linux-imx

/*

 * Framework for buffer objects that can be shared across devices/subsystems.

 *

 * Copyright(C) 2011 Linaro Limited. All rights reserved.

 * Author: Sumit Semwal <sumit.semwal@ti.com>

 *

 * Many thanks to linaro-mm-sig list, and specially

 * Arnd Bergmann <arnd@arndb.de>, Rob Clark <rob@ti.com> and

 * Daniel Vetter <daniel@ffwll.ch> for their support in creation and

 * refining of this idea.

 *

 * This program is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 as published by

 * the Free Software Foundation.

 *

 * 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.

 *

 * You should have received a copy of the GNU General Public License along with

 * this program.  If not, see <http://www.gnu.org/licenses/>.

 */

​

#include <linux/fs.h>

#include <linux/slab.h>

#include <linux/dma-buf.h>

#include <linux/dma-fence.h>

#include <linux/anon_inodes.h>

#include <linux/export.h>

#include <linux/debugfs.h>

#include <linux/module.h>

#include <linux/seq_file.h>

#include <linux/poll.h>

#include <linux/reservation.h>

#include <linux/mm.h>

​

#include <uapi/linux/dma-buf.h>

​

static inline int is_dma_buf_file(struct file *);

​

struct dma_buf_list {

    struct list_head head;

    struct mutex lock;

};

​

static struct dma_buf_list db_list;

​

static int dma_buf_release(struct inode *inode, struct file *file)

{

    struct dma_buf *dmabuf;

​

    if (!is_dma_buf_file(file))

        return -EINVAL;

​

    dmabuf = file->private_data;

​

    BUG_ON(dmabuf->vmapping_counter);

​

    /*

     * Any fences that a dma-buf poll can wait on should be signaled

     * before releasing dma-buf. This is the responsibility of each

     * driver that uses the reservation objects.

     *

     * If you hit this BUG() it means someone dropped their ref to the

     * dma-buf while still having pending operation to the buffer.

     */

    BUG_ON(dmabuf->cb_shared.active || dmabuf->cb_excl.active);

​

    dmabuf->ops->release(dmabuf);

​

    mutex_lock(&db_list.lock);

    list_del(&dmabuf->list_node);

    mutex_unlock(&db_list.lock);

​

    if (dmabuf->resv == (struct reservation_object *)&dmabuf[1])

        reservation_object_fini(dmabuf->resv);

​

    module_put(dmabuf->owner);

    kfree(dmabuf);

    return 0;

}

​

static int dma_buf_mmap_internal(struct file *file, struct vm_area_struct *vma)

{

    struct dma_buf *dmabuf;

​

    if (!is_dma_buf_file(file))

        return -EINVAL;

​

    dmabuf = file->private_data;

​