Kindly review the patch. Patchv2 had refcount issue which is fixed here.
On Tue, 12 Jan 2016 09:31:46 +0530
Rohit kumar <rohit...@samsung.com> wrote:
> 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: Rohit kumar <rohit...@samsung.com>
> ---
> v2: Updated commit message with use case explanation, as suggested by
> Laura Abbott<labb...@redhat.com>
> v3: Fixed dmabuf refcount issue in ion_import_dma_buf. dma_buf_put()
> was being called without dma_buf_get(), so moving it to
> ion_import_dma_buf_fd().
>
> drivers/staging/android/ion/ion.c | 26 ++++++++++++++++++--------
> drivers/staging/android/ion/ion.h | 20 ++++++++++++++++----
> 2 files changed, 34 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/staging/android/ion/ion.c
> b/drivers/staging/android/ion/ion.c index e237e9f..7e86e18 100644
> --- a/drivers/staging/android/ion/ion.c
> +++ b/drivers/staging/android/ion/ion.c
> @@ -1151,22 +1151,18 @@ 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;
> @@ -1194,11 +1190,25 @@ 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;
> @@ -1306,7 +1316,7 @@ 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
> diff --git a/drivers/staging/android/ion/ion.h
> b/drivers/staging/android/ion/ion.h index b860c5f..a1331fc 100644
> --- a/drivers/staging/android/ion/ion.h
> +++ b/drivers/staging/android/ion/ion.h
> @@ -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,
> - * import that fd and return a handle representing it. If a dma-buf
> from
> + * 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 */
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