Commit d8fbe341 authored by Sumit Semwal's avatar Sumit Semwal
Browse files

dma-buf: cleanup dma_buf_export() to make it easily extensible 



At present, dma_buf_export() takes a series of parameters, which
makes it difficult to add any new parameters for exporters, if required.

Make it simpler by moving all these parameters into a struct, and pass
the struct * as parameter to dma_buf_export().

While at it, unite dma_buf_export_named() with dma_buf_export(), and
change all callers accordingly.

Reviewed-by: default avatarMaarten Lankhorst <maarten.lankhorst@canonical.com>
Reviewed-by: default avatarDaniel Thompson <daniel.thompson@linaro.org>
Acked-by: default avatarMauro Carvalho Chehab <mchehab@osg.samsung.com>
Acked-by: default avatarDave Airlie <airlied@redhat.com>
Signed-off-by: default avatarSumit Semwal <sumit.semwal@linaro.org>
parent 646da631

Documentation/dma-buf-sharing.txt

+12 −11
Original line number Diff line number Diff line
@@ -49,25 +49,26 @@ The dma_buf buffer sharing API usage contains the following steps: 
   The buffer exporter announces its wish to export a buffer. In this, it

   connects its own private buffer data, provides implementation for operations

   that can be performed on the exported dma_buf, and flags for the file

   associated with this buffer.

   associated with this buffer. All these fields are filled in struct

   dma_buf_export_info, defined via the DEFINE_DMA_BUF_EXPORT_INFO macro.



   Interface:

      struct dma_buf *dma_buf_export_named(void *priv, struct dma_buf_ops *ops,

				     size_t size, int flags,

				     const char *exp_name)

      DEFINE_DMA_BUF_EXPORT_INFO(exp_info)

      struct dma_buf *dma_buf_export(struct dma_buf_export_info *exp_info)



   If this succeeds, dma_buf_export_named allocates a dma_buf structure, and

   If this succeeds, dma_buf_export allocates a dma_buf structure, and

   returns a pointer to the same. It also associates an anonymous file with this

   buffer, so it can be exported. On failure to allocate the dma_buf object,

   it returns NULL.



   'exp_name' is the name of exporter - to facilitate information while

   debugging.

   'exp_name' in struct dma_buf_export_info is the name of exporter - to

   facilitate information while debugging. It is set to KBUILD_MODNAME by

   default, so exporters don't have to provide a specific name, if they don't

   wish to.



   DEFINE_DMA_BUF_EXPORT_INFO macro defines the struct dma_buf_export_info,

   zeroes it out and pre-populates exp_name in it.



   Exporting modules which do not wish to provide any specific name may use the

   helper define 'dma_buf_export()', with the same arguments as above, but

   without the last argument; a KBUILD_MODNAME pre-processor directive will be

   inserted in place of 'exp_name' instead.



2. Userspace gets a handle to pass around to potential buffer-users

drivers/dma-buf/dma-buf.c

+22 −25
Original line number Diff line number Diff line
@@ -265,43 +265,40 @@ static inline int is_dma_buf_file(struct file *file) 
}



/**

 * dma_buf_export_named - Creates a new dma_buf, and associates an anon file

 * dma_buf_export - 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.

 * @resv:	[in]	reservation-object, NULL to allocate default one.

 * @exp_info:	[in]	holds all the export related information provided

 *			by the exporter. see struct dma_buf_export_info

 *			for further details.

 *

 * 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 reservation_object *resv)

struct dma_buf *dma_buf_export(const struct dma_buf_export_info *exp_info)

{

	struct dma_buf *dmabuf;

	struct reservation_object *resv = exp_info->resv;

	struct file *file;

	size_t alloc_size = sizeof(struct dma_buf);

	if (!resv)

	if (!exp_info->resv)

		alloc_size += sizeof(struct reservation_object);

	else

		/* prevent &dma_buf[1] == dma_buf->resv */

		alloc_size += 1;



	if (WARN_ON(!priv || !ops

			  || !ops->map_dma_buf

			  || !ops->unmap_dma_buf

			  || !ops->release

			  || !ops->kmap_atomic

			  || !ops->kmap

			  || !ops->mmap)) {

	if (WARN_ON(!exp_info->priv

			  || !exp_info->ops

			  || !exp_info->ops->map_dma_buf

			  || !exp_info->ops->unmap_dma_buf

			  || !exp_info->ops->release

			  || !exp_info->ops->kmap_atomic

			  || !exp_info->ops->kmap

			  || !exp_info->ops->mmap)) {

		return ERR_PTR(-EINVAL);

	}
@@ -309,10 +306,10 @@ struct dma_buf *dma_buf_export_named(void *priv, const struct dma_buf_ops *ops, 
	if (dmabuf == NULL)

		return ERR_PTR(-ENOMEM);



	dmabuf->priv = priv;

	dmabuf->ops = ops;

	dmabuf->size = size;

	dmabuf->exp_name = exp_name;

	dmabuf->priv = exp_info->priv;

	dmabuf->ops = exp_info->ops;

	dmabuf->size = exp_info->size;

	dmabuf->exp_name = exp_info->exp_name;

	init_waitqueue_head(&dmabuf->poll);

	dmabuf->cb_excl.poll = dmabuf->cb_shared.poll = &dmabuf->poll;

	dmabuf->cb_excl.active = dmabuf->cb_shared.active = 0;
@@ -323,7 +320,8 @@ struct dma_buf *dma_buf_export_named(void *priv, const struct dma_buf_ops *ops, 
	}

	dmabuf->resv = resv;



	file = anon_inode_getfile("dmabuf", &dma_buf_fops, dmabuf, flags);

	file = anon_inode_getfile("dmabuf", &dma_buf_fops, dmabuf,

					exp_info->flags);

	if (IS_ERR(file)) {

		kfree(dmabuf);

		return ERR_CAST(file);
@@ -341,8 +339,7 @@ struct dma_buf *dma_buf_export_named(void *priv, const struct dma_buf_ops *ops, 


	return dmabuf;

}

EXPORT_SYMBOL_GPL(dma_buf_export_named);



EXPORT_SYMBOL_GPL(dma_buf_export);



/**

 * dma_buf_fd - returns a file descriptor for the given dma_buf

drivers/gpu/drm/armada/armada_gem.c

+8 −2
Original line number Diff line number Diff line
@@ -538,8 +538,14 @@ struct dma_buf * 
armada_gem_prime_export(struct drm_device *dev, struct drm_gem_object *obj,

	int flags)

{

	return dma_buf_export(obj, &armada_gem_prime_dmabuf_ops, obj->size,

			      O_RDWR, NULL);

	DEFINE_DMA_BUF_EXPORT_INFO(exp_info);



	exp_info.ops = &armada_gem_prime_dmabuf_ops;

	exp_info.size = obj->size;

	exp_info.flags = O_RDWR;

	exp_info.priv = obj;



	return dma_buf_export(&exp_info);

}



struct drm_gem_object *

drivers/gpu/drm/drm_prime.c

+8 −4
Original line number Diff line number Diff line
@@ -339,13 +339,17 @@ static const struct dma_buf_ops drm_gem_prime_dmabuf_ops = { 
struct dma_buf *drm_gem_prime_export(struct drm_device *dev,

				     struct drm_gem_object *obj, int flags)

{

	struct reservation_object *robj = NULL;

	DEFINE_DMA_BUF_EXPORT_INFO(exp_info);



	exp_info.ops = &drm_gem_prime_dmabuf_ops;

	exp_info.size = obj->size;

	exp_info.flags = flags;

	exp_info.priv = obj;



	if (dev->driver->gem_prime_res_obj)

		robj = dev->driver->gem_prime_res_obj(obj);

		exp_info.resv = dev->driver->gem_prime_res_obj(obj);



	return dma_buf_export(obj, &drm_gem_prime_dmabuf_ops, obj->size,

			      flags, robj);

	return dma_buf_export(&exp_info);

}

EXPORT_SYMBOL(drm_gem_prime_export);

drivers/gpu/drm/exynos/exynos_drm_dmabuf.c

+7 −2
Original line number Diff line number Diff line
@@ -185,9 +185,14 @@ struct dma_buf *exynos_dmabuf_prime_export(struct drm_device *drm_dev, 
				struct drm_gem_object *obj, int flags)

{

	struct exynos_drm_gem_obj *exynos_gem_obj = to_exynos_gem_obj(obj);

	DEFINE_DMA_BUF_EXPORT_INFO(exp_info);



	return dma_buf_export(obj, &exynos_dmabuf_ops,

				exynos_gem_obj->base.size, flags, NULL);

	exp_info.ops = &exynos_dmabuf_ops;

	exp_info.size = exynos_gem_obj->base.size;

	exp_info.flags = flags;

	exp_info.priv = obj;



	return dma_buf_export(&exp_info);

}



struct drm_gem_object *exynos_dmabuf_prime_import(struct drm_device *drm_dev,

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