Re: [PATCH v2 1/9] dma-buf: move to drivers/dma-buf

[Arend van Spriel <arend@broadcom.com>]

On 01-07-14 12:57, Maarten Lankhorst wrote:
> Signed-off-by: Maarten Lankhorst <maarten.lankhorst@canonical.com>

It would help to use '-M' option with format-patch for this kind of rework.

Regards,
Arend

> ---
>  Documentation/DocBook/device-drivers.tmpl |    3 
>  MAINTAINERS                               |    4 
>  drivers/Makefile                          |    1 
>  drivers/base/Makefile                     |    1 
>  drivers/base/dma-buf.c                    |  743 -----------------------------
>  drivers/base/reservation.c                |   39 --
>  drivers/dma-buf/Makefile                  |    1 
>  drivers/dma-buf/dma-buf.c                 |  743 +++++++++++++++++++++++++++++
>  drivers/dma-buf/reservation.c             |   39 ++
>  9 files changed, 787 insertions(+), 787 deletions(-)
>  delete mode 100644 drivers/base/dma-buf.c
>  delete mode 100644 drivers/base/reservation.c
>  create mode 100644 drivers/dma-buf/Makefile
>  create mode 100644 drivers/dma-buf/dma-buf.c
>  create mode 100644 drivers/dma-buf/reservation.c
> 
> diff --git a/Documentation/DocBook/device-drivers.tmpl b/Documentation/DocBook/device-drivers.tmpl
> index cc63f30de166..ac61ebd92875 100644
> --- a/Documentation/DocBook/device-drivers.tmpl
> +++ b/Documentation/DocBook/device-drivers.tmpl
> @@ -128,8 +128,7 @@ X!Edrivers/base/interface.c
>  !Edrivers/base/bus.c
>       </sect1>
>       <sect1><title>Device Drivers DMA Management</title>
> -!Edrivers/base/dma-buf.c
> -!Edrivers/base/reservation.c
> +!Edrivers/dma-buf/dma-buf.c
>  !Iinclude/linux/reservation.h
>  !Edrivers/base/dma-coherent.c
>  !Edrivers/base/dma-mapping.c
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 134483f206e4..c948e53a4ee6 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -2882,8 +2882,8 @@ S:	Maintained
>  L:	linux-media@vger.kernel.org
>  L:	dri-devel@lists.freedesktop.org
>  L:	linaro-mm-sig@lists.linaro.org
> -F:	drivers/base/dma-buf*
> -F:	include/linux/dma-buf*
> +F:	drivers/dma-buf/
> +F:	include/linux/dma-buf* include/linux/reservation.h
>  F:	Documentation/dma-buf-sharing.txt
>  T:	git git://git.linaro.org/people/sumitsemwal/linux-dma-buf.git
>  
> diff --git a/drivers/Makefile b/drivers/Makefile
> index f98b50d8251d..c00337be5351 100644
> --- a/drivers/Makefile
> +++ b/drivers/Makefile
> @@ -61,6 +61,7 @@ obj-$(CONFIG_FB_INTEL)          += video/fbdev/intelfb/
>  
>  obj-$(CONFIG_PARPORT)		+= parport/
>  obj-y				+= base/ block/ misc/ mfd/ nfc/
> +obj-$(CONFIG_DMA_SHARED_BUFFER) += dma-buf/
>  obj-$(CONFIG_NUBUS)		+= nubus/
>  obj-y				+= macintosh/
>  obj-$(CONFIG_IDE)		+= ide/
> diff --git a/drivers/base/Makefile b/drivers/base/Makefile
> index 04b314e0fa51..4aab26ec0292 100644
> --- a/drivers/base/Makefile
> +++ b/drivers/base/Makefile
> @@ -10,7 +10,6 @@ obj-$(CONFIG_DMA_CMA) += dma-contiguous.o
>  obj-y			+= power/
>  obj-$(CONFIG_HAS_DMA)	+= dma-mapping.o
>  obj-$(CONFIG_HAVE_GENERIC_DMA_COHERENT) += dma-coherent.o
> -obj-$(CONFIG_DMA_SHARED_BUFFER) += dma-buf.o reservation.o
>  obj-$(CONFIG_ISA)	+= isa.o
>  obj-$(CONFIG_FW_LOADER)	+= firmware_class.o
>  obj-$(CONFIG_NUMA)	+= node.o
> diff --git a/drivers/base/dma-buf.c b/drivers/base/dma-buf.c
> deleted file mode 100644
> index 840c7fa80983..000000000000
> --- a/drivers/base/dma-buf.c
> +++ /dev/null
> @@ -1,743 +0,0 @@
> -/*
> - * 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/anon_inodes.h>
> -#include <linux/export.h>
> -#include <linux/debugfs.h>
> -#include <linux/seq_file.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);
> -
> -	dmabuf->ops->release(dmabuf);
> -
> -	mutex_lock(&db_list.lock);
> -	list_del(&dmabuf->list_node);
> -	mutex_unlock(&db_list.lock);
> -
> -	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;
> -
> -	/* check for overflowing the buffer's size */
> -	if (vma->vm_pgoff + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) >
> -	    dmabuf->size >> PAGE_SHIFT)
> -		return -EINVAL;
> -
> -	return dmabuf->ops->mmap(dmabuf, vma);
> -}
> -
> -static loff_t dma_buf_llseek(struct file *file, loff_t offset, int whence)
> -{
> -	struct dma_buf *dmabuf;
> -	loff_t base;
> -
> -	if (!is_dma_buf_file(file))
> -		return -EBADF;
> -
> -	dmabuf = file->private_data;
> -
> -	/* only support discovering the end of the buffer,
> -	   but also allow SEEK_SET to maintain the idiomatic
> -	   SEEK_END(0), SEEK_CUR(0) pattern */
> -	if (whence == SEEK_END)
> -		base = dmabuf->size;
> -	else if (whence == SEEK_SET)
> -		base = 0;
> -	else
> -		return -EINVAL;
> -
> -	if (offset != 0)
> -		return -EINVAL;
> -
> -	return base + offset;
> -}
> -
> -static const struct file_operations dma_buf_fops = {
> -	.release	= dma_buf_release,
> -	.mmap		= dma_buf_mmap_internal,
> -	.llseek		= dma_buf_llseek,
> -};
> -
> -/*
> - * is_dma_buf_file - Check if struct file* is associated with dma_buf
> - */
> -static inline int is_dma_buf_file(struct file *file)
> -{
> -	return file->f_op == &dma_buf_fops;
> -}
> -
> -/**
> - * dma_buf_export_named - Creates a new dma_buf, and associates an anon file
> - * with this buffer, so it can be exported.
> - * Also connect the allocator specific data and ops to the buffer.
> - * Additionally, provide a name string for exporter; useful in debugging.
> - *
> - * @priv:	[in]	Attach private data of allocator to this buffer
> - * @ops:	[in]	Attach allocator-defined dma buf ops to the new buffer.
> - * @size:	[in]	Size of the buffer
> - * @flags:	[in]	mode flags for the file.
> - * @exp_name:	[in]	name of the exporting module - useful for debugging.
> - *
> - * Returns, on success, a newly created dma_buf object, which wraps the
> - * supplied private data and operations for dma_buf_ops. On either missing
> - * ops, or error in allocating struct dma_buf, will return negative error.
> - *
> - */
> -struct dma_buf *dma_buf_export_named(void *priv, const struct dma_buf_ops *ops,
> -				size_t size, int flags, const char *exp_name)
> -{
> -	struct dma_buf *dmabuf;
> -	struct file *file;
> -
> -	if (WARN_ON(!priv || !ops
> -			  || !ops->map_dma_buf
> -			  || !ops->unmap_dma_buf
> -			  || !ops->release
> -			  || !ops->kmap_atomic
> -			  || !ops->kmap
> -			  || !ops->mmap)) {
> -		return ERR_PTR(-EINVAL);
> -	}
> -
> -	dmabuf = kzalloc(sizeof(struct dma_buf), GFP_KERNEL);
> -	if (dmabuf == NULL)
> -		return ERR_PTR(-ENOMEM);
> -
> -	dmabuf->priv = priv;
> -	dmabuf->ops = ops;
> -	dmabuf->size = size;
> -	dmabuf->exp_name = exp_name;
> -
> -	file = anon_inode_getfile("dmabuf", &dma_buf_fops, dmabuf, flags);
> -	if (IS_ERR(file)) {
> -		kfree(dmabuf);
> -		return ERR_CAST(file);
> -	}
> -
> -	file->f_mode |= FMODE_LSEEK;
> -	dmabuf->file = file;
> -
> -	mutex_init(&dmabuf->lock);
> -	INIT_LIST_HEAD(&dmabuf->attachments);
> -
> -	mutex_lock(&db_list.lock);
> -	list_add(&dmabuf->list_node, &db_list.head);
> -	mutex_unlock(&db_list.lock);
> -
> -	return dmabuf;
> -}
> -EXPORT_SYMBOL_GPL(dma_buf_export_named);
> -
> -
> -/**
> - * dma_buf_fd - returns a file descriptor for the given dma_buf
> - * @dmabuf:	[in]	pointer to dma_buf for which fd is required.
> - * @flags:      [in]    flags to give to fd
> - *
> - * On success, returns an associated 'fd'. Else, returns error.
> - */
> -int dma_buf_fd(struct dma_buf *dmabuf, int flags)
> -{
> -	int fd;
> -
> -	if (!dmabuf || !dmabuf->file)
> -		return -EINVAL;
> -
> -	fd = get_unused_fd_flags(flags);
> -	if (fd < 0)
> -		return fd;
> -
> -	fd_install(fd, dmabuf->file);
> -
> -	return fd;
> -}
> -EXPORT_SYMBOL_GPL(dma_buf_fd);
> -
> -/**
> - * dma_buf_get - returns the dma_buf structure related to an fd
> - * @fd:	[in]	fd associated with the dma_buf to be returned
> - *
> - * On success, returns the dma_buf structure associated with an fd; uses
> - * file's refcounting done by fget to increase refcount. returns ERR_PTR
> - * otherwise.
> - */
> -struct dma_buf *dma_buf_get(int fd)
> -{
> -	struct file *file;
> -
> -	file = fget(fd);
> -
> -	if (!file)
> -		return ERR_PTR(-EBADF);
> -
> -	if (!is_dma_buf_file(file)) {
> -		fput(file);
> -		return ERR_PTR(-EINVAL);
> -	}
> -
> -	return file->private_data;
> -}
> -EXPORT_SYMBOL_GPL(dma_buf_get);
> -
> -/**
> - * dma_buf_put - decreases refcount of the buffer
> - * @dmabuf:	[in]	buffer to reduce refcount of
> - *
> - * Uses file's refcounting done implicitly by fput()
> - */
> -void dma_buf_put(struct dma_buf *dmabuf)
> -{
> -	if (WARN_ON(!dmabuf || !dmabuf->file))
> -		return;
> -
> -	fput(dmabuf->file);
> -}
> -EXPORT_SYMBOL_GPL(dma_buf_put);
> -
> -/**
> - * dma_buf_attach - Add the device to dma_buf's attachments list; optionally,
> - * calls attach() of dma_buf_ops to allow device-specific attach functionality
> - * @dmabuf:	[in]	buffer to attach device to.
> - * @dev:	[in]	device to be attached.
> - *
> - * Returns struct dma_buf_attachment * for this attachment; returns ERR_PTR on
> - * error.
> - */
> -struct dma_buf_attachment *dma_buf_attach(struct dma_buf *dmabuf,
> -					  struct device *dev)
> -{
> -	struct dma_buf_attachment *attach;
> -	int ret;
> -
> -	if (WARN_ON(!dmabuf || !dev))
> -		return ERR_PTR(-EINVAL);
> -
> -	attach = kzalloc(sizeof(struct dma_buf_attachment), GFP_KERNEL);
> -	if (attach == NULL)
> -		return ERR_PTR(-ENOMEM);
> -
> -	attach->dev = dev;
> -	attach->dmabuf = dmabuf;
> -
> -	mutex_lock(&dmabuf->lock);
> -
> -	if (dmabuf->ops->attach) {
> -		ret = dmabuf->ops->attach(dmabuf, dev, attach);
> -		if (ret)
> -			goto err_attach;
> -	}
> -	list_add(&attach->node, &dmabuf->attachments);
> -
> -	mutex_unlock(&dmabuf->lock);
> -	return attach;
> -
> -err_attach:
> -	kfree(attach);
> -	mutex_unlock(&dmabuf->lock);
> -	return ERR_PTR(ret);
> -}
> -EXPORT_SYMBOL_GPL(dma_buf_attach);
> -
> -/**
> - * dma_buf_detach - Remove the given attachment from dmabuf's attachments list;
> - * optionally calls detach() of dma_buf_ops for device-specific detach
> - * @dmabuf:	[in]	buffer to detach from.
> - * @attach:	[in]	attachment to be detached; is free'd after this call.
> - *
> - */
> -void dma_buf_detach(struct dma_buf *dmabuf, struct dma_buf_attachment *attach)
> -{
> -	if (WARN_ON(!dmabuf || !attach))
> -		return;
> -
> -	mutex_lock(&dmabuf->lock);
> -	list_del(&attach->node);
> -	if (dmabuf->ops->detach)
> -		dmabuf->ops->detach(dmabuf, attach);
> -
> -	mutex_unlock(&dmabuf->lock);
> -	kfree(attach);
> -}
> -EXPORT_SYMBOL_GPL(dma_buf_detach);
> -
> -/**
> - * dma_buf_map_attachment - Returns the scatterlist table of the attachment;
> - * mapped into _device_ address space. Is a wrapper for map_dma_buf() of the
> - * dma_buf_ops.
> - * @attach:	[in]	attachment whose scatterlist is to be returned
> - * @direction:	[in]	direction of DMA transfer
> - *
> - * Returns sg_table containing the scatterlist to be returned; returns ERR_PTR
> - * on error.
> - */
> -struct sg_table *dma_buf_map_attachment(struct dma_buf_attachment *attach,
> -					enum dma_data_direction direction)
> -{
> -	struct sg_table *sg_table = ERR_PTR(-EINVAL);
> -
> -	might_sleep();
> -
> -	if (WARN_ON(!attach || !attach->dmabuf))
> -		return ERR_PTR(-EINVAL);
> -
> -	sg_table = attach->dmabuf->ops->map_dma_buf(attach, direction);
> -	if (!sg_table)
> -		sg_table = ERR_PTR(-ENOMEM);
> -
> -	return sg_table;
> -}
> -EXPORT_SYMBOL_GPL(dma_buf_map_attachment);
> -
> -/**
> - * dma_buf_unmap_attachment - unmaps and decreases usecount of the buffer;might
> - * deallocate the scatterlist associated. Is a wrapper for unmap_dma_buf() of
> - * dma_buf_ops.
> - * @attach:	[in]	attachment to unmap buffer from
> - * @sg_table:	[in]	scatterlist info of the buffer to unmap
> - * @direction:  [in]    direction of DMA transfer
> - *
> - */
> -void dma_buf_unmap_attachment(struct dma_buf_attachment *attach,
> -				struct sg_table *sg_table,
> -				enum dma_data_direction direction)
> -{
> -	might_sleep();
> -
> -	if (WARN_ON(!attach || !attach->dmabuf || !sg_table))
> -		return;
> -
> -	attach->dmabuf->ops->unmap_dma_buf(attach, sg_table,
> -						direction);
> -}
> -EXPORT_SYMBOL_GPL(dma_buf_unmap_attachment);
> -
> -
> -/**
> - * dma_buf_begin_cpu_access - Must be called before accessing a dma_buf from the
> - * cpu in the kernel context. Calls begin_cpu_access to allow exporter-specific
> - * preparations. Coherency is only guaranteed in the specified range for the
> - * specified access direction.
> - * @dmabuf:	[in]	buffer to prepare cpu access for.
> - * @start:	[in]	start of range for cpu access.
> - * @len:	[in]	length of range for cpu access.
> - * @direction:	[in]	length of range for cpu access.
> - *
> - * Can return negative error values, returns 0 on success.
> - */
> -int dma_buf_begin_cpu_access(struct dma_buf *dmabuf, size_t start, size_t len,
> -			     enum dma_data_direction direction)
> -{
> -	int ret = 0;
> -
> -	if (WARN_ON(!dmabuf))
> -		return -EINVAL;
> -
> -	if (dmabuf->ops->begin_cpu_access)
> -		ret = dmabuf->ops->begin_cpu_access(dmabuf, start, len, direction);
> -
> -	return ret;
> -}
> -EXPORT_SYMBOL_GPL(dma_buf_begin_cpu_access);
> -
> -/**
> - * dma_buf_end_cpu_access - Must be called after accessing a dma_buf from the
> - * cpu in the kernel context. Calls end_cpu_access to allow exporter-specific
> - * actions. Coherency is only guaranteed in the specified range for the
> - * specified access direction.
> - * @dmabuf:	[in]	buffer to complete cpu access for.
> - * @start:	[in]	start of range for cpu access.
> - * @len:	[in]	length of range for cpu access.
> - * @direction:	[in]	length of range for cpu access.
> - *
> - * This call must always succeed.
> - */
> -void dma_buf_end_cpu_access(struct dma_buf *dmabuf, size_t start, size_t len,
> -			    enum dma_data_direction direction)
> -{
> -	WARN_ON(!dmabuf);
> -
> -	if (dmabuf->ops->end_cpu_access)
> -		dmabuf->ops->end_cpu_access(dmabuf, start, len, direction);
> -}
> -EXPORT_SYMBOL_GPL(dma_buf_end_cpu_access);
> -
> -/**
> - * dma_buf_kmap_atomic - Map a page of the buffer object into kernel address
> - * space. The same restrictions as for kmap_atomic and friends apply.
> - * @dmabuf:	[in]	buffer to map page from.
> - * @page_num:	[in]	page in PAGE_SIZE units to map.
> - *
> - * This call must always succeed, any necessary preparations that might fail
> - * need to be done in begin_cpu_access.
> - */
> -void *dma_buf_kmap_atomic(struct dma_buf *dmabuf, unsigned long page_num)
> -{
> -	WARN_ON(!dmabuf);
> -
> -	return dmabuf->ops->kmap_atomic(dmabuf, page_num);
> -}
> -EXPORT_SYMBOL_GPL(dma_buf_kmap_atomic);
> -
> -/**
> - * dma_buf_kunmap_atomic - Unmap a page obtained by dma_buf_kmap_atomic.
> - * @dmabuf:	[in]	buffer to unmap page from.
> - * @page_num:	[in]	page in PAGE_SIZE units to unmap.
> - * @vaddr:	[in]	kernel space pointer obtained from dma_buf_kmap_atomic.
> - *
> - * This call must always succeed.
> - */
> -void dma_buf_kunmap_atomic(struct dma_buf *dmabuf, unsigned long page_num,
> -			   void *vaddr)
> -{
> -	WARN_ON(!dmabuf);
> -
> -	if (dmabuf->ops->kunmap_atomic)
> -		dmabuf->ops->kunmap_atomic(dmabuf, page_num, vaddr);
> -}
> -EXPORT_SYMBOL_GPL(dma_buf_kunmap_atomic);
> -
> -/**
> - * dma_buf_kmap - Map a page of the buffer object into kernel address space. The
> - * same restrictions as for kmap and friends apply.
> - * @dmabuf:	[in]	buffer to map page from.
> - * @page_num:	[in]	page in PAGE_SIZE units to map.
> - *
> - * This call must always succeed, any necessary preparations that might fail
> - * need to be done in begin_cpu_access.
> - */
> -void *dma_buf_kmap(struct dma_buf *dmabuf, unsigned long page_num)
> -{
> -	WARN_ON(!dmabuf);
> -
> -	return dmabuf->ops->kmap(dmabuf, page_num);
> -}
> -EXPORT_SYMBOL_GPL(dma_buf_kmap);
> -
> -/**
> - * dma_buf_kunmap - Unmap a page obtained by dma_buf_kmap.
> - * @dmabuf:	[in]	buffer to unmap page from.
> - * @page_num:	[in]	page in PAGE_SIZE units to unmap.
> - * @vaddr:	[in]	kernel space pointer obtained from dma_buf_kmap.
> - *
> - * This call must always succeed.
> - */
> -void dma_buf_kunmap(struct dma_buf *dmabuf, unsigned long page_num,
> -		    void *vaddr)
> -{
> -	WARN_ON(!dmabuf);
> -
> -	if (dmabuf->ops->kunmap)
> -		dmabuf->ops->kunmap(dmabuf, page_num, vaddr);
> -}
> -EXPORT_SYMBOL_GPL(dma_buf_kunmap);
> -
> -
> -/**
> - * dma_buf_mmap - Setup up a userspace mmap with the given vma
> - * @dmabuf:	[in]	buffer that should back the vma
> - * @vma:	[in]	vma for the mmap
> - * @pgoff:	[in]	offset in pages where this mmap should start within the
> - * 			dma-buf buffer.
> - *
> - * This function adjusts the passed in vma so that it points at the file of the
> - * dma_buf operation. It also adjusts the starting pgoff and does bounds
> - * checking on the size of the vma. Then it calls the exporters mmap function to
> - * set up the mapping.
> - *
> - * Can return negative error values, returns 0 on success.
> - */
> -int dma_buf_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma,
> -		 unsigned long pgoff)
> -{
> -	struct file *oldfile;
> -	int ret;
> -
> -	if (WARN_ON(!dmabuf || !vma))
> -		return -EINVAL;
> -
> -	/* check for offset overflow */
> -	if (pgoff + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) < pgoff)
> -		return -EOVERFLOW;
> -
> -	/* check for overflowing the buffer's size */
> -	if (pgoff + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) >
> -	    dmabuf->size >> PAGE_SHIFT)
> -		return -EINVAL;
> -
> -	/* readjust the vma */
> -	get_file(dmabuf->file);
> -	oldfile = vma->vm_file;
> -	vma->vm_file = dmabuf->file;
> -	vma->vm_pgoff = pgoff;
> -
> -	ret = dmabuf->ops->mmap(dmabuf, vma);
> -	if (ret) {
> -		/* restore old parameters on failure */
> -		vma->vm_file = oldfile;
> -		fput(dmabuf->file);
> -	} else {
> -		if (oldfile)
> -			fput(oldfile);
> -	}
> -	return ret;
> -
> -}
> -EXPORT_SYMBOL_GPL(dma_buf_mmap);
> -
> -/**
> - * dma_buf_vmap - Create virtual mapping for the buffer object into kernel
> - * address space. Same restrictions as for vmap and friends apply.
> - * @dmabuf:	[in]	buffer to vmap
> - *
> - * This call may fail due to lack of virtual mapping address space.
> - * These calls are optional in drivers. The intended use for them
> - * is for mapping objects linear in kernel space for high use objects.
> - * Please attempt to use kmap/kunmap before thinking about these interfaces.
> - *
> - * Returns NULL on error.
> - */
> -void *dma_buf_vmap(struct dma_buf *dmabuf)
> -{
> -	void *ptr;
> -
> -	if (WARN_ON(!dmabuf))
> -		return NULL;
> -
> -	if (!dmabuf->ops->vmap)
> -		return NULL;
> -
> -	mutex_lock(&dmabuf->lock);
> -	if (dmabuf->vmapping_counter) {
> -		dmabuf->vmapping_counter++;
> -		BUG_ON(!dmabuf->vmap_ptr);
> -		ptr = dmabuf->vmap_ptr;
> -		goto out_unlock;
> -	}
> -
> -	BUG_ON(dmabuf->vmap_ptr);
> -
> -	ptr = dmabuf->ops->vmap(dmabuf);
> -	if (WARN_ON_ONCE(IS_ERR(ptr)))
> -		ptr = NULL;
> -	if (!ptr)
> -		goto out_unlock;
> -
> -	dmabuf->vmap_ptr = ptr;
> -	dmabuf->vmapping_counter = 1;
> -
> -out_unlock:
> -	mutex_unlock(&dmabuf->lock);
> -	return ptr;
> -}
> -EXPORT_SYMBOL_GPL(dma_buf_vmap);
> -
> -/**
> - * dma_buf_vunmap - Unmap a vmap obtained by dma_buf_vmap.
> - * @dmabuf:	[in]	buffer to vunmap
> - * @vaddr:	[in]	vmap to vunmap
> - */
> -void dma_buf_vunmap(struct dma_buf *dmabuf, void *vaddr)
> -{
> -	if (WARN_ON(!dmabuf))
> -		return;
> -
> -	BUG_ON(!dmabuf->vmap_ptr);
> -	BUG_ON(dmabuf->vmapping_counter == 0);
> -	BUG_ON(dmabuf->vmap_ptr != vaddr);
> -
> -	mutex_lock(&dmabuf->lock);
> -	if (--dmabuf->vmapping_counter == 0) {
> -		if (dmabuf->ops->vunmap)
> -			dmabuf->ops->vunmap(dmabuf, vaddr);
> -		dmabuf->vmap_ptr = NULL;
> -	}
> -	mutex_unlock(&dmabuf->lock);
> -}
> -EXPORT_SYMBOL_GPL(dma_buf_vunmap);
> -
> -#ifdef CONFIG_DEBUG_FS
> -static int dma_buf_describe(struct seq_file *s)
> -{
> -	int ret;
> -	struct dma_buf *buf_obj;
> -	struct dma_buf_attachment *attach_obj;
> -	int count = 0, attach_count;
> -	size_t size = 0;
> -
> -	ret = mutex_lock_interruptible(&db_list.lock);
> -
> -	if (ret)
> -		return ret;
> -
> -	seq_puts(s, "\nDma-buf Objects:\n");
> -	seq_puts(s, "size\tflags\tmode\tcount\texp_name\n");
> -
> -	list_for_each_entry(buf_obj, &db_list.head, list_node) {
> -		ret = mutex_lock_interruptible(&buf_obj->lock);
> -
> -		if (ret) {
> -			seq_puts(s,
> -				 "\tERROR locking buffer object: skipping\n");
> -			continue;
> -		}
> -
> -		seq_printf(s, "%08zu\t%08x\t%08x\t%08ld\t%s\n",
> -				buf_obj->size,
> -				buf_obj->file->f_flags, buf_obj->file->f_mode,
> -				(long)(buf_obj->file->f_count.counter),
> -				buf_obj->exp_name);
> -
> -		seq_puts(s, "\tAttached Devices:\n");
> -		attach_count = 0;
> -
> -		list_for_each_entry(attach_obj, &buf_obj->attachments, node) {
> -			seq_puts(s, "\t");
> -
> -			seq_printf(s, "%s\n", dev_name(attach_obj->dev));
> -			attach_count++;
> -		}
> -
> -		seq_printf(s, "Total %d devices attached\n\n",
> -				attach_count);
> -
> -		count++;
> -		size += buf_obj->size;
> -		mutex_unlock(&buf_obj->lock);
> -	}
> -
> -	seq_printf(s, "\nTotal %d objects, %zu bytes\n", count, size);
> -
> -	mutex_unlock(&db_list.lock);
> -	return 0;
> -}
> -
> -static int dma_buf_show(struct seq_file *s, void *unused)
> -{
> -	void (*func)(struct seq_file *) = s->private;
> -	func(s);
> -	return 0;
> -}
> -
> -static int dma_buf_debug_open(struct inode *inode, struct file *file)
> -{
> -	return single_open(file, dma_buf_show, inode->i_private);
> -}
> -
> -static const struct file_operations dma_buf_debug_fops = {
> -	.open           = dma_buf_debug_open,
> -	.read           = seq_read,
> -	.llseek         = seq_lseek,
> -	.release        = single_release,
> -};
> -
> -static struct dentry *dma_buf_debugfs_dir;
> -
> -static int dma_buf_init_debugfs(void)
> -{
> -	int err = 0;
> -	dma_buf_debugfs_dir = debugfs_create_dir("dma_buf", NULL);
> -	if (IS_ERR(dma_buf_debugfs_dir)) {
> -		err = PTR_ERR(dma_buf_debugfs_dir);
> -		dma_buf_debugfs_dir = NULL;
> -		return err;
> -	}
> -
> -	err = dma_buf_debugfs_create_file("bufinfo", dma_buf_describe);
> -
> -	if (err)
> -		pr_debug("dma_buf: debugfs: failed to create node bufinfo\n");
> -
> -	return err;
> -}
> -
> -static void dma_buf_uninit_debugfs(void)
> -{
> -	if (dma_buf_debugfs_dir)
> -		debugfs_remove_recursive(dma_buf_debugfs_dir);
> -}
> -
> -int dma_buf_debugfs_create_file(const char *name,
> -				int (*write)(struct seq_file *))
> -{
> -	struct dentry *d;
> -
> -	d = debugfs_create_file(name, S_IRUGO, dma_buf_debugfs_dir,
> -			write, &dma_buf_debug_fops);
> -
> -	return PTR_ERR_OR_ZERO(d);
> -}
> -#else
> -static inline int dma_buf_init_debugfs(void)
> -{
> -	return 0;
> -}
> -static inline void dma_buf_uninit_debugfs(void)
> -{
> -}
> -#endif
> -
> -static int __init dma_buf_init(void)
> -{
> -	mutex_init(&db_list.lock);
> -	INIT_LIST_HEAD(&db_list.head);
> -	dma_buf_init_debugfs();
> -	return 0;
> -}
> -subsys_initcall(dma_buf_init);
> -
> -static void __exit dma_buf_deinit(void)
> -{
> -	dma_buf_uninit_debugfs();
> -}
> -__exitcall(dma_buf_deinit);
> diff --git a/drivers/base/reservation.c b/drivers/base/reservation.c
> deleted file mode 100644
> index a73fbf3b8e56..000000000000
> --- a/drivers/base/reservation.c
> +++ /dev/null
> @@ -1,39 +0,0 @@
> -/*
> - * Copyright (C) 2012-2013 Canonical Ltd
> - *
> - * Based on bo.c which bears the following copyright notice,
> - * but is dual licensed:
> - *
> - * Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., USA
> - * All Rights Reserved.
> - *
> - * Permission is hereby granted, free of charge, to any person obtaining a
> - * copy of this software and associated documentation files (the
> - * "Software"), to deal in the Software without restriction, including
> - * without limitation the rights to use, copy, modify, merge, publish,
> - * distribute, sub license, and/or sell copies of the Software, and to
> - * permit persons to whom the Software is furnished to do so, subject to
> - * the following conditions:
> - *
> - * The above copyright notice and this permission notice (including the
> - * next paragraph) shall be included in all copies or substantial portions
> - * of the Software.
> - *
> - * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
> - * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
> - * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
> - * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
> - * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
> - * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
> - * USE OR OTHER DEALINGS IN THE SOFTWARE.
> - *
> - **************************************************************************/
> -/*
> - * Authors: Thomas Hellstrom <thellstrom-at-vmware-dot-com>
> - */
> -
> -#include <linux/reservation.h>
> -#include <linux/export.h>
> -
> -DEFINE_WW_CLASS(reservation_ww_class);
> -EXPORT_SYMBOL(reservation_ww_class);
> diff --git a/drivers/dma-buf/Makefile b/drivers/dma-buf/Makefile
> new file mode 100644
> index 000000000000..4a4f4c9bacd0
> --- /dev/null
> +++ b/drivers/dma-buf/Makefile
> @@ -0,0 +1 @@
> +obj-y := dma-buf.o reservation.o
> diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c
> new file mode 100644
> index 000000000000..840c7fa80983
> --- /dev/null
> +++ b/drivers/dma-buf/dma-buf.c
> @@ -0,0 +1,743 @@
> +/*
> + * 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/anon_inodes.h>
> +#include <linux/export.h>
> +#include <linux/debugfs.h>
> +#include <linux/seq_file.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);
> +
> +	dmabuf->ops->release(dmabuf);
> +
> +	mutex_lock(&db_list.lock);
> +	list_del(&dmabuf->list_node);
> +	mutex_unlock(&db_list.lock);
> +
> +	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;
> +
> +	/* check for overflowing the buffer's size */
> +	if (vma->vm_pgoff + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) >
> +	    dmabuf->size >> PAGE_SHIFT)
> +		return -EINVAL;
> +
> +	return dmabuf->ops->mmap(dmabuf, vma);
> +}
> +
> +static loff_t dma_buf_llseek(struct file *file, loff_t offset, int whence)
> +{
> +	struct dma_buf *dmabuf;
> +	loff_t base;
> +
> +	if (!is_dma_buf_file(file))
> +		return -EBADF;
> +
> +	dmabuf = file->private_data;
> +
> +	/* only support discovering the end of the buffer,
> +	   but also allow SEEK_SET to maintain the idiomatic
> +	   SEEK_END(0), SEEK_CUR(0) pattern */
> +	if (whence == SEEK_END)
> +		base = dmabuf->size;
> +	else if (whence == SEEK_SET)
> +		base = 0;
> +	else
> +		return -EINVAL;
> +
> +	if (offset != 0)
> +		return -EINVAL;
> +
> +	return base + offset;
> +}
> +
> +static const struct file_operations dma_buf_fops = {
> +	.release	= dma_buf_release,
> +	.mmap		= dma_buf_mmap_internal,
> +	.llseek		= dma_buf_llseek,
> +};
> +
> +/*
> + * is_dma_buf_file - Check if struct file* is associated with dma_buf
> + */
> +static inline int is_dma_buf_file(struct file *file)
> +{
> +	return file->f_op == &dma_buf_fops;
> +}
> +
> +/**
> + * dma_buf_export_named - Creates a new dma_buf, and associates an anon file
> + * with this buffer, so it can be exported.
> + * Also connect the allocator specific data and ops to the buffer.
> + * Additionally, provide a name string for exporter; useful in debugging.
> + *
> + * @priv:	[in]	Attach private data of allocator to this buffer
> + * @ops:	[in]	Attach allocator-defined dma buf ops to the new buffer.
> + * @size:	[in]	Size of the buffer
> + * @flags:	[in]	mode flags for the file.
> + * @exp_name:	[in]	name of the exporting module - useful for debugging.
> + *
> + * Returns, on success, a newly created dma_buf object, which wraps the
> + * supplied private data and operations for dma_buf_ops. On either missing
> + * ops, or error in allocating struct dma_buf, will return negative error.
> + *
> + */
> +struct dma_buf *dma_buf_export_named(void *priv, const struct dma_buf_ops *ops,
> +				size_t size, int flags, const char *exp_name)
> +{
> +	struct dma_buf *dmabuf;
> +	struct file *file;
> +
> +	if (WARN_ON(!priv || !ops
> +			  || !ops->map_dma_buf
> +			  || !ops->unmap_dma_buf
> +			  || !ops->release
> +			  || !ops->kmap_atomic
> +			  || !ops->kmap
> +			  || !ops->mmap)) {
> +		return ERR_PTR(-EINVAL);
> +	}
> +
> +	dmabuf = kzalloc(sizeof(struct dma_buf), GFP_KERNEL);
> +	if (dmabuf == NULL)
> +		return ERR_PTR(-ENOMEM);
> +
> +	dmabuf->priv = priv;
> +	dmabuf->ops = ops;
> +	dmabuf->size = size;
> +	dmabuf->exp_name = exp_name;
> +
> +	file = anon_inode_getfile("dmabuf", &dma_buf_fops, dmabuf, flags);
> +	if (IS_ERR(file)) {
> +		kfree(dmabuf);
> +		return ERR_CAST(file);
> +	}
> +
> +	file->f_mode |= FMODE_LSEEK;
> +	dmabuf->file = file;
> +
> +	mutex_init(&dmabuf->lock);
> +	INIT_LIST_HEAD(&dmabuf->attachments);
> +
> +	mutex_lock(&db_list.lock);
> +	list_add(&dmabuf->list_node, &db_list.head);
> +	mutex_unlock(&db_list.lock);
> +
> +	return dmabuf;
> +}
> +EXPORT_SYMBOL_GPL(dma_buf_export_named);
> +
> +
> +/**
> + * dma_buf_fd - returns a file descriptor for the given dma_buf
> + * @dmabuf:	[in]	pointer to dma_buf for which fd is required.
> + * @flags:      [in]    flags to give to fd
> + *
> + * On success, returns an associated 'fd'. Else, returns error.
> + */
> +int dma_buf_fd(struct dma_buf *dmabuf, int flags)
> +{
> +	int fd;
> +
> +	if (!dmabuf || !dmabuf->file)
> +		return -EINVAL;
> +
> +	fd = get_unused_fd_flags(flags);
> +	if (fd < 0)
> +		return fd;
> +
> +	fd_install(fd, dmabuf->file);
> +
> +	return fd;
> +}
> +EXPORT_SYMBOL_GPL(dma_buf_fd);
> +
> +/**
> + * dma_buf_get - returns the dma_buf structure related to an fd
> + * @fd:	[in]	fd associated with the dma_buf to be returned
> + *
> + * On success, returns the dma_buf structure associated with an fd; uses
> + * file's refcounting done by fget to increase refcount. returns ERR_PTR
> + * otherwise.
> + */
> +struct dma_buf *dma_buf_get(int fd)
> +{
> +	struct file *file;
> +
> +	file = fget(fd);
> +
> +	if (!file)
> +		return ERR_PTR(-EBADF);
> +
> +	if (!is_dma_buf_file(file)) {
> +		fput(file);
> +		return ERR_PTR(-EINVAL);
> +	}
> +
> +	return file->private_data;
> +}
> +EXPORT_SYMBOL_GPL(dma_buf_get);
> +
> +/**
> + * dma_buf_put - decreases refcount of the buffer
> + * @dmabuf:	[in]	buffer to reduce refcount of
> + *
> + * Uses file's refcounting done implicitly by fput()
> + */
> +void dma_buf_put(struct dma_buf *dmabuf)
> +{
> +	if (WARN_ON(!dmabuf || !dmabuf->file))
> +		return;
> +
> +	fput(dmabuf->file);
> +}
> +EXPORT_SYMBOL_GPL(dma_buf_put);
> +
> +/**
> + * dma_buf_attach - Add the device to dma_buf's attachments list; optionally,
> + * calls attach() of dma_buf_ops to allow device-specific attach functionality
> + * @dmabuf:	[in]	buffer to attach device to.
> + * @dev:	[in]	device to be attached.
> + *
> + * Returns struct dma_buf_attachment * for this attachment; returns ERR_PTR on
> + * error.
> + */
> +struct dma_buf_attachment *dma_buf_attach(struct dma_buf *dmabuf,
> +					  struct device *dev)
> +{
> +	struct dma_buf_attachment *attach;
> +	int ret;
> +
> +	if (WARN_ON(!dmabuf || !dev))
> +		return ERR_PTR(-EINVAL);
> +
> +	attach = kzalloc(sizeof(struct dma_buf_attachment), GFP_KERNEL);
> +	if (attach == NULL)
> +		return ERR_PTR(-ENOMEM);
> +
> +	attach->dev = dev;
> +	attach->dmabuf = dmabuf;
> +
> +	mutex_lock(&dmabuf->lock);
> +
> +	if (dmabuf->ops->attach) {
> +		ret = dmabuf->ops->attach(dmabuf, dev, attach);
> +		if (ret)
> +			goto err_attach;
> +	}
> +	list_add(&attach->node, &dmabuf->attachments);
> +
> +	mutex_unlock(&dmabuf->lock);
> +	return attach;
> +
> +err_attach:
> +	kfree(attach);
> +	mutex_unlock(&dmabuf->lock);
> +	return ERR_PTR(ret);
> +}
> +EXPORT_SYMBOL_GPL(dma_buf_attach);
> +
> +/**
> + * dma_buf_detach - Remove the given attachment from dmabuf's attachments list;
> + * optionally calls detach() of dma_buf_ops for device-specific detach
> + * @dmabuf:	[in]	buffer to detach from.
> + * @attach:	[in]	attachment to be detached; is free'd after this call.
> + *
> + */
> +void dma_buf_detach(struct dma_buf *dmabuf, struct dma_buf_attachment *attach)
> +{
> +	if (WARN_ON(!dmabuf || !attach))
> +		return;
> +
> +	mutex_lock(&dmabuf->lock);
> +	list_del(&attach->node);
> +	if (dmabuf->ops->detach)
> +		dmabuf->ops->detach(dmabuf, attach);
> +
> +	mutex_unlock(&dmabuf->lock);
> +	kfree(attach);
> +}
> +EXPORT_SYMBOL_GPL(dma_buf_detach);
> +
> +/**
> + * dma_buf_map_attachment - Returns the scatterlist table of the attachment;
> + * mapped into _device_ address space. Is a wrapper for map_dma_buf() of the
> + * dma_buf_ops.
> + * @attach:	[in]	attachment whose scatterlist is to be returned
> + * @direction:	[in]	direction of DMA transfer
> + *
> + * Returns sg_table containing the scatterlist to be returned; returns ERR_PTR
> + * on error.
> + */
> +struct sg_table *dma_buf_map_attachment(struct dma_buf_attachment *attach,
> +					enum dma_data_direction direction)
> +{
> +	struct sg_table *sg_table = ERR_PTR(-EINVAL);
> +
> +	might_sleep();
> +
> +	if (WARN_ON(!attach || !attach->dmabuf))
> +		return ERR_PTR(-EINVAL);
> +
> +	sg_table = attach->dmabuf->ops->map_dma_buf(attach, direction);
> +	if (!sg_table)
> +		sg_table = ERR_PTR(-ENOMEM);
> +
> +	return sg_table;
> +}
> +EXPORT_SYMBOL_GPL(dma_buf_map_attachment);
> +
> +/**
> + * dma_buf_unmap_attachment - unmaps and decreases usecount of the buffer;might
> + * deallocate the scatterlist associated. Is a wrapper for unmap_dma_buf() of
> + * dma_buf_ops.
> + * @attach:	[in]	attachment to unmap buffer from
> + * @sg_table:	[in]	scatterlist info of the buffer to unmap
> + * @direction:  [in]    direction of DMA transfer
> + *
> + */
> +void dma_buf_unmap_attachment(struct dma_buf_attachment *attach,
> +				struct sg_table *sg_table,
> +				enum dma_data_direction direction)
> +{
> +	might_sleep();
> +
> +	if (WARN_ON(!attach || !attach->dmabuf || !sg_table))
> +		return;
> +
> +	attach->dmabuf->ops->unmap_dma_buf(attach, sg_table,
> +						direction);
> +}
> +EXPORT_SYMBOL_GPL(dma_buf_unmap_attachment);
> +
> +
> +/**
> + * dma_buf_begin_cpu_access - Must be called before accessing a dma_buf from the
> + * cpu in the kernel context. Calls begin_cpu_access to allow exporter-specific
> + * preparations. Coherency is only guaranteed in the specified range for the
> + * specified access direction.
> + * @dmabuf:	[in]	buffer to prepare cpu access for.
> + * @start:	[in]	start of range for cpu access.
> + * @len:	[in]	length of range for cpu access.
> + * @direction:	[in]	length of range for cpu access.
> + *
> + * Can return negative error values, returns 0 on success.
> + */
> +int dma_buf_begin_cpu_access(struct dma_buf *dmabuf, size_t start, size_t len,
> +			     enum dma_data_direction direction)
> +{
> +	int ret = 0;
> +
> +	if (WARN_ON(!dmabuf))
> +		return -EINVAL;
> +
> +	if (dmabuf->ops->begin_cpu_access)
> +		ret = dmabuf->ops->begin_cpu_access(dmabuf, start, len, direction);
> +
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(dma_buf_begin_cpu_access);
> +
> +/**
> + * dma_buf_end_cpu_access - Must be called after accessing a dma_buf from the
> + * cpu in the kernel context. Calls end_cpu_access to allow exporter-specific
> + * actions. Coherency is only guaranteed in the specified range for the
> + * specified access direction.
> + * @dmabuf:	[in]	buffer to complete cpu access for.
> + * @start:	[in]	start of range for cpu access.
> + * @len:	[in]	length of range for cpu access.
> + * @direction:	[in]	length of range for cpu access.
> + *
> + * This call must always succeed.
> + */
> +void dma_buf_end_cpu_access(struct dma_buf *dmabuf, size_t start, size_t len,
> +			    enum dma_data_direction direction)
> +{
> +	WARN_ON(!dmabuf);
> +
> +	if (dmabuf->ops->end_cpu_access)
> +		dmabuf->ops->end_cpu_access(dmabuf, start, len, direction);
> +}
> +EXPORT_SYMBOL_GPL(dma_buf_end_cpu_access);
> +
> +/**
> + * dma_buf_kmap_atomic - Map a page of the buffer object into kernel address
> + * space. The same restrictions as for kmap_atomic and friends apply.
> + * @dmabuf:	[in]	buffer to map page from.
> + * @page_num:	[in]	page in PAGE_SIZE units to map.
> + *
> + * This call must always succeed, any necessary preparations that might fail
> + * need to be done in begin_cpu_access.
> + */
> +void *dma_buf_kmap_atomic(struct dma_buf *dmabuf, unsigned long page_num)
> +{
> +	WARN_ON(!dmabuf);
> +
> +	return dmabuf->ops->kmap_atomic(dmabuf, page_num);
> +}
> +EXPORT_SYMBOL_GPL(dma_buf_kmap_atomic);
> +
> +/**
> + * dma_buf_kunmap_atomic - Unmap a page obtained by dma_buf_kmap_atomic.
> + * @dmabuf:	[in]	buffer to unmap page from.
> + * @page_num:	[in]	page in PAGE_SIZE units to unmap.
> + * @vaddr:	[in]	kernel space pointer obtained from dma_buf_kmap_atomic.
> + *
> + * This call must always succeed.
> + */
> +void dma_buf_kunmap_atomic(struct dma_buf *dmabuf, unsigned long page_num,
> +			   void *vaddr)
> +{
> +	WARN_ON(!dmabuf);
> +
> +	if (dmabuf->ops->kunmap_atomic)
> +		dmabuf->ops->kunmap_atomic(dmabuf, page_num, vaddr);
> +}
> +EXPORT_SYMBOL_GPL(dma_buf_kunmap_atomic);
> +
> +/**
> + * dma_buf_kmap - Map a page of the buffer object into kernel address space. The
> + * same restrictions as for kmap and friends apply.
> + * @dmabuf:	[in]	buffer to map page from.
> + * @page_num:	[in]	page in PAGE_SIZE units to map.
> + *
> + * This call must always succeed, any necessary preparations that might fail
> + * need to be done in begin_cpu_access.
> + */
> +void *dma_buf_kmap(struct dma_buf *dmabuf, unsigned long page_num)
> +{
> +	WARN_ON(!dmabuf);
> +
> +	return dmabuf->ops->kmap(dmabuf, page_num);
> +}
> +EXPORT_SYMBOL_GPL(dma_buf_kmap);
> +
> +/**
> + * dma_buf_kunmap - Unmap a page obtained by dma_buf_kmap.
> + * @dmabuf:	[in]	buffer to unmap page from.
> + * @page_num:	[in]	page in PAGE_SIZE units to unmap.
> + * @vaddr:	[in]	kernel space pointer obtained from dma_buf_kmap.
> + *
> + * This call must always succeed.
> + */
> +void dma_buf_kunmap(struct dma_buf *dmabuf, unsigned long page_num,
> +		    void *vaddr)
> +{
> +	WARN_ON(!dmabuf);
> +
> +	if (dmabuf->ops->kunmap)
> +		dmabuf->ops->kunmap(dmabuf, page_num, vaddr);
> +}
> +EXPORT_SYMBOL_GPL(dma_buf_kunmap);
> +
> +
> +/**
> + * dma_buf_mmap - Setup up a userspace mmap with the given vma
> + * @dmabuf:	[in]	buffer that should back the vma
> + * @vma:	[in]	vma for the mmap
> + * @pgoff:	[in]	offset in pages where this mmap should start within the
> + * 			dma-buf buffer.
> + *
> + * This function adjusts the passed in vma so that it points at the file of the
> + * dma_buf operation. It also adjusts the starting pgoff and does bounds
> + * checking on the size of the vma. Then it calls the exporters mmap function to
> + * set up the mapping.
> + *
> + * Can return negative error values, returns 0 on success.
> + */
> +int dma_buf_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma,
> +		 unsigned long pgoff)
> +{
> +	struct file *oldfile;
> +	int ret;
> +
> +	if (WARN_ON(!dmabuf || !vma))
> +		return -EINVAL;
> +
> +	/* check for offset overflow */
> +	if (pgoff + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) < pgoff)
> +		return -EOVERFLOW;
> +
> +	/* check for overflowing the buffer's size */
> +	if (pgoff + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) >
> +	    dmabuf->size >> PAGE_SHIFT)
> +		return -EINVAL;
> +
> +	/* readjust the vma */
> +	get_file(dmabuf->file);
> +	oldfile = vma->vm_file;
> +	vma->vm_file = dmabuf->file;
> +	vma->vm_pgoff = pgoff;
> +
> +	ret = dmabuf->ops->mmap(dmabuf, vma);
> +	if (ret) {
> +		/* restore old parameters on failure */
> +		vma->vm_file = oldfile;
> +		fput(dmabuf->file);
> +	} else {
> +		if (oldfile)
> +			fput(oldfile);
> +	}
> +	return ret;
> +
> +}
> +EXPORT_SYMBOL_GPL(dma_buf_mmap);
> +
> +/**
> + * dma_buf_vmap - Create virtual mapping for the buffer object into kernel
> + * address space. Same restrictions as for vmap and friends apply.
> + * @dmabuf:	[in]	buffer to vmap
> + *
> + * This call may fail due to lack of virtual mapping address space.
> + * These calls are optional in drivers. The intended use for them
> + * is for mapping objects linear in kernel space for high use objects.
> + * Please attempt to use kmap/kunmap before thinking about these interfaces.
> + *
> + * Returns NULL on error.
> + */
> +void *dma_buf_vmap(struct dma_buf *dmabuf)
> +{
> +	void *ptr;
> +
> +	if (WARN_ON(!dmabuf))
> +		return NULL;
> +
> +	if (!dmabuf->ops->vmap)
> +		return NULL;
> +
> +	mutex_lock(&dmabuf->lock);
> +	if (dmabuf->vmapping_counter) {
> +		dmabuf->vmapping_counter++;
> +		BUG_ON(!dmabuf->vmap_ptr);
> +		ptr = dmabuf->vmap_ptr;
> +		goto out_unlock;
> +	}
> +
> +	BUG_ON(dmabuf->vmap_ptr);
> +
> +	ptr = dmabuf->ops->vmap(dmabuf);
> +	if (WARN_ON_ONCE(IS_ERR(ptr)))
> +		ptr = NULL;
> +	if (!ptr)
> +		goto out_unlock;
> +
> +	dmabuf->vmap_ptr = ptr;
> +	dmabuf->vmapping_counter = 1;
> +
> +out_unlock:
> +	mutex_unlock(&dmabuf->lock);
> +	return ptr;
> +}
> +EXPORT_SYMBOL_GPL(dma_buf_vmap);
> +
> +/**
> + * dma_buf_vunmap - Unmap a vmap obtained by dma_buf_vmap.
> + * @dmabuf:	[in]	buffer to vunmap
> + * @vaddr:	[in]	vmap to vunmap
> + */
> +void dma_buf_vunmap(struct dma_buf *dmabuf, void *vaddr)
> +{
> +	if (WARN_ON(!dmabuf))
> +		return;
> +
> +	BUG_ON(!dmabuf->vmap_ptr);
> +	BUG_ON(dmabuf->vmapping_counter == 0);
> +	BUG_ON(dmabuf->vmap_ptr != vaddr);
> +
> +	mutex_lock(&dmabuf->lock);
> +	if (--dmabuf->vmapping_counter == 0) {
> +		if (dmabuf->ops->vunmap)
> +			dmabuf->ops->vunmap(dmabuf, vaddr);
> +		dmabuf->vmap_ptr = NULL;
> +	}
> +	mutex_unlock(&dmabuf->lock);
> +}
> +EXPORT_SYMBOL_GPL(dma_buf_vunmap);
> +
> +#ifdef CONFIG_DEBUG_FS
> +static int dma_buf_describe(struct seq_file *s)
> +{
> +	int ret;
> +	struct dma_buf *buf_obj;
> +	struct dma_buf_attachment *attach_obj;
> +	int count = 0, attach_count;
> +	size_t size = 0;
> +
> +	ret = mutex_lock_interruptible(&db_list.lock);
> +
> +	if (ret)
> +		return ret;
> +
> +	seq_puts(s, "\nDma-buf Objects:\n");
> +	seq_puts(s, "size\tflags\tmode\tcount\texp_name\n");
> +
> +	list_for_each_entry(buf_obj, &db_list.head, list_node) {
> +		ret = mutex_lock_interruptible(&buf_obj->lock);
> +
> +		if (ret) {
> +			seq_puts(s,
> +				 "\tERROR locking buffer object: skipping\n");
> +			continue;
> +		}
> +
> +		seq_printf(s, "%08zu\t%08x\t%08x\t%08ld\t%s\n",
> +				buf_obj->size,
> +				buf_obj->file->f_flags, buf_obj->file->f_mode,
> +				(long)(buf_obj->file->f_count.counter),
> +				buf_obj->exp_name);
> +
> +		seq_puts(s, "\tAttached Devices:\n");
> +		attach_count = 0;
> +
> +		list_for_each_entry(attach_obj, &buf_obj->attachments, node) {
> +			seq_puts(s, "\t");
> +
> +			seq_printf(s, "%s\n", dev_name(attach_obj->dev));
> +			attach_count++;
> +		}
> +
> +		seq_printf(s, "Total %d devices attached\n\n",
> +				attach_count);
> +
> +		count++;
> +		size += buf_obj->size;
> +		mutex_unlock(&buf_obj->lock);
> +	}
> +
> +	seq_printf(s, "\nTotal %d objects, %zu bytes\n", count, size);
> +
> +	mutex_unlock(&db_list.lock);
> +	return 0;
> +}
> +
> +static int dma_buf_show(struct seq_file *s, void *unused)
> +{
> +	void (*func)(struct seq_file *) = s->private;
> +	func(s);
> +	return 0;
> +}
> +
> +static int dma_buf_debug_open(struct inode *inode, struct file *file)
> +{
> +	return single_open(file, dma_buf_show, inode->i_private);
> +}
> +
> +static const struct file_operations dma_buf_debug_fops = {
> +	.open           = dma_buf_debug_open,
> +	.read           = seq_read,
> +	.llseek         = seq_lseek,
> +	.release        = single_release,
> +};
> +
> +static struct dentry *dma_buf_debugfs_dir;
> +
> +static int dma_buf_init_debugfs(void)
> +{
> +	int err = 0;
> +	dma_buf_debugfs_dir = debugfs_create_dir("dma_buf", NULL);
> +	if (IS_ERR(dma_buf_debugfs_dir)) {
> +		err = PTR_ERR(dma_buf_debugfs_dir);
> +		dma_buf_debugfs_dir = NULL;
> +		return err;
> +	}
> +
> +	err = dma_buf_debugfs_create_file("bufinfo", dma_buf_describe);
> +
> +	if (err)
> +		pr_debug("dma_buf: debugfs: failed to create node bufinfo\n");
> +
> +	return err;
> +}
> +
> +static void dma_buf_uninit_debugfs(void)
> +{
> +	if (dma_buf_debugfs_dir)
> +		debugfs_remove_recursive(dma_buf_debugfs_dir);
> +}
> +
> +int dma_buf_debugfs_create_file(const char *name,
> +				int (*write)(struct seq_file *))
> +{
> +	struct dentry *d;
> +
> +	d = debugfs_create_file(name, S_IRUGO, dma_buf_debugfs_dir,
> +			write, &dma_buf_debug_fops);
> +
> +	return PTR_ERR_OR_ZERO(d);
> +}
> +#else
> +static inline int dma_buf_init_debugfs(void)
> +{
> +	return 0;
> +}
> +static inline void dma_buf_uninit_debugfs(void)
> +{
> +}
> +#endif
> +
> +static int __init dma_buf_init(void)
> +{
> +	mutex_init(&db_list.lock);
> +	INIT_LIST_HEAD(&db_list.head);
> +	dma_buf_init_debugfs();
> +	return 0;
> +}
> +subsys_initcall(dma_buf_init);
> +
> +static void __exit dma_buf_deinit(void)
> +{
> +	dma_buf_uninit_debugfs();
> +}
> +__exitcall(dma_buf_deinit);
> diff --git a/drivers/dma-buf/reservation.c b/drivers/dma-buf/reservation.c
> new file mode 100644
> index 000000000000..a73fbf3b8e56
> --- /dev/null
> +++ b/drivers/dma-buf/reservation.c
> @@ -0,0 +1,39 @@
> +/*
> + * Copyright (C) 2012-2013 Canonical Ltd
> + *
> + * Based on bo.c which bears the following copyright notice,
> + * but is dual licensed:
> + *
> + * Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., USA
> + * All Rights Reserved.
> + *
> + * Permission is hereby granted, free of charge, to any person obtaining a
> + * copy of this software and associated documentation files (the
> + * "Software"), to deal in the Software without restriction, including
> + * without limitation the rights to use, copy, modify, merge, publish,
> + * distribute, sub license, and/or sell copies of the Software, and to
> + * permit persons to whom the Software is furnished to do so, subject to
> + * the following conditions:
> + *
> + * The above copyright notice and this permission notice (including the
> + * next paragraph) shall be included in all copies or substantial portions
> + * of the Software.
> + *
> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
> + * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
> + * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
> + * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
> + * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
> + * USE OR OTHER DEALINGS IN THE SOFTWARE.
> + *
> + **************************************************************************/
> +/*
> + * Authors: Thomas Hellstrom <thellstrom-at-vmware-dot-com>
> + */
> +
> +#include <linux/reservation.h>
> +#include <linux/export.h>
> +
> +DEFINE_WW_CLASS(reservation_ww_class);
> +EXPORT_SYMBOL(reservation_ww_class);
> 
> --
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