diff mbox

[2/9] ashmem: Move ashmem to staging

Message ID 1323405908-26046-3-git-send-email-john.stultz@linaro.org
State Superseded
Headers show

Commit Message

John Stultz Dec. 9, 2011, 4:45 a.m. UTC
Move ashmem code under the drivers/staging/android dir.

NOTE: This patch will be folded into the previous before
I submit the queue to staging.

CC: Brian Swetland <swetland@google.com>
CC: Colin Cross <ccross@android.com>
CC: Arve Hjønnevåg <arve@android.com>
CC: Dima Zavin <dima@android.com>
CC: Robert Love <rlove@google.com>
CC: Greg KH <greg@kroah.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
---
 drivers/staging/android/Kconfig  |    9 +
 drivers/staging/android/Makefile |    1 +
 drivers/staging/android/ashmem.c |  670 ++++++++++++++++++++++++++++++++++++++
 drivers/staging/android/ashmem.h |   48 +++
 include/linux/ashmem.h           |   48 ---
 init/Kconfig                     |    9 -
 mm/Makefile                      |    1 -
 mm/ashmem.c                      |  670 --------------------------------------
 8 files changed, 728 insertions(+), 728 deletions(-)
 create mode 100644 drivers/staging/android/ashmem.c
 create mode 100644 drivers/staging/android/ashmem.h
 delete mode 100644 include/linux/ashmem.h
 delete mode 100644 mm/ashmem.c
diff mbox

Patch

diff --git a/drivers/staging/android/Kconfig b/drivers/staging/android/Kconfig
index 2471949..a72142d 100644
--- a/drivers/staging/android/Kconfig
+++ b/drivers/staging/android/Kconfig
@@ -12,6 +12,15 @@  config ANDROID_BINDER_IPC
 	bool "Android Binder IPC Driver"
 	default n
 
+config ASHMEM
+	bool "Enable the Anonymous Shared Memory Subsystem"
+	default n
+	depends on SHMEM || TINY_SHMEM
+	help
+	  The ashmem subsystem is a new shared memory allocator, similar to
+	  POSIX SHM but with different behavior and sporting a simpler
+	  file-based API.
+
 config ANDROID_LOGGER
 	tristate "Android log driver"
 	default n
diff --git a/drivers/staging/android/Makefile b/drivers/staging/android/Makefile
index 8e057e6..206e70c 100644
--- a/drivers/staging/android/Makefile
+++ b/drivers/staging/android/Makefile
@@ -1,4 +1,5 @@ 
 obj-$(CONFIG_ANDROID_BINDER_IPC)	+= binder.o
+obj-$(CONFIG_ASHMEM)			+= ashmem.o
 obj-$(CONFIG_ANDROID_LOGGER)		+= logger.o
 obj-$(CONFIG_ANDROID_RAM_CONSOLE)	+= ram_console.o
 obj-$(CONFIG_ANDROID_TIMED_OUTPUT)	+= timed_output.o
diff --git a/drivers/staging/android/ashmem.c b/drivers/staging/android/ashmem.c
new file mode 100644
index 0000000..34a5f8b
--- /dev/null
+++ b/drivers/staging/android/ashmem.c
@@ -0,0 +1,670 @@ 
+/* mm/ashmem.c
+**
+** Anonymous Shared Memory Subsystem, ashmem
+**
+** Copyright (C) 2008 Google, Inc.
+**
+** Robert Love <rlove@google.com>
+**
+** 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/module.h>
+#include <linux/file.h>
+#include <linux/fs.h>
+#include <linux/miscdevice.h>
+#include <linux/security.h>
+#include <linux/mm.h>
+#include <linux/mman.h>
+#include <linux/uaccess.h>
+#include <linux/personality.h>
+#include <linux/bitops.h>
+#include <linux/mutex.h>
+#include <linux/shmem_fs.h>
+#include "ashmem.h"
+
+#define ASHMEM_NAME_PREFIX "dev/ashmem/"
+#define ASHMEM_NAME_PREFIX_LEN (sizeof(ASHMEM_NAME_PREFIX) - 1)
+#define ASHMEM_FULL_NAME_LEN (ASHMEM_NAME_LEN + ASHMEM_NAME_PREFIX_LEN)
+
+/*
+ * ashmem_area - anonymous shared memory area
+ * Lifecycle: From our parent file's open() until its release()
+ * Locking: Protected by `ashmem_mutex'
+ * Big Note: Mappings do NOT pin this structure; it dies on close()
+ */
+struct ashmem_area {
+	char name[ASHMEM_FULL_NAME_LEN];/* optional name for /proc/pid/maps */
+	struct list_head unpinned_list;	/* list of all ashmem areas */
+	struct file *file;		/* the shmem-based backing file */
+	size_t size;			/* size of the mapping, in bytes */
+	unsigned long prot_mask;	/* allowed prot bits, as vm_flags */
+};
+
+/*
+ * ashmem_range - represents an interval of unpinned (evictable) pages
+ * Lifecycle: From unpin to pin
+ * Locking: Protected by `ashmem_mutex'
+ */
+struct ashmem_range {
+	struct list_head lru;		/* entry in LRU list */
+	struct list_head unpinned;	/* entry in its area's unpinned list */
+	struct ashmem_area *asma;	/* associated area */
+	size_t pgstart;			/* starting page, inclusive */
+	size_t pgend;			/* ending page, inclusive */
+	unsigned int purged;		/* ASHMEM_NOT or ASHMEM_WAS_PURGED */
+};
+
+/* LRU list of unpinned pages, protected by ashmem_mutex */
+static LIST_HEAD(ashmem_lru_list);
+
+/* Count of pages on our LRU list, protected by ashmem_mutex */
+static unsigned long lru_count;
+
+/*
+ * ashmem_mutex - protects the list of and each individual ashmem_area
+ *
+ * Lock Ordering: ashmex_mutex -> i_mutex -> i_alloc_sem
+ */
+static DEFINE_MUTEX(ashmem_mutex);
+
+static struct kmem_cache *ashmem_area_cachep __read_mostly;
+static struct kmem_cache *ashmem_range_cachep __read_mostly;
+
+#define range_size(range) \
+  ((range)->pgend - (range)->pgstart + 1)
+
+#define range_on_lru(range) \
+  ((range)->purged == ASHMEM_NOT_PURGED)
+
+#define page_range_subsumes_range(range, start, end) \
+  (((range)->pgstart >= (start)) && ((range)->pgend <= (end)))
+
+#define page_range_subsumed_by_range(range, start, end) \
+  (((range)->pgstart <= (start)) && ((range)->pgend >= (end)))
+
+#define page_in_range(range, page) \
+ (((range)->pgstart <= (page)) && ((range)->pgend >= (page)))
+
+#define page_range_in_range(range, start, end) \
+  (page_in_range(range, start) || page_in_range(range, end) || \
+   page_range_subsumes_range(range, start, end))
+
+#define range_before_page(range, page) \
+  ((range)->pgend < (page))
+
+#define PROT_MASK		(PROT_EXEC | PROT_READ | PROT_WRITE)
+
+static inline void lru_add(struct ashmem_range *range)
+{
+	list_add_tail(&range->lru, &ashmem_lru_list);
+	lru_count += range_size(range);
+}
+
+static inline void lru_del(struct ashmem_range *range)
+{
+	list_del(&range->lru);
+	lru_count -= range_size(range);
+}
+
+/*
+ * range_alloc - allocate and initialize a new ashmem_range structure
+ *
+ * 'asma' - associated ashmem_area
+ * 'prev_range' - the previous ashmem_range in the sorted asma->unpinned list
+ * 'purged' - initial purge value (ASMEM_NOT_PURGED or ASHMEM_WAS_PURGED)
+ * 'start' - starting page, inclusive
+ * 'end' - ending page, inclusive
+ *
+ * Caller must hold ashmem_mutex.
+ */
+static int range_alloc(struct ashmem_area *asma,
+		       struct ashmem_range *prev_range, unsigned int purged,
+		       size_t start, size_t end)
+{
+	struct ashmem_range *range;
+
+	range = kmem_cache_zalloc(ashmem_range_cachep, GFP_KERNEL);
+	if (unlikely(!range))
+		return -ENOMEM;
+
+	range->asma = asma;
+	range->pgstart = start;
+	range->pgend = end;
+	range->purged = purged;
+
+	list_add_tail(&range->unpinned, &prev_range->unpinned);
+
+	if (range_on_lru(range))
+		lru_add(range);
+
+	return 0;
+}
+
+static void range_del(struct ashmem_range *range)
+{
+	list_del(&range->unpinned);
+	if (range_on_lru(range))
+		lru_del(range);
+	kmem_cache_free(ashmem_range_cachep, range);
+}
+
+/*
+ * range_shrink - shrinks a range
+ *
+ * Caller must hold ashmem_mutex.
+ */
+static inline void range_shrink(struct ashmem_range *range,
+				size_t start, size_t end)
+{
+	size_t pre = range_size(range);
+
+	range->pgstart = start;
+	range->pgend = end;
+
+	if (range_on_lru(range))
+		lru_count -= pre - range_size(range);
+}
+
+static int ashmem_open(struct inode *inode, struct file *file)
+{
+	struct ashmem_area *asma;
+	int ret;
+
+	ret = nonseekable_open(inode, file);
+	if (unlikely(ret))
+		return ret;
+
+	asma = kmem_cache_zalloc(ashmem_area_cachep, GFP_KERNEL);
+	if (unlikely(!asma))
+		return -ENOMEM;
+
+	INIT_LIST_HEAD(&asma->unpinned_list);
+	memcpy(asma->name, ASHMEM_NAME_PREFIX, ASHMEM_NAME_PREFIX_LEN);
+	asma->prot_mask = PROT_MASK;
+	file->private_data = asma;
+
+	return 0;
+}
+
+static int ashmem_release(struct inode *ignored, struct file *file)
+{
+	struct ashmem_area *asma = file->private_data;
+	struct ashmem_range *range, *next;
+
+	mutex_lock(&ashmem_mutex);
+	list_for_each_entry_safe(range, next, &asma->unpinned_list, unpinned)
+		range_del(range);
+	mutex_unlock(&ashmem_mutex);
+
+	if (asma->file)
+		fput(asma->file);
+	kmem_cache_free(ashmem_area_cachep, asma);
+
+	return 0;
+}
+
+static int ashmem_mmap(struct file *file, struct vm_area_struct *vma)
+{
+	struct ashmem_area *asma = file->private_data;
+	int ret = 0;
+
+	mutex_lock(&ashmem_mutex);
+
+	/* user needs to SET_SIZE before mapping */
+	if (unlikely(!asma->size)) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	/* requested protection bits must match our allowed protection mask */
+	if (unlikely((vma->vm_flags & ~asma->prot_mask) & PROT_MASK)) {
+		ret = -EPERM;
+		goto out;
+	}
+
+	if (!asma->file) {
+		char *name = ASHMEM_NAME_DEF;
+		struct file *vmfile;
+
+		if (asma->name[ASHMEM_NAME_PREFIX_LEN] != '\0')
+			name = asma->name;
+
+		/* ... and allocate the backing shmem file */
+		vmfile = shmem_file_setup(name, asma->size, vma->vm_flags);
+		if (unlikely(IS_ERR(vmfile))) {
+			ret = PTR_ERR(vmfile);
+			goto out;
+		}
+		asma->file = vmfile;
+	}
+	get_file(asma->file);
+
+	if (vma->vm_flags & VM_SHARED)
+		shmem_set_file(vma, asma->file);
+	else {
+		if (vma->vm_file)
+			fput(vma->vm_file);
+		vma->vm_file = asma->file;
+	}
+	vma->vm_flags |= VM_CAN_NONLINEAR;
+
+out:
+	mutex_unlock(&ashmem_mutex);
+	return ret;
+}
+
+/*
+ * ashmem_shrink - our cache shrinker, called from mm/vmscan.c :: shrink_slab
+ *
+ * 'nr_to_scan' is the number of objects (pages) to prune, or 0 to query how
+ * many objects (pages) we have in total.
+ *
+ * 'gfp_mask' is the mask of the allocation that got us into this mess.
+ *
+ * Return value is the number of objects (pages) remaining, or -1 if we cannot
+ * proceed without risk of deadlock (due to gfp_mask).
+ *
+ * We approximate LRU via least-recently-unpinned, jettisoning unpinned partial
+ * chunks of ashmem regions LRU-wise one-at-a-time until we hit 'nr_to_scan'
+ * pages freed.
+ */
+static int ashmem_shrink(int nr_to_scan, gfp_t gfp_mask)
+{
+	struct ashmem_range *range, *next;
+
+	/* We might recurse into filesystem code, so bail out if necessary */
+	if (nr_to_scan && !(gfp_mask & __GFP_FS))
+		return -1;
+	if (!nr_to_scan)
+		return lru_count;
+
+	mutex_lock(&ashmem_mutex);
+	list_for_each_entry_safe(range, next, &ashmem_lru_list, lru) {
+		struct inode *inode = range->asma->file->f_dentry->d_inode;
+		loff_t start = range->pgstart * PAGE_SIZE;
+		loff_t end = (range->pgend + 1) * PAGE_SIZE - 1;
+
+		vmtruncate_range(inode, start, end);
+		range->purged = ASHMEM_WAS_PURGED;
+		lru_del(range);
+
+		nr_to_scan -= range_size(range);
+		if (nr_to_scan <= 0)
+			break;
+	}
+	mutex_unlock(&ashmem_mutex);
+
+	return lru_count;
+}
+
+static struct shrinker ashmem_shrinker = {
+	.shrink = ashmem_shrink,
+	.seeks = DEFAULT_SEEKS * 4,
+};
+
+static int set_prot_mask(struct ashmem_area *asma, unsigned long prot)
+{
+	int ret = 0;
+
+	mutex_lock(&ashmem_mutex);
+
+	/* the user can only remove, not add, protection bits */
+	if (unlikely((asma->prot_mask & prot) != prot)) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	/* does the application expect PROT_READ to imply PROT_EXEC? */
+	if ((prot & PROT_READ) && (current->personality & READ_IMPLIES_EXEC))
+		prot |= PROT_EXEC;
+
+	asma->prot_mask = prot;
+
+out:
+	mutex_unlock(&ashmem_mutex);
+	return ret;
+}
+
+static int set_name(struct ashmem_area *asma, void __user *name)
+{
+	int ret = 0;
+
+	mutex_lock(&ashmem_mutex);
+
+	/* cannot change an existing mapping's name */
+	if (unlikely(asma->file)) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	if (unlikely(copy_from_user(asma->name + ASHMEM_NAME_PREFIX_LEN,
+				    name, ASHMEM_NAME_LEN)))
+		ret = -EFAULT;
+	asma->name[ASHMEM_FULL_NAME_LEN-1] = '\0';
+
+out:
+	mutex_unlock(&ashmem_mutex);
+
+	return ret;
+}
+
+static int get_name(struct ashmem_area *asma, void __user *name)
+{
+	int ret = 0;
+
+	mutex_lock(&ashmem_mutex);
+	if (asma->name[ASHMEM_NAME_PREFIX_LEN] != '\0') {
+		size_t len;
+
+		/*
+		 * Copying only `len', instead of ASHMEM_NAME_LEN, bytes
+		 * prevents us from revealing one user's stack to another.
+		 */
+		len = strlen(asma->name + ASHMEM_NAME_PREFIX_LEN) + 1;
+		if (unlikely(copy_to_user(name,
+				asma->name + ASHMEM_NAME_PREFIX_LEN, len)))
+			ret = -EFAULT;
+	} else {
+		if (unlikely(copy_to_user(name, ASHMEM_NAME_DEF,
+					  sizeof(ASHMEM_NAME_DEF))))
+			ret = -EFAULT;
+	}
+	mutex_unlock(&ashmem_mutex);
+
+	return ret;
+}
+
+/*
+ * ashmem_pin - pin the given ashmem region, returning whether it was
+ * previously purged (ASHMEM_WAS_PURGED) or not (ASHMEM_NOT_PURGED).
+ *
+ * Caller must hold ashmem_mutex.
+ */
+static int ashmem_pin(struct ashmem_area *asma, size_t pgstart, size_t pgend)
+{
+	struct ashmem_range *range, *next;
+	int ret = ASHMEM_NOT_PURGED;
+
+	list_for_each_entry_safe(range, next, &asma->unpinned_list, unpinned) {
+		/* moved past last applicable page; we can short circuit */
+		if (range_before_page(range, pgstart))
+			break;
+
+		/*
+		 * The user can ask us to pin pages that span multiple ranges,
+		 * or to pin pages that aren't even unpinned, so this is messy.
+		 *
+		 * Four cases:
+		 * 1. The requested range subsumes an existing range, so we
+		 *    just remove the entire matching range.
+		 * 2. The requested range overlaps the start of an existing
+		 *    range, so we just update that range.
+		 * 3. The requested range overlaps the end of an existing
+		 *    range, so we just update that range.
+		 * 4. The requested range punches a hole in an existing range,
+		 *    so we have to update one side of the range and then
+		 *    create a new range for the other side.
+		 */
+		if (page_range_in_range(range, pgstart, pgend)) {
+			ret |= range->purged;
+
+			/* Case #1: Easy. Just nuke the whole thing. */
+			if (page_range_subsumes_range(range, pgstart, pgend)) {
+				range_del(range);
+				continue;
+			}
+
+			/* Case #2: We overlap from the start, so adjust it */
+			if (range->pgstart >= pgstart) {
+				range_shrink(range, pgend + 1, range->pgend);
+				continue;
+			}
+
+			/* Case #3: We overlap from the rear, so adjust it */
+			if (range->pgend <= pgend) {
+				range_shrink(range, range->pgstart, pgstart-1);
+				continue;
+			}
+
+			/*
+			 * Case #4: We eat a chunk out of the middle. A bit
+			 * more complicated, we allocate a new range for the
+			 * second half and adjust the first chunk's endpoint.
+			 */
+			range_alloc(asma, range, range->purged,
+				    pgend + 1, range->pgend);
+			range_shrink(range, range->pgstart, pgstart - 1);
+			break;
+		}
+	}
+
+	return ret;
+}
+
+/*
+ * ashmem_unpin - unpin the given range of pages. Returns zero on success.
+ *
+ * Caller must hold ashmem_mutex.
+ */
+static int ashmem_unpin(struct ashmem_area *asma, size_t pgstart, size_t pgend)
+{
+	struct ashmem_range *range, *next;
+	unsigned int purged = ASHMEM_NOT_PURGED;
+
+restart:
+	list_for_each_entry_safe(range, next, &asma->unpinned_list, unpinned) {
+		/* short circuit: this is our insertion point */
+		if (range_before_page(range, pgstart))
+			break;
+
+		/*
+		 * The user can ask us to unpin pages that are already entirely
+		 * or partially pinned. We handle those two cases here.
+		 */
+		if (page_range_subsumed_by_range(range, pgstart, pgend))
+			return 0;
+		if (page_range_in_range(range, pgstart, pgend)) {
+			pgstart = min_t(size_t, range->pgstart, pgstart),
+			pgend = max_t(size_t, range->pgend, pgend);
+			purged |= range->purged;
+			range_del(range);
+			goto restart;
+		}
+	}
+
+	return range_alloc(asma, range, purged, pgstart, pgend);
+}
+
+/*
+ * ashmem_get_pin_status - Returns ASHMEM_IS_UNPINNED if _any_ pages in the
+ * given interval are unpinned and ASHMEM_IS_PINNED otherwise.
+ *
+ * Caller must hold ashmem_mutex.
+ */
+static int ashmem_get_pin_status(struct ashmem_area *asma, size_t pgstart,
+				 size_t pgend)
+{
+	struct ashmem_range *range;
+	int ret = ASHMEM_IS_PINNED;
+
+	list_for_each_entry(range, &asma->unpinned_list, unpinned) {
+		if (range_before_page(range, pgstart))
+			break;
+		if (page_range_in_range(range, pgstart, pgend)) {
+			ret = ASHMEM_IS_UNPINNED;
+			break;
+		}
+	}
+
+	return ret;
+}
+
+static int ashmem_pin_unpin(struct ashmem_area *asma, unsigned long cmd,
+			    void __user *p)
+{
+	struct ashmem_pin pin;
+	size_t pgstart, pgend;
+	int ret = -EINVAL;
+
+	if (unlikely(!asma->file))
+		return -EINVAL;
+
+	if (unlikely(copy_from_user(&pin, p, sizeof(pin))))
+		return -EFAULT;
+
+	/* per custom, you can pass zero for len to mean "everything onward" */
+	if (!pin.len)
+		pin.len = PAGE_ALIGN(asma->size) - pin.offset;
+
+	if (unlikely((pin.offset | pin.len) & ~PAGE_MASK))
+		return -EINVAL;
+
+	if (unlikely(((__u32) -1) - pin.offset < pin.len))
+		return -EINVAL;
+
+	if (unlikely(PAGE_ALIGN(asma->size) < pin.offset + pin.len))
+		return -EINVAL;
+
+	pgstart = pin.offset / PAGE_SIZE;
+	pgend = pgstart + (pin.len / PAGE_SIZE) - 1;
+
+	mutex_lock(&ashmem_mutex);
+
+	switch (cmd) {
+	case ASHMEM_PIN:
+		ret = ashmem_pin(asma, pgstart, pgend);
+		break;
+	case ASHMEM_UNPIN:
+		ret = ashmem_unpin(asma, pgstart, pgend);
+		break;
+	case ASHMEM_GET_PIN_STATUS:
+		ret = ashmem_get_pin_status(asma, pgstart, pgend);
+		break;
+	}
+
+	mutex_unlock(&ashmem_mutex);
+
+	return ret;
+}
+
+static long ashmem_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+	struct ashmem_area *asma = file->private_data;
+	long ret = -ENOTTY;
+
+	switch (cmd) {
+	case ASHMEM_SET_NAME:
+		ret = set_name(asma, (void __user *) arg);
+		break;
+	case ASHMEM_GET_NAME:
+		ret = get_name(asma, (void __user *) arg);
+		break;
+	case ASHMEM_SET_SIZE:
+		ret = -EINVAL;
+		if (!asma->file) {
+			ret = 0;
+			asma->size = (size_t) arg;
+		}
+		break;
+	case ASHMEM_GET_SIZE:
+		ret = asma->size;
+		break;
+	case ASHMEM_SET_PROT_MASK:
+		ret = set_prot_mask(asma, arg);
+		break;
+	case ASHMEM_GET_PROT_MASK:
+		ret = asma->prot_mask;
+		break;
+	case ASHMEM_PIN:
+	case ASHMEM_UNPIN:
+	case ASHMEM_GET_PIN_STATUS:
+		ret = ashmem_pin_unpin(asma, cmd, (void __user *) arg);
+		break;
+	case ASHMEM_PURGE_ALL_CACHES:
+		ret = -EPERM;
+		if (capable(CAP_SYS_ADMIN)) {
+			ret = ashmem_shrink(0, GFP_KERNEL);
+			ashmem_shrink(ret, GFP_KERNEL);
+		}
+		break;
+	}
+
+	return ret;
+}
+
+static struct file_operations ashmem_fops = {
+	.owner = THIS_MODULE,
+	.open = ashmem_open,
+	.release = ashmem_release,
+	.mmap = ashmem_mmap,
+	.unlocked_ioctl = ashmem_ioctl,
+	.compat_ioctl = ashmem_ioctl,
+};
+
+static struct miscdevice ashmem_misc = {
+	.minor = MISC_DYNAMIC_MINOR,
+	.name = "ashmem",
+	.fops = &ashmem_fops,
+};
+
+static int __init ashmem_init(void)
+{
+	int ret;
+
+	ashmem_area_cachep = kmem_cache_create("ashmem_area_cache",
+					  sizeof(struct ashmem_area),
+					  0, 0, NULL);
+	if (unlikely(!ashmem_area_cachep)) {
+		printk(KERN_ERR "ashmem: failed to create slab cache\n");
+		return -ENOMEM;
+	}
+
+	ashmem_range_cachep = kmem_cache_create("ashmem_range_cache",
+					  sizeof(struct ashmem_range),
+					  0, 0, NULL);
+	if (unlikely(!ashmem_range_cachep)) {
+		printk(KERN_ERR "ashmem: failed to create slab cache\n");
+		return -ENOMEM;
+	}
+
+	ret = misc_register(&ashmem_misc);
+	if (unlikely(ret)) {
+		printk(KERN_ERR "ashmem: failed to register misc device!\n");
+		return ret;
+	}
+
+	register_shrinker(&ashmem_shrinker);
+
+	printk(KERN_INFO "ashmem: initialized\n");
+
+	return 0;
+}
+
+static void __exit ashmem_exit(void)
+{
+	int ret;
+
+	unregister_shrinker(&ashmem_shrinker);
+
+	ret = misc_deregister(&ashmem_misc);
+	if (unlikely(ret))
+		printk(KERN_ERR "ashmem: failed to unregister misc device!\n");
+
+	kmem_cache_destroy(ashmem_range_cachep);
+	kmem_cache_destroy(ashmem_area_cachep);
+
+	printk(KERN_INFO "ashmem: unloaded\n");
+}
+
+module_init(ashmem_init);
+module_exit(ashmem_exit);
+
+MODULE_LICENSE("GPL");
diff --git a/drivers/staging/android/ashmem.h b/drivers/staging/android/ashmem.h
new file mode 100644
index 0000000..1976b10
--- /dev/null
+++ b/drivers/staging/android/ashmem.h
@@ -0,0 +1,48 @@ 
+/*
+ * include/linux/ashmem.h
+ *
+ * Copyright 2008 Google Inc.
+ * Author: Robert Love
+ *
+ * This file is dual licensed.  It may be redistributed and/or modified
+ * under the terms of the Apache 2.0 License OR version 2 of the GNU
+ * General Public License.
+ */
+
+#ifndef _LINUX_ASHMEM_H
+#define _LINUX_ASHMEM_H
+
+#include <linux/limits.h>
+#include <linux/ioctl.h>
+
+#define ASHMEM_NAME_LEN		256
+
+#define ASHMEM_NAME_DEF		"dev/ashmem"
+
+/* Return values from ASHMEM_PIN: Was the mapping purged while unpinned? */
+#define ASHMEM_NOT_PURGED	0
+#define ASHMEM_WAS_PURGED	1
+
+/* Return values from ASHMEM_GET_PIN_STATUS: Is the mapping pinned? */
+#define ASHMEM_IS_UNPINNED	0
+#define ASHMEM_IS_PINNED	1
+
+struct ashmem_pin {
+	__u32 offset;	/* offset into region, in bytes, page-aligned */
+	__u32 len;	/* length forward from offset, in bytes, page-aligned */
+};
+
+#define __ASHMEMIOC		0x77
+
+#define ASHMEM_SET_NAME		_IOW(__ASHMEMIOC, 1, char[ASHMEM_NAME_LEN])
+#define ASHMEM_GET_NAME		_IOR(__ASHMEMIOC, 2, char[ASHMEM_NAME_LEN])
+#define ASHMEM_SET_SIZE		_IOW(__ASHMEMIOC, 3, size_t)
+#define ASHMEM_GET_SIZE		_IO(__ASHMEMIOC, 4)
+#define ASHMEM_SET_PROT_MASK	_IOW(__ASHMEMIOC, 5, unsigned long)
+#define ASHMEM_GET_PROT_MASK	_IO(__ASHMEMIOC, 6)
+#define ASHMEM_PIN		_IOW(__ASHMEMIOC, 7, struct ashmem_pin)
+#define ASHMEM_UNPIN		_IOW(__ASHMEMIOC, 8, struct ashmem_pin)
+#define ASHMEM_GET_PIN_STATUS	_IO(__ASHMEMIOC, 9)
+#define ASHMEM_PURGE_ALL_CACHES	_IO(__ASHMEMIOC, 10)
+
+#endif	/* _LINUX_ASHMEM_H */
diff --git a/include/linux/ashmem.h b/include/linux/ashmem.h
deleted file mode 100644
index 1976b10..0000000
--- a/include/linux/ashmem.h
+++ /dev/null
@@ -1,48 +0,0 @@ 
-/*
- * include/linux/ashmem.h
- *
- * Copyright 2008 Google Inc.
- * Author: Robert Love
- *
- * This file is dual licensed.  It may be redistributed and/or modified
- * under the terms of the Apache 2.0 License OR version 2 of the GNU
- * General Public License.
- */
-
-#ifndef _LINUX_ASHMEM_H
-#define _LINUX_ASHMEM_H
-
-#include <linux/limits.h>
-#include <linux/ioctl.h>
-
-#define ASHMEM_NAME_LEN		256
-
-#define ASHMEM_NAME_DEF		"dev/ashmem"
-
-/* Return values from ASHMEM_PIN: Was the mapping purged while unpinned? */
-#define ASHMEM_NOT_PURGED	0
-#define ASHMEM_WAS_PURGED	1
-
-/* Return values from ASHMEM_GET_PIN_STATUS: Is the mapping pinned? */
-#define ASHMEM_IS_UNPINNED	0
-#define ASHMEM_IS_PINNED	1
-
-struct ashmem_pin {
-	__u32 offset;	/* offset into region, in bytes, page-aligned */
-	__u32 len;	/* length forward from offset, in bytes, page-aligned */
-};
-
-#define __ASHMEMIOC		0x77
-
-#define ASHMEM_SET_NAME		_IOW(__ASHMEMIOC, 1, char[ASHMEM_NAME_LEN])
-#define ASHMEM_GET_NAME		_IOR(__ASHMEMIOC, 2, char[ASHMEM_NAME_LEN])
-#define ASHMEM_SET_SIZE		_IOW(__ASHMEMIOC, 3, size_t)
-#define ASHMEM_GET_SIZE		_IO(__ASHMEMIOC, 4)
-#define ASHMEM_SET_PROT_MASK	_IOW(__ASHMEMIOC, 5, unsigned long)
-#define ASHMEM_GET_PROT_MASK	_IO(__ASHMEMIOC, 6)
-#define ASHMEM_PIN		_IOW(__ASHMEMIOC, 7, struct ashmem_pin)
-#define ASHMEM_UNPIN		_IOW(__ASHMEMIOC, 8, struct ashmem_pin)
-#define ASHMEM_GET_PIN_STATUS	_IO(__ASHMEMIOC, 9)
-#define ASHMEM_PURGE_ALL_CACHES	_IO(__ASHMEMIOC, 10)
-
-#endif	/* _LINUX_ASHMEM_H */
diff --git a/init/Kconfig b/init/Kconfig
index 4dbd8da..43298f9 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -1100,15 +1100,6 @@  config SHMEM
 	  option replaces shmem and tmpfs with the much simpler ramfs code,
 	  which may be appropriate on small systems without swap.
 
-config ASHMEM
-	bool "Enable the Anonymous Shared Memory Subsystem"
-	default n
-	depends on SHMEM || TINY_SHMEM
-	help
-	  The ashmem subsystem is a new shared memory allocator, similar to
-	  POSIX SHM but with different behavior and sporting a simpler
-	  file-based API.
-
 config AIO
 	bool "Enable AIO support" if EXPERT
 	default y
diff --git a/mm/Makefile b/mm/Makefile
index b48c3cf..50ec00e 100644
--- a/mm/Makefile
+++ b/mm/Makefile
@@ -31,7 +31,6 @@  obj-$(CONFIG_HUGETLBFS)	+= hugetlb.o
 obj-$(CONFIG_NUMA) 	+= mempolicy.o
 obj-$(CONFIG_SPARSEMEM)	+= sparse.o
 obj-$(CONFIG_SPARSEMEM_VMEMMAP) += sparse-vmemmap.o
-obj-$(CONFIG_ASHMEM) += ashmem.o
 obj-$(CONFIG_SLOB) += slob.o
 obj-$(CONFIG_COMPACTION) += compaction.o
 obj-$(CONFIG_MMU_NOTIFIER) += mmu_notifier.o
diff --git a/mm/ashmem.c b/mm/ashmem.c
deleted file mode 100644
index 230810f..0000000
--- a/mm/ashmem.c
+++ /dev/null
@@ -1,670 +0,0 @@ 
-/* mm/ashmem.c
-**
-** Anonymous Shared Memory Subsystem, ashmem
-**
-** Copyright (C) 2008 Google, Inc.
-**
-** Robert Love <rlove@google.com>
-**
-** 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/module.h>
-#include <linux/file.h>
-#include <linux/fs.h>
-#include <linux/miscdevice.h>
-#include <linux/security.h>
-#include <linux/mm.h>
-#include <linux/mman.h>
-#include <linux/uaccess.h>
-#include <linux/personality.h>
-#include <linux/bitops.h>
-#include <linux/mutex.h>
-#include <linux/shmem_fs.h>
-#include <linux/ashmem.h>
-
-#define ASHMEM_NAME_PREFIX "dev/ashmem/"
-#define ASHMEM_NAME_PREFIX_LEN (sizeof(ASHMEM_NAME_PREFIX) - 1)
-#define ASHMEM_FULL_NAME_LEN (ASHMEM_NAME_LEN + ASHMEM_NAME_PREFIX_LEN)
-
-/*
- * ashmem_area - anonymous shared memory area
- * Lifecycle: From our parent file's open() until its release()
- * Locking: Protected by `ashmem_mutex'
- * Big Note: Mappings do NOT pin this structure; it dies on close()
- */
-struct ashmem_area {
-	char name[ASHMEM_FULL_NAME_LEN];/* optional name for /proc/pid/maps */
-	struct list_head unpinned_list;	/* list of all ashmem areas */
-	struct file *file;		/* the shmem-based backing file */
-	size_t size;			/* size of the mapping, in bytes */
-	unsigned long prot_mask;	/* allowed prot bits, as vm_flags */
-};
-
-/*
- * ashmem_range - represents an interval of unpinned (evictable) pages
- * Lifecycle: From unpin to pin
- * Locking: Protected by `ashmem_mutex'
- */
-struct ashmem_range {
-	struct list_head lru;		/* entry in LRU list */
-	struct list_head unpinned;	/* entry in its area's unpinned list */
-	struct ashmem_area *asma;	/* associated area */
-	size_t pgstart;			/* starting page, inclusive */
-	size_t pgend;			/* ending page, inclusive */
-	unsigned int purged;		/* ASHMEM_NOT or ASHMEM_WAS_PURGED */
-};
-
-/* LRU list of unpinned pages, protected by ashmem_mutex */
-static LIST_HEAD(ashmem_lru_list);
-
-/* Count of pages on our LRU list, protected by ashmem_mutex */
-static unsigned long lru_count;
-
-/*
- * ashmem_mutex - protects the list of and each individual ashmem_area
- *
- * Lock Ordering: ashmex_mutex -> i_mutex -> i_alloc_sem
- */
-static DEFINE_MUTEX(ashmem_mutex);
-
-static struct kmem_cache *ashmem_area_cachep __read_mostly;
-static struct kmem_cache *ashmem_range_cachep __read_mostly;
-
-#define range_size(range) \
-  ((range)->pgend - (range)->pgstart + 1)
-
-#define range_on_lru(range) \
-  ((range)->purged == ASHMEM_NOT_PURGED)
-
-#define page_range_subsumes_range(range, start, end) \
-  (((range)->pgstart >= (start)) && ((range)->pgend <= (end)))
-
-#define page_range_subsumed_by_range(range, start, end) \
-  (((range)->pgstart <= (start)) && ((range)->pgend >= (end)))
-
-#define page_in_range(range, page) \
- (((range)->pgstart <= (page)) && ((range)->pgend >= (page)))
-
-#define page_range_in_range(range, start, end) \
-  (page_in_range(range, start) || page_in_range(range, end) || \
-   page_range_subsumes_range(range, start, end))
-
-#define range_before_page(range, page) \
-  ((range)->pgend < (page))
-
-#define PROT_MASK		(PROT_EXEC | PROT_READ | PROT_WRITE)
-
-static inline void lru_add(struct ashmem_range *range)
-{
-	list_add_tail(&range->lru, &ashmem_lru_list);
-	lru_count += range_size(range);
-}
-
-static inline void lru_del(struct ashmem_range *range)
-{
-	list_del(&range->lru);
-	lru_count -= range_size(range);
-}
-
-/*
- * range_alloc - allocate and initialize a new ashmem_range structure
- *
- * 'asma' - associated ashmem_area
- * 'prev_range' - the previous ashmem_range in the sorted asma->unpinned list
- * 'purged' - initial purge value (ASMEM_NOT_PURGED or ASHMEM_WAS_PURGED)
- * 'start' - starting page, inclusive
- * 'end' - ending page, inclusive
- *
- * Caller must hold ashmem_mutex.
- */
-static int range_alloc(struct ashmem_area *asma,
-		       struct ashmem_range *prev_range, unsigned int purged,
-		       size_t start, size_t end)
-{
-	struct ashmem_range *range;
-
-	range = kmem_cache_zalloc(ashmem_range_cachep, GFP_KERNEL);
-	if (unlikely(!range))
-		return -ENOMEM;
-
-	range->asma = asma;
-	range->pgstart = start;
-	range->pgend = end;
-	range->purged = purged;
-
-	list_add_tail(&range->unpinned, &prev_range->unpinned);
-
-	if (range_on_lru(range))
-		lru_add(range);
-
-	return 0;
-}
-
-static void range_del(struct ashmem_range *range)
-{
-	list_del(&range->unpinned);
-	if (range_on_lru(range))
-		lru_del(range);
-	kmem_cache_free(ashmem_range_cachep, range);
-}
-
-/*
- * range_shrink - shrinks a range
- *
- * Caller must hold ashmem_mutex.
- */
-static inline void range_shrink(struct ashmem_range *range,
-				size_t start, size_t end)
-{
-	size_t pre = range_size(range);
-
-	range->pgstart = start;
-	range->pgend = end;
-
-	if (range_on_lru(range))
-		lru_count -= pre - range_size(range);
-}
-
-static int ashmem_open(struct inode *inode, struct file *file)
-{
-	struct ashmem_area *asma;
-	int ret;
-
-	ret = nonseekable_open(inode, file);
-	if (unlikely(ret))
-		return ret;
-
-	asma = kmem_cache_zalloc(ashmem_area_cachep, GFP_KERNEL);
-	if (unlikely(!asma))
-		return -ENOMEM;
-
-	INIT_LIST_HEAD(&asma->unpinned_list);
-	memcpy(asma->name, ASHMEM_NAME_PREFIX, ASHMEM_NAME_PREFIX_LEN);
-	asma->prot_mask = PROT_MASK;
-	file->private_data = asma;
-
-	return 0;
-}
-
-static int ashmem_release(struct inode *ignored, struct file *file)
-{
-	struct ashmem_area *asma = file->private_data;
-	struct ashmem_range *range, *next;
-
-	mutex_lock(&ashmem_mutex);
-	list_for_each_entry_safe(range, next, &asma->unpinned_list, unpinned)
-		range_del(range);
-	mutex_unlock(&ashmem_mutex);
-
-	if (asma->file)
-		fput(asma->file);
-	kmem_cache_free(ashmem_area_cachep, asma);
-
-	return 0;
-}
-
-static int ashmem_mmap(struct file *file, struct vm_area_struct *vma)
-{
-	struct ashmem_area *asma = file->private_data;
-	int ret = 0;
-
-	mutex_lock(&ashmem_mutex);
-
-	/* user needs to SET_SIZE before mapping */
-	if (unlikely(!asma->size)) {
-		ret = -EINVAL;
-		goto out;
-	}
-
-	/* requested protection bits must match our allowed protection mask */
-	if (unlikely((vma->vm_flags & ~asma->prot_mask) & PROT_MASK)) {
-		ret = -EPERM;
-		goto out;
-	}
-
-	if (!asma->file) {
-		char *name = ASHMEM_NAME_DEF;
-		struct file *vmfile;
-
-		if (asma->name[ASHMEM_NAME_PREFIX_LEN] != '\0')
-			name = asma->name;
-
-		/* ... and allocate the backing shmem file */
-		vmfile = shmem_file_setup(name, asma->size, vma->vm_flags);
-		if (unlikely(IS_ERR(vmfile))) {
-			ret = PTR_ERR(vmfile);
-			goto out;
-		}
-		asma->file = vmfile;
-	}
-	get_file(asma->file);
-
-	if (vma->vm_flags & VM_SHARED)
-		shmem_set_file(vma, asma->file);
-	else {
-		if (vma->vm_file)
-			fput(vma->vm_file);
-		vma->vm_file = asma->file;
-	}
-	vma->vm_flags |= VM_CAN_NONLINEAR;
-
-out:
-	mutex_unlock(&ashmem_mutex);
-	return ret;
-}
-
-/*
- * ashmem_shrink - our cache shrinker, called from mm/vmscan.c :: shrink_slab
- *
- * 'nr_to_scan' is the number of objects (pages) to prune, or 0 to query how
- * many objects (pages) we have in total.
- *
- * 'gfp_mask' is the mask of the allocation that got us into this mess.
- *
- * Return value is the number of objects (pages) remaining, or -1 if we cannot
- * proceed without risk of deadlock (due to gfp_mask).
- *
- * We approximate LRU via least-recently-unpinned, jettisoning unpinned partial
- * chunks of ashmem regions LRU-wise one-at-a-time until we hit 'nr_to_scan'
- * pages freed.
- */
-static int ashmem_shrink(int nr_to_scan, gfp_t gfp_mask)
-{
-	struct ashmem_range *range, *next;
-
-	/* We might recurse into filesystem code, so bail out if necessary */
-	if (nr_to_scan && !(gfp_mask & __GFP_FS))
-		return -1;
-	if (!nr_to_scan)
-		return lru_count;
-
-	mutex_lock(&ashmem_mutex);
-	list_for_each_entry_safe(range, next, &ashmem_lru_list, lru) {
-		struct inode *inode = range->asma->file->f_dentry->d_inode;
-		loff_t start = range->pgstart * PAGE_SIZE;
-		loff_t end = (range->pgend + 1) * PAGE_SIZE - 1;
-
-		vmtruncate_range(inode, start, end);
-		range->purged = ASHMEM_WAS_PURGED;
-		lru_del(range);
-
-		nr_to_scan -= range_size(range);
-		if (nr_to_scan <= 0)
-			break;
-	}
-	mutex_unlock(&ashmem_mutex);
-
-	return lru_count;
-}
-
-static struct shrinker ashmem_shrinker = {
-	.shrink = ashmem_shrink,
-	.seeks = DEFAULT_SEEKS * 4,
-};
-
-static int set_prot_mask(struct ashmem_area *asma, unsigned long prot)
-{
-	int ret = 0;
-
-	mutex_lock(&ashmem_mutex);
-
-	/* the user can only remove, not add, protection bits */
-	if (unlikely((asma->prot_mask & prot) != prot)) {
-		ret = -EINVAL;
-		goto out;
-	}
-
-	/* does the application expect PROT_READ to imply PROT_EXEC? */
-	if ((prot & PROT_READ) && (current->personality & READ_IMPLIES_EXEC))
-		prot |= PROT_EXEC;
-
-	asma->prot_mask = prot;
-
-out:
-	mutex_unlock(&ashmem_mutex);
-	return ret;
-}
-
-static int set_name(struct ashmem_area *asma, void __user *name)
-{
-	int ret = 0;
-
-	mutex_lock(&ashmem_mutex);
-
-	/* cannot change an existing mapping's name */
-	if (unlikely(asma->file)) {
-		ret = -EINVAL;
-		goto out;
-	}
-
-	if (unlikely(copy_from_user(asma->name + ASHMEM_NAME_PREFIX_LEN,
-				    name, ASHMEM_NAME_LEN)))
-		ret = -EFAULT;
-	asma->name[ASHMEM_FULL_NAME_LEN-1] = '\0';
-
-out:
-	mutex_unlock(&ashmem_mutex);
-
-	return ret;
-}
-
-static int get_name(struct ashmem_area *asma, void __user *name)
-{
-	int ret = 0;
-
-	mutex_lock(&ashmem_mutex);
-	if (asma->name[ASHMEM_NAME_PREFIX_LEN] != '\0') {
-		size_t len;
-
-		/*
-		 * Copying only `len', instead of ASHMEM_NAME_LEN, bytes
-		 * prevents us from revealing one user's stack to another.
-		 */
-		len = strlen(asma->name + ASHMEM_NAME_PREFIX_LEN) + 1;
-		if (unlikely(copy_to_user(name,
-				asma->name + ASHMEM_NAME_PREFIX_LEN, len)))
-			ret = -EFAULT;
-	} else {
-		if (unlikely(copy_to_user(name, ASHMEM_NAME_DEF,
-					  sizeof(ASHMEM_NAME_DEF))))
-			ret = -EFAULT;
-	}
-	mutex_unlock(&ashmem_mutex);
-
-	return ret;
-}
-
-/*
- * ashmem_pin - pin the given ashmem region, returning whether it was
- * previously purged (ASHMEM_WAS_PURGED) or not (ASHMEM_NOT_PURGED).
- *
- * Caller must hold ashmem_mutex.
- */
-static int ashmem_pin(struct ashmem_area *asma, size_t pgstart, size_t pgend)
-{
-	struct ashmem_range *range, *next;
-	int ret = ASHMEM_NOT_PURGED;
-
-	list_for_each_entry_safe(range, next, &asma->unpinned_list, unpinned) {
-		/* moved past last applicable page; we can short circuit */
-		if (range_before_page(range, pgstart))
-			break;
-
-		/*
-		 * The user can ask us to pin pages that span multiple ranges,
-		 * or to pin pages that aren't even unpinned, so this is messy.
-		 *
-		 * Four cases:
-		 * 1. The requested range subsumes an existing range, so we
-		 *    just remove the entire matching range.
-		 * 2. The requested range overlaps the start of an existing
-		 *    range, so we just update that range.
-		 * 3. The requested range overlaps the end of an existing
-		 *    range, so we just update that range.
-		 * 4. The requested range punches a hole in an existing range,
-		 *    so we have to update one side of the range and then
-		 *    create a new range for the other side.
-		 */
-		if (page_range_in_range(range, pgstart, pgend)) {
-			ret |= range->purged;
-
-			/* Case #1: Easy. Just nuke the whole thing. */
-			if (page_range_subsumes_range(range, pgstart, pgend)) {
-				range_del(range);
-				continue;
-			}
-
-			/* Case #2: We overlap from the start, so adjust it */
-			if (range->pgstart >= pgstart) {
-				range_shrink(range, pgend + 1, range->pgend);
-				continue;
-			}
-
-			/* Case #3: We overlap from the rear, so adjust it */
-			if (range->pgend <= pgend) {
-				range_shrink(range, range->pgstart, pgstart-1);
-				continue;
-			}
-
-			/*
-			 * Case #4: We eat a chunk out of the middle. A bit
-			 * more complicated, we allocate a new range for the
-			 * second half and adjust the first chunk's endpoint.
-			 */
-			range_alloc(asma, range, range->purged,
-				    pgend + 1, range->pgend);
-			range_shrink(range, range->pgstart, pgstart - 1);
-			break;
-		}
-	}
-
-	return ret;
-}
-
-/*
- * ashmem_unpin - unpin the given range of pages. Returns zero on success.
- *
- * Caller must hold ashmem_mutex.
- */
-static int ashmem_unpin(struct ashmem_area *asma, size_t pgstart, size_t pgend)
-{
-	struct ashmem_range *range, *next;
-	unsigned int purged = ASHMEM_NOT_PURGED;
-
-restart:
-	list_for_each_entry_safe(range, next, &asma->unpinned_list, unpinned) {
-		/* short circuit: this is our insertion point */
-		if (range_before_page(range, pgstart))
-			break;
-
-		/*
-		 * The user can ask us to unpin pages that are already entirely
-		 * or partially pinned. We handle those two cases here.
-		 */
-		if (page_range_subsumed_by_range(range, pgstart, pgend))
-			return 0;
-		if (page_range_in_range(range, pgstart, pgend)) {
-			pgstart = min_t(size_t, range->pgstart, pgstart),
-			pgend = max_t(size_t, range->pgend, pgend);
-			purged |= range->purged;
-			range_del(range);
-			goto restart;
-		}
-	}
-
-	return range_alloc(asma, range, purged, pgstart, pgend);
-}
-
-/*
- * ashmem_get_pin_status - Returns ASHMEM_IS_UNPINNED if _any_ pages in the
- * given interval are unpinned and ASHMEM_IS_PINNED otherwise.
- *
- * Caller must hold ashmem_mutex.
- */
-static int ashmem_get_pin_status(struct ashmem_area *asma, size_t pgstart,
-				 size_t pgend)
-{
-	struct ashmem_range *range;
-	int ret = ASHMEM_IS_PINNED;
-
-	list_for_each_entry(range, &asma->unpinned_list, unpinned) {
-		if (range_before_page(range, pgstart))
-			break;
-		if (page_range_in_range(range, pgstart, pgend)) {
-			ret = ASHMEM_IS_UNPINNED;
-			break;
-		}
-	}
-
-	return ret;
-}
-
-static int ashmem_pin_unpin(struct ashmem_area *asma, unsigned long cmd,
-			    void __user *p)
-{
-	struct ashmem_pin pin;
-	size_t pgstart, pgend;
-	int ret = -EINVAL;
-
-	if (unlikely(!asma->file))
-		return -EINVAL;
-
-	if (unlikely(copy_from_user(&pin, p, sizeof(pin))))
-		return -EFAULT;
-
-	/* per custom, you can pass zero for len to mean "everything onward" */
-	if (!pin.len)
-		pin.len = PAGE_ALIGN(asma->size) - pin.offset;
-
-	if (unlikely((pin.offset | pin.len) & ~PAGE_MASK))
-		return -EINVAL;
-
-	if (unlikely(((__u32) -1) - pin.offset < pin.len))
-		return -EINVAL;
-
-	if (unlikely(PAGE_ALIGN(asma->size) < pin.offset + pin.len))
-		return -EINVAL;
-
-	pgstart = pin.offset / PAGE_SIZE;
-	pgend = pgstart + (pin.len / PAGE_SIZE) - 1;
-
-	mutex_lock(&ashmem_mutex);
-
-	switch (cmd) {
-	case ASHMEM_PIN:
-		ret = ashmem_pin(asma, pgstart, pgend);
-		break;
-	case ASHMEM_UNPIN:
-		ret = ashmem_unpin(asma, pgstart, pgend);
-		break;
-	case ASHMEM_GET_PIN_STATUS:
-		ret = ashmem_get_pin_status(asma, pgstart, pgend);
-		break;
-	}
-
-	mutex_unlock(&ashmem_mutex);
-
-	return ret;
-}
-
-static long ashmem_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
-{
-	struct ashmem_area *asma = file->private_data;
-	long ret = -ENOTTY;
-
-	switch (cmd) {
-	case ASHMEM_SET_NAME:
-		ret = set_name(asma, (void __user *) arg);
-		break;
-	case ASHMEM_GET_NAME:
-		ret = get_name(asma, (void __user *) arg);
-		break;
-	case ASHMEM_SET_SIZE:
-		ret = -EINVAL;
-		if (!asma->file) {
-			ret = 0;
-			asma->size = (size_t) arg;
-		}
-		break;
-	case ASHMEM_GET_SIZE:
-		ret = asma->size;
-		break;
-	case ASHMEM_SET_PROT_MASK:
-		ret = set_prot_mask(asma, arg);
-		break;
-	case ASHMEM_GET_PROT_MASK:
-		ret = asma->prot_mask;
-		break;
-	case ASHMEM_PIN:
-	case ASHMEM_UNPIN:
-	case ASHMEM_GET_PIN_STATUS:
-		ret = ashmem_pin_unpin(asma, cmd, (void __user *) arg);
-		break;
-	case ASHMEM_PURGE_ALL_CACHES:
-		ret = -EPERM;
-		if (capable(CAP_SYS_ADMIN)) {
-			ret = ashmem_shrink(0, GFP_KERNEL);
-			ashmem_shrink(ret, GFP_KERNEL);
-		}
-		break;
-	}
-
-	return ret;
-}
-
-static struct file_operations ashmem_fops = {
-	.owner = THIS_MODULE,
-	.open = ashmem_open,
-	.release = ashmem_release,
-	.mmap = ashmem_mmap,
-	.unlocked_ioctl = ashmem_ioctl,
-	.compat_ioctl = ashmem_ioctl,
-};
-
-static struct miscdevice ashmem_misc = {
-	.minor = MISC_DYNAMIC_MINOR,
-	.name = "ashmem",
-	.fops = &ashmem_fops,
-};
-
-static int __init ashmem_init(void)
-{
-	int ret;
-
-	ashmem_area_cachep = kmem_cache_create("ashmem_area_cache",
-					  sizeof(struct ashmem_area),
-					  0, 0, NULL);
-	if (unlikely(!ashmem_area_cachep)) {
-		printk(KERN_ERR "ashmem: failed to create slab cache\n");
-		return -ENOMEM;
-	}
-
-	ashmem_range_cachep = kmem_cache_create("ashmem_range_cache",
-					  sizeof(struct ashmem_range),
-					  0, 0, NULL);
-	if (unlikely(!ashmem_range_cachep)) {
-		printk(KERN_ERR "ashmem: failed to create slab cache\n");
-		return -ENOMEM;
-	}
-
-	ret = misc_register(&ashmem_misc);
-	if (unlikely(ret)) {
-		printk(KERN_ERR "ashmem: failed to register misc device!\n");
-		return ret;
-	}
-
-	register_shrinker(&ashmem_shrinker);
-
-	printk(KERN_INFO "ashmem: initialized\n");
-
-	return 0;
-}
-
-static void __exit ashmem_exit(void)
-{
-	int ret;
-
-	unregister_shrinker(&ashmem_shrinker);
-
-	ret = misc_deregister(&ashmem_misc);
-	if (unlikely(ret))
-		printk(KERN_ERR "ashmem: failed to unregister misc device!\n");
-
-	kmem_cache_destroy(ashmem_range_cachep);
-	kmem_cache_destroy(ashmem_area_cachep);
-
-	printk(KERN_INFO "ashmem: unloaded\n");
-}
-
-module_init(ashmem_init);
-module_exit(ashmem_exit);
-
-MODULE_LICENSE("GPL");