diff --git a/src/kernel/linux/v4.14/mm/dmapool.c b/src/kernel/linux/v4.14/mm/dmapool.c
new file mode 100644
index 0000000..4d90a64
--- /dev/null
+++ b/src/kernel/linux/v4.14/mm/dmapool.c
@@ -0,0 +1,533 @@
+/*
+ * DMA Pool allocator
+ *
+ * Copyright 2001 David Brownell
+ * Copyright 2007 Intel Corporation
+ *   Author: Matthew Wilcox <willy@linux.intel.com>
+ *
+ * This software may be redistributed and/or modified under the terms of
+ * the GNU General Public License ("GPL") version 2 as published by the
+ * Free Software Foundation.
+ *
+ * This allocator returns small blocks of a given size which are DMA-able by
+ * the given device.  It uses the dma_alloc_coherent page allocator to get
+ * new pages, then splits them up into blocks of the required size.
+ * Many older drivers still have their own code to do this.
+ *
+ * The current design of this allocator is fairly simple.  The pool is
+ * represented by the 'struct dma_pool' which keeps a doubly-linked list of
+ * allocated pages.  Each page in the page_list is split into blocks of at
+ * least 'size' bytes.  Free blocks are tracked in an unsorted singly-linked
+ * list of free blocks within the page.  Used blocks aren't tracked, but we
+ * keep a count of how many are currently allocated from each page.
+ */
+
+#include <linux/device.h>
+#include <linux/dma-mapping.h>
+#include <linux/dmapool.h>
+#include <linux/kernel.h>
+#include <linux/list.h>
+#include <linux/export.h>
+#include <linux/mutex.h>
+#include <linux/poison.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/stat.h>
+#include <linux/spinlock.h>
+#include <linux/string.h>
+#include <linux/types.h>
+#include <linux/wait.h>
+
+#if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_SLUB_DEBUG_ON)
+#define DMAPOOL_DEBUG 1
+#endif
+
+struct dma_pool {		/* the pool */
+	struct list_head page_list;
+	spinlock_t lock;
+	size_t size;
+	struct device *dev;
+	size_t allocation;
+	size_t boundary;
+	char name[32];
+	struct list_head pools;
+};
+
+struct dma_page {		/* cacheable header for 'allocation' bytes */
+	struct list_head page_list;
+	void *vaddr;
+	dma_addr_t dma;
+	unsigned int in_use;
+	unsigned int offset;
+};
+
+static DEFINE_MUTEX(pools_lock);
+static DEFINE_MUTEX(pools_reg_lock);
+
+static ssize_t
+show_pools(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	unsigned temp;
+	unsigned size;
+	char *next;
+	struct dma_page *page;
+	struct dma_pool *pool;
+
+	next = buf;
+	size = PAGE_SIZE;
+
+	temp = scnprintf(next, size, "poolinfo - 0.1\n");
+	size -= temp;
+	next += temp;
+
+	mutex_lock(&pools_lock);
+	list_for_each_entry(pool, &dev->dma_pools, pools) {
+		unsigned pages = 0;
+		unsigned blocks = 0;
+
+		spin_lock_irq(&pool->lock);
+		list_for_each_entry(page, &pool->page_list, page_list) {
+			pages++;
+			blocks += page->in_use;
+		}
+		spin_unlock_irq(&pool->lock);
+
+		/* per-pool info, no real statistics yet */
+		temp = scnprintf(next, size, "%-16s %4u %4zu %4zu %2u\n",
+				 pool->name, blocks,
+				 pages * (pool->allocation / pool->size),
+				 pool->size, pages);
+		size -= temp;
+		next += temp;
+	}
+	mutex_unlock(&pools_lock);
+
+	return PAGE_SIZE - size;
+}
+
+static DEVICE_ATTR(pools, S_IRUGO, show_pools, NULL);
+
+/**
+ * dma_pool_create - Creates a pool of consistent memory blocks, for dma.
+ * @name: name of pool, for diagnostics
+ * @dev: device that will be doing the DMA
+ * @size: size of the blocks in this pool.
+ * @align: alignment requirement for blocks; must be a power of two
+ * @boundary: returned blocks won't cross this power of two boundary
+ * Context: !in_interrupt()
+ *
+ * Returns a dma allocation pool with the requested characteristics, or
+ * null if one can't be created.  Given one of these pools, dma_pool_alloc()
+ * may be used to allocate memory.  Such memory will all have "consistent"
+ * DMA mappings, accessible by the device and its driver without using
+ * cache flushing primitives.  The actual size of blocks allocated may be
+ * larger than requested because of alignment.
+ *
+ * If @boundary is nonzero, objects returned from dma_pool_alloc() won't
+ * cross that size boundary.  This is useful for devices which have
+ * addressing restrictions on individual DMA transfers, such as not crossing
+ * boundaries of 4KBytes.
+ */
+struct dma_pool *dma_pool_create(const char *name, struct device *dev,
+				 size_t size, size_t align, size_t boundary)
+{
+	struct dma_pool *retval;
+	size_t allocation;
+	bool empty = false;
+
+	if (align == 0)
+		align = 1;
+	else if (align & (align - 1))
+		return NULL;
+
+	if (size == 0)
+		return NULL;
+	else if (size < 4)
+		size = 4;
+
+	if ((size % align) != 0)
+		size = ALIGN(size, align);
+
+	allocation = max_t(size_t, size, PAGE_SIZE);
+
+	if (!boundary)
+		boundary = allocation;
+	else if ((boundary < size) || (boundary & (boundary - 1)))
+		return NULL;
+
+	retval = kmalloc_node(sizeof(*retval), GFP_KERNEL, dev_to_node(dev));
+	if (!retval)
+		return retval;
+
+	strlcpy(retval->name, name, sizeof(retval->name));
+
+	retval->dev = dev;
+
+	INIT_LIST_HEAD(&retval->page_list);
+	spin_lock_init(&retval->lock);
+	retval->size = size;
+	retval->boundary = boundary;
+	retval->allocation = allocation;
+
+	INIT_LIST_HEAD(&retval->pools);
+
+	/*
+	 * pools_lock ensures that the ->dma_pools list does not get corrupted.
+	 * pools_reg_lock ensures that there is not a race between
+	 * dma_pool_create() and dma_pool_destroy() or within dma_pool_create()
+	 * when the first invocation of dma_pool_create() failed on
+	 * device_create_file() and the second assumes that it has been done (I
+	 * know it is a short window).
+	 */
+	mutex_lock(&pools_reg_lock);
+	mutex_lock(&pools_lock);
+	if (list_empty(&dev->dma_pools))
+		empty = true;
+	list_add(&retval->pools, &dev->dma_pools);
+	mutex_unlock(&pools_lock);
+	if (empty) {
+		int err;
+
+		err = device_create_file(dev, &dev_attr_pools);
+		if (err) {
+			mutex_lock(&pools_lock);
+			list_del(&retval->pools);
+			mutex_unlock(&pools_lock);
+			mutex_unlock(&pools_reg_lock);
+			kfree(retval);
+			return NULL;
+		}
+	}
+	mutex_unlock(&pools_reg_lock);
+	return retval;
+}
+EXPORT_SYMBOL(dma_pool_create);
+
+static void pool_initialise_page(struct dma_pool *pool, struct dma_page *page)
+{
+	unsigned int offset = 0;
+	unsigned int next_boundary = pool->boundary;
+
+	do {
+		unsigned int next = offset + pool->size;
+		if (unlikely((next + pool->size) >= next_boundary)) {
+			next = next_boundary;
+			next_boundary += pool->boundary;
+		}
+		*(int *)(page->vaddr + offset) = next;
+		offset = next;
+	} while (offset < pool->allocation);
+}
+
+static struct dma_page *pool_alloc_page(struct dma_pool *pool, gfp_t mem_flags)
+{
+	struct dma_page *page;
+
+	page = kmalloc(sizeof(*page), mem_flags);
+	if (!page)
+		return NULL;
+	page->vaddr = dma_alloc_coherent(pool->dev, pool->allocation,
+					 &page->dma, mem_flags);
+	if (page->vaddr) {
+#ifdef	DMAPOOL_DEBUG
+		memset(page->vaddr, POOL_POISON_FREED, pool->allocation);
+#endif
+		pool_initialise_page(pool, page);
+		page->in_use = 0;
+		page->offset = 0;
+	} else {
+		kfree(page);
+		page = NULL;
+	}
+	return page;
+}
+
+static inline bool is_page_busy(struct dma_page *page)
+{
+	return page->in_use != 0;
+}
+
+static void pool_free_page(struct dma_pool *pool, struct dma_page *page)
+{
+	dma_addr_t dma = page->dma;
+
+#ifdef	DMAPOOL_DEBUG
+	memset(page->vaddr, POOL_POISON_FREED, pool->allocation);
+#endif
+	dma_free_coherent(pool->dev, pool->allocation, page->vaddr, dma);
+	list_del(&page->page_list);
+	kfree(page);
+}
+
+/**
+ * dma_pool_destroy - destroys a pool of dma memory blocks.
+ * @pool: dma pool that will be destroyed
+ * Context: !in_interrupt()
+ *
+ * Caller guarantees that no more memory from the pool is in use,
+ * and that nothing will try to use the pool after this call.
+ */
+void dma_pool_destroy(struct dma_pool *pool)
+{
+	bool empty = false;
+
+	if (unlikely(!pool))
+		return;
+
+	mutex_lock(&pools_reg_lock);
+	mutex_lock(&pools_lock);
+	list_del(&pool->pools);
+	if (pool->dev && list_empty(&pool->dev->dma_pools))
+		empty = true;
+	mutex_unlock(&pools_lock);
+	if (empty)
+		device_remove_file(pool->dev, &dev_attr_pools);
+	mutex_unlock(&pools_reg_lock);
+
+	while (!list_empty(&pool->page_list)) {
+		struct dma_page *page;
+		page = list_entry(pool->page_list.next,
+				  struct dma_page, page_list);
+		if (is_page_busy(page)) {
+			if (pool->dev)
+				dev_err(pool->dev,
+					"dma_pool_destroy %s, %p busy\n",
+					pool->name, page->vaddr);
+			else
+				pr_err("dma_pool_destroy %s, %p busy\n",
+				       pool->name, page->vaddr);
+			/* leak the still-in-use consistent memory */
+			list_del(&page->page_list);
+			kfree(page);
+		} else
+			pool_free_page(pool, page);
+	}
+
+	kfree(pool);
+}
+EXPORT_SYMBOL(dma_pool_destroy);
+
+/**
+ * dma_pool_alloc - get a block of consistent memory
+ * @pool: dma pool that will produce the block
+ * @mem_flags: GFP_* bitmask
+ * @handle: pointer to dma address of block
+ *
+ * This returns the kernel virtual address of a currently unused block,
+ * and reports its dma address through the handle.
+ * If such a memory block can't be allocated, %NULL is returned.
+ */
+void *dma_pool_alloc(struct dma_pool *pool, gfp_t mem_flags,
+		     dma_addr_t *handle)
+{
+	unsigned long flags;
+	struct dma_page *page;
+	size_t offset;
+	void *retval;
+
+	might_sleep_if(gfpflags_allow_blocking(mem_flags));
+
+	spin_lock_irqsave(&pool->lock, flags);
+	list_for_each_entry(page, &pool->page_list, page_list) {
+		if (page->offset < pool->allocation)
+			goto ready;
+	}
+
+	/* pool_alloc_page() might sleep, so temporarily drop &pool->lock */
+	spin_unlock_irqrestore(&pool->lock, flags);
+
+	page = pool_alloc_page(pool, mem_flags & (~__GFP_ZERO));
+	if (!page)
+		return NULL;
+
+	spin_lock_irqsave(&pool->lock, flags);
+
+	list_add(&page->page_list, &pool->page_list);
+ ready:
+	page->in_use++;
+	offset = page->offset;
+	page->offset = *(int *)(page->vaddr + offset);
+	retval = offset + page->vaddr;
+	*handle = offset + page->dma;
+#ifdef	DMAPOOL_DEBUG
+	{
+		int i;
+		u8 *data = retval;
+		/* page->offset is stored in first 4 bytes */
+		for (i = sizeof(page->offset); i < pool->size; i++) {
+			if (data[i] == POOL_POISON_FREED)
+				continue;
+			if (pool->dev)
+				dev_err(pool->dev,
+					"dma_pool_alloc %s, %p (corrupted)\n",
+					pool->name, retval);
+			else
+				pr_err("dma_pool_alloc %s, %p (corrupted)\n",
+					pool->name, retval);
+
+			/*
+			 * Dump the first 4 bytes even if they are not
+			 * POOL_POISON_FREED
+			 */
+			print_hex_dump(KERN_ERR, "", DUMP_PREFIX_OFFSET, 16, 1,
+					data, pool->size, 1);
+			break;
+		}
+	}
+	if (!(mem_flags & __GFP_ZERO))
+		memset(retval, POOL_POISON_ALLOCATED, pool->size);
+#endif
+	spin_unlock_irqrestore(&pool->lock, flags);
+
+	if (mem_flags & __GFP_ZERO)
+		memset(retval, 0, pool->size);
+
+	return retval;
+}
+EXPORT_SYMBOL(dma_pool_alloc);
+
+static struct dma_page *pool_find_page(struct dma_pool *pool, dma_addr_t dma)
+{
+	struct dma_page *page;
+
+	list_for_each_entry(page, &pool->page_list, page_list) {
+		if (dma < page->dma)
+			continue;
+		if ((dma - page->dma) < pool->allocation)
+			return page;
+	}
+	return NULL;
+}
+
+/**
+ * dma_pool_free - put block back into dma pool
+ * @pool: the dma pool holding the block
+ * @vaddr: virtual address of block
+ * @dma: dma address of block
+ *
+ * Caller promises neither device nor driver will again touch this block
+ * unless it is first re-allocated.
+ */
+void dma_pool_free(struct dma_pool *pool, void *vaddr, dma_addr_t dma)
+{
+	struct dma_page *page;
+	unsigned long flags;
+	unsigned int offset;
+
+	spin_lock_irqsave(&pool->lock, flags);
+	page = pool_find_page(pool, dma);
+	if (!page) {
+		spin_unlock_irqrestore(&pool->lock, flags);
+		if (pool->dev)
+			dev_err(pool->dev,
+				"dma_pool_free %s, %p/%lx (bad dma)\n",
+				pool->name, vaddr, (unsigned long)dma);
+		else
+			pr_err("dma_pool_free %s, %p/%lx (bad dma)\n",
+			       pool->name, vaddr, (unsigned long)dma);
+		return;
+	}
+
+	offset = vaddr - page->vaddr;
+#ifdef	DMAPOOL_DEBUG
+	if ((dma - page->dma) != offset) {
+		spin_unlock_irqrestore(&pool->lock, flags);
+		if (pool->dev)
+			dev_err(pool->dev,
+				"dma_pool_free %s, %p (bad vaddr)/%pad\n",
+				pool->name, vaddr, &dma);
+		else
+			pr_err("dma_pool_free %s, %p (bad vaddr)/%pad\n",
+			       pool->name, vaddr, &dma);
+		return;
+	}
+	{
+		unsigned int chain = page->offset;
+		while (chain < pool->allocation) {
+			if (chain != offset) {
+				chain = *(int *)(page->vaddr + chain);
+				continue;
+			}
+			spin_unlock_irqrestore(&pool->lock, flags);
+			if (pool->dev)
+				dev_err(pool->dev, "dma_pool_free %s, dma %pad already free\n",
+					pool->name, &dma);
+			else
+				pr_err("dma_pool_free %s, dma %pad already free\n",
+				       pool->name, &dma);
+			return;
+		}
+	}
+	memset(vaddr, POOL_POISON_FREED, pool->size);
+#endif
+
+	page->in_use--;
+	*(int *)vaddr = page->offset;
+	page->offset = offset;
+	/*
+	 * Resist a temptation to do
+	 *    if (!is_page_busy(page)) pool_free_page(pool, page);
+	 * Better have a few empty pages hang around.
+	 */
+	spin_unlock_irqrestore(&pool->lock, flags);
+}
+EXPORT_SYMBOL(dma_pool_free);
+
+/*
+ * Managed DMA pool
+ */
+static void dmam_pool_release(struct device *dev, void *res)
+{
+	struct dma_pool *pool = *(struct dma_pool **)res;
+
+	dma_pool_destroy(pool);
+}
+
+static int dmam_pool_match(struct device *dev, void *res, void *match_data)
+{
+	return *(struct dma_pool **)res == match_data;
+}
+
+/**
+ * dmam_pool_create - Managed dma_pool_create()
+ * @name: name of pool, for diagnostics
+ * @dev: device that will be doing the DMA
+ * @size: size of the blocks in this pool.
+ * @align: alignment requirement for blocks; must be a power of two
+ * @allocation: returned blocks won't cross this boundary (or zero)
+ *
+ * Managed dma_pool_create().  DMA pool created with this function is
+ * automatically destroyed on driver detach.
+ */
+struct dma_pool *dmam_pool_create(const char *name, struct device *dev,
+				  size_t size, size_t align, size_t allocation)
+{
+	struct dma_pool **ptr, *pool;
+
+	ptr = devres_alloc(dmam_pool_release, sizeof(*ptr), GFP_KERNEL);
+	if (!ptr)
+		return NULL;
+
+	pool = *ptr = dma_pool_create(name, dev, size, align, allocation);
+	if (pool)
+		devres_add(dev, ptr);
+	else
+		devres_free(ptr);
+
+	return pool;
+}
+EXPORT_SYMBOL(dmam_pool_create);
+
+/**
+ * dmam_pool_destroy - Managed dma_pool_destroy()
+ * @pool: dma pool that will be destroyed
+ *
+ * Managed dma_pool_destroy().
+ */
+void dmam_pool_destroy(struct dma_pool *pool)
+{
+	struct device *dev = pool->dev;
+
+	WARN_ON(devres_release(dev, dmam_pool_release, dmam_pool_match, pool));
+}
+EXPORT_SYMBOL(dmam_pool_destroy);