linux-kernel - Re: [PATCH v3 1/3] udmabuf: add documentation

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Message-ID: <4d4ffe16-f46d-5dda-68b6-38f59e228214@infradead.org>
Date:   Wed, 12 Sep 2018 09:40:37 -0700
From:   Randy Dunlap <rdunlap@...radead.org>
To:     Gerd Hoffmann <kraxel@...hat.com>, dri-devel@...ts.freedesktop.org
Cc:     laurent.pinchart@...asonboard.com, daniel@...ll.ch,
        Sumit Semwal <sumit.semwal@...aro.org>,
        Jonathan Corbet <corbet@....net>,
        "open list:DMA BUFFER SHARING FRAMEWORK" 
        <linux-media@...r.kernel.org>,
        "moderated list:DMA BUFFER SHARING FRAMEWORK" 
        <linaro-mm-sig@...ts.linaro.org>,
        "open list:DOCUMENTATION" <linux-doc@...r.kernel.org>,
        open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v3 1/3] udmabuf: add documentation

Hi Gerd,

Missed one from yesterday:

On 9/11/18 11:33 PM, Gerd Hoffmann wrote:
> Signed-off-by: Gerd Hoffmann <kraxel@...hat.com>
> ---
>  include/uapi/linux/udmabuf.h         | 51 +++++++++++++++++++++++++++++++++---
>  Documentation/driver-api/dma-buf.rst |  8 ++++++
>  2 files changed, 56 insertions(+), 3 deletions(-)
> 
> diff --git a/include/uapi/linux/udmabuf.h b/include/uapi/linux/udmabuf.h
> index 46b6532ed8..281e2c52f1 100644
> --- a/include/uapi/linux/udmabuf.h
> +++ b/include/uapi/linux/udmabuf.h
> @@ -5,8 +5,39 @@
>  #include <linux/types.h>
>  #include <linux/ioctl.h>
>  
> +/**
> + * DOC: udmabuf
> + *
> + * udmabuf is a device driver which allows userspace to create
> + * dmabufs.  The memory used for these dmabufs must be backed by
> + * memfd.  The memfd must have F_SEAL_SHRINK and it must not have
> + * F_SEAL_WRITE.
> + *
> + * The driver has two ioctls, one to create a dmabuf from a single
> + * memory block and one to create a dmabuf from a list of memory
> + * blocks.
> + *
> + * UDMABUF_CREATE - _IOW('u', 0x42, udmabuf_create)
> + *
> + * UDMABUF_CREATE_LIST - _IOW('u', 0x43, udmabuf_create_list)
> + */
> +
> +#define UDMABUF_CREATE       _IOW('u', 0x42, struct udmabuf_create)
> +#define UDMABUF_CREATE_LIST  _IOW('u', 0x43, struct udmabuf_create_list)
> +
>  #define UDMABUF_FLAGS_CLOEXEC	0x01
>  
> +/**
> + * struct udmabuf_create - create a dmabuf from a single memory block.
> + *
> + * @memfd: The file handle.
> + * @offset: Start of the buffer (from memfd start).
> + * Must be page aligned.
> + * @size: Size of the buffer.  Must be rounded to page size.
> + *
> + * @flags:
> + * UDMABUF_FLAGS_CLOEXEC: set CLOEXEC flag for the dmabuf.
> + */
>  struct udmabuf_create {
>  	__u32 memfd;
>  	__u32 flags;
> @@ -14,6 +45,14 @@ struct udmabuf_create {
>  	__u64 size;
>  };
>  
> +/**
> + * struct udmabuf_create_item - one memory block list item.
> + *
> + * @memfd: The file handle.
> + * @offset: Start of the buffer (from memfd start).
> + * Must be page aligned.
> + * @size: Size of the buffer.  Must be rounded to page size.
> + */
>  struct udmabuf_create_item {
>  	__u32 memfd;
>  	__u32 __pad;
> @@ -21,13 +60,19 @@ struct udmabuf_create_item {
>  	__u64 size;
>  };
>  
> +/**
> + * struct udmabuf_create_list - create a dmabuf from a memory block list.
> + *
> + * @count: The number of list elements.
> + * @list: The memory block list
> + *
> + * flags:

      @flags:

> + * UDMABUF_FLAGS_CLOEXEC: set CLOEXEC flag for the dmabuf.
> + */
>  struct udmabuf_create_list {
>  	__u32 flags;
>  	__u32 count;
>  	struct udmabuf_create_item list[];
>  };

-- 
~Randy