1/*
  2 * Copyright (c) Red Hat Inc.
  3
  4 * Permission is hereby granted, free of charge, to any person obtaining a
  5 * copy of this software and associated documentation files (the "Software"),
  6 * to deal in the Software without restriction, including without limitation
  7 * the rights to use, copy, modify, merge, publish, distribute, sub license,
  8 * and/or sell copies of the Software, and to permit persons to whom the
  9 * Software is furnished to do so, subject to the following conditions:
 10 *
 11 * The above copyright notice and this permission notice (including the
 12 * next paragraph) shall be included in all copies or substantial portions
 13 * of the Software.
 14 *
 15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 17 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
 18 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 20 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 21 * DEALINGS IN THE SOFTWARE.
 22 *
 23 * Authors: Dave Airlie <airlied@redhat.com>
 24 *          Jerome Glisse <jglisse@redhat.com>
 25 *          Pauli Nieminen <suokkos@gmail.com>
 26 */
 27
 28/* simple list based uncached page pool
 29 * - Pool collects resently freed pages for reuse
 30 * - Use page->lru to keep a free list
 31 * - doesn't track currently in use pages
 32 */
 33
 34#define pr_fmt(fmt) "[TTM] " fmt
 35
 36#include <linux/list.h>
 37#include <linux/spinlock.h>
 38#include <linux/highmem.h>
 39#include <linux/mm_types.h>
 40#include <linux/module.h>
 41#include <linux/mm.h>
 42#include <linux/seq_file.h> /* for seq_printf */
 43#include <linux/slab.h>
 44#include <linux/dma-mapping.h>
 45
 46#include <linux/atomic.h>
 47
 48#include <drm/ttm/ttm_bo_driver.h>
 49#include <drm/ttm/ttm_page_alloc.h>
 50
 51#ifdef TTM_HAS_AGP
 52#include <asm/agp.h>
 53#endif
 54
 55#define NUM_PAGES_TO_ALLOC		(PAGE_SIZE/sizeof(struct page *))
 56#define SMALL_ALLOCATION		16
 57#define FREE_ALL_PAGES			(~0U)
 58/* times are in msecs */
 59#define PAGE_FREE_INTERVAL		1000
 60
 61/**
 62 * struct ttm_page_pool - Pool to reuse recently allocated uc/wc pages.
 63 *
 64 * @lock: Protects the shared pool from concurrnet access. Must be used with
 65 * irqsave/irqrestore variants because pool allocator maybe called from
 66 * delayed work.
 67 * @fill_lock: Prevent concurrent calls to fill.
 68 * @list: Pool of free uc/wc pages for fast reuse.
 69 * @gfp_flags: Flags to pass for alloc_page.
 70 * @npages: Number of pages in pool.
 71 */
 72struct ttm_page_pool {
 73	spinlock_t		lock;
 74	bool			fill_lock;
 75	struct list_head	list;
 76	gfp_t			gfp_flags;
 77	unsigned		npages;
 78	char			*name;
 79	unsigned long		nfrees;
 80	unsigned long		nrefills;
 81};
 82
 83/**
 84 * Limits for the pool. They are handled without locks because only place where
 85 * they may change is in sysfs store. They won't have immediate effect anyway
 86 * so forcing serialization to access them is pointless.
 87 */
 88
 89struct ttm_pool_opts {
 90	unsigned	alloc_size;
 91	unsigned	max_size;
 92	unsigned	small;
 93};
 94
 95#define NUM_POOLS 4
 96
 97/**
 98 * struct ttm_pool_manager - Holds memory pools for fst allocation
 99 *
100 * Manager is read only object for pool code so it doesn't need locking.
101 *
102 * @free_interval: minimum number of jiffies between freeing pages from pool.
103 * @page_alloc_inited: reference counting for pool allocation.
104 * @work: Work that is used to shrink the pool. Work is only run when there is
105 * some pages to free.
106 * @small_allocation: Limit in number of pages what is small allocation.
107 *
108 * @pools: All pool objects in use.
109 **/
110struct ttm_pool_manager {
111	struct kobject		kobj;
112	struct shrinker		mm_shrink;
113	struct ttm_pool_opts	options;
114
115	union {
116		struct ttm_page_pool	pools[NUM_POOLS];
117		struct {
118			struct ttm_page_pool	wc_pool;
119			struct ttm_page_pool	uc_pool;
120			struct ttm_page_pool	wc_pool_dma32;
121			struct ttm_page_pool	uc_pool_dma32;
122		} ;
123	};
124};
125
126static struct attribute ttm_page_pool_max = {
127	.name = "pool_max_size",
128	.mode = S_IRUGO | S_IWUSR
129};
130static struct attribute ttm_page_pool_small = {
131	.name = "pool_small_allocation",
132	.mode = S_IRUGO | S_IWUSR
133};
134static struct attribute ttm_page_pool_alloc_size = {
135	.name = "pool_allocation_size",
136	.mode = S_IRUGO | S_IWUSR
137};
138
139static struct attribute *ttm_pool_attrs[] = {
140	&ttm_page_pool_max,
141	&ttm_page_pool_small,
142	&ttm_page_pool_alloc_size,
143	NULL
144};
145
146static void ttm_pool_kobj_release(struct kobject *kobj)
147{
148	struct ttm_pool_manager *m =
149		container_of(kobj, struct ttm_pool_manager, kobj);
150	kfree(m);
151}
152
153static ssize_t ttm_pool_store(struct kobject *kobj,
154		struct attribute *attr, const char *buffer, size_t size)
155{
156	struct ttm_pool_manager *m =
157		container_of(kobj, struct ttm_pool_manager, kobj);
158	int chars;
159	unsigned val;
160	chars = sscanf(buffer, "%u", &val);
161	if (chars == 0)
162		return size;
163
164	/* Convert kb to number of pages */
165	val = val / (PAGE_SIZE >> 10);
166
167	if (attr == &ttm_page_pool_max)
168		m->options.max_size = val;
169	else if (attr == &ttm_page_pool_small)
170		m->options.small = val;
171	else if (attr == &ttm_page_pool_alloc_size) {
172		if (val > NUM_PAGES_TO_ALLOC*8) {
173			pr_err("Setting allocation size to %lu is not allowed. Recommended size is %lu\n",
174			       NUM_PAGES_TO_ALLOC*(PAGE_SIZE >> 7),
175			       NUM_PAGES_TO_ALLOC*(PAGE_SIZE >> 10));
176			return size;
177		} else if (val > NUM_PAGES_TO_ALLOC) {
178			pr_warn("Setting allocation size to larger than %lu is not recommended\n",
179				NUM_PAGES_TO_ALLOC*(PAGE_SIZE >> 10));
180		}
181		m->options.alloc_size = val;
182	}
183
184	return size;
185}
186
187static ssize_t ttm_pool_show(struct kobject *kobj,
188		struct attribute *attr, char *buffer)
189{
190	struct ttm_pool_manager *m =
191		container_of(kobj, struct ttm_pool_manager, kobj);
192	unsigned val = 0;
193
194	if (attr == &ttm_page_pool_max)
195		val = m->options.max_size;
196	else if (attr == &ttm_page_pool_small)
197		val = m->options.small;
198	else if (attr == &ttm_page_pool_alloc_size)
199		val = m->options.alloc_size;
200
201	val = val * (PAGE_SIZE >> 10);
202
203	return snprintf(buffer, PAGE_SIZE, "%u\n", val);
204}
205
206static const struct sysfs_ops ttm_pool_sysfs_ops = {
207	.show = &ttm_pool_show,
208	.store = &ttm_pool_store,
209};
210
211static struct kobj_type ttm_pool_kobj_type = {
212	.release = &ttm_pool_kobj_release,
213	.sysfs_ops = &ttm_pool_sysfs_ops,
214	.default_attrs = ttm_pool_attrs,
215};
216
217static struct ttm_pool_manager *_manager;
218
219#ifndef CONFIG_X86
220static int set_pages_array_wb(struct page **pages, int addrinarray)
221{
222#ifdef TTM_HAS_AGP
223	int i;
224
225	for (i = 0; i < addrinarray; i++)
226		unmap_page_from_agp(pages[i]);
227#endif
228	return 0;
229}
230
231static int set_pages_array_wc(struct page **pages, int addrinarray)
232{
233#ifdef TTM_HAS_AGP
234	int i;
235
236	for (i = 0; i < addrinarray; i++)
237		map_page_into_agp(pages[i]);
238#endif
239	return 0;
240}
241
242static int set_pages_array_uc(struct page **pages, int addrinarray)
243{
244#ifdef TTM_HAS_AGP
245	int i;
246
247	for (i = 0; i < addrinarray; i++)
248		map_page_into_agp(pages[i]);
249#endif
250	return 0;
251}
252#endif
253
254/**
255 * Select the right pool or requested caching state and ttm flags. */
256static struct ttm_page_pool *ttm_get_pool(int flags,
257		enum ttm_caching_state cstate)
258{
259	int pool_index;
260
261	if (cstate == tt_cached)
262		return NULL;
263
264	if (cstate == tt_wc)
265		pool_index = 0x0;
266	else
267		pool_index = 0x1;
268
269	if (flags & TTM_PAGE_FLAG_DMA32)
270		pool_index |= 0x2;
271
272	return &_manager->pools[pool_index];
273}
274
275/* set memory back to wb and free the pages. */
276static void ttm_pages_put(struct page *pages[], unsigned npages)
277{
278	unsigned i;
279	if (set_pages_array_wb(pages, npages))
280		pr_err("Failed to set %d pages to wb!\n", npages);
281	for (i = 0; i < npages; ++i)
282		__free_page(pages[i]);
283}
284
285static void ttm_pool_update_free_locked(struct ttm_page_pool *pool,
286		unsigned freed_pages)
287{
288	pool->npages -= freed_pages;
289	pool->nfrees += freed_pages;
290}
291
292/**
293 * Free pages from pool.
294 *
295 * To prevent hogging the ttm_swap process we only free NUM_PAGES_TO_ALLOC
296 * number of pages in one go.
297 *
298 * @pool: to free the pages from
299 * @free_all: If set to true will free all pages in pool
300 * @use_static: Safe to use static buffer
301 **/
302static int ttm_page_pool_free(struct ttm_page_pool *pool, unsigned nr_free,
303			      bool use_static)
304{
305	static struct page *static_buf[NUM_PAGES_TO_ALLOC];
306	unsigned long irq_flags;
307	struct page *p;
308	struct page **pages_to_free;
309	unsigned freed_pages = 0,
310		 npages_to_free = nr_free;
311
312	if (NUM_PAGES_TO_ALLOC < nr_free)
313		npages_to_free = NUM_PAGES_TO_ALLOC;
314
315	if (use_static)
316		pages_to_free = static_buf;
317	else
318		pages_to_free = kmalloc(npages_to_free * sizeof(struct page *),
319					GFP_KERNEL);
320	if (!pages_to_free) {
321		pr_err("Failed to allocate memory for pool free operation\n");
322		return 0;
323	}
324
325restart:
326	spin_lock_irqsave(&pool->lock, irq_flags);
327
328	list_for_each_entry_reverse(p, &pool->list, lru) {
329		if (freed_pages >= npages_to_free)
330			break;
331
332		pages_to_free[freed_pages++] = p;
333		/* We can only remove NUM_PAGES_TO_ALLOC at a time. */
334		if (freed_pages >= NUM_PAGES_TO_ALLOC) {
335			/* remove range of pages from the pool */
336			__list_del(p->lru.prev, &pool->list);
337
338			ttm_pool_update_free_locked(pool, freed_pages);
339			/**
340			 * Because changing page caching is costly
341			 * we unlock the pool to prevent stalling.
342			 */
343			spin_unlock_irqrestore(&pool->lock, irq_flags);
344
345			ttm_pages_put(pages_to_free, freed_pages);
346			if (likely(nr_free != FREE_ALL_PAGES))
347				nr_free -= freed_pages;
348
349			if (NUM_PAGES_TO_ALLOC >= nr_free)
350				npages_to_free = nr_free;
351			else
352				npages_to_free = NUM_PAGES_TO_ALLOC;
353
354			freed_pages = 0;
355
356			/* free all so restart the processing */
357			if (nr_free)
358				goto restart;
359
360			/* Not allowed to fall through or break because
361			 * following context is inside spinlock while we are
362			 * outside here.
363			 */
364			goto out;
365
366		}
367	}
368
369	/* remove range of pages from the pool */
370	if (freed_pages) {
371		__list_del(&p->lru, &pool->list);
372
373		ttm_pool_update_free_locked(pool, freed_pages);
374		nr_free -= freed_pages;
375	}
376
377	spin_unlock_irqrestore(&pool->lock, irq_flags);
378
379	if (freed_pages)
380		ttm_pages_put(pages_to_free, freed_pages);
381out:
382	if (pages_to_free != static_buf)
383		kfree(pages_to_free);
384	return nr_free;
385}
386
 
 
 
 
 
 
 
 
 
 
 
387/**
388 * Callback for mm to request pool to reduce number of page held.
389 *
390 * XXX: (dchinner) Deadlock warning!
391 *
392 * This code is crying out for a shrinker per pool....
393 */
394static unsigned long
395ttm_pool_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
396{
397	static DEFINE_MUTEX(lock);
398	static unsigned start_pool;
399	unsigned i;
400	unsigned pool_offset;
401	struct ttm_page_pool *pool;
402	int shrink_pages = sc->nr_to_scan;
403	unsigned long freed = 0;
404
405	if (!mutex_trylock(&lock))
406		return SHRINK_STOP;
407	pool_offset = ++start_pool % NUM_POOLS;
408	/* select start pool in round robin fashion */
409	for (i = 0; i < NUM_POOLS; ++i) {
410		unsigned nr_free = shrink_pages;
411		if (shrink_pages == 0)
412			break;
413		pool = &_manager->pools[(i + pool_offset)%NUM_POOLS];
414		/* OK to use static buffer since global mutex is held. */
415		shrink_pages = ttm_page_pool_free(pool, nr_free, true);
416		freed += nr_free - shrink_pages;
417	}
418	mutex_unlock(&lock);
419	return freed;
420}
421
422
423static unsigned long
424ttm_pool_shrink_count(struct shrinker *shrink, struct shrink_control *sc)
425{
426	unsigned i;
427	unsigned long count = 0;
428
429	for (i = 0; i < NUM_POOLS; ++i)
430		count += _manager->pools[i].npages;
431
432	return count;
433}
434
435static void ttm_pool_mm_shrink_init(struct ttm_pool_manager *manager)
436{
437	manager->mm_shrink.count_objects = ttm_pool_shrink_count;
438	manager->mm_shrink.scan_objects = ttm_pool_shrink_scan;
439	manager->mm_shrink.seeks = 1;
440	register_shrinker(&manager->mm_shrink);
441}
442
443static void ttm_pool_mm_shrink_fini(struct ttm_pool_manager *manager)
444{
445	unregister_shrinker(&manager->mm_shrink);
446}
447
448static int ttm_set_pages_caching(struct page **pages,
449		enum ttm_caching_state cstate, unsigned cpages)
450{
451	int r = 0;
452	/* Set page caching */
453	switch (cstate) {
454	case tt_uncached:
455		r = set_pages_array_uc(pages, cpages);
456		if (r)
457			pr_err("Failed to set %d pages to uc!\n", cpages);
458		break;
459	case tt_wc:
460		r = set_pages_array_wc(pages, cpages);
461		if (r)
462			pr_err("Failed to set %d pages to wc!\n", cpages);
463		break;
464	default:
465		break;
466	}
467	return r;
468}
469
470/**
471 * Free pages the pages that failed to change the caching state. If there is
472 * any pages that have changed their caching state already put them to the
473 * pool.
474 */
475static void ttm_handle_caching_state_failure(struct list_head *pages,
476		int ttm_flags, enum ttm_caching_state cstate,
477		struct page **failed_pages, unsigned cpages)
478{
479	unsigned i;
480	/* Failed pages have to be freed */
481	for (i = 0; i < cpages; ++i) {
482		list_del(&failed_pages[i]->lru);
483		__free_page(failed_pages[i]);
484	}
485}
486
487/**
488 * Allocate new pages with correct caching.
489 *
490 * This function is reentrant if caller updates count depending on number of
491 * pages returned in pages array.
492 */
493static int ttm_alloc_new_pages(struct list_head *pages, gfp_t gfp_flags,
494		int ttm_flags, enum ttm_caching_state cstate, unsigned count)
495{
496	struct page **caching_array;
497	struct page *p;
498	int r = 0;
499	unsigned i, cpages;
500	unsigned max_cpages = min(count,
501			(unsigned)(PAGE_SIZE/sizeof(struct page *)));
502
503	/* allocate array for page caching change */
504	caching_array = kmalloc(max_cpages*sizeof(struct page *), GFP_KERNEL);
505
506	if (!caching_array) {
507		pr_err("Unable to allocate table for new pages\n");
508		return -ENOMEM;
509	}
510
511	for (i = 0, cpages = 0; i < count; ++i) {
512		p = alloc_page(gfp_flags);
513
514		if (!p) {
515			pr_err("Unable to get page %u\n", i);
516
517			/* store already allocated pages in the pool after
518			 * setting the caching state */
519			if (cpages) {
520				r = ttm_set_pages_caching(caching_array,
521							  cstate, cpages);
522				if (r)
523					ttm_handle_caching_state_failure(pages,
524						ttm_flags, cstate,
525						caching_array, cpages);
526			}
527			r = -ENOMEM;
528			goto out;
529		}
530
531#ifdef CONFIG_HIGHMEM
532		/* gfp flags of highmem page should never be dma32 so we
533		 * we should be fine in such case
534		 */
535		if (!PageHighMem(p))
536#endif
537		{
538			caching_array[cpages++] = p;
539			if (cpages == max_cpages) {
540
541				r = ttm_set_pages_caching(caching_array,
542						cstate, cpages);
543				if (r) {
544					ttm_handle_caching_state_failure(pages,
545						ttm_flags, cstate,
546						caching_array, cpages);
547					goto out;
548				}
549				cpages = 0;
550			}
551		}
552
553		list_add(&p->lru, pages);
554	}
555
556	if (cpages) {
557		r = ttm_set_pages_caching(caching_array, cstate, cpages);
558		if (r)
559			ttm_handle_caching_state_failure(pages,
560					ttm_flags, cstate,
561					caching_array, cpages);
562	}
563out:
564	kfree(caching_array);
565
566	return r;
567}
568
569/**
570 * Fill the given pool if there aren't enough pages and the requested number of
571 * pages is small.
572 */
573static void ttm_page_pool_fill_locked(struct ttm_page_pool *pool,
574		int ttm_flags, enum ttm_caching_state cstate, unsigned count,
575		unsigned long *irq_flags)
576{
577	struct page *p;
578	int r;
579	unsigned cpages = 0;
580	/**
581	 * Only allow one pool fill operation at a time.
582	 * If pool doesn't have enough pages for the allocation new pages are
583	 * allocated from outside of pool.
584	 */
585	if (pool->fill_lock)
586		return;
587
588	pool->fill_lock = true;
589
590	/* If allocation request is small and there are not enough
591	 * pages in a pool we fill the pool up first. */
592	if (count < _manager->options.small
593		&& count > pool->npages) {
594		struct list_head new_pages;
595		unsigned alloc_size = _manager->options.alloc_size;
596
597		/**
598		 * Can't change page caching if in irqsave context. We have to
599		 * drop the pool->lock.
600		 */
601		spin_unlock_irqrestore(&pool->lock, *irq_flags);
602
603		INIT_LIST_HEAD(&new_pages);
604		r = ttm_alloc_new_pages(&new_pages, pool->gfp_flags, ttm_flags,
605				cstate,	alloc_size);
606		spin_lock_irqsave(&pool->lock, *irq_flags);
607
608		if (!r) {
609			list_splice(&new_pages, &pool->list);
610			++pool->nrefills;
611			pool->npages += alloc_size;
612		} else {
613			pr_err("Failed to fill pool (%p)\n", pool);
614			/* If we have any pages left put them to the pool. */
615			list_for_each_entry(p, &pool->list, lru) {
616				++cpages;
617			}
618			list_splice(&new_pages, &pool->list);
619			pool->npages += cpages;
620		}
621
622	}
623	pool->fill_lock = false;
624}
625
626/**
627 * Cut 'count' number of pages from the pool and put them on the return list.
628 *
629 * @return count of pages still required to fulfill the request.
630 */
631static unsigned ttm_page_pool_get_pages(struct ttm_page_pool *pool,
632					struct list_head *pages,
633					int ttm_flags,
634					enum ttm_caching_state cstate,
635					unsigned count)
636{
637	unsigned long irq_flags;
638	struct list_head *p;
639	unsigned i;
640
641	spin_lock_irqsave(&pool->lock, irq_flags);
642	ttm_page_pool_fill_locked(pool, ttm_flags, cstate, count, &irq_flags);
643
644	if (count >= pool->npages) {
645		/* take all pages from the pool */
646		list_splice_init(&pool->list, pages);
647		count -= pool->npages;
648		pool->npages = 0;
649		goto out;
650	}
651	/* find the last pages to include for requested number of pages. Split
652	 * pool to begin and halve it to reduce search space. */
653	if (count <= pool->npages/2) {
654		i = 0;
655		list_for_each(p, &pool->list) {
656			if (++i == count)
657				break;
658		}
659	} else {
660		i = pool->npages + 1;
661		list_for_each_prev(p, &pool->list) {
662			if (--i == count)
663				break;
664		}
665	}
666	/* Cut 'count' number of pages from the pool */
667	list_cut_position(pages, &pool->list, p);
668	pool->npages -= count;
669	count = 0;
670out:
671	spin_unlock_irqrestore(&pool->lock, irq_flags);
672	return count;
673}
674
675/* Put all pages in pages list to correct pool to wait for reuse */
676static void ttm_put_pages(struct page **pages, unsigned npages, int flags,
677			  enum ttm_caching_state cstate)
678{
679	unsigned long irq_flags;
680	struct ttm_page_pool *pool = ttm_get_pool(flags, cstate);
681	unsigned i;
682
683	if (pool == NULL) {
684		/* No pool for this memory type so free the pages */
685		for (i = 0; i < npages; i++) {
686			if (pages[i]) {
687				if (page_count(pages[i]) != 1)
688					pr_err("Erroneous page count. Leaking pages.\n");
689				__free_page(pages[i]);
690				pages[i] = NULL;
691			}
692		}
693		return;
694	}
695
696	spin_lock_irqsave(&pool->lock, irq_flags);
697	for (i = 0; i < npages; i++) {
698		if (pages[i]) {
699			if (page_count(pages[i]) != 1)
700				pr_err("Erroneous page count. Leaking pages.\n");
701			list_add_tail(&pages[i]->lru, &pool->list);
702			pages[i] = NULL;
703			pool->npages++;
704		}
705	}
706	/* Check that we don't go over the pool limit */
707	npages = 0;
708	if (pool->npages > _manager->options.max_size) {
709		npages = pool->npages - _manager->options.max_size;
710		/* free at least NUM_PAGES_TO_ALLOC number of pages
711		 * to reduce calls to set_memory_wb */
712		if (npages < NUM_PAGES_TO_ALLOC)
713			npages = NUM_PAGES_TO_ALLOC;
714	}
715	spin_unlock_irqrestore(&pool->lock, irq_flags);
716	if (npages)
717		ttm_page_pool_free(pool, npages, false);
718}
719
720/*
721 * On success pages list will hold count number of correctly
722 * cached pages.
723 */
724static int ttm_get_pages(struct page **pages, unsigned npages, int flags,
725			 enum ttm_caching_state cstate)
726{
727	struct ttm_page_pool *pool = ttm_get_pool(flags, cstate);
728	struct list_head plist;
729	struct page *p = NULL;
730	gfp_t gfp_flags = GFP_USER;
731	unsigned count;
732	int r;
733
734	/* set zero flag for page allocation if required */
735	if (flags & TTM_PAGE_FLAG_ZERO_ALLOC)
736		gfp_flags |= __GFP_ZERO;
737
738	/* No pool for cached pages */
739	if (pool == NULL) {
740		if (flags & TTM_PAGE_FLAG_DMA32)
741			gfp_flags |= GFP_DMA32;
742		else
743			gfp_flags |= GFP_HIGHUSER;
744
745		for (r = 0; r < npages; ++r) {
746			p = alloc_page(gfp_flags);
747			if (!p) {
748
749				pr_err("Unable to allocate page\n");
750				return -ENOMEM;
751			}
752
753			pages[r] = p;
754		}
755		return 0;
756	}
757
758	/* combine zero flag to pool flags */
759	gfp_flags |= pool->gfp_flags;
760
761	/* First we take pages from the pool */
762	INIT_LIST_HEAD(&plist);
763	npages = ttm_page_pool_get_pages(pool, &plist, flags, cstate, npages);
764	count = 0;
765	list_for_each_entry(p, &plist, lru) {
766		pages[count++] = p;
767	}
768
769	/* clear the pages coming from the pool if requested */
770	if (flags & TTM_PAGE_FLAG_ZERO_ALLOC) {
771		list_for_each_entry(p, &plist, lru) {
772			if (PageHighMem(p))
773				clear_highpage(p);
774			else
775				clear_page(page_address(p));
776		}
777	}
778
779	/* If pool didn't have enough pages allocate new one. */
780	if (npages > 0) {
781		/* ttm_alloc_new_pages doesn't reference pool so we can run
782		 * multiple requests in parallel.
783		 **/
784		INIT_LIST_HEAD(&plist);
785		r = ttm_alloc_new_pages(&plist, gfp_flags, flags, cstate, npages);
786		list_for_each_entry(p, &plist, lru) {
787			pages[count++] = p;
788		}
789		if (r) {
790			/* If there is any pages in the list put them back to
791			 * the pool. */
792			pr_err("Failed to allocate extra pages for large request\n");
793			ttm_put_pages(pages, count, flags, cstate);
794			return r;
795		}
796	}
797
798	return 0;
799}
800
801static void ttm_page_pool_init_locked(struct ttm_page_pool *pool, gfp_t flags,
802		char *name)
803{
804	spin_lock_init(&pool->lock);
805	pool->fill_lock = false;
806	INIT_LIST_HEAD(&pool->list);
807	pool->npages = pool->nfrees = 0;
808	pool->gfp_flags = flags;
809	pool->name = name;
810}
811
812int ttm_page_alloc_init(struct ttm_mem_global *glob, unsigned max_pages)
813{
814	int ret;
815
816	WARN_ON(_manager);
817
818	pr_info("Initializing pool allocator\n");
819
820	_manager = kzalloc(sizeof(*_manager), GFP_KERNEL);
821
822	ttm_page_pool_init_locked(&_manager->wc_pool, GFP_HIGHUSER, "wc");
823
824	ttm_page_pool_init_locked(&_manager->uc_pool, GFP_HIGHUSER, "uc");
825
826	ttm_page_pool_init_locked(&_manager->wc_pool_dma32,
827				  GFP_USER | GFP_DMA32, "wc dma");
828
829	ttm_page_pool_init_locked(&_manager->uc_pool_dma32,
830				  GFP_USER | GFP_DMA32, "uc dma");
831
832	_manager->options.max_size = max_pages;
833	_manager->options.small = SMALL_ALLOCATION;
834	_manager->options.alloc_size = NUM_PAGES_TO_ALLOC;
835
836	ret = kobject_init_and_add(&_manager->kobj, &ttm_pool_kobj_type,
837				   &glob->kobj, "pool");
838	if (unlikely(ret != 0)) {
839		kobject_put(&_manager->kobj);
840		_manager = NULL;
841		return ret;
842	}
843
844	ttm_pool_mm_shrink_init(_manager);
845
846	return 0;
847}
848
849void ttm_page_alloc_fini(void)
850{
851	int i;
852
853	pr_info("Finalizing pool allocator\n");
854	ttm_pool_mm_shrink_fini(_manager);
855
856	/* OK to use static buffer since global mutex is no longer used. */
857	for (i = 0; i < NUM_POOLS; ++i)
858		ttm_page_pool_free(&_manager->pools[i], FREE_ALL_PAGES, true);
859
860	kobject_put(&_manager->kobj);
861	_manager = NULL;
862}
863
864int ttm_pool_populate(struct ttm_tt *ttm)
865{
866	struct ttm_mem_global *mem_glob = ttm->glob->mem_glob;
867	unsigned i;
868	int ret;
869
870	if (ttm->state != tt_unpopulated)
871		return 0;
872
873	for (i = 0; i < ttm->num_pages; ++i) {
874		ret = ttm_get_pages(&ttm->pages[i], 1,
875				    ttm->page_flags,
876				    ttm->caching_state);
877		if (ret != 0) {
878			ttm_pool_unpopulate(ttm);
879			return -ENOMEM;
880		}
881
882		ret = ttm_mem_global_alloc_page(mem_glob, ttm->pages[i],
883						false, false);
884		if (unlikely(ret != 0)) {
885			ttm_pool_unpopulate(ttm);
886			return -ENOMEM;
887		}
888	}
889
890	if (unlikely(ttm->page_flags & TTM_PAGE_FLAG_SWAPPED)) {
891		ret = ttm_tt_swapin(ttm);
892		if (unlikely(ret != 0)) {
893			ttm_pool_unpopulate(ttm);
894			return ret;
895		}
896	}
897
898	ttm->state = tt_unbound;
899	return 0;
900}
901EXPORT_SYMBOL(ttm_pool_populate);
902
903void ttm_pool_unpopulate(struct ttm_tt *ttm)
904{
905	unsigned i;
906
907	for (i = 0; i < ttm->num_pages; ++i) {
908		if (ttm->pages[i]) {
909			ttm_mem_global_free_page(ttm->glob->mem_glob,
910						 ttm->pages[i]);
911			ttm_put_pages(&ttm->pages[i], 1,
912				      ttm->page_flags,
913				      ttm->caching_state);
914		}
915	}
916	ttm->state = tt_unpopulated;
917}
918EXPORT_SYMBOL(ttm_pool_unpopulate);
919
920int ttm_page_alloc_debugfs(struct seq_file *m, void *data)
921{
922	struct ttm_page_pool *p;
923	unsigned i;
924	char *h[] = {"pool", "refills", "pages freed", "size"};
925	if (!_manager) {
926		seq_printf(m, "No pool allocator running.\n");
927		return 0;
928	}
929	seq_printf(m, "%6s %12s %13s %8s\n",
930			h[0], h[1], h[2], h[3]);
931	for (i = 0; i < NUM_POOLS; ++i) {
932		p = &_manager->pools[i];
933
934		seq_printf(m, "%6s %12ld %13ld %8d\n",
935				p->name, p->nrefills,
936				p->nfrees, p->npages);
937	}
938	return 0;
939}
940EXPORT_SYMBOL(ttm_page_alloc_debugfs);