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SubjectRe: [RFC][PATCH 1/2] dma-buf: add importer private data to attachment
Op 31-05-13 10:54, Seung-Woo Kim schreef:
> dma-buf attachment has only exporter private data, but importer private data
> can be useful for importer especially to re-import the same dma-buf.
> To use importer private data in attachment of the device, the function to
> search attachment in the attachment list of dma-buf is also added.
>
> Signed-off-by: Seung-Woo Kim <sw0312.kim@samsung.com>
> ---
> drivers/base/dma-buf.c | 31 +++++++++++++++++++++++++++++++
> include/linux/dma-buf.h | 4 ++++
> 2 files changed, 35 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/base/dma-buf.c b/drivers/base/dma-buf.c
> index 08fe897..a1eaaf2 100644
> --- a/drivers/base/dma-buf.c
> +++ b/drivers/base/dma-buf.c
> @@ -259,6 +259,37 @@ err_attach:
> EXPORT_SYMBOL_GPL(dma_buf_attach);
>
> /**
> + * dma_buf_get_attachment - Get attachment with the device from dma_buf's
> + * attachments list
> + * @dmabuf: [in] buffer to find device from.
> + * @dev: [in] device to be found.
> + *
> + * Returns struct dma_buf_attachment * attaching the device; may return
> + * negative error codes.
> + *
> + */
> +struct dma_buf_attachment *dma_buf_get_attachment(struct dma_buf *dmabuf,
> + struct device *dev)
> +{
> + struct dma_buf_attachment *attach;
> +
> + if (WARN_ON(!dmabuf || !dev))
> + return ERR_PTR(-EINVAL);
> +
> + mutex_lock(&dmabuf->lock);
> + list_for_each_entry(attach, &dmabuf->attachments, node) {
> + if (attach->dev == dev) {
> + mutex_unlock(&dmabuf->lock);
> + return attach;
> + }
> + }
> + mutex_unlock(&dmabuf->lock);
> +
> + return ERR_PTR(-ENODEV);
> +}
> +EXPORT_SYMBOL_GPL(dma_buf_get_attachment);
NAK in any form..

Spot the race condition between dma_buf_get_attachment and dma_buf_attach....

~Maarten



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