Adding upstream version 4.19.249.upstream/4.19.249

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1244 insertions, 0 deletions

diff --git a/drivers/gpu/drm/ttm/ttm_page_alloc_dma.c b/drivers/gpu/drm/ttm/ttm_page_alloc_dma.c
new file mode 100644
index 000000000..507be7ac1
--- /dev/null
+++ b/drivers/gpu/drm/ttm/ttm_page_alloc_dma.c
@@ -0,0 +1,1244 @@
+/*
+ * Copyright 2011 (c) Oracle Corp.
+
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sub license,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the
+ * next paragraph) shall be included in all copies or substantial portions
+ * of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ *
+ * Author: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
+ */
+
+/*
+ * A simple DMA pool losely based on dmapool.c. It has certain advantages
+ * over the DMA pools:
+ * - Pool collects resently freed pages for reuse (and hooks up to
+ *   the shrinker).
+ * - Tracks currently in use pages
+ * - Tracks whether the page is UC, WB or cached (and reverts to WB
+ *   when freed).
+ */
+
+#if defined(CONFIG_SWIOTLB) || defined(CONFIG_INTEL_IOMMU)
+#define pr_fmt(fmt) "[TTM] " fmt
+
+#include <linux/dma-mapping.h>
+#include <linux/list.h>
+#include <linux/seq_file.h> /* for seq_printf */
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/highmem.h>
+#include <linux/mm_types.h>
+#include <linux/module.h>
+#include <linux/mm.h>
+#include <linux/atomic.h>
+#include <linux/device.h>
+#include <linux/kthread.h>
+#include <drm/ttm/ttm_bo_driver.h>
+#include <drm/ttm/ttm_page_alloc.h>
+#include <drm/ttm/ttm_set_memory.h>
+
+#define NUM_PAGES_TO_ALLOC		(PAGE_SIZE/sizeof(struct page *))
+#define SMALL_ALLOCATION		4
+#define FREE_ALL_PAGES			(~0U)
+#define VADDR_FLAG_HUGE_POOL		1UL
+#define VADDR_FLAG_UPDATED_COUNT	2UL
+
+enum pool_type {
+	IS_UNDEFINED	= 0,
+	IS_WC		= 1 << 1,
+	IS_UC		= 1 << 2,
+	IS_CACHED	= 1 << 3,
+	IS_DMA32	= 1 << 4,
+	IS_HUGE		= 1 << 5
+};
+
+/*
+ * The pool structure. There are up to nine pools:
+ *  - generic (not restricted to DMA32):
+ *      - write combined, uncached, cached.
+ *  - dma32 (up to 2^32 - so up 4GB):
+ *      - write combined, uncached, cached.
+ *  - huge (not restricted to DMA32):
+ *      - write combined, uncached, cached.
+ * for each 'struct device'. The 'cached' is for pages that are actively used.
+ * The other ones can be shrunk by the shrinker API if neccessary.
+ * @pools: The 'struct device->dma_pools' link.
+ * @type: Type of the pool
+ * @lock: Protects the free_list from concurrnet access. Must be
+ * used with irqsave/irqrestore variants because pool allocator maybe called
+ * from delayed work.
+ * @free_list: Pool of pages that are free to be used. No order requirements.
+ * @dev: The device that is associated with these pools.
+ * @size: Size used during DMA allocation.
+ * @npages_free: Count of available pages for re-use.
+ * @npages_in_use: Count of pages that are in use.
+ * @nfrees: Stats when pool is shrinking.
+ * @nrefills: Stats when the pool is grown.
+ * @gfp_flags: Flags to pass for alloc_page.
+ * @name: Name of the pool.
+ * @dev_name: Name derieved from dev - similar to how dev_info works.
+ *   Used during shutdown as the dev_info during release is unavailable.
+ */
+struct dma_pool {
+	struct list_head pools; /* The 'struct device->dma_pools link */
+	enum pool_type type;
+	spinlock_t lock;
+	struct list_head free_list;
+	struct device *dev;
+	unsigned size;
+	unsigned npages_free;
+	unsigned npages_in_use;
+	unsigned long nfrees; /* Stats when shrunk. */
+	unsigned long nrefills; /* Stats when grown. */
+	gfp_t gfp_flags;
+	char name[13]; /* "cached dma32" */
+	char dev_name[64]; /* Constructed from dev */
+};
+
+/*
+ * The accounting page keeping track of the allocated page along with
+ * the DMA address.
+ * @page_list: The link to the 'page_list' in 'struct dma_pool'.
+ * @vaddr: The virtual address of the page and a flag if the page belongs to a
+ * huge pool
+ * @dma: The bus address of the page. If the page is not allocated
+ *   via the DMA API, it will be -1.
+ */
+struct dma_page {
+	struct list_head page_list;
+	unsigned long vaddr;
+	struct page *p;
+	dma_addr_t dma;
+};
+
+/*
+ * Limits for the pool. They are handled without locks because only place where
+ * they may change is in sysfs store. They won't have immediate effect anyway
+ * so forcing serialization to access them is pointless.
+ */
+
+struct ttm_pool_opts {
+	unsigned	alloc_size;
+	unsigned	max_size;
+	unsigned	small;
+};
+
+/*
+ * Contains the list of all of the 'struct device' and their corresponding
+ * DMA pools. Guarded by _mutex->lock.
+ * @pools: The link to 'struct ttm_pool_manager->pools'
+ * @dev: The 'struct device' associated with the 'pool'
+ * @pool: The 'struct dma_pool' associated with the 'dev'
+ */
+struct device_pools {
+	struct list_head pools;
+	struct device *dev;
+	struct dma_pool *pool;
+};
+
+/*
+ * struct ttm_pool_manager - Holds memory pools for fast allocation
+ *
+ * @lock: Lock used when adding/removing from pools
+ * @pools: List of 'struct device' and 'struct dma_pool' tuples.
+ * @options: Limits for the pool.
+ * @npools: Total amount of pools in existence.
+ * @shrinker: The structure used by [un|]register_shrinker
+ */
+struct ttm_pool_manager {
+	struct mutex		lock;
+	struct list_head	pools;
+	struct ttm_pool_opts	options;
+	unsigned		npools;
+	struct shrinker		mm_shrink;
+	struct kobject		kobj;
+};
+
+static struct ttm_pool_manager *_manager;
+
+static struct attribute ttm_page_pool_max = {
+	.name = "pool_max_size",
+	.mode = S_IRUGO | S_IWUSR
+};
+static struct attribute ttm_page_pool_small = {
+	.name = "pool_small_allocation",
+	.mode = S_IRUGO | S_IWUSR
+};
+static struct attribute ttm_page_pool_alloc_size = {
+	.name = "pool_allocation_size",
+	.mode = S_IRUGO | S_IWUSR
+};
+
+static struct attribute *ttm_pool_attrs[] = {
+	&ttm_page_pool_max,
+	&ttm_page_pool_small,
+	&ttm_page_pool_alloc_size,
+	NULL
+};
+
+static void ttm_pool_kobj_release(struct kobject *kobj)
+{
+	struct ttm_pool_manager *m =
+		container_of(kobj, struct ttm_pool_manager, kobj);
+	kfree(m);
+}
+
+static ssize_t ttm_pool_store(struct kobject *kobj, struct attribute *attr,
+			      const char *buffer, size_t size)
+{
+	struct ttm_pool_manager *m =
+		container_of(kobj, struct ttm_pool_manager, kobj);
+	int chars;
+	unsigned val;
+
+	chars = sscanf(buffer, "%u", &val);
+	if (chars == 0)
+		return size;
+
+	/* Convert kb to number of pages */
+	val = val / (PAGE_SIZE >> 10);
+
+	if (attr == &ttm_page_pool_max) {
+		m->options.max_size = val;
+	} else if (attr == &ttm_page_pool_small) {
+		m->options.small = val;
+	} else if (attr == &ttm_page_pool_alloc_size) {
+		if (val > NUM_PAGES_TO_ALLOC*8) {
+			pr_err("Setting allocation size to %lu is not allowed. Recommended size is %lu\n",
+			       NUM_PAGES_TO_ALLOC*(PAGE_SIZE >> 7),
+			       NUM_PAGES_TO_ALLOC*(PAGE_SIZE >> 10));
+			return size;
+		} else if (val > NUM_PAGES_TO_ALLOC) {
+			pr_warn("Setting allocation size to larger than %lu is not recommended\n",
+				NUM_PAGES_TO_ALLOC*(PAGE_SIZE >> 10));
+		}
+		m->options.alloc_size = val;
+	}
+
+	return size;
+}
+
+static ssize_t ttm_pool_show(struct kobject *kobj, struct attribute *attr,
+			     char *buffer)
+{
+	struct ttm_pool_manager *m =
+		container_of(kobj, struct ttm_pool_manager, kobj);
+	unsigned val = 0;
+
+	if (attr == &ttm_page_pool_max)
+		val = m->options.max_size;
+	else if (attr == &ttm_page_pool_small)
+		val = m->options.small;
+	else if (attr == &ttm_page_pool_alloc_size)
+		val = m->options.alloc_size;
+
+	val = val * (PAGE_SIZE >> 10);
+
+	return snprintf(buffer, PAGE_SIZE, "%u\n", val);
+}
+
+static const struct sysfs_ops ttm_pool_sysfs_ops = {
+	.show = &ttm_pool_show,
+	.store = &ttm_pool_store,
+};
+
+static struct kobj_type ttm_pool_kobj_type = {
+	.release = &ttm_pool_kobj_release,
+	.sysfs_ops = &ttm_pool_sysfs_ops,
+	.default_attrs = ttm_pool_attrs,
+};
+
+static int ttm_set_pages_caching(struct dma_pool *pool,
+				 struct page **pages, unsigned cpages)
+{
+	int r = 0;
+	/* Set page caching */
+	if (pool->type & IS_UC) {
+		r = ttm_set_pages_array_uc(pages, cpages);
+		if (r)
+			pr_err("%s: Failed to set %d pages to uc!\n",
+			       pool->dev_name, cpages);
+	}
+	if (pool->type & IS_WC) {
+		r = ttm_set_pages_array_wc(pages, cpages);
+		if (r)
+			pr_err("%s: Failed to set %d pages to wc!\n",
+			       pool->dev_name, cpages);
+	}
+	return r;
+}
+
+static void __ttm_dma_free_page(struct dma_pool *pool, struct dma_page *d_page)
+{
+	dma_addr_t dma = d_page->dma;
+	d_page->vaddr &= ~VADDR_FLAG_HUGE_POOL;
+	dma_free_coherent(pool->dev, pool->size, (void *)d_page->vaddr, dma);
+
+	kfree(d_page);
+	d_page = NULL;
+}
+static struct dma_page *__ttm_dma_alloc_page(struct dma_pool *pool)
+{
+	struct dma_page *d_page;
+	unsigned long attrs = 0;
+	void *vaddr;
+
+	d_page = kmalloc(sizeof(struct dma_page), GFP_KERNEL);
+	if (!d_page)
+		return NULL;
+
+	if (pool->type & IS_HUGE)
+		attrs = DMA_ATTR_NO_WARN;
+
+	vaddr = dma_alloc_attrs(pool->dev, pool->size, &d_page->dma,
+				pool->gfp_flags, attrs);
+	if (vaddr) {
+		if (is_vmalloc_addr(vaddr))
+			d_page->p = vmalloc_to_page(vaddr);
+		else
+			d_page->p = virt_to_page(vaddr);
+		d_page->vaddr = (unsigned long)vaddr;
+		if (pool->type & IS_HUGE)
+			d_page->vaddr |= VADDR_FLAG_HUGE_POOL;
+	} else {
+		kfree(d_page);
+		d_page = NULL;
+	}
+	return d_page;
+}
+static enum pool_type ttm_to_type(int flags, enum ttm_caching_state cstate)
+{
+	enum pool_type type = IS_UNDEFINED;
+
+	if (flags & TTM_PAGE_FLAG_DMA32)
+		type |= IS_DMA32;
+	if (cstate == tt_cached)
+		type |= IS_CACHED;
+	else if (cstate == tt_uncached)
+		type |= IS_UC;
+	else
+		type |= IS_WC;
+
+	return type;
+}
+
+static void ttm_pool_update_free_locked(struct dma_pool *pool,
+					unsigned freed_pages)
+{
+	pool->npages_free -= freed_pages;
+	pool->nfrees += freed_pages;
+
+}
+
+/* set memory back to wb and free the pages. */
+static void ttm_dma_page_put(struct dma_pool *pool, struct dma_page *d_page)
+{
+	struct page *page = d_page->p;
+	unsigned num_pages;
+
+	/* Don't set WB on WB page pool. */
+	if (!(pool->type & IS_CACHED)) {
+		num_pages = pool->size / PAGE_SIZE;
+		if (ttm_set_pages_wb(page, num_pages))
+			pr_err("%s: Failed to set %d pages to wb!\n",
+			       pool->dev_name, num_pages);
+	}
+
+	list_del(&d_page->page_list);
+	__ttm_dma_free_page(pool, d_page);
+}
+
+static void ttm_dma_pages_put(struct dma_pool *pool, struct list_head *d_pages,
+			      struct page *pages[], unsigned npages)
+{
+	struct dma_page *d_page, *tmp;
+
+	if (pool->type & IS_HUGE) {
+		list_for_each_entry_safe(d_page, tmp, d_pages, page_list)
+			ttm_dma_page_put(pool, d_page);
+
+		return;
+	}
+
+	/* Don't set WB on WB page pool. */
+	if (npages && !(pool->type & IS_CACHED) &&
+	    ttm_set_pages_array_wb(pages, npages))
+		pr_err("%s: Failed to set %d pages to wb!\n",
+		       pool->dev_name, npages);
+
+	list_for_each_entry_safe(d_page, tmp, d_pages, page_list) {
+		list_del(&d_page->page_list);
+		__ttm_dma_free_page(pool, d_page);
+	}
+}
+
+/*
+ * Free pages from pool.
+ *
+ * To prevent hogging the ttm_swap process we only free NUM_PAGES_TO_ALLOC
+ * number of pages in one go.
+ *
+ * @pool: to free the pages from
+ * @nr_free: If set to true will free all pages in pool
+ * @use_static: Safe to use static buffer
+ **/
+static unsigned ttm_dma_page_pool_free(struct dma_pool *pool, unsigned nr_free,
+				       bool use_static)
+{
+	static struct page *static_buf[NUM_PAGES_TO_ALLOC];
+	unsigned long irq_flags;
+	struct dma_page *dma_p, *tmp;
+	struct page **pages_to_free;
+	struct list_head d_pages;
+	unsigned freed_pages = 0,
+		 npages_to_free = nr_free;
+
+	if (NUM_PAGES_TO_ALLOC < nr_free)
+		npages_to_free = NUM_PAGES_TO_ALLOC;
+#if 0
+	if (nr_free > 1) {
+		pr_debug("%s: (%s:%d) Attempting to free %d (%d) pages\n",
+			 pool->dev_name, pool->name, current->pid,
+			 npages_to_free, nr_free);
+	}
+#endif
+	if (use_static)
+		pages_to_free = static_buf;
+	else
+		pages_to_free = kmalloc_array(npages_to_free,
+					      sizeof(struct page *),
+					      GFP_KERNEL);
+
+	if (!pages_to_free) {
+		pr_debug("%s: Failed to allocate memory for pool free operation\n",
+		       pool->dev_name);
+		return 0;
+	}
+	INIT_LIST_HEAD(&d_pages);
+restart:
+	spin_lock_irqsave(&pool->lock, irq_flags);
+
+	/* We picking the oldest ones off the list */
+	list_for_each_entry_safe_reverse(dma_p, tmp, &pool->free_list,
+					 page_list) {
+		if (freed_pages >= npages_to_free)
+			break;
+
+		/* Move the dma_page from one list to another. */
+		list_move(&dma_p->page_list, &d_pages);
+
+		pages_to_free[freed_pages++] = dma_p->p;
+		/* We can only remove NUM_PAGES_TO_ALLOC at a time. */
+		if (freed_pages >= NUM_PAGES_TO_ALLOC) {
+
+			ttm_pool_update_free_locked(pool, freed_pages);
+			/**
+			 * Because changing page caching is costly
+			 * we unlock the pool to prevent stalling.
+			 */
+			spin_unlock_irqrestore(&pool->lock, irq_flags);
+
+			ttm_dma_pages_put(pool, &d_pages, pages_to_free,
+					  freed_pages);
+
+			INIT_LIST_HEAD(&d_pages);
+
+			if (likely(nr_free != FREE_ALL_PAGES))
+				nr_free -= freed_pages;
+
+			if (NUM_PAGES_TO_ALLOC >= nr_free)
+				npages_to_free = nr_free;
+			else
+				npages_to_free = NUM_PAGES_TO_ALLOC;
+
+			freed_pages = 0;
+
+			/* free all so restart the processing */
+			if (nr_free)
+				goto restart;
+
+			/* Not allowed to fall through or break because
+			 * following context is inside spinlock while we are
+			 * outside here.
+			 */
+			goto out;
+
+		}
+	}
+
+	/* remove range of pages from the pool */
+	if (freed_pages) {
+		ttm_pool_update_free_locked(pool, freed_pages);
+		nr_free -= freed_pages;
+	}
+
+	spin_unlock_irqrestore(&pool->lock, irq_flags);
+
+	if (freed_pages)
+		ttm_dma_pages_put(pool, &d_pages, pages_to_free, freed_pages);
+out:
+	if (pages_to_free != static_buf)
+		kfree(pages_to_free);
+	return nr_free;
+}
+
+static void ttm_dma_free_pool(struct device *dev, enum pool_type type)
+{
+	struct device_pools *p;
+	struct dma_pool *pool;
+
+	if (!dev)
+		return;
+
+	mutex_lock(&_manager->lock);
+	list_for_each_entry_reverse(p, &_manager->pools, pools) {
+		if (p->dev != dev)
+			continue;
+		pool = p->pool;
+		if (pool->type != type)
+			continue;
+
+		list_del(&p->pools);
+		kfree(p);
+		_manager->npools--;
+		break;
+	}
+	list_for_each_entry_reverse(pool, &dev->dma_pools, pools) {
+		if (pool->type != type)
+			continue;
+		/* Takes a spinlock.. */
+		/* OK to use static buffer since global mutex is held. */
+		ttm_dma_page_pool_free(pool, FREE_ALL_PAGES, true);
+		WARN_ON(((pool->npages_in_use + pool->npages_free) != 0));
+		/* This code path is called after _all_ references to the
+		 * struct device has been dropped - so nobody should be
+		 * touching it. In case somebody is trying to _add_ we are
+		 * guarded by the mutex. */
+		list_del(&pool->pools);
+		kfree(pool);
+		break;
+	}
+	mutex_unlock(&_manager->lock);
+}
+
+/*
+ * On free-ing of the 'struct device' this deconstructor is run.
+ * Albeit the pool might have already been freed earlier.
+ */
+static void ttm_dma_pool_release(struct device *dev, void *res)
+{
+	struct dma_pool *pool = *(struct dma_pool **)res;
+
+	if (pool)
+		ttm_dma_free_pool(dev, pool->type);
+}
+
+static int ttm_dma_pool_match(struct device *dev, void *res, void *match_data)
+{
+	return *(struct dma_pool **)res == match_data;
+}
+
+static struct dma_pool *ttm_dma_pool_init(struct device *dev, gfp_t flags,
+					  enum pool_type type)
+{
+	const char *n[] = {"wc", "uc", "cached", " dma32", "huge"};
+	enum pool_type t[] = {IS_WC, IS_UC, IS_CACHED, IS_DMA32, IS_HUGE};
+	struct device_pools *sec_pool = NULL;
+	struct dma_pool *pool = NULL, **ptr;
+	unsigned i;
+	int ret = -ENODEV;
+	char *p;
+
+	if (!dev)
+		return NULL;
+
+	ptr = devres_alloc(ttm_dma_pool_release, sizeof(*ptr), GFP_KERNEL);
+	if (!ptr)
+		return NULL;
+
+	ret = -ENOMEM;
+
+	pool = kmalloc_node(sizeof(struct dma_pool), GFP_KERNEL,
+			    dev_to_node(dev));
+	if (!pool)
+		goto err_mem;
+
+	sec_pool = kmalloc_node(sizeof(struct device_pools), GFP_KERNEL,
+				dev_to_node(dev));
+	if (!sec_pool)
+		goto err_mem;
+
+	INIT_LIST_HEAD(&sec_pool->pools);
+	sec_pool->dev = dev;
+	sec_pool->pool =  pool;
+
+	INIT_LIST_HEAD(&pool->free_list);
+	INIT_LIST_HEAD(&pool->pools);
+	spin_lock_init(&pool->lock);
+	pool->dev = dev;
+	pool->npages_free = pool->npages_in_use = 0;
+	pool->nfrees = 0;
+	pool->gfp_flags = flags;
+	if (type & IS_HUGE)
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+		pool->size = HPAGE_PMD_SIZE;
+#else
+		BUG();
+#endif
+	else
+		pool->size = PAGE_SIZE;
+	pool->type = type;
+	pool->nrefills = 0;
+	p = pool->name;
+	for (i = 0; i < ARRAY_SIZE(t); i++) {
+		if (type & t[i]) {
+			p += snprintf(p, sizeof(pool->name) - (p - pool->name),
+				      "%s", n[i]);
+		}
+	}
+	*p = 0;
+	/* We copy the name for pr_ calls b/c when dma_pool_destroy is called
+	 * - the kobj->name has already been deallocated.*/
+	snprintf(pool->dev_name, sizeof(pool->dev_name), "%s %s",
+		 dev_driver_string(dev), dev_name(dev));
+	mutex_lock(&_manager->lock);
+	/* You can get the dma_pool from either the global: */
+	list_add(&sec_pool->pools, &_manager->pools);
+	_manager->npools++;
+	/* or from 'struct device': */
+	list_add(&pool->pools, &dev->dma_pools);
+	mutex_unlock(&_manager->lock);
+
+	*ptr = pool;
+	devres_add(dev, ptr);
+
+	return pool;
+err_mem:
+	devres_free(ptr);
+	kfree(sec_pool);
+	kfree(pool);
+	return ERR_PTR(ret);
+}
+
+static struct dma_pool *ttm_dma_find_pool(struct device *dev,
+					  enum pool_type type)
+{
+	struct dma_pool *pool, *tmp;
+
+	if (type == IS_UNDEFINED)
+		return NULL;
+
+	/* NB: We iterate on the 'struct dev' which has no spinlock, but
+	 * it does have a kref which we have taken. The kref is taken during
+	 * graphic driver loading - in the drm_pci_init it calls either
+	 * pci_dev_get or pci_register_driver which both end up taking a kref
+	 * on 'struct device'.
+	 *
+	 * On teardown, the graphic drivers end up quiescing the TTM (put_pages)
+	 * and calls the dev_res deconstructors: ttm_dma_pool_release. The nice
+	 * thing is at that point of time there are no pages associated with the
+	 * driver so this function will not be called.
+	 */
+	list_for_each_entry_safe(pool, tmp, &dev->dma_pools, pools)
+		if (pool->type == type)
+			return pool;
+	return NULL;
+}
+
+/*
+ * Free pages the pages that failed to change the caching state. If there
+ * are pages that have changed their caching state already put them to the
+ * pool.
+ */
+static void ttm_dma_handle_caching_state_failure(struct dma_pool *pool,
+						 struct list_head *d_pages,
+						 struct page **failed_pages,
+						 unsigned cpages)
+{
+	struct dma_page *d_page, *tmp;
+	struct page *p;
+	unsigned i = 0;
+
+	p = failed_pages[0];
+	if (!p)
+		return;
+	/* Find the failed page. */
+	list_for_each_entry_safe(d_page, tmp, d_pages, page_list) {
+		if (d_page->p != p)
+			continue;
+		/* .. and then progress over the full list. */
+		list_del(&d_page->page_list);
+		__ttm_dma_free_page(pool, d_page);
+		if (++i < cpages)
+			p = failed_pages[i];
+		else
+			break;
+	}
+
+}
+
+/*
+ * Allocate 'count' pages, and put 'need' number of them on the
+ * 'pages' and as well on the 'dma_address' starting at 'dma_offset' offset.
+ * The full list of pages should also be on 'd_pages'.
+ * We return zero for success, and negative numbers as errors.
+ */
+static int ttm_dma_pool_alloc_new_pages(struct dma_pool *pool,
+					struct list_head *d_pages,
+					unsigned count)
+{
+	struct page **caching_array;
+	struct dma_page *dma_p;
+	struct page *p;
+	int r = 0;
+	unsigned i, j, npages, cpages;
+	unsigned max_cpages = min(count,
+			(unsigned)(PAGE_SIZE/sizeof(struct page *)));
+
+	/* allocate array for page caching change */
+	caching_array = kmalloc_array(max_cpages, sizeof(struct page *),
+				      GFP_KERNEL);
+
+	if (!caching_array) {
+		pr_debug("%s: Unable to allocate table for new pages\n",
+		       pool->dev_name);
+		return -ENOMEM;
+	}
+
+	if (count > 1)
+		pr_debug("%s: (%s:%d) Getting %d pages\n",
+			 pool->dev_name, pool->name, current->pid, count);
+
+	for (i = 0, cpages = 0; i < count; ++i) {
+		dma_p = __ttm_dma_alloc_page(pool);
+		if (!dma_p) {
+			pr_debug("%s: Unable to get page %u\n",
+				 pool->dev_name, i);
+
+			/* store already allocated pages in the pool after
+			 * setting the caching state */
+			if (cpages) {
+				r = ttm_set_pages_caching(pool, caching_array,
+							  cpages);
+				if (r)
+					ttm_dma_handle_caching_state_failure(
+						pool, d_pages, caching_array,
+						cpages);
+			}
+			r = -ENOMEM;
+			goto out;
+		}
+		p = dma_p->p;
+		list_add(&dma_p->page_list, d_pages);
+
+#ifdef CONFIG_HIGHMEM
+		/* gfp flags of highmem page should never be dma32 so we
+		 * we should be fine in such case
+		 */
+		if (PageHighMem(p))
+			continue;
+#endif
+
+		npages = pool->size / PAGE_SIZE;
+		for (j = 0; j < npages; ++j) {
+			caching_array[cpages++] = p + j;
+			if (cpages == max_cpages) {
+				/* Note: Cannot hold the spinlock */
+				r = ttm_set_pages_caching(pool, caching_array,
+							  cpages);
+				if (r) {
+					ttm_dma_handle_caching_state_failure(
+					     pool, d_pages, caching_array,
+					     cpages);
+					goto out;
+				}
+				cpages = 0;
+			}
+		}
+	}
+
+	if (cpages) {
+		r = ttm_set_pages_caching(pool, caching_array, cpages);
+		if (r)
+			ttm_dma_handle_caching_state_failure(pool, d_pages,
+					caching_array, cpages);
+	}
+out:
+	kfree(caching_array);
+	return r;
+}
+
+/*
+ * @return count of pages still required to fulfill the request.
+ */
+static int ttm_dma_page_pool_fill_locked(struct dma_pool *pool,
+					 unsigned long *irq_flags)
+{
+	unsigned count = _manager->options.small;
+	int r = pool->npages_free;
+
+	if (count > pool->npages_free) {
+		struct list_head d_pages;
+
+		INIT_LIST_HEAD(&d_pages);
+
+		spin_unlock_irqrestore(&pool->lock, *irq_flags);
+
+		/* Returns how many more are neccessary to fulfill the
+		 * request. */
+		r = ttm_dma_pool_alloc_new_pages(pool, &d_pages, count);
+
+		spin_lock_irqsave(&pool->lock, *irq_flags);
+		if (!r) {
+			/* Add the fresh to the end.. */
+			list_splice(&d_pages, &pool->free_list);
+			++pool->nrefills;
+			pool->npages_free += count;
+			r = count;
+		} else {
+			struct dma_page *d_page;
+			unsigned cpages = 0;
+
+			pr_debug("%s: Failed to fill %s pool (r:%d)!\n",
+				 pool->dev_name, pool->name, r);
+
+			list_for_each_entry(d_page, &d_pages, page_list) {
+				cpages++;
+			}
+			list_splice_tail(&d_pages, &pool->free_list);
+			pool->npages_free += cpages;
+			r = cpages;
+		}
+	}
+	return r;
+}
+
+/*
+ * The populate list is actually a stack (not that is matters as TTM
+ * allocates one page at a time.
+ * return dma_page pointer if success, otherwise NULL.
+ */
+static struct dma_page *ttm_dma_pool_get_pages(struct dma_pool *pool,
+				  struct ttm_dma_tt *ttm_dma,
+				  unsigned index)
+{
+	struct dma_page *d_page = NULL;
+	struct ttm_tt *ttm = &ttm_dma->ttm;
+	unsigned long irq_flags;
+	int count;
+
+	spin_lock_irqsave(&pool->lock, irq_flags);
+	count = ttm_dma_page_pool_fill_locked(pool, &irq_flags);
+	if (count) {
+		d_page = list_first_entry(&pool->free_list, struct dma_page, page_list);
+		ttm->pages[index] = d_page->p;
+		ttm_dma->dma_address[index] = d_page->dma;
+		list_move_tail(&d_page->page_list, &ttm_dma->pages_list);
+		pool->npages_in_use += 1;
+		pool->npages_free -= 1;
+	}
+	spin_unlock_irqrestore(&pool->lock, irq_flags);
+	return d_page;
+}
+
+static gfp_t ttm_dma_pool_gfp_flags(struct ttm_dma_tt *ttm_dma, bool huge)
+{
+	struct ttm_tt *ttm = &ttm_dma->ttm;
+	gfp_t gfp_flags;
+
+	if (ttm->page_flags & TTM_PAGE_FLAG_DMA32)
+		gfp_flags = GFP_USER | GFP_DMA32;
+	else
+		gfp_flags = GFP_HIGHUSER;
+	if (ttm->page_flags & TTM_PAGE_FLAG_ZERO_ALLOC)
+		gfp_flags |= __GFP_ZERO;
+
+	if (huge) {
+		gfp_flags |= GFP_TRANSHUGE_LIGHT | __GFP_NORETRY |
+			__GFP_KSWAPD_RECLAIM;
+		gfp_flags &= ~__GFP_MOVABLE;
+		gfp_flags &= ~__GFP_COMP;
+	}
+
+	if (ttm->page_flags & TTM_PAGE_FLAG_NO_RETRY)
+		gfp_flags |= __GFP_RETRY_MAYFAIL;
+
+	return gfp_flags;
+}
+
+/*
+ * On success pages list will hold count number of correctly
+ * cached pages. On failure will hold the negative return value (-ENOMEM, etc).
+ */
+int ttm_dma_populate(struct ttm_dma_tt *ttm_dma, struct device *dev,
+			struct ttm_operation_ctx *ctx)
+{
+	struct ttm_tt *ttm = &ttm_dma->ttm;
+	struct ttm_mem_global *mem_glob = ttm->bdev->glob->mem_glob;
+	unsigned long num_pages = ttm->num_pages;
+	struct dma_pool *pool;
+	struct dma_page *d_page;
+	enum pool_type type;
+	unsigned i;
+	int ret;
+
+	if (ttm->state != tt_unpopulated)
+		return 0;
+
+	if (ttm_check_under_lowerlimit(mem_glob, num_pages, ctx))
+		return -ENOMEM;
+
+	INIT_LIST_HEAD(&ttm_dma->pages_list);
+	i = 0;
+
+	type = ttm_to_type(ttm->page_flags, ttm->caching_state);
+
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+	if (ttm->page_flags & TTM_PAGE_FLAG_DMA32)
+		goto skip_huge;
+
+	pool = ttm_dma_find_pool(dev, type | IS_HUGE);
+	if (!pool) {
+		gfp_t gfp_flags = ttm_dma_pool_gfp_flags(ttm_dma, true);
+
+		pool = ttm_dma_pool_init(dev, gfp_flags, type | IS_HUGE);
+		if (IS_ERR_OR_NULL(pool))
+			goto skip_huge;
+	}
+
+	while (num_pages >= HPAGE_PMD_NR) {
+		unsigned j;
+
+		d_page = ttm_dma_pool_get_pages(pool, ttm_dma, i);
+		if (!d_page)
+			break;
+
+		ret = ttm_mem_global_alloc_page(mem_glob, ttm->pages[i],
+						pool->size, ctx);
+		if (unlikely(ret != 0)) {
+			ttm_dma_unpopulate(ttm_dma, dev);
+			return -ENOMEM;
+		}
+
+		d_page->vaddr |= VADDR_FLAG_UPDATED_COUNT;
+		for (j = i + 1; j < (i + HPAGE_PMD_NR); ++j) {
+			ttm->pages[j] = ttm->pages[j - 1] + 1;
+			ttm_dma->dma_address[j] = ttm_dma->dma_address[j - 1] +
+				PAGE_SIZE;
+		}
+
+		i += HPAGE_PMD_NR;
+		num_pages -= HPAGE_PMD_NR;
+	}
+
+skip_huge:
+#endif
+
+	pool = ttm_dma_find_pool(dev, type);
+	if (!pool) {
+		gfp_t gfp_flags = ttm_dma_pool_gfp_flags(ttm_dma, false);
+
+		pool = ttm_dma_pool_init(dev, gfp_flags, type);
+		if (IS_ERR_OR_NULL(pool))
+			return -ENOMEM;
+	}
+
+	while (num_pages) {
+		d_page = ttm_dma_pool_get_pages(pool, ttm_dma, i);
+		if (!d_page) {
+			ttm_dma_unpopulate(ttm_dma, dev);
+			return -ENOMEM;
+		}
+
+		ret = ttm_mem_global_alloc_page(mem_glob, ttm->pages[i],
+						pool->size, ctx);
+		if (unlikely(ret != 0)) {
+			ttm_dma_unpopulate(ttm_dma, dev);
+			return -ENOMEM;
+		}
+
+		d_page->vaddr |= VADDR_FLAG_UPDATED_COUNT;
+		++i;
+		--num_pages;
+	}
+
+	if (unlikely(ttm->page_flags & TTM_PAGE_FLAG_SWAPPED)) {
+		ret = ttm_tt_swapin(ttm);
+		if (unlikely(ret != 0)) {
+			ttm_dma_unpopulate(ttm_dma, dev);
+			return ret;
+		}
+	}
+
+	ttm->state = tt_unbound;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(ttm_dma_populate);
+
+/* Put all pages in pages list to correct pool to wait for reuse */
+void ttm_dma_unpopulate(struct ttm_dma_tt *ttm_dma, struct device *dev)
+{
+	struct ttm_tt *ttm = &ttm_dma->ttm;
+	struct ttm_mem_global *mem_glob = ttm->bdev->glob->mem_glob;
+	struct dma_pool *pool;
+	struct dma_page *d_page, *next;
+	enum pool_type type;
+	bool is_cached = false;
+	unsigned count, i, npages = 0;
+	unsigned long irq_flags;
+
+	type = ttm_to_type(ttm->page_flags, ttm->caching_state);
+
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+	pool = ttm_dma_find_pool(dev, type | IS_HUGE);
+	if (pool) {
+		count = 0;
+		list_for_each_entry_safe(d_page, next, &ttm_dma->pages_list,
+					 page_list) {
+			if (!(d_page->vaddr & VADDR_FLAG_HUGE_POOL))
+				continue;
+
+			count++;
+			if (d_page->vaddr & VADDR_FLAG_UPDATED_COUNT) {
+				ttm_mem_global_free_page(mem_glob, d_page->p,
+							 pool->size);
+				d_page->vaddr &= ~VADDR_FLAG_UPDATED_COUNT;
+			}
+			ttm_dma_page_put(pool, d_page);
+		}
+
+		spin_lock_irqsave(&pool->lock, irq_flags);
+		pool->npages_in_use -= count;
+		pool->nfrees += count;
+		spin_unlock_irqrestore(&pool->lock, irq_flags);
+	}
+#endif
+
+	pool = ttm_dma_find_pool(dev, type);
+	if (!pool)
+		return;
+
+	is_cached = (ttm_dma_find_pool(pool->dev,
+		     ttm_to_type(ttm->page_flags, tt_cached)) == pool);
+
+	/* make sure pages array match list and count number of pages */
+	count = 0;
+	list_for_each_entry_safe(d_page, next, &ttm_dma->pages_list,
+				 page_list) {
+		ttm->pages[count] = d_page->p;
+		count++;
+
+		if (d_page->vaddr & VADDR_FLAG_UPDATED_COUNT) {
+			ttm_mem_global_free_page(mem_glob, d_page->p,
+						 pool->size);
+			d_page->vaddr &= ~VADDR_FLAG_UPDATED_COUNT;
+		}
+
+		if (is_cached)
+			ttm_dma_page_put(pool, d_page);
+	}
+
+	spin_lock_irqsave(&pool->lock, irq_flags);
+	pool->npages_in_use -= count;
+	if (is_cached) {
+		pool->nfrees += count;
+	} else {
+		pool->npages_free += count;
+		list_splice(&ttm_dma->pages_list, &pool->free_list);
+		/*
+		 * Wait to have at at least NUM_PAGES_TO_ALLOC number of pages
+		 * to free in order to minimize calls to set_memory_wb().
+		 */
+		if (pool->npages_free >= (_manager->options.max_size +
+					  NUM_PAGES_TO_ALLOC))
+			npages = pool->npages_free - _manager->options.max_size;
+	}
+	spin_unlock_irqrestore(&pool->lock, irq_flags);
+
+	INIT_LIST_HEAD(&ttm_dma->pages_list);
+	for (i = 0; i < ttm->num_pages; i++) {
+		ttm->pages[i] = NULL;
+		ttm_dma->dma_address[i] = 0;
+	}
+
+	/* shrink pool if necessary (only on !is_cached pools)*/
+	if (npages)
+		ttm_dma_page_pool_free(pool, npages, false);
+	ttm->state = tt_unpopulated;
+}
+EXPORT_SYMBOL_GPL(ttm_dma_unpopulate);
+
+/**
+ * Callback for mm to request pool to reduce number of page held.
+ *
+ * XXX: (dchinner) Deadlock warning!
+ *
+ * I'm getting sadder as I hear more pathetical whimpers about needing per-pool
+ * shrinkers
+ */
+static unsigned long
+ttm_dma_pool_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
+{
+	static unsigned start_pool;
+	unsigned idx = 0;
+	unsigned pool_offset;
+	unsigned shrink_pages = sc->nr_to_scan;
+	struct device_pools *p;
+	unsigned long freed = 0;
+
+	if (list_empty(&_manager->pools))
+		return SHRINK_STOP;
+
+	if (!mutex_trylock(&_manager->lock))
+		return SHRINK_STOP;
+	if (!_manager->npools)
+		goto out;
+	pool_offset = ++start_pool % _manager->npools;
+	list_for_each_entry(p, &_manager->pools, pools) {
+		unsigned nr_free;
+
+		if (!p->dev)
+			continue;
+		if (shrink_pages == 0)
+			break;
+		/* Do it in round-robin fashion. */
+		if (++idx < pool_offset)
+			continue;
+		nr_free = shrink_pages;
+		/* OK to use static buffer since global mutex is held. */
+		shrink_pages = ttm_dma_page_pool_free(p->pool, nr_free, true);
+		freed += nr_free - shrink_pages;
+
+		pr_debug("%s: (%s:%d) Asked to shrink %d, have %d more to go\n",
+			 p->pool->dev_name, p->pool->name, current->pid,
+			 nr_free, shrink_pages);
+	}
+out:
+	mutex_unlock(&_manager->lock);
+	return freed;
+}
+
+static unsigned long
+ttm_dma_pool_shrink_count(struct shrinker *shrink, struct shrink_control *sc)
+{
+	struct device_pools *p;
+	unsigned long count = 0;
+
+	if (!mutex_trylock(&_manager->lock))
+		return 0;
+	list_for_each_entry(p, &_manager->pools, pools)
+		count += p->pool->npages_free;
+	mutex_unlock(&_manager->lock);
+	return count;
+}
+
+static int ttm_dma_pool_mm_shrink_init(struct ttm_pool_manager *manager)
+{
+	manager->mm_shrink.count_objects = ttm_dma_pool_shrink_count;
+	manager->mm_shrink.scan_objects = &ttm_dma_pool_shrink_scan;
+	manager->mm_shrink.seeks = 1;
+	return register_shrinker(&manager->mm_shrink);
+}
+
+static void ttm_dma_pool_mm_shrink_fini(struct ttm_pool_manager *manager)
+{
+	unregister_shrinker(&manager->mm_shrink);
+}
+
+int ttm_dma_page_alloc_init(struct ttm_mem_global *glob, unsigned max_pages)
+{
+	int ret;
+
+	WARN_ON(_manager);
+
+	pr_info("Initializing DMA pool allocator\n");
+
+	_manager = kzalloc(sizeof(*_manager), GFP_KERNEL);
+	if (!_manager)
+		return -ENOMEM;
+
+	mutex_init(&_manager->lock);
+	INIT_LIST_HEAD(&_manager->pools);
+
+	_manager->options.max_size = max_pages;
+	_manager->options.small = SMALL_ALLOCATION;
+	_manager->options.alloc_size = NUM_PAGES_TO_ALLOC;
+
+	/* This takes care of auto-freeing the _manager */
+	ret = kobject_init_and_add(&_manager->kobj, &ttm_pool_kobj_type,
+				   &glob->kobj, "dma_pool");
+	if (unlikely(ret != 0))
+		goto error;
+
+	ret = ttm_dma_pool_mm_shrink_init(_manager);
+	if (unlikely(ret != 0))
+		goto error;
+	return 0;
+
+error:
+	kobject_put(&_manager->kobj);
+	_manager = NULL;
+	return ret;
+}
+
+void ttm_dma_page_alloc_fini(void)
+{
+	struct device_pools *p, *t;
+
+	pr_info("Finalizing DMA pool allocator\n");
+	ttm_dma_pool_mm_shrink_fini(_manager);
+
+	list_for_each_entry_safe_reverse(p, t, &_manager->pools, pools) {
+		dev_dbg(p->dev, "(%s:%d) Freeing.\n", p->pool->name,
+			current->pid);
+		WARN_ON(devres_destroy(p->dev, ttm_dma_pool_release,
+			ttm_dma_pool_match, p->pool));
+		ttm_dma_free_pool(p->dev, p->pool->type);
+	}
+	kobject_put(&_manager->kobj);
+	_manager = NULL;
+}
+
+int ttm_dma_page_alloc_debugfs(struct seq_file *m, void *data)
+{
+	struct device_pools *p;
+	struct dma_pool *pool = NULL;
+
+	if (!_manager) {
+		seq_printf(m, "No pool allocator running.\n");
+		return 0;
+	}
+	seq_printf(m, "         pool      refills   pages freed    inuse available     name\n");
+	mutex_lock(&_manager->lock);
+	list_for_each_entry(p, &_manager->pools, pools) {
+		struct device *dev = p->dev;
+		if (!dev)
+			continue;
+		pool = p->pool;
+		seq_printf(m, "%13s %12ld %13ld %8d %8d %8s\n",
+				pool->name, pool->nrefills,
+				pool->nfrees, pool->npages_in_use,
+				pool->npages_free,
+				pool->dev_name);
+	}
+	mutex_unlock(&_manager->lock);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(ttm_dma_page_alloc_debugfs);
+
+#endif