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 
46 static 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 
page_pool_get_stats(struct page_pool * pool,struct page_pool_stats * stats)60 bool 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 }
89 EXPORT_SYMBOL(page_pool_get_stats);
90 
page_pool_ethtool_stats_get_strings(u8 * data)91 u8 *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 }
102 EXPORT_SYMBOL(page_pool_ethtool_stats_get_strings);
103 
page_pool_ethtool_stats_get_count(void)104 int page_pool_ethtool_stats_get_count(void)
105 {
106 	return ARRAY_SIZE(pp_stats);
107 }
108 EXPORT_SYMBOL(page_pool_ethtool_stats_get_count);
109 
page_pool_ethtool_stats_get(u64 * data,void * stats)110 u64 *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 }
128 EXPORT_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 
page_pool_init(struct page_pool * pool,const struct page_pool_params * params)136 static 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 
page_pool_create(const struct page_pool_params * params)203 struct 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 }
221 EXPORT_SYMBOL(page_pool_create);
222 
223 static void page_pool_return_page(struct page_pool *pool, struct page *page);
224 
225 noinline
page_pool_refill_alloc_cache(struct page_pool * pool)226 static 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 */
__page_pool_get_cached(struct page_pool * pool)279 static 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 
page_pool_dma_sync_for_device(struct page_pool * pool,struct page * page,unsigned int dma_sync_size)295 static 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 
page_pool_dma_map(struct page_pool * pool,struct page * page)307 static 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 
page_pool_set_pp_info(struct page_pool * pool,struct page * page)330 static 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 
page_pool_clear_pp_info(struct page * page)339 static void page_pool_clear_pp_info(struct page *page)
340 {
341 	page->pp_magic = 0;
342 	page->pp = NULL;
343 }
344 
__page_pool_alloc_page_order(struct page_pool * pool,gfp_t gfp)345 static 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 */
371 noinline
__page_pool_alloc_pages_slow(struct page_pool * pool,gfp_t gfp)372 static 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(gfp, bulk, pool->alloc.cache);
393 	if (unlikely(!nr_pages))
394 		return NULL;
395 
396 	/* Pages have been filled into alloc.cache array, but count is zero and
397 	 * page element have not been (possibly) DMA mapped.
398 	 */
399 	for (i = 0; i < nr_pages; i++) {
400 		page = pool->alloc.cache[i];
401 		if ((pp_flags & PP_FLAG_DMA_MAP) &&
402 		    unlikely(!page_pool_dma_map(pool, page))) {
403 			put_page(page);
404 			continue;
405 		}
406 
407 		page_pool_set_pp_info(pool, page);
408 		pool->alloc.cache[pool->alloc.count++] = page;
409 		/* Track how many pages are held 'in-flight' */
410 		pool->pages_state_hold_cnt++;
411 		trace_page_pool_state_hold(pool, page,
412 					   pool->pages_state_hold_cnt);
413 	}
414 
415 	/* Return last page */
416 	if (likely(pool->alloc.count > 0)) {
417 		page = pool->alloc.cache[--pool->alloc.count];
418 		alloc_stat_inc(pool, slow);
419 	} else {
420 		page = NULL;
421 	}
422 
423 	/* When page just alloc'ed is should/must have refcnt 1. */
424 	return page;
425 }
426 
427 /* For using page_pool replace: alloc_pages() API calls, but provide
428  * synchronization guarantee for allocation side.
429  */
page_pool_alloc_pages(struct page_pool * pool,gfp_t gfp)430 struct page *page_pool_alloc_pages(struct page_pool *pool, gfp_t gfp)
431 {
432 	struct page *page;
433 
434 	/* Fast-path: Get a page from cache */
435 	page = __page_pool_get_cached(pool);
436 	if (page)
437 		return page;
438 
439 	/* Slow-path: cache empty, do real allocation */
440 	page = __page_pool_alloc_pages_slow(pool, gfp);
441 	return page;
442 }
443 EXPORT_SYMBOL(page_pool_alloc_pages);
444 
445 /* Calculate distance between two u32 values, valid if distance is below 2^(31)
446  *  https://en.wikipedia.org/wiki/Serial_number_arithmetic#General_Solution
447  */
448 #define _distance(a, b)	(s32)((a) - (b))
449 
page_pool_inflight(struct page_pool * pool)450 static s32 page_pool_inflight(struct page_pool *pool)
451 {
452 	u32 release_cnt = atomic_read(&pool->pages_state_release_cnt);
453 	u32 hold_cnt = READ_ONCE(pool->pages_state_hold_cnt);
454 	s32 inflight;
455 
456 	inflight = _distance(hold_cnt, release_cnt);
457 
458 	trace_page_pool_release(pool, inflight, hold_cnt, release_cnt);
459 	WARN(inflight < 0, "Negative(%d) inflight packet-pages", inflight);
460 
461 	return inflight;
462 }
463 
464 /* Disconnects a page (from a page_pool).  API users can have a need
465  * to disconnect a page (from a page_pool), to allow it to be used as
466  * a regular page (that will eventually be returned to the normal
467  * page-allocator via put_page).
468  */
page_pool_release_page(struct page_pool * pool,struct page * page)469 void page_pool_release_page(struct page_pool *pool, struct page *page)
470 {
471 	dma_addr_t dma;
472 	int count;
473 
474 	if (!(pool->p.flags & PP_FLAG_DMA_MAP))
475 		/* Always account for inflight pages, even if we didn't
476 		 * map them
477 		 */
478 		goto skip_dma_unmap;
479 
480 	dma = page_pool_get_dma_addr(page);
481 
482 	/* When page is unmapped, it cannot be returned to our pool */
483 	dma_unmap_page_attrs(pool->p.dev, dma,
484 			     PAGE_SIZE << pool->p.order, pool->p.dma_dir,
485 			     DMA_ATTR_SKIP_CPU_SYNC);
486 	page_pool_set_dma_addr(page, 0);
487 skip_dma_unmap:
488 	page_pool_clear_pp_info(page);
489 
490 	/* This may be the last page returned, releasing the pool, so
491 	 * it is not safe to reference pool afterwards.
492 	 */
493 	count = atomic_inc_return_relaxed(&pool->pages_state_release_cnt);
494 	trace_page_pool_state_release(pool, page, count);
495 }
496 EXPORT_SYMBOL(page_pool_release_page);
497 
498 /* Return a page to the page allocator, cleaning up our state */
page_pool_return_page(struct page_pool * pool,struct page * page)499 static void page_pool_return_page(struct page_pool *pool, struct page *page)
500 {
501 	page_pool_release_page(pool, page);
502 
503 	put_page(page);
504 	/* An optimization would be to call __free_pages(page, pool->p.order)
505 	 * knowing page is not part of page-cache (thus avoiding a
506 	 * __page_cache_release() call).
507 	 */
508 }
509 
page_pool_recycle_in_ring(struct page_pool * pool,struct page * page)510 static bool page_pool_recycle_in_ring(struct page_pool *pool, struct page *page)
511 {
512 	int ret;
513 	/* BH protection not needed if current is serving softirq */
514 	if (in_serving_softirq())
515 		ret = ptr_ring_produce(&pool->ring, page);
516 	else
517 		ret = ptr_ring_produce_bh(&pool->ring, page);
518 
519 	if (!ret) {
520 		recycle_stat_inc(pool, ring);
521 		return true;
522 	}
523 
524 	return false;
525 }
526 
527 /* Only allow direct recycling in special circumstances, into the
528  * alloc side cache.  E.g. during RX-NAPI processing for XDP_DROP use-case.
529  *
530  * Caller must provide appropriate safe context.
531  */
page_pool_recycle_in_cache(struct page * page,struct page_pool * pool)532 static bool page_pool_recycle_in_cache(struct page *page,
533 				       struct page_pool *pool)
534 {
535 	if (unlikely(pool->alloc.count == PP_ALLOC_CACHE_SIZE)) {
536 		recycle_stat_inc(pool, cache_full);
537 		return false;
538 	}
539 
540 	/* Caller MUST have verified/know (page_ref_count(page) == 1) */
541 	pool->alloc.cache[pool->alloc.count++] = page;
542 	recycle_stat_inc(pool, cached);
543 	return true;
544 }
545 
546 /* If the page refcnt == 1, this will try to recycle the page.
547  * if PP_FLAG_DMA_SYNC_DEV is set, we'll try to sync the DMA area for
548  * the configured size min(dma_sync_size, pool->max_len).
549  * If the page refcnt != 1, then the page will be returned to memory
550  * subsystem.
551  */
552 static __always_inline struct page *
__page_pool_put_page(struct page_pool * pool,struct page * page,unsigned int dma_sync_size,bool allow_direct)553 __page_pool_put_page(struct page_pool *pool, struct page *page,
554 		     unsigned int dma_sync_size, bool allow_direct)
555 {
556 	/* This allocator is optimized for the XDP mode that uses
557 	 * one-frame-per-page, but have fallbacks that act like the
558 	 * regular page allocator APIs.
559 	 *
560 	 * refcnt == 1 means page_pool owns page, and can recycle it.
561 	 *
562 	 * page is NOT reusable when allocated when system is under
563 	 * some pressure. (page_is_pfmemalloc)
564 	 */
565 	if (likely(page_ref_count(page) == 1 && !page_is_pfmemalloc(page))) {
566 		/* Read barrier done in page_ref_count / READ_ONCE */
567 
568 		if (pool->p.flags & PP_FLAG_DMA_SYNC_DEV)
569 			page_pool_dma_sync_for_device(pool, page,
570 						      dma_sync_size);
571 
572 		if (allow_direct && in_serving_softirq() &&
573 		    page_pool_recycle_in_cache(page, pool))
574 			return NULL;
575 
576 		/* Page found as candidate for recycling */
577 		return page;
578 	}
579 	/* Fallback/non-XDP mode: API user have elevated refcnt.
580 	 *
581 	 * Many drivers split up the page into fragments, and some
582 	 * want to keep doing this to save memory and do refcnt based
583 	 * recycling. Support this use case too, to ease drivers
584 	 * switching between XDP/non-XDP.
585 	 *
586 	 * In-case page_pool maintains the DMA mapping, API user must
587 	 * call page_pool_put_page once.  In this elevated refcnt
588 	 * case, the DMA is unmapped/released, as driver is likely
589 	 * doing refcnt based recycle tricks, meaning another process
590 	 * will be invoking put_page.
591 	 */
592 	recycle_stat_inc(pool, released_refcnt);
593 	/* Do not replace this with page_pool_return_page() */
594 	page_pool_release_page(pool, page);
595 	put_page(page);
596 
597 	return NULL;
598 }
599 
page_pool_put_defragged_page(struct page_pool * pool,struct page * page,unsigned int dma_sync_size,bool allow_direct)600 void page_pool_put_defragged_page(struct page_pool *pool, struct page *page,
601 				  unsigned int dma_sync_size, bool allow_direct)
602 {
603 	page = __page_pool_put_page(pool, page, dma_sync_size, allow_direct);
604 	if (page && !page_pool_recycle_in_ring(pool, page)) {
605 		/* Cache full, fallback to free pages */
606 		recycle_stat_inc(pool, ring_full);
607 		page_pool_return_page(pool, page);
608 	}
609 }
610 EXPORT_SYMBOL(page_pool_put_defragged_page);
611 
612 /* Caller must not use data area after call, as this function overwrites it */
page_pool_put_page_bulk(struct page_pool * pool,void ** data,int count)613 void page_pool_put_page_bulk(struct page_pool *pool, void **data,
614 			     int count)
615 {
616 	int i, bulk_len = 0;
617 
618 	for (i = 0; i < count; i++) {
619 		struct page *page = virt_to_head_page(data[i]);
620 
621 		/* It is not the last user for the page frag case */
622 		if (!page_pool_is_last_frag(pool, page))
623 			continue;
624 
625 		page = __page_pool_put_page(pool, page, -1, false);
626 		/* Approved for bulk recycling in ptr_ring cache */
627 		if (page)
628 			data[bulk_len++] = page;
629 	}
630 
631 	if (unlikely(!bulk_len))
632 		return;
633 
634 	/* Bulk producer into ptr_ring page_pool cache */
635 	page_pool_ring_lock(pool);
636 	for (i = 0; i < bulk_len; i++) {
637 		if (__ptr_ring_produce(&pool->ring, data[i])) {
638 			/* ring full */
639 			recycle_stat_inc(pool, ring_full);
640 			break;
641 		}
642 	}
643 	recycle_stat_add(pool, ring, i);
644 	page_pool_ring_unlock(pool);
645 
646 	/* Hopefully all pages was return into ptr_ring */
647 	if (likely(i == bulk_len))
648 		return;
649 
650 	/* ptr_ring cache full, free remaining pages outside producer lock
651 	 * since put_page() with refcnt == 1 can be an expensive operation
652 	 */
653 	for (; i < bulk_len; i++)
654 		page_pool_return_page(pool, data[i]);
655 }
656 EXPORT_SYMBOL(page_pool_put_page_bulk);
657 
page_pool_drain_frag(struct page_pool * pool,struct page * page)658 static struct page *page_pool_drain_frag(struct page_pool *pool,
659 					 struct page *page)
660 {
661 	long drain_count = BIAS_MAX - pool->frag_users;
662 
663 	/* Some user is still using the page frag */
664 	if (likely(page_pool_defrag_page(page, drain_count)))
665 		return NULL;
666 
667 	if (page_ref_count(page) == 1 && !page_is_pfmemalloc(page)) {
668 		if (pool->p.flags & PP_FLAG_DMA_SYNC_DEV)
669 			page_pool_dma_sync_for_device(pool, page, -1);
670 
671 		return page;
672 	}
673 
674 	page_pool_return_page(pool, page);
675 	return NULL;
676 }
677 
page_pool_free_frag(struct page_pool * pool)678 static void page_pool_free_frag(struct page_pool *pool)
679 {
680 	long drain_count = BIAS_MAX - pool->frag_users;
681 	struct page *page = pool->frag_page;
682 
683 	pool->frag_page = NULL;
684 
685 	if (!page || page_pool_defrag_page(page, drain_count))
686 		return;
687 
688 	page_pool_return_page(pool, page);
689 }
690 
page_pool_alloc_frag(struct page_pool * pool,unsigned int * offset,unsigned int size,gfp_t gfp)691 struct page *page_pool_alloc_frag(struct page_pool *pool,
692 				  unsigned int *offset,
693 				  unsigned int size, gfp_t gfp)
694 {
695 	unsigned int max_size = PAGE_SIZE << pool->p.order;
696 	struct page *page = pool->frag_page;
697 
698 	if (WARN_ON(!(pool->p.flags & PP_FLAG_PAGE_FRAG) ||
699 		    size > max_size))
700 		return NULL;
701 
702 	size = ALIGN(size, dma_get_cache_alignment());
703 	*offset = pool->frag_offset;
704 
705 	if (page && *offset + size > max_size) {
706 		page = page_pool_drain_frag(pool, page);
707 		if (page) {
708 			alloc_stat_inc(pool, fast);
709 			goto frag_reset;
710 		}
711 	}
712 
713 	if (!page) {
714 		page = page_pool_alloc_pages(pool, gfp);
715 		if (unlikely(!page)) {
716 			pool->frag_page = NULL;
717 			return NULL;
718 		}
719 
720 		pool->frag_page = page;
721 
722 frag_reset:
723 		pool->frag_users = 1;
724 		*offset = 0;
725 		pool->frag_offset = size;
726 		page_pool_fragment_page(page, BIAS_MAX);
727 		return page;
728 	}
729 
730 	pool->frag_users++;
731 	pool->frag_offset = *offset + size;
732 	alloc_stat_inc(pool, fast);
733 	return page;
734 }
735 EXPORT_SYMBOL(page_pool_alloc_frag);
736 
page_pool_empty_ring(struct page_pool * pool)737 static void page_pool_empty_ring(struct page_pool *pool)
738 {
739 	struct page *page;
740 
741 	/* Empty recycle ring */
742 	while ((page = ptr_ring_consume_bh(&pool->ring))) {
743 		/* Verify the refcnt invariant of cached pages */
744 		if (!(page_ref_count(page) == 1))
745 			pr_crit("%s() page_pool refcnt %d violation\n",
746 				__func__, page_ref_count(page));
747 
748 		page_pool_return_page(pool, page);
749 	}
750 }
751 
page_pool_free(struct page_pool * pool)752 static void page_pool_free(struct page_pool *pool)
753 {
754 	if (pool->disconnect)
755 		pool->disconnect(pool);
756 
757 	ptr_ring_cleanup(&pool->ring, NULL);
758 
759 	if (pool->p.flags & PP_FLAG_DMA_MAP)
760 		put_device(pool->p.dev);
761 
762 #ifdef CONFIG_PAGE_POOL_STATS
763 	free_percpu(pool->recycle_stats);
764 #endif
765 	kfree(pool);
766 }
767 
page_pool_empty_alloc_cache_once(struct page_pool * pool)768 static void page_pool_empty_alloc_cache_once(struct page_pool *pool)
769 {
770 	struct page *page;
771 
772 	if (pool->destroy_cnt)
773 		return;
774 
775 	/* Empty alloc cache, assume caller made sure this is
776 	 * no-longer in use, and page_pool_alloc_pages() cannot be
777 	 * call concurrently.
778 	 */
779 	while (pool->alloc.count) {
780 		page = pool->alloc.cache[--pool->alloc.count];
781 		page_pool_return_page(pool, page);
782 	}
783 }
784 
page_pool_scrub(struct page_pool * pool)785 static void page_pool_scrub(struct page_pool *pool)
786 {
787 	page_pool_empty_alloc_cache_once(pool);
788 	pool->destroy_cnt++;
789 
790 	/* No more consumers should exist, but producers could still
791 	 * be in-flight.
792 	 */
793 	page_pool_empty_ring(pool);
794 }
795 
page_pool_release(struct page_pool * pool)796 static int page_pool_release(struct page_pool *pool)
797 {
798 	int inflight;
799 
800 	page_pool_scrub(pool);
801 	inflight = page_pool_inflight(pool);
802 	if (!inflight)
803 		page_pool_free(pool);
804 
805 	return inflight;
806 }
807 
page_pool_release_retry(struct work_struct * wq)808 static void page_pool_release_retry(struct work_struct *wq)
809 {
810 	struct delayed_work *dwq = to_delayed_work(wq);
811 	struct page_pool *pool = container_of(dwq, typeof(*pool), release_dw);
812 	int inflight;
813 
814 	inflight = page_pool_release(pool);
815 	if (!inflight)
816 		return;
817 
818 	/* Periodic warning */
819 	if (time_after_eq(jiffies, pool->defer_warn)) {
820 		int sec = (s32)((u32)jiffies - (u32)pool->defer_start) / HZ;
821 
822 		pr_warn("%s() stalled pool shutdown %d inflight %d sec\n",
823 			__func__, inflight, sec);
824 		pool->defer_warn = jiffies + DEFER_WARN_INTERVAL;
825 	}
826 
827 	/* Still not ready to be disconnected, retry later */
828 	schedule_delayed_work(&pool->release_dw, DEFER_TIME);
829 }
830 
page_pool_use_xdp_mem(struct page_pool * pool,void (* disconnect)(void *),struct xdp_mem_info * mem)831 void page_pool_use_xdp_mem(struct page_pool *pool, void (*disconnect)(void *),
832 			   struct xdp_mem_info *mem)
833 {
834 	refcount_inc(&pool->user_cnt);
835 	pool->disconnect = disconnect;
836 	pool->xdp_mem_id = mem->id;
837 }
838 
page_pool_destroy(struct page_pool * pool)839 void page_pool_destroy(struct page_pool *pool)
840 {
841 	if (!pool)
842 		return;
843 
844 	if (!page_pool_put(pool))
845 		return;
846 
847 	page_pool_free_frag(pool);
848 
849 	if (!page_pool_release(pool))
850 		return;
851 
852 	pool->defer_start = jiffies;
853 	pool->defer_warn  = jiffies + DEFER_WARN_INTERVAL;
854 
855 	INIT_DELAYED_WORK(&pool->release_dw, page_pool_release_retry);
856 	schedule_delayed_work(&pool->release_dw, DEFER_TIME);
857 }
858 EXPORT_SYMBOL(page_pool_destroy);
859 
860 /* Caller must provide appropriate safe context, e.g. NAPI. */
page_pool_update_nid(struct page_pool * pool,int new_nid)861 void page_pool_update_nid(struct page_pool *pool, int new_nid)
862 {
863 	struct page *page;
864 
865 	trace_page_pool_update_nid(pool, new_nid);
866 	pool->p.nid = new_nid;
867 
868 	/* Flush pool alloc cache, as refill will check NUMA node */
869 	while (pool->alloc.count) {
870 		page = pool->alloc.cache[--pool->alloc.count];
871 		page_pool_return_page(pool, page);
872 	}
873 }
874 EXPORT_SYMBOL(page_pool_update_nid);
875 
page_pool_return_skb_page(struct page * page)876 bool page_pool_return_skb_page(struct page *page)
877 {
878 	struct page_pool *pp;
879 
880 	page = compound_head(page);
881 
882 	/* page->pp_magic is OR'ed with PP_SIGNATURE after the allocation
883 	 * in order to preserve any existing bits, such as bit 0 for the
884 	 * head page of compound page and bit 1 for pfmemalloc page, so
885 	 * mask those bits for freeing side when doing below checking,
886 	 * and page_is_pfmemalloc() is checked in __page_pool_put_page()
887 	 * to avoid recycling the pfmemalloc page.
888 	 */
889 	if (unlikely((page->pp_magic & ~0x3UL) != PP_SIGNATURE))
890 		return false;
891 
892 	pp = page->pp;
893 
894 	/* Driver set this to memory recycling info. Reset it on recycle.
895 	 * This will *not* work for NIC using a split-page memory model.
896 	 * The page will be returned to the pool here regardless of the
897 	 * 'flipped' fragment being in use or not.
898 	 */
899 	page_pool_put_full_page(pp, page, false);
900 
901 	return true;
902 }
903 EXPORT_SYMBOL(page_pool_return_skb_page);
904