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Commit 9f90381b authored by Rohit kumar's avatar Rohit kumar Committed by Greg Kroah-Hartman
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staging/ion: Add support to get ion handle from dma buf 



Currently we can only import dma buf fd's to get ion_handle.
Adding support to import dma buf handles to support kernel
specific use cases.

An example use case is in linux platforms such as Tizen, in which
DRM-GEM is used for buffer management for graphics. It has gem_handle
corresponding to a buffer and uses gem_name for sharing the buffer
with other processes. However,it also uses dma_buf fd for 3d operations.
For wayland, there are multiple calls for gem_handle to dma_buf fd
conversion. So, we store dma_buf associated with buffer. But, there is
no api for getting ion_handle from dma_buf. This patch exposes api to
retrieve the ion handle from dma_buf for similar use cases. With this
patch, we can integrate ION within DRM-GEM for buffer management and
dma_buf sharing.

Signed-off-by: default avatarRohit kumar <rohit.kr@samsung.com>
Reviewed-by: default avatarLaura Abbott <labbott@redhat.com>
Reviewed-by: default avatarSumit Semwal <sumit.semwal@linaro.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 323de43f

drivers/staging/android/ion/ion.c

+18 −8
Original line number Diff line number Diff line
@@ -1153,22 +1153,18 @@ int ion_share_dma_buf_fd(struct ion_client *client, struct ion_handle *handle) 
}

EXPORT_SYMBOL(ion_share_dma_buf_fd);



struct ion_handle *ion_import_dma_buf(struct ion_client *client, int fd)

struct ion_handle *ion_import_dma_buf(struct ion_client *client,

				      struct dma_buf *dmabuf)

{

	struct dma_buf *dmabuf;

	struct ion_buffer *buffer;

	struct ion_handle *handle;

	int ret;



	dmabuf = dma_buf_get(fd);

	if (IS_ERR(dmabuf))

		return ERR_CAST(dmabuf);

	/* if this memory came from ion */



	if (dmabuf->ops != &dma_buf_ops) {

		pr_err("%s: can not import dmabuf from another exporter\n",

		       __func__);

		dma_buf_put(dmabuf);

		return ERR_PTR(-EINVAL);

	}

	buffer = dmabuf->priv;
@@ -1196,11 +1192,25 @@ struct ion_handle *ion_import_dma_buf(struct ion_client *client, int fd) 
	}



end:

	dma_buf_put(dmabuf);

	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;
@@ -1308,7 +1318,7 @@ static long ion_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) 
	{

		struct ion_handle *handle;



		handle = ion_import_dma_buf(client, data.fd.fd);

		handle = ion_import_dma_buf_fd(client, data.fd.fd);

		if (IS_ERR(handle))

			ret = PTR_ERR(handle);

		else

drivers/staging/android/ion/ion.h

+16 −4
Original line number Diff line number Diff line
@@ -192,14 +192,26 @@ struct dma_buf *ion_share_dma_buf(struct ion_client *client, 
int ion_share_dma_buf_fd(struct ion_client *client, struct ion_handle *handle);



/**

 * ion_import_dma_buf() - given an dma-buf fd from the ion exporter get handle

 * ion_import_dma_buf() - get ion_handle from dma-buf

 * @client:	the client

 * @dmabuf:	the dma-buf

 *

 * Get the ion_buffer associated with the dma-buf and return the ion_handle.

 * If no ion_handle exists for this buffer, return newly created ion_handle.

 * If dma-buf from another exporter is passed, return ERR_PTR(-EINVAL)

 */

struct ion_handle *ion_import_dma_buf(struct ion_client *client,

				      struct dma_buf *dmabuf);



/**

 * ion_import_dma_buf_fd() - given a dma-buf fd from the ion exporter get handle

 * @client:	the client

 * @fd:		the dma-buf fd

 *

 * Given an dma-buf fd that was allocated through ion via ion_share_dma_buf,

 * Given an dma-buf fd that was allocated through ion via ion_share_dma_buf_fd,

 * import that fd and return a handle representing it. If a dma-buf from

 * another exporter is passed in this function will return ERR_PTR(-EINVAL)

 */

struct ion_handle *ion_import_dma_buf(struct ion_client *client, int fd);

struct ion_handle *ion_import_dma_buf_fd(struct ion_client *client, int fd);



#endif /* _LINUX_ION_H */