1 files changed, 182 insertions, 0 deletions
diff --git a/drivers/staging/android/ion/ion_page_pool.c b/drivers/staging/android/ion/ion_page_pool.c
new file mode 100644
index 000000000..4b88f11e5
--- /dev/null
+++ b/drivers/staging/android/ion/ion_page_pool.c
@@ -0,0 +1,182 @@
+/*
+ * drivers/staging/android/ion/ion_mem_pool.c
+ *
+ * Copyright (C) 2011 Google, Inc.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#include <linux/debugfs.h>
+#include <linux/dma-mapping.h>
+#include <linux/err.h>
+#include <linux/fs.h>
+#include <linux/list.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/swap.h>
+#include "ion_priv.h"
+
+static void *ion_page_pool_alloc_pages(struct ion_page_pool *pool)
+{
+	struct page *page = alloc_pages(pool->gfp_mask, pool->order);
+
+	if (!page)
+		return NULL;
+	ion_pages_sync_for_device(NULL, page, PAGE_SIZE << pool->order,
+						DMA_BIDIRECTIONAL);
+	return page;
+}
+
+static void ion_page_pool_free_pages(struct ion_page_pool *pool,
+				     struct page *page)
+{
+	__free_pages(page, pool->order);
+}
+
+static int ion_page_pool_add(struct ion_page_pool *pool, struct page *page)
+{
+	mutex_lock(&pool->mutex);
+	if (PageHighMem(page)) {
+		list_add_tail(&page->lru, &pool->high_items);
+		pool->high_count++;
+	} else {
+		list_add_tail(&page->lru, &pool->low_items);
+		pool->low_count++;
+	}
+	mutex_unlock(&pool->mutex);
+	return 0;
+}
+
+static struct page *ion_page_pool_remove(struct ion_page_pool *pool, bool high)
+{
+	struct page *page;
+
+	if (high) {
+		BUG_ON(!pool->high_count);
+		page = list_first_entry(&pool->high_items, struct page, lru);
+		pool->high_count--;
+	} else {
+		BUG_ON(!pool->low_count);
+		page = list_first_entry(&pool->low_items, struct page, lru);
+		pool->low_count--;
+	}
+
+	list_del(&page->lru);
+	return page;
+}
+
+struct page *ion_page_pool_alloc(struct ion_page_pool *pool)
+{
+	struct page *page = NULL;
+
+	BUG_ON(!pool);
+
+	mutex_lock(&pool->mutex);
+	if (pool->high_count)
+		page = ion_page_pool_remove(pool, true);
+	else if (pool->low_count)
+		page = ion_page_pool_remove(pool, false);
+	mutex_unlock(&pool->mutex);
+
+	if (!page)
+		page = ion_page_pool_alloc_pages(pool);
+
+	return page;
+}
+
+void ion_page_pool_free(struct ion_page_pool *pool, struct page *page)
+{
+	int ret;
+
+	BUG_ON(pool->order != compound_order(page));
+
+	ret = ion_page_pool_add(pool, page);
+	if (ret)
+		ion_page_pool_free_pages(pool, page);
+}
+
+static int ion_page_pool_total(struct ion_page_pool *pool, bool high)
+{
+	int count = pool->low_count;
+
+	if (high)
+		count += pool->high_count;
+
+	return count << pool->order;
+}
+
+int ion_page_pool_shrink(struct ion_page_pool *pool, gfp_t gfp_mask,
+				int nr_to_scan)
+{
+	int freed;
+	bool high;
+
+	if (current_is_kswapd())
+		high = true;
+	else
+		high = !!(gfp_mask & __GFP_HIGHMEM);
+
+	if (nr_to_scan == 0)
+		return ion_page_pool_total(pool, high);
+
+	for (freed = 0; freed < nr_to_scan; freed++) {
+		struct page *page;
+
+		mutex_lock(&pool->mutex);
+		if (pool->low_count) {
+			page = ion_page_pool_remove(pool, false);
+		} else if (high && pool->high_count) {
+			page = ion_page_pool_remove(pool, true);
+		} else {
+			mutex_unlock(&pool->mutex);
+			break;
+		}
+		mutex_unlock(&pool->mutex);
+		ion_page_pool_free_pages(pool, page);
+	}
+
+	return freed;
+}
+
+struct ion_page_pool *ion_page_pool_create(gfp_t gfp_mask, unsigned int order)
+{
+	struct ion_page_pool *pool = kmalloc(sizeof(struct ion_page_pool),
+					     GFP_KERNEL);
+	if (!pool)
+		return NULL;
+	pool->high_count = 0;
+	pool->low_count = 0;
+	INIT_LIST_HEAD(&pool->low_items);
+	INIT_LIST_HEAD(&pool->high_items);
+	pool->gfp_mask = gfp_mask | __GFP_COMP;
+	pool->order = order;
+	mutex_init(&pool->mutex);
+	plist_node_init(&pool->list, order);
+
+	return pool;
+}
+
+void ion_page_pool_destroy(struct ion_page_pool *pool)
+{
+	kfree(pool);
+}
+
+static int __init ion_page_pool_init(void)
+{
+	return 0;
+}
+
+static void __exit ion_page_pool_exit(void)
+{
+}
+
+module_init(ion_page_pool_init);
+module_exit(ion_page_pool_exit);