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_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  */
page_pool_alloc_pages(struct page_pool * pool,gfp_t gfp)431 struct 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 }
444 EXPORT_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 
page_pool_inflight(struct page_pool * pool)451 static 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  */
page_pool_release_page(struct page_pool * pool,struct page * page)470 void 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);
488 skip_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 }
497 EXPORT_SYMBOL(page_pool_release_page);
498 
499 /* Return a page to the page allocator, cleaning up our state */
page_pool_return_page(struct page_pool * pool,struct page * page)500 static 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 
page_pool_recycle_in_ring(struct page_pool * pool,struct page * page)511 static 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  */
page_pool_recycle_in_cache(struct page * page,struct page_pool * pool)533 static 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  */
553 static __always_inline struct page *
__page_pool_put_page(struct page_pool * pool,struct page * page,unsigned int dma_sync_size,bool allow_direct)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 
page_pool_put_defragged_page(struct page_pool * pool,struct page * page,unsigned int dma_sync_size,bool allow_direct)601 void 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 }
611 EXPORT_SYMBOL(page_pool_put_defragged_page);
612 
613 /* 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)614 void 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 }
657 EXPORT_SYMBOL(page_pool_put_page_bulk);
658 
page_pool_drain_frag(struct page_pool * pool,struct page * page)659 static 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 
page_pool_free_frag(struct page_pool * pool)679 static 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 
page_pool_alloc_frag(struct page_pool * pool,unsigned int * offset,unsigned int size,gfp_t gfp)692 struct 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 
723 frag_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 }
736 EXPORT_SYMBOL(page_pool_alloc_frag);
737 
page_pool_empty_ring(struct page_pool * pool)738 static 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 
page_pool_free(struct page_pool * pool)753 static 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 
page_pool_empty_alloc_cache_once(struct page_pool * pool)769 static 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 
page_pool_scrub(struct page_pool * pool)786 static 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 
page_pool_release(struct page_pool * pool)797 static 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 
page_pool_release_retry(struct work_struct * wq)809 static 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 
page_pool_use_xdp_mem(struct page_pool * pool,void (* disconnect)(void *),struct xdp_mem_info * mem)832 void 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 
page_pool_destroy(struct page_pool * pool)840 void 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 }
859 EXPORT_SYMBOL(page_pool_destroy);
860 
861 /* Caller must provide appropriate safe context, e.g. NAPI. */
page_pool_update_nid(struct page_pool * pool,int new_nid)862 void 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 }
875 EXPORT_SYMBOL(page_pool_update_nid);
876 
page_pool_return_skb_page(struct page * page)877 bool 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 }
904 EXPORT_SYMBOL(page_pool_return_skb_page);
905