put_page(pool, page, -1, false);
627 /* Approved for bulk recycling in ptr_ring cache */
628 if (page)
629 data[bulk_len++] = page;
630 }
631
632 if (unlikely(!bulk_len))
633 return;
634
635 /* Bulk producer into ptr_ring page_pool cache */
636 page_pool_ring_lock(pool);
637 for (i = 0; i < bulk_len; i++) {
638 if (__ptr_ring_produce(&pool->ring, data[i])) {
639 /* ring full */
640 recycle_stat_inc(pool, ring_full);
641 break;
642 }
643 }
644 recycle_stat_add(pool, ring, i);
645 page_pool_ring_unlock(pool);
646
647 /* Hopefully all pages was return into ptr_ring */
648 if (likely(i == bulk_len))
649 return;
650
651 /* ptr_ring cache full, free remaining pages outside producer lock
652 * since put_page() with refcnt == 1 can be an expensive operation
653 */
654 for (; i < bulk_len; i++)
655 page_pool_return_page(pool, data[i]);
656}
657EXPORT_SYMBOL(page_pool_put_page_bulk);
658
659static struct page *page_pool_drain_frag(struct page_pool *pool,
660 struct page *page)
661{
662 long drain_count = BIAS_MAX - pool->frag_users;
663
664 /* Some user is still using the page frag */
665 if (likely(page_pool_defrag_page(page, drain_count)))
666 return NULL;
667
668 if (page_ref_count(page) == 1 && !page_is_pfmemalloc(page)) {
669 if (pool->p.flags & PP_FLAG_DMA_SYNC_DEV)
670 page_pool_dma_sync_for_device(pool, page, -1);
671
672 return page;
673 }
674
675 page_pool_return_page(pool, page);
676 return NULL;
677}
678
679static void page_pool_free_frag(struct page_pool *pool)
680{
681 long drain_count = BIAS_MAX - pool->frag_users;
682 struct page *page = pool->frag_page;
683
684 pool->frag_page = NULL;
685
686 if (!page || page_pool_defrag_page(page, drain_count))
687 return;
688
689 page_pool_return_page(pool, page);
690}
691
692struct page *page_pool_alloc_frag(struct page_pool *pool,
693 unsigned int *offset,
694 unsigned int size, gfp_t gfp)
695{
696 unsigned int max_size = PAGE_SIZE << pool->p.order;
697 struct page *page = pool->frag_page;
698
699 if (WARN_ON(!(pool->p.flags & PP_FLAG_PAGE_FRAG) ||
700 size > max_size))
701 return NULL;
702
703 size = ALIGN(size, dma_get_cache_alignment());
704 *offset = pool->frag_offset;
705
706 if (page && *offset + size > max_size) {
707 page = page_pool_drain_frag(pool, page);
708 if (page) {
709 alloc_stat_inc(pool, fast);
710 goto frag_reset;
711 }
712 }
713
714 if (!page) {
715 page = page_pool_alloc_pages(pool, gfp);
716 if (unlikely(!page)) {
717 pool->frag_page = NULL;
718 return NULL;
719 }
720
721 pool->frag_page = page;
722
723frag_reset:
724 pool->frag_users = 1;
725 *offset = 0;
726 pool->frag_offset = size;
727 page_pool_fragment_page(page, BIAS_MAX);
728 return page;
729 }
730
731 pool->frag_users++;
732 pool->frag_offset = *offset + size;
733 alloc_stat_inc(pool, fast);
734 return page;
735}
736EXPORT_SYMBOL(page_pool_alloc_frag);
737
738static void page_pool_empty_ring(struct page_pool *pool)
739{
740 struct page *page;
741
742 /* Empty recycle ring */
743 while ((page = ptr_ring_consume_bh(&pool->ring))) {
744 /* Verify the refcnt invariant of cached pages */
745 if (!(page_ref_count(page) == 1))
746 pr_crit("%s() page_pool refcnt %d violation\n",
747 __func__, page_ref_count(page));
748
749 page_pool_return_page(pool, page);
750 }
751}
752
753static void page_pool_free(struct page_pool *pool)
754{
755 if (pool->disconnect)
756 pool->disconnect(pool);
757
758 ptr_ring_cleanup(&pool->ring, NULL);
759
760 if (pool->p.flags & PP_FLAG_DMA_MAP)
761 put_device(pool->p.dev);
762
763#ifdef CONFIG_PAGE_POOL_STATS
764 free_percpu(pool->recycle_stats);
765#endif
766 kfree(pool);
767}
768
769static void page_pool_empty_alloc_cache_once(struct page_pool *pool)
770{
771 struct page *page;
772
773 if (pool->destroy_cnt)
774 return;
775
776 /* Empty alloc cache, assume caller made sure this is
777 * no-longer in use, and page_pool_alloc_pages() cannot be
778 * call concurrently.
779 */
780 while (pool->alloc.count) {
781 page = pool->alloc.cache[--pool->alloc.count];
782 page_pool_return_page(pool, page);
783 }
784}
785
786static void page_pool_scrub(struct page_pool *pool)
787{
788 page_pool_empty_alloc_cache_once(pool);
789 pool->destroy_cnt++;
790
791 /* No more consumers should exist, but producers could still
792 * be in-flight.
793 */
794 page_pool_empty_ring(pool);
795}
796
797static int page_pool_release(struct page_pool *pool)
798{
799 int inflight;
800
801 page_pool_scrub(pool);
802 inflight = page_pool_inflight(pool);
803 if (!inflight)
804 page_pool_free(pool);
805
806 return inflight;
807}
808
809static void page_pool_release_retry(struct work_struct *wq)
810{
811 struct delayed_work *dwq = to_delayed_work(wq);
812 struct page_pool *pool = container_of(dwq, typeof(*pool), release_dw);
813 int inflight;
814
815 inflight = page_pool_release(pool);
816 if (!inflight)
817 return;
818
819 /* Periodic warning */
820 if (time_after_eq(jiffies, pool->defer_warn)) {
821 int sec = (s32)((u32)jiffies - (u32)pool->defer_start) / HZ;
822
823 pr_warn("%s() stalled pool shutdown %d inflight %d sec\n",
824 __func__, inflight, sec);
825 pool->defer_warn = jiffies + DEFER_WARN_INTERVAL;
826 }
827
828 /* Still not ready to be disconnected, retry later */
829 schedule_delayed_work(&pool->release_dw, DEFER_TIME);
830}
831
832void page_pool_use_xdp_mem(struct page_pool *pool, void (*disconnect)(void *),
833 struct xdp_mem_info *mem)
834{
835 refcount_inc(&pool->user_cnt);
836 pool->disconnect = disconnect;
837 pool->xdp_mem_id = mem->id;
838}
839
840void page_pool_destroy(struct page_pool *pool)
841{
842 if (!pool)
843 return;
844
845 if (!page_pool_put(pool))
846 return;
847
848 page_pool_free_frag(pool);
849
850 if (!page_pool_release(pool))
851 return;
852
853 pool->defer_start = jiffies;
854 pool->defer_warn = jiffies + DEFER_WARN_INTERVAL;
855
856 INIT_DELAYED_WORK(&pool->release_dw, page_pool_release_retry);
857 schedule_delayed_work(&pool->release_dw, DEFER_TIME);
858}
859EXPORT_SYMBOL(page_pool_destroy);
860
861/* Caller must provide appropriate safe context, e.g. NAPI. */
862void page_pool_update_nid(struct page_pool *pool, int new_nid)
863{
864 struct page *page;
865
866 trace_page_pool_update_nid(pool, new_nid);
867 pool->p.nid = new_nid;
868
869 /* Flush pool alloc cache, as refill will check NUMA node */
870 while (pool->alloc.count) {
871 page = pool->alloc.cache[--pool->alloc.count];
872 page_pool_return_page(pool, page);
873 }
874}
875EXPORT_SYMBOL(page_pool_update_nid);
876
877bool page_pool_return_skb_page(struct page *page)
878{
879 struct page_pool *pp;
880
881 page = compound_head(page);
882
883 /* page->pp_magic is OR'ed with PP_SIGNATURE after the allocation
884 * in order to preserve any existing bits, such as bit 0 for the
885 * head page of compound page and bit 1 for pfmemalloc page, so
886 * mask those bits for freeing side when doing below checking,
887 * and page_is_pfmemalloc() is checked in __page_pool_put_page()
888 * to avoid recycling the pfmemalloc page.
889 */
890 if (unlikely((page->pp_magic & ~0x3UL) != PP_SIGNATURE))
891 return false;
892
893 pp = page->pp;
894
895 /* Driver set this to memory recycling info. Reset it on recycle.
896 * This will *not* work for NIC using a split-page memory model.
897 * The page will be returned to the pool here regardless of the
898 * 'flipped' fragment being in use or not.
899 */
900 page_pool_put_full_page(pp, page, false);
901
902 return true;
903}
904EXPORT_SYMBOL(page_pool_return_skb_page);