[deliverable/linux.git] / drivers / staging / android / ion / ion.c

/*
 *
 * drivers/staging/android/ion/ion.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/device.h>
#include <linux/err.h>
#include <linux/file.h>
#include <linux/freezer.h>
#include <linux/fs.h>
#include <linux/anon_inodes.h>
#include <linux/kthread.h>
#include <linux/list.h>
#include <linux/memblock.h>
#include <linux/miscdevice.h>
#include <linux/export.h>
#include <linux/mm.h>
#include <linux/mm_types.h>
#include <linux/rbtree.h>
#include <linux/slab.h>
#include <linux/seq_file.h>
#include <linux/uaccess.h>
#include <linux/vmalloc.h>
#include <linux/debugfs.h>
#include <linux/dma-buf.h>
#include <linux/idr.h>

#include "ion.h"
#include "ion_priv.h"
#include "compat_ion.h"

/**
 * struct ion_device - the metadata of the ion device node
 * @dev:                the actual misc device
 * @buffers:            an rb tree of all the existing buffers
 * @buffer_lock:        lock protecting the tree of buffers
 * @lock:               rwsem protecting the tree of heaps and clients
 * @heaps:              list of all the heaps in the system
 * @user_clients:       list of all the clients created from userspace
 */
struct ion_device {
        struct miscdevice dev;
        struct rb_root buffers;
        struct mutex buffer_lock;
        struct rw_semaphore lock;
        struct plist_head heaps;
        long (*custom_ioctl)(struct ion_client *client, unsigned int cmd,
                             unsigned long arg);
        struct rb_root clients;
        struct dentry *debug_root;
        struct dentry *heaps_debug_root;
        struct dentry *clients_debug_root;
};

/**
 * struct ion_client - a process/hw block local address space
 * @node:               node in the tree of all clients
 * @dev:                backpointer to ion device
 * @handles:            an rb tree of all the handles in this client
 * @idr:                an idr space for allocating handle ids
 * @lock:               lock protecting the tree of handles
 * @name:               used for debugging
 * @display_name:       used for debugging (unique version of @name)
 * @display_serial:     used for debugging (to make display_name unique)
 * @task:               used for debugging
 *
 * A client represents a list of buffers this client may access.
 * The mutex stored here is used to protect both handles tree
 * as well as the handles themselves, and should be held while modifying either.
 */
struct ion_client {
        struct rb_node node;
        struct ion_device *dev;
        struct rb_root handles;
        struct idr idr;
        struct mutex lock;
        const char *name;
        char *display_name;
        int display_serial;
        struct task_struct *task;
        pid_t pid;
        struct dentry *debug_root;
};

/**
 * ion_handle - a client local reference to a buffer
 * @ref:                reference count
 * @client:             back pointer to the client the buffer resides in
 * @buffer:             pointer to the buffer
 * @node:               node in the client's handle rbtree
 * @kmap_cnt:           count of times this client has mapped to kernel
 * @id:                 client-unique id allocated by client->idr
 *
 * Modifications to node, map_cnt or mapping should be protected by the
 * lock in the client.  Other fields are never changed after initialization.
 */
struct ion_handle {
        struct kref ref;
        struct ion_client *client;
        struct ion_buffer *buffer;
        struct rb_node node;
        unsigned int kmap_cnt;
        int id;
};

bool ion_buffer_fault_user_mappings(struct ion_buffer *buffer)
{
        return (buffer->flags & ION_FLAG_CACHED) &&
                !(buffer->flags & ION_FLAG_CACHED_NEEDS_SYNC);
}

bool ion_buffer_cached(struct ion_buffer *buffer)
{
        return !!(buffer->flags & ION_FLAG_CACHED);
}

static inline struct page *ion_buffer_page(struct page *page)
{
        return (struct page *)((unsigned long)page & ~(1UL));
}

static inline bool ion_buffer_page_is_dirty(struct page *page)
{
        return !!((unsigned long)page & 1UL);
}

static inline void ion_buffer_page_dirty(struct page **page)
{
        *page = (struct page *)((unsigned long)(*page) | 1UL);
}

static inline void ion_buffer_page_clean(struct page **page)
{
        *page = (struct page *)((unsigned long)(*page) & ~(1UL));
}

/* this function should only be called while dev->lock is held */
static void ion_buffer_add(struct ion_device *dev,
                           struct ion_buffer *buffer)
{
        struct rb_node **p = &dev->buffers.rb_node;
        struct rb_node *parent = NULL;
        struct ion_buffer *entry;

        while (*p) {
                parent = *p;
                entry = rb_entry(parent, struct ion_buffer, node);

                if (buffer < entry) {
                        p = &(*p)->rb_left;
                } else if (buffer > entry) {
                        p = &(*p)->rb_right;
                } else {
                        pr_err("%s: buffer already found.", __func__);
                        BUG();
                }
        }

        rb_link_node(&buffer->node, parent, p);
        rb_insert_color(&buffer->node, &dev->buffers);
}

/* this function should only be called while dev->lock is held */
static struct ion_buffer *ion_buffer_create(struct ion_heap *heap,
                                     struct ion_device *dev,
                                     unsigned long len,
                                     unsigned long align,
                                     unsigned long flags)
{
        struct ion_buffer *buffer;
        struct sg_table *table;
        struct scatterlist *sg;
        int i, ret;

        buffer = kzalloc(sizeof(struct ion_buffer), GFP_KERNEL);
        if (!buffer)
                return ERR_PTR(-ENOMEM);

        buffer->heap = heap;
        buffer->flags = flags;
        kref_init(&buffer->ref);

        ret = heap->ops->allocate(heap, buffer, len, align, flags);

        if (ret) {
                if (!(heap->flags & ION_HEAP_FLAG_DEFER_FREE))
                        goto err2;

                ion_heap_freelist_drain(heap, 0);
                ret = heap->ops->allocate(heap, buffer, len, align,
                                          flags);
                if (ret)
                        goto err2;
        }

        buffer->dev = dev;
        buffer->size = len;

        table = heap->ops->map_dma(heap, buffer);
        if (WARN_ONCE(table == NULL,
                        "heap->ops->map_dma should return ERR_PTR on error"))
                table = ERR_PTR(-EINVAL);
        if (IS_ERR(table)) {
                ret = -EINVAL;
                goto err1;
        }

        buffer->sg_table = table;
        if (ion_buffer_fault_user_mappings(buffer)) {
                int num_pages = PAGE_ALIGN(buffer->size) / PAGE_SIZE;
                struct scatterlist *sg;
                int i, j, k = 0;

                buffer->pages = vmalloc(sizeof(struct page *) * num_pages);
                if (!buffer->pages) {
                        ret = -ENOMEM;
                        goto err;
                }

                for_each_sg(table->sgl, sg, table->nents, i) {
                        struct page *page = sg_page(sg);

                        for (j = 0; j < sg->length / PAGE_SIZE; j++)
                                buffer->pages[k++] = page++;
                }
        }

        buffer->dev = dev;
        buffer->size = len;
        INIT_LIST_HEAD(&buffer->vmas);
        mutex_init(&buffer->lock);
        /*
         * this will set up dma addresses for the sglist -- it is not
         * technically correct as per the dma api -- a specific
         * device isn't really taking ownership here.  However, in practice on
         * our systems the only dma_address space is physical addresses.
         * Additionally, we can't afford the overhead of invalidating every
         * allocation via dma_map_sg. The implicit contract here is that
         * memory coming from the heaps is ready for dma, ie if it has a
         * cached mapping that mapping has been invalidated
         */
        for_each_sg(buffer->sg_table->sgl, sg, buffer->sg_table->nents, i) {
                sg_dma_address(sg) = sg_phys(sg);
                sg_dma_len(sg) = sg->length;
        }
        mutex_lock(&dev->buffer_lock);
        ion_buffer_add(dev, buffer);
        mutex_unlock(&dev->buffer_lock);
        return buffer;

err:
        heap->ops->unmap_dma(heap, buffer);
err1:
        heap->ops->free(buffer);
err2:
        kfree(buffer);
        return ERR_PTR(ret);
}

void ion_buffer_destroy(struct ion_buffer *buffer)
{
        if (WARN_ON(buffer->kmap_cnt > 0))
                buffer->heap->ops->unmap_kernel(buffer->heap, buffer);
        buffer->heap->ops->unmap_dma(buffer->heap, buffer);
        buffer->heap->ops->free(buffer);
        vfree(buffer->pages);
        kfree(buffer);
}

static void _ion_buffer_destroy(struct kref *kref)
{
        struct ion_buffer *buffer = container_of(kref, struct ion_buffer, ref);
        struct ion_heap *heap = buffer->heap;
        struct ion_device *dev = buffer->dev;

        mutex_lock(&dev->buffer_lock);
        rb_erase(&buffer->node, &dev->buffers);
        mutex_unlock(&dev->buffer_lock);

        if (heap->flags & ION_HEAP_FLAG_DEFER_FREE)
                ion_heap_freelist_add(heap, buffer);
        else
                ion_buffer_destroy(buffer);
}

static void ion_buffer_get(struct ion_buffer *buffer)
{
        kref_get(&buffer->ref);
}

static int ion_buffer_put(struct ion_buffer *buffer)
{
        return kref_put(&buffer->ref, _ion_buffer_destroy);
}

static void ion_buffer_add_to_handle(struct ion_buffer *buffer)
{
        mutex_lock(&buffer->lock);
        buffer->handle_count++;
        mutex_unlock(&buffer->lock);
}

static void ion_buffer_remove_from_handle(struct ion_buffer *buffer)
{
        /*
         * when a buffer is removed from a handle, if it is not in
         * any other handles, copy the taskcomm and the pid of the
         * process it's being removed from into the buffer.  At this
         * point there will be no way to track what processes this buffer is
         * being used by, it only exists as a dma_buf file descriptor.
         * The taskcomm and pid can provide a debug hint as to where this fd
         * is in the system
         */
        mutex_lock(&buffer->lock);
        buffer->handle_count--;
        BUG_ON(buffer->handle_count < 0);
        if (!buffer->handle_count) {
                struct task_struct *task;

                task = current->group_leader;
                get_task_comm(buffer->task_comm, task);
                buffer->pid = task_pid_nr(task);
        }
        mutex_unlock(&buffer->lock);
}

static struct ion_handle *ion_handle_create(struct ion_client *client,
                                     struct ion_buffer *buffer)
{
        struct ion_handle *handle;

        handle = kzalloc(sizeof(struct ion_handle), GFP_KERNEL);
        if (!handle)
                return ERR_PTR(-ENOMEM);
        kref_init(&handle->ref);
        RB_CLEAR_NODE(&handle->node);
        handle->client = client;
        ion_buffer_get(buffer);
        ion_buffer_add_to_handle(buffer);
        handle->buffer = buffer;

        return handle;
}

static void ion_handle_kmap_put(struct ion_handle *);

static void ion_handle_destroy(struct kref *kref)
{
        struct ion_handle *handle = container_of(kref, struct ion_handle, ref);
        struct ion_client *client = handle->client;
        struct ion_buffer *buffer = handle->buffer;

        mutex_lock(&buffer->lock);
        while (handle->kmap_cnt)
                ion_handle_kmap_put(handle);
        mutex_unlock(&buffer->lock);

        idr_remove(&client->idr, handle->id);
        if (!RB_EMPTY_NODE(&handle->node))
                rb_erase(&handle->node, &client->handles);

        ion_buffer_remove_from_handle(buffer);
        ion_buffer_put(buffer);

        kfree(handle);
}

struct ion_buffer *ion_handle_buffer(struct ion_handle *handle)
{
        return handle->buffer;
}

static void ion_handle_get(struct ion_handle *handle)
{
        kref_get(&handle->ref);
}

static int ion_handle_put_nolock(struct ion_handle *handle)
{
        int ret;

        ret = kref_put(&handle->ref, ion_handle_destroy);

        return ret;
}

int ion_handle_put(struct ion_handle *handle)
{
        struct ion_client *client = handle->client;
        int ret;

        mutex_lock(&client->lock);
        ret = ion_handle_put_nolock(handle);
        mutex_unlock(&client->lock);

        return ret;
}

static struct ion_handle *ion_handle_lookup(struct ion_client *client,
                                            struct ion_buffer *buffer)
{
        struct rb_node *n = client->handles.rb_node;

        while (n) {
                struct ion_handle *entry = rb_entry(n, struct ion_handle, node);

                if (buffer < entry->buffer)
                        n = n->rb_left;
                else if (buffer > entry->buffer)
                        n = n->rb_right;
                else
                        return entry;
        }
        return ERR_PTR(-EINVAL);
}

static struct ion_handle *ion_handle_get_by_id_nolock(struct ion_client *client,
                                                int id)
{
        struct ion_handle *handle;

        handle = idr_find(&client->idr, id);
        if (handle)
                ion_handle_get(handle);

        return handle ? handle : ERR_PTR(-EINVAL);
}

struct ion_handle *ion_handle_get_by_id(struct ion_client *client,
                                                int id)
{
        struct ion_handle *handle;

        mutex_lock(&client->lock);
        handle = ion_handle_get_by_id_nolock(client, id);
        mutex_unlock(&client->lock);

        return handle;
}

static bool ion_handle_validate(struct ion_client *client,
                                struct ion_handle *handle)
{
        WARN_ON(!mutex_is_locked(&client->lock));
        return idr_find(&client->idr, handle->id) == handle;
}

static int ion_handle_add(struct ion_client *client, struct ion_handle *handle)
{
        int id;
        struct rb_node **p = &client->handles.rb_node;
        struct rb_node *parent = NULL;
        struct ion_handle *entry;

        id = idr_alloc(&client->idr, handle, 1, 0, GFP_KERNEL);
        if (id < 0)
                return id;

        handle->id = id;

        while (*p) {
                parent = *p;
                entry = rb_entry(parent, struct ion_handle, node);

                if (handle->buffer < entry->buffer)
                        p = &(*p)->rb_left;
                else if (handle->buffer > entry->buffer)
                        p = &(*p)->rb_right;
                else
                        WARN(1, "%s: buffer already found.", __func__);
        }

        rb_link_node(&handle->node, parent, p);
        rb_insert_color(&handle->node, &client->handles);

        return 0;
}

struct ion_handle *ion_alloc(struct ion_client *client, size_t len,
                             size_t align, unsigned int heap_id_mask,
                             unsigned int flags)
{
        struct ion_handle *handle;
        struct ion_device *dev = client->dev;
        struct ion_buffer *buffer = NULL;
        struct ion_heap *heap;
        int ret;

        pr_debug("%s: len %zu align %zu heap_id_mask %u flags %x\n", __func__,
                 len, align, heap_id_mask, flags);
        /*
         * traverse the list of heaps available in this system in priority
         * order.  If the heap type is supported by the client, and matches the
         * request of the caller allocate from it.  Repeat until allocate has
         * succeeded or all heaps have been tried
         */
        len = PAGE_ALIGN(len);

        if (!len)
                return ERR_PTR(-EINVAL);

        down_read(&dev->lock);
        plist_for_each_entry(heap, &dev->heaps, node) {
                /* if the caller didn't specify this heap id */
                if (!((1 << heap->id) & heap_id_mask))
                        continue;
                buffer = ion_buffer_create(heap, dev, len, align, flags);
                if (!IS_ERR(buffer))
                        break;
        }
        up_read(&dev->lock);

        if (buffer == NULL)
                return ERR_PTR(-ENODEV);

        if (IS_ERR(buffer))
                return ERR_CAST(buffer);

        handle = ion_handle_create(client, buffer);

        /*
         * ion_buffer_create will create a buffer with a ref_cnt of 1,
         * and ion_handle_create will take a second reference, drop one here
         */
        ion_buffer_put(buffer);

        if (IS_ERR(handle))
                return handle;

        mutex_lock(&client->lock);
        ret = ion_handle_add(client, handle);
        mutex_unlock(&client->lock);
        if (ret) {
                ion_handle_put(handle);
                handle = ERR_PTR(ret);
        }

        return handle;
}
EXPORT_SYMBOL(ion_alloc);

static void ion_free_nolock(struct ion_client *client, struct ion_handle *handle)
{
        bool valid_handle;

        BUG_ON(client != handle->client);

        valid_handle = ion_handle_validate(client, handle);

        if (!valid_handle) {
                WARN(1, "%s: invalid handle passed to free.\n", __func__);
                return;
        }
        ion_handle_put_nolock(handle);
}

void ion_free(struct ion_client *client, struct ion_handle *handle)
{
        BUG_ON(client != handle->client);

        mutex_lock(&client->lock);
        ion_free_nolock(client, handle);
        mutex_unlock(&client->lock);
}
EXPORT_SYMBOL(ion_free);

int ion_phys(struct ion_client *client, struct ion_handle *handle,
             ion_phys_addr_t *addr, size_t *len)
{
        struct ion_buffer *buffer;
        int ret;

        mutex_lock(&client->lock);
        if (!ion_handle_validate(client, handle)) {
                mutex_unlock(&client->lock);
                return -EINVAL;
        }

        buffer = handle->buffer;

        if (!buffer->heap->ops->phys) {
                pr_err("%s: ion_phys is not implemented by this heap (name=%s, type=%d).\n",
                        __func__, buffer->heap->name, buffer->heap->type);
                mutex_unlock(&client->lock);
                return -ENODEV;
        }
        mutex_unlock(&client->lock);
        ret = buffer->heap->ops->phys(buffer->heap, buffer, addr, len);
        return ret;
}
EXPORT_SYMBOL(ion_phys);

static void *ion_buffer_kmap_get(struct ion_buffer *buffer)
{
        void *vaddr;

        if (buffer->kmap_cnt) {
                buffer->kmap_cnt++;
                return buffer->vaddr;
        }
        vaddr = buffer->heap->ops->map_kernel(buffer->heap, buffer);
        if (WARN_ONCE(vaddr == NULL,
                        "heap->ops->map_kernel should return ERR_PTR on error"))
                return ERR_PTR(-EINVAL);
        if (IS_ERR(vaddr))
                return vaddr;
        buffer->vaddr = vaddr;
        buffer->kmap_cnt++;
        return vaddr;
}

static void *ion_handle_kmap_get(struct ion_handle *handle)
{
        struct ion_buffer *buffer = handle->buffer;
        void *vaddr;

        if (handle->kmap_cnt) {
                handle->kmap_cnt++;
                return buffer->vaddr;
        }
        vaddr = ion_buffer_kmap_get(buffer);
        if (IS_ERR(vaddr))
                return vaddr;
        handle->kmap_cnt++;
        return vaddr;
}

static void ion_buffer_kmap_put(struct ion_buffer *buffer)
{
        buffer->kmap_cnt--;
        if (!buffer->kmap_cnt) {
                buffer->heap->ops->unmap_kernel(buffer->heap, buffer);
                buffer->vaddr = NULL;
        }
}

static void ion_handle_kmap_put(struct ion_handle *handle)
{
        struct ion_buffer *buffer = handle->buffer;

        if (!handle->kmap_cnt) {
                WARN(1, "%s: Double unmap detected! bailing...\n", __func__);
                return;
        }
        handle->kmap_cnt--;
        if (!handle->kmap_cnt)
                ion_buffer_kmap_put(buffer);
}

void *ion_map_kernel(struct ion_client *client, struct ion_handle *handle)
{
        struct ion_buffer *buffer;
        void *vaddr;

        mutex_lock(&client->lock);
        if (!ion_handle_validate(client, handle)) {
                pr_err("%s: invalid handle passed to map_kernel.\n",
                       __func__);
                mutex_unlock(&client->lock);
                return ERR_PTR(-EINVAL);
        }

        buffer = handle->buffer;

        if (!handle->buffer->heap->ops->map_kernel) {
                pr_err("%s: map_kernel is not implemented by this heap.\n",
                       __func__);
                mutex_unlock(&client->lock);
                return ERR_PTR(-ENODEV);
        }

        mutex_lock(&buffer->lock);
        vaddr = ion_handle_kmap_get(handle);
        mutex_unlock(&buffer->lock);
        mutex_unlock(&client->lock);
        return vaddr;
}
EXPORT_SYMBOL(ion_map_kernel);

void ion_unmap_kernel(struct ion_client *client, struct ion_handle *handle)
{
        struct ion_buffer *buffer;

        mutex_lock(&client->lock);
        buffer = handle->buffer;
        mutex_lock(&buffer->lock);
        ion_handle_kmap_put(handle);
        mutex_unlock(&buffer->lock);
        mutex_unlock(&client->lock);
}
EXPORT_SYMBOL(ion_unmap_kernel);

static struct mutex debugfs_mutex;
static struct rb_root *ion_root_client;
static int is_client_alive(struct ion_client *client)
{
        struct rb_node *node;
        struct ion_client *tmp;
        struct ion_device *dev;

        node = ion_root_client->rb_node;
        dev = container_of(ion_root_client, struct ion_device, clients);

        down_read(&dev->lock);
        while (node) {
                tmp = rb_entry(node, struct ion_client, node);
                if (client < tmp) {
                        node = node->rb_left;
                } else if (client > tmp) {
                        node = node->rb_right;
                } else {
                        up_read(&dev->lock);
                        return 1;
                }
        }

        up_read(&dev->lock);
        return 0;
}

static int ion_debug_client_show(struct seq_file *s, void *unused)
{
        struct ion_client *client = s->private;
        struct rb_node *n;
        size_t sizes[ION_NUM_HEAP_IDS] = {0};
        const char *names[ION_NUM_HEAP_IDS] = {NULL};
        int i;

        mutex_lock(&debugfs_mutex);
        if (!is_client_alive(client)) {
                seq_printf(s, "ion_client 0x%p dead, can't dump its buffers\n",
                           client);
                mutex_unlock(&debugfs_mutex);
                return 0;
        }

        mutex_lock(&client->lock);
        for (n = rb_first(&client->handles); n; n = rb_next(n)) {
                struct ion_handle *handle = rb_entry(n, struct ion_handle,
                                                     node);
                unsigned int id = handle->buffer->heap->id;

                if (!names[id])
                        names[id] = handle->buffer->heap->name;
                sizes[id] += handle->buffer->size;
        }
        mutex_unlock(&client->lock);
        mutex_unlock(&debugfs_mutex);

        seq_printf(s, "%16.16s: %16.16s\n", "heap_name", "size_in_bytes");
        for (i = 0; i < ION_NUM_HEAP_IDS; i++) {
                if (!names[i])
                        continue;
                seq_printf(s, "%16.16s: %16zu\n", names[i], sizes[i]);
        }
        return 0;
}

static int ion_debug_client_open(struct inode *inode, struct file *file)
{
        return single_open(file, ion_debug_client_show, inode->i_private);
}

static const struct file_operations debug_client_fops = {
        .open = ion_debug_client_open,
        .read = seq_read,
        .llseek = seq_lseek,
        .release = single_release,
};

static int ion_get_client_serial(const struct rb_root *root,
                                        const unsigned char *name)
{
        int serial = -1;
        struct rb_node *node;

        for (node = rb_first(root); node; node = rb_next(node)) {
                struct ion_client *client = rb_entry(node, struct ion_client,
                                                node);

                if (strcmp(client->name, name))
                        continue;
                serial = max(serial, client->display_serial);
        }
        return serial + 1;
}

struct ion_client *ion_client_create(struct ion_device *dev,
                                     const char *name)
{
        struct ion_client *client;
        struct task_struct *task;
        struct rb_node **p;
        struct rb_node *parent = NULL;
        struct ion_client *entry;
        pid_t pid;

        if (!name) {
                pr_err("%s: Name cannot be null\n", __func__);
                return ERR_PTR(-EINVAL);
        }

        get_task_struct(current->group_leader);
        task_lock(current->group_leader);
        pid = task_pid_nr(current->group_leader);
        /*
         * don't bother to store task struct for kernel threads,
         * they can't be killed anyway
         */
        if (current->group_leader->flags & PF_KTHREAD) {
                put_task_struct(current->group_leader);
                task = NULL;
        } else {
                task = current->group_leader;
        }
        task_unlock(current->group_leader);

        client = kzalloc(sizeof(struct ion_client), GFP_KERNEL);
        if (!client)
                goto err_put_task_struct;

        client->dev = dev;
        client->handles = RB_ROOT;
        idr_init(&client->idr);
        mutex_init(&client->lock);
        client->task = task;
        client->pid = pid;
        client->name = kstrdup(name, GFP_KERNEL);
        if (!client->name)
                goto err_free_client;

        down_write(&dev->lock);
        client->display_serial = ion_get_client_serial(&dev->clients, name);
        client->display_name = kasprintf(
                GFP_KERNEL, "%s-%d", name, client->display_serial);
        if (!client->display_name) {
                up_write(&dev->lock);
                goto err_free_client_name;
        }
        p = &dev->clients.rb_node;
        while (*p) {
                parent = *p;
                entry = rb_entry(parent, struct ion_client, node);

                if (client < entry)
                        p = &(*p)->rb_left;
                else if (client > entry)
                        p = &(*p)->rb_right;
        }
        rb_link_node(&client->node, parent, p);
        rb_insert_color(&client->node, &dev->clients);

        client->debug_root = debugfs_create_file(client->display_name, 0664,
                                                dev->clients_debug_root,
                                                client, &debug_client_fops);
        if (!client->debug_root) {
                char buf[256], *path;

                path = dentry_path(dev->clients_debug_root, buf, 256);
                pr_err("Failed to create client debugfs at %s/%s\n",
                        path, client->display_name);
        }

        up_write(&dev->lock);

        return client;

err_free_client_name:
        kfree(client->name);
err_free_client:
        kfree(client);
err_put_task_struct:
        if (task)
                put_task_struct(current->group_leader);
        return ERR_PTR(-ENOMEM);
}
EXPORT_SYMBOL(ion_client_create);

void ion_client_destroy(struct ion_client *client)
{
        struct ion_device *dev = client->dev;
        struct rb_node *n;

        pr_debug("%s: %d\n", __func__, __LINE__);
        mutex_lock(&debugfs_mutex);
        while ((n = rb_first(&client->handles))) {
                struct ion_handle *handle = rb_entry(n, struct ion_handle,
                                                     node);
                ion_handle_destroy(&handle->ref);
        }

        idr_destroy(&client->idr);

        down_write(&dev->lock);
        if (client->task)
                put_task_struct(client->task);
        rb_erase(&client->node, &dev->clients);
        debugfs_remove_recursive(client->debug_root);
        up_write(&dev->lock);

        kfree(client->display_name);
        kfree(client->name);
        kfree(client);
        mutex_unlock(&debugfs_mutex);
}
EXPORT_SYMBOL(ion_client_destroy);

struct sg_table *ion_sg_table(struct ion_client *client,
                              struct ion_handle *handle)
{
        struct ion_buffer *buffer;
        struct sg_table *table;

        mutex_lock(&client->lock);
        if (!ion_handle_validate(client, handle)) {
                pr_err("%s: invalid handle passed to map_dma.\n",
                       __func__);
                mutex_unlock(&client->lock);
                return ERR_PTR(-EINVAL);
        }
        buffer = handle->buffer;
        table = buffer->sg_table;
        mutex_unlock(&client->lock);
        return table;
}
EXPORT_SYMBOL(ion_sg_table);

static void ion_buffer_sync_for_device(struct ion_buffer *buffer,
                                       struct device *dev,
                                       enum dma_data_direction direction);

static struct sg_table *ion_map_dma_buf(struct dma_buf_attachment *attachment,
                                        enum dma_data_direction direction)
{
        struct dma_buf *dmabuf = attachment->dmabuf;
        struct ion_buffer *buffer = dmabuf->priv;

        ion_buffer_sync_for_device(buffer, attachment->dev, direction);
        return buffer->sg_table;
}

static void ion_unmap_dma_buf(struct dma_buf_attachment *attachment,
                              struct sg_table *table,
                              enum dma_data_direction direction)
{
}

void ion_pages_sync_for_device(struct device *dev, struct page *page,
                size_t size, enum dma_data_direction dir)
{
        struct scatterlist sg;

        sg_init_table(&sg, 1);
        sg_set_page(&sg, page, size, 0);
        /*
         * This is not correct - sg_dma_address needs a dma_addr_t that is valid
         * for the targeted device, but this works on the currently targeted
         * hardware.
         */
        sg_dma_address(&sg) = page_to_phys(page);
        dma_sync_sg_for_device(dev, &sg, 1, dir);
}

struct ion_vma_list {
        struct list_head list;
        struct vm_area_struct *vma;
};

static void ion_buffer_sync_for_device(struct ion_buffer *buffer,
                                       struct device *dev,
                                       enum dma_data_direction dir)
{
        struct ion_vma_list *vma_list;
        int pages = PAGE_ALIGN(buffer->size) / PAGE_SIZE;
        int i;

        pr_debug("%s: syncing for device %s\n", __func__,
                 dev ? dev_name(dev) : "null");

        if (!ion_buffer_fault_user_mappings(buffer))
                return;

        mutex_lock(&buffer->lock);
        for (i = 0; i < pages; i++) {
                struct page *page = buffer->pages[i];

                if (ion_buffer_page_is_dirty(page))
                        ion_pages_sync_for_device(dev, ion_buffer_page(page),
                                                        PAGE_SIZE, dir);

                ion_buffer_page_clean(buffer->pages + i);
        }
        list_for_each_entry(vma_list, &buffer->vmas, list) {
                struct vm_area_struct *vma = vma_list->vma;

                zap_page_range(vma, vma->vm_start, vma->vm_end - vma->vm_start,
                               NULL);
        }
        mutex_unlock(&buffer->lock);
}

static int ion_vm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
{
        struct ion_buffer *buffer = vma->vm_private_data;
        unsigned long pfn;
        int ret;

        mutex_lock(&buffer->lock);
        ion_buffer_page_dirty(buffer->pages + vmf->pgoff);
        BUG_ON(!buffer->pages || !buffer->pages[vmf->pgoff]);

        pfn = page_to_pfn(ion_buffer_page(buffer->pages[vmf->pgoff]));
        ret = vm_insert_pfn(vma, (unsigned long)vmf->virtual_address, pfn);
        mutex_unlock(&buffer->lock);
        if (ret)
                return VM_FAULT_ERROR;

        return VM_FAULT_NOPAGE;
}

static void ion_vm_open(struct vm_area_struct *vma)
{
        struct ion_buffer *buffer = vma->vm_private_data;
        struct ion_vma_list *vma_list;

        vma_list = kmalloc(sizeof(struct ion_vma_list), GFP_KERNEL);
        if (!vma_list)
                return;
        vma_list->vma = vma;
        mutex_lock(&buffer->lock);
        list_add(&vma_list->list, &buffer->vmas);
        mutex_unlock(&buffer->lock);
        pr_debug("%s: adding %p\n", __func__, vma);
}

static void ion_vm_close(struct vm_area_struct *vma)
{
        struct ion_buffer *buffer = vma->vm_private_data;
        struct ion_vma_list *vma_list, *tmp;

        pr_debug("%s\n", __func__);
        mutex_lock(&buffer->lock);
        list_for_each_entry_safe(vma_list, tmp, &buffer->vmas, list) {
                if (vma_list->vma != vma)
                        continue;
                list_del(&vma_list->list);
                kfree(vma_list);
                pr_debug("%s: deleting %p\n", __func__, vma);
                break;
        }
        mutex_unlock(&buffer->lock);
}

static const struct vm_operations_struct ion_vma_ops = {
        .open = ion_vm_open,
        .close = ion_vm_close,
        .fault = ion_vm_fault,
};

static int ion_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma)
{
        struct ion_buffer *buffer = dmabuf->priv;
        int ret = 0;

        if (!buffer->heap->ops->map_user) {
                pr_err("%s: this heap does not define a method for mapping to userspace\n",
                        __func__);
                return -EINVAL;
        }

        if (ion_buffer_fault_user_mappings(buffer)) {
                vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND |
                                                        VM_DONTDUMP;
                vma->vm_private_data = buffer;
                vma->vm_ops = &ion_vma_ops;
                ion_vm_open(vma);
                return 0;
        }

        if (!(buffer->flags & ION_FLAG_CACHED))
                vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot);

        mutex_lock(&buffer->lock);
        /* now map it to userspace */
        ret = buffer->heap->ops->map_user(buffer->heap, buffer, vma);
        mutex_unlock(&buffer->lock);

        if (ret)
                pr_err("%s: failure mapping buffer to userspace\n",
                       __func__);

        return ret;
}

static void ion_dma_buf_release(struct dma_buf *dmabuf)
{
        struct ion_buffer *buffer = dmabuf->priv;

        ion_buffer_put(buffer);
}

static void *ion_dma_buf_kmap(struct dma_buf *dmabuf, unsigned long offset)
{
        struct ion_buffer *buffer = dmabuf->priv;

        return buffer->vaddr + offset * PAGE_SIZE;
}

static void ion_dma_buf_kunmap(struct dma_buf *dmabuf, unsigned long offset,
                               void *ptr)
{
}

static int ion_dma_buf_begin_cpu_access(struct dma_buf *dmabuf, size_t start,
                                        size_t len,
                                        enum dma_data_direction direction)
{
        struct ion_buffer *buffer = dmabuf->priv;
        void *vaddr;

        if (!buffer->heap->ops->map_kernel) {
                pr_err("%s: map kernel is not implemented by this heap.\n",
                       __func__);
                return -ENODEV;
        }

        mutex_lock(&buffer->lock);
        vaddr = ion_buffer_kmap_get(buffer);
        mutex_unlock(&buffer->lock);
        return PTR_ERR_OR_ZERO(vaddr);
}

static void ion_dma_buf_end_cpu_access(struct dma_buf *dmabuf, size_t start,
                                       size_t len,
                                       enum dma_data_direction direction)
{
        struct ion_buffer *buffer = dmabuf->priv;

        mutex_lock(&buffer->lock);
        ion_buffer_kmap_put(buffer);
        mutex_unlock(&buffer->lock);
}

static struct dma_buf_ops dma_buf_ops = {
        .map_dma_buf = ion_map_dma_buf,
        .unmap_dma_buf = ion_unmap_dma_buf,
        .mmap = ion_mmap,
        .release = ion_dma_buf_release,
        .begin_cpu_access = ion_dma_buf_begin_cpu_access,
        .end_cpu_access = ion_dma_buf_end_cpu_access,
        .kmap_atomic = ion_dma_buf_kmap,
        .kunmap_atomic = ion_dma_buf_kunmap,
        .kmap = ion_dma_buf_kmap,
        .kunmap = ion_dma_buf_kunmap,
};

struct dma_buf *ion_share_dma_buf(struct ion_client *client,
                                                struct ion_handle *handle)
{
        DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
        struct ion_buffer *buffer;
        struct dma_buf *dmabuf;
        bool valid_handle;

        mutex_lock(&client->lock);
        valid_handle = ion_handle_validate(client, handle);
        if (!valid_handle) {
                WARN(1, "%s: invalid handle passed to share.\n", __func__);
                mutex_unlock(&client->lock);
                return ERR_PTR(-EINVAL);
        }
        buffer = handle->buffer;
        ion_buffer_get(buffer);
        mutex_unlock(&client->lock);

        exp_info.ops = &dma_buf_ops;
        exp_info.size = buffer->size;
        exp_info.flags = O_RDWR;
        exp_info.priv = buffer;

        dmabuf = dma_buf_export(&exp_info);
        if (IS_ERR(dmabuf)) {
                ion_buffer_put(buffer);
                return dmabuf;
        }

        return dmabuf;
}
EXPORT_SYMBOL(ion_share_dma_buf);

int ion_share_dma_buf_fd(struct ion_client *client, struct ion_handle *handle)
{
        struct dma_buf *dmabuf;
        int fd;

        dmabuf = ion_share_dma_buf(client, handle);
        if (IS_ERR(dmabuf))
                return PTR_ERR(dmabuf);

        fd = dma_buf_fd(dmabuf, O_CLOEXEC);
        if (fd < 0)
                dma_buf_put(dmabuf);

        return fd;
}
EXPORT_SYMBOL(ion_share_dma_buf_fd);

struct ion_handle *ion_import_dma_buf(struct ion_client *client,
                                      struct dma_buf *dmabuf)
{
        struct ion_buffer *buffer;
        struct ion_handle *handle;
        int ret;

        /* if this memory came from ion */

        if (dmabuf->ops != &dma_buf_ops) {
                pr_err("%s: can not import dmabuf from another exporter\n",
                       __func__);
                return ERR_PTR(-EINVAL);
        }
        buffer = dmabuf->priv;

        mutex_lock(&client->lock);
        /* if a handle exists for this buffer just take a reference to it */
        handle = ion_handle_lookup(client, buffer);
        if (!IS_ERR(handle)) {
                ion_handle_get(handle);
                mutex_unlock(&client->lock);
                goto end;
        }

        handle = ion_handle_create(client, buffer);
        if (IS_ERR(handle)) {
                mutex_unlock(&client->lock);
                goto end;
        }

        ret = ion_handle_add(client, handle);
        mutex_unlock(&client->lock);
        if (ret) {
                ion_handle_put(handle);
                handle = ERR_PTR(ret);
        }

end:
        return handle;
}
EXPORT_SYMBOL(ion_import_dma_buf);

struct ion_handle *ion_import_dma_buf_fd(struct ion_client *client, int fd)
{
        struct dma_buf *dmabuf;
        struct ion_handle *handle;

        dmabuf = dma_buf_get(fd);
        if (IS_ERR(dmabuf))
                return ERR_CAST(dmabuf);

        handle = ion_import_dma_buf(client, dmabuf);
        dma_buf_put(dmabuf);
        return handle;
}
EXPORT_SYMBOL(ion_import_dma_buf_fd);

static int ion_sync_for_device(struct ion_client *client, int fd)
{
        struct dma_buf *dmabuf;
        struct ion_buffer *buffer;

        dmabuf = dma_buf_get(fd);
        if (IS_ERR(dmabuf))
                return PTR_ERR(dmabuf);

        /* if this memory came from ion */
        if (dmabuf->ops != &dma_buf_ops) {
                pr_err("%s: can not sync dmabuf from another exporter\n",
                       __func__);
                dma_buf_put(dmabuf);
                return -EINVAL;
        }
        buffer = dmabuf->priv;

        dma_sync_sg_for_device(NULL, buffer->sg_table->sgl,
                               buffer->sg_table->nents, DMA_BIDIRECTIONAL);
        dma_buf_put(dmabuf);
        return 0;
}

/* fix up the cases where the ioctl direction bits are incorrect */
static unsigned int ion_ioctl_dir(unsigned int cmd)
{
        switch (cmd) {
        case ION_IOC_SYNC:
        case ION_IOC_FREE:
        case ION_IOC_CUSTOM:
                return _IOC_WRITE;
        default:
                return _IOC_DIR(cmd);
        }
}

static long ion_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
{
        struct ion_client *client = filp->private_data;
        struct ion_device *dev = client->dev;
        struct ion_handle *cleanup_handle = NULL;
        int ret = 0;
        unsigned int dir;

        union {
                struct ion_fd_data fd;
                struct ion_allocation_data allocation;
                struct ion_handle_data handle;
                struct ion_custom_data custom;
        } data;

        dir = ion_ioctl_dir(cmd);

        if (_IOC_SIZE(cmd) > sizeof(data))
                return -EINVAL;

        if (dir & _IOC_WRITE)
                if (copy_from_user(&data, (void __user *)arg, _IOC_SIZE(cmd)))
                        return -EFAULT;

        switch (cmd) {
        case ION_IOC_ALLOC:
        {
                struct ion_handle *handle;

                handle = ion_alloc(client, data.allocation.len,
                                                data.allocation.align,
                                                data.allocation.heap_id_mask,
                                                data.allocation.flags);
                if (IS_ERR(handle))
                        return PTR_ERR(handle);

                data.allocation.handle = handle->id;

                cleanup_handle = handle;
                break;
        }
        case ION_IOC_FREE:
        {
                struct ion_handle *handle;

                mutex_lock(&client->lock);
                handle = ion_handle_get_by_id_nolock(client, data.handle.handle);
                if (IS_ERR(handle)) {
                        mutex_unlock(&client->lock);
                        return PTR_ERR(handle);
                }
                ion_free_nolock(client, handle);
                ion_handle_put_nolock(handle);
                mutex_unlock(&client->lock);
                break;
        }
        case ION_IOC_SHARE:
        case ION_IOC_MAP:
        {
                struct ion_handle *handle;

                handle = ion_handle_get_by_id(client, data.handle.handle);
                if (IS_ERR(handle))
                        return PTR_ERR(handle);
                data.fd.fd = ion_share_dma_buf_fd(client, handle);
                ion_handle_put(handle);
                if (data.fd.fd < 0)
                        ret = data.fd.fd;
                break;
        }
        case ION_IOC_IMPORT:
        {
                struct ion_handle *handle;

                handle = ion_import_dma_buf_fd(client, data.fd.fd);
                if (IS_ERR(handle))
                        ret = PTR_ERR(handle);
                else
                        data.handle.handle = handle->id;
                break;
        }
        case ION_IOC_SYNC:
        {
                ret = ion_sync_for_device(client, data.fd.fd);
                break;
        }
        case ION_IOC_CUSTOM:
        {
                if (!dev->custom_ioctl)
                        return -ENOTTY;
                ret = dev->custom_ioctl(client, data.custom.cmd,
                                                data.custom.arg);
                break;
        }
        default:
                return -ENOTTY;
        }

        if (dir & _IOC_READ) {
                if (copy_to_user((void __user *)arg, &data, _IOC_SIZE(cmd))) {
                        if (cleanup_handle)
                                ion_free(client, cleanup_handle);
                        return -EFAULT;
                }
        }
        return ret;
}

static int ion_release(struct inode *inode, struct file *file)
{
        struct ion_client *client = file->private_data;

        pr_debug("%s: %d\n", __func__, __LINE__);
        ion_client_destroy(client);
        return 0;
}

static int ion_open(struct inode *inode, struct file *file)
{
        struct miscdevice *miscdev = file->private_data;
        struct ion_device *dev = container_of(miscdev, struct ion_device, dev);
        struct ion_client *client;
        char debug_name[64];

        pr_debug("%s: %d\n", __func__, __LINE__);
        snprintf(debug_name, 64, "%u", task_pid_nr(current->group_leader));
        client = ion_client_create(dev, debug_name);
        if (IS_ERR(client))
                return PTR_ERR(client);
        file->private_data = client;

        return 0;
}

static const struct file_operations ion_fops = {
        .owner          = THIS_MODULE,
        .open           = ion_open,
        .release        = ion_release,
        .unlocked_ioctl = ion_ioctl,
        .compat_ioctl   = compat_ion_ioctl,
};

static size_t ion_debug_heap_total(struct ion_client *client,
                                   unsigned int id)
{
        size_t size = 0;
        struct rb_node *n;

        mutex_lock(&client->lock);
        for (n = rb_first(&client->handles); n; n = rb_next(n)) {
                struct ion_handle *handle = rb_entry(n,
                                                     struct ion_handle,
                                                     node);
                if (handle->buffer->heap->id == id)
                        size += handle->buffer->size;
        }
        mutex_unlock(&client->lock);
        return size;
}

static int ion_debug_heap_show(struct seq_file *s, void *unused)
{
        struct ion_heap *heap = s->private;
        struct ion_device *dev = heap->dev;
        struct rb_node *n;
        size_t total_size = 0;
        size_t total_orphaned_size = 0;

        seq_printf(s, "%16s %16s %16s\n", "client", "pid", "size");
        seq_puts(s, "----------------------------------------------------\n");

        mutex_lock(&debugfs_mutex);
        for (n = rb_first(&dev->clients); n; n = rb_next(n)) {
                struct ion_client *client = rb_entry(n, struct ion_client,
                                                     node);
                size_t size = ion_debug_heap_total(client, heap->id);

                if (!size)
                        continue;
                if (client->task) {
                        char task_comm[TASK_COMM_LEN];

                        get_task_comm(task_comm, client->task);
                        seq_printf(s, "%16s %16u %16zu\n", task_comm,
                                   client->pid, size);
                } else {
                        seq_printf(s, "%16s %16u %16zu\n", client->name,
                                   client->pid, size);
                }
        }
        mutex_unlock(&debugfs_mutex);

        seq_puts(s, "----------------------------------------------------\n");
        seq_puts(s, "orphaned allocations (info is from last known client):\n");
        mutex_lock(&dev->buffer_lock);
        for (n = rb_first(&dev->buffers); n; n = rb_next(n)) {
                struct ion_buffer *buffer = rb_entry(n, struct ion_buffer,
                                                     node);
                if (buffer->heap->id != heap->id)
                        continue;
                total_size += buffer->size;
                if (!buffer->handle_count) {
                        seq_printf(s, "%16s %16u %16zu %d %d\n",
                                   buffer->task_comm, buffer->pid,
                                   buffer->size, buffer->kmap_cnt,
                                   atomic_read(&buffer->ref.refcount));
                        total_orphaned_size += buffer->size;
                }
        }
        mutex_unlock(&dev->buffer_lock);
        seq_puts(s, "----------------------------------------------------\n");
        seq_printf(s, "%16s %16zu\n", "total orphaned",
                   total_orphaned_size);
        seq_printf(s, "%16s %16zu\n", "total ", total_size);
        if (heap->flags & ION_HEAP_FLAG_DEFER_FREE)
                seq_printf(s, "%16s %16zu\n", "deferred free",
                                heap->free_list_size);
        seq_puts(s, "----------------------------------------------------\n");

        if (heap->debug_show)
                heap->debug_show(heap, s, unused);

        return 0;
}

static int ion_debug_heap_open(struct inode *inode, struct file *file)
{
        return single_open(file, ion_debug_heap_show, inode->i_private);
}

static const struct file_operations debug_heap_fops = {
        .open = ion_debug_heap_open,
        .read = seq_read,
        .llseek = seq_lseek,
        .release = single_release,
};

static int debug_shrink_set(void *data, u64 val)
{
        struct ion_heap *heap = data;
        struct shrink_control sc;
        int objs;

        sc.gfp_mask = GFP_HIGHUSER;
        sc.nr_to_scan = val;

        if (!val) {
                objs = heap->shrinker.count_objects(&heap->shrinker, &sc);
                sc.nr_to_scan = objs;
        }

        heap->shrinker.scan_objects(&heap->shrinker, &sc);
        return 0;
}

static int debug_shrink_get(void *data, u64 *val)
{
        struct ion_heap *heap = data;
        struct shrink_control sc;
        int objs;

        sc.gfp_mask = GFP_HIGHUSER;
        sc.nr_to_scan = 0;

        objs = heap->shrinker.count_objects(&heap->shrinker, &sc);
        *val = objs;
        return 0;
}

DEFINE_SIMPLE_ATTRIBUTE(debug_shrink_fops, debug_shrink_get,
                        debug_shrink_set, "%llu\n");

void ion_device_add_heap(struct ion_device *dev, struct ion_heap *heap)
{
        struct dentry *debug_file;

        if (!heap->ops->allocate || !heap->ops->free || !heap->ops->map_dma ||
            !heap->ops->unmap_dma)
                pr_err("%s: can not add heap with invalid ops struct.\n",
                       __func__);

        spin_lock_init(&heap->free_lock);
        heap->free_list_size = 0;

        if (heap->flags & ION_HEAP_FLAG_DEFER_FREE)
                ion_heap_init_deferred_free(heap);

        if ((heap->flags & ION_HEAP_FLAG_DEFER_FREE) || heap->ops->shrink)
                ion_heap_init_shrinker(heap);

        heap->dev = dev;
        down_write(&dev->lock);
        /*
         * use negative heap->id to reverse the priority -- when traversing
         * the list later attempt higher id numbers first
         */
        plist_node_init(&heap->node, -heap->id);
        plist_add(&heap->node, &dev->heaps);
        debug_file = debugfs_create_file(heap->name, 0664,
                                        dev->heaps_debug_root, heap,
                                        &debug_heap_fops);

        if (!debug_file) {
                char buf[256], *path;

                path = dentry_path(dev->heaps_debug_root, buf, 256);
                pr_err("Failed to create heap debugfs at %s/%s\n",
                        path, heap->name);
        }

        if (heap->shrinker.count_objects && heap->shrinker.scan_objects) {
                char debug_name[64];

                snprintf(debug_name, 64, "%s_shrink", heap->name);
                debug_file = debugfs_create_file(
                        debug_name, 0644, dev->heaps_debug_root, heap,
                        &debug_shrink_fops);
                if (!debug_file) {
                        char buf[256], *path;

                        path = dentry_path(dev->heaps_debug_root, buf, 256);
                        pr_err("Failed to create heap shrinker debugfs at %s/%s\n",
                                path, debug_name);
                }
        }

        up_write(&dev->lock);
}
EXPORT_SYMBOL(ion_device_add_heap);

struct ion_device *ion_device_create(long (*custom_ioctl)
                                     (struct ion_client *client,
                                      unsigned int cmd,
                                      unsigned long arg))
{
        struct ion_device *idev;
        int ret;

        idev = kzalloc(sizeof(struct ion_device), GFP_KERNEL);
        if (!idev)
                return ERR_PTR(-ENOMEM);

        idev->dev.minor = MISC_DYNAMIC_MINOR;
        idev->dev.name = "ion";
        idev->dev.fops = &ion_fops;
        idev->dev.parent = NULL;
        ret = misc_register(&idev->dev);
        if (ret) {
                pr_err("ion: failed to register misc device.\n");
                kfree(idev);
                return ERR_PTR(ret);
        }

        idev->debug_root = debugfs_create_dir("ion", NULL);
        if (!idev->debug_root) {
                pr_err("ion: failed to create debugfs root directory.\n");
                goto debugfs_done;
        }
        idev->heaps_debug_root = debugfs_create_dir("heaps", idev->debug_root);
        if (!idev->heaps_debug_root) {
                pr_err("ion: failed to create debugfs heaps directory.\n");
                goto debugfs_done;
        }
        idev->clients_debug_root = debugfs_create_dir("clients",
                                                idev->debug_root);
        if (!idev->clients_debug_root)
                pr_err("ion: failed to create debugfs clients directory.\n");

debugfs_done:

        idev->custom_ioctl = custom_ioctl;
        idev->buffers = RB_ROOT;
        mutex_init(&idev->buffer_lock);
        init_rwsem(&idev->lock);
        plist_head_init(&idev->heaps);
        idev->clients = RB_ROOT;
        ion_root_client = &idev->clients;
        mutex_init(&debugfs_mutex);
        return idev;
}
EXPORT_SYMBOL(ion_device_create);

void ion_device_destroy(struct ion_device *dev)
{
        misc_deregister(&dev->dev);
        debugfs_remove_recursive(dev->debug_root);
        /* XXX need to free the heaps and clients ? */
        kfree(dev);
}
EXPORT_SYMBOL(ion_device_destroy);

void __init ion_reserve(struct ion_platform_data *data)
{
        int i;

        for (i = 0; i < data->nr; i++) {
                if (data->heaps[i].size == 0)
                        continue;

                if (data->heaps[i].base == 0) {
                        phys_addr_t paddr;

                        paddr = memblock_alloc_base(data->heaps[i].size,
                                                    data->heaps[i].align,
                                                    MEMBLOCK_ALLOC_ANYWHERE);
                        if (!paddr) {
                                pr_err("%s: error allocating memblock for heap %d\n",
                                        __func__, i);
                                continue;
                        }
                        data->heaps[i].base = paddr;
                } else {
                        int ret = memblock_reserve(data->heaps[i].base,
                                               data->heaps[i].size);
                        if (ret)
                                pr_err("memblock reserve of %zx@%lx failed\n",
                                       data->heaps[i].size,
                                       data->heaps[i].base);
                }
                pr_info("%s: %s reserved base %lx size %zu\n", __func__,
                        data->heaps[i].name,
                        data->heaps[i].base,
                        data->heaps[i].size);
        }
}