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Subject: Re: [PATCH v2 2/2] dmabuf: Add dmabuf inode number to /proc/*/fdinfo
To:     Kalesh Singh <kaleshsingh@google.com>
Cc:     jannh@google.com, jeffv@google.com, keescook@chromium.org,
        surenb@google.com, minchan@kernel.org, hridya@google.com,
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        Alexey Dobriyan <adobriyan@gmail.com>,
        "Eric W. Biederman" <ebiederm@xmission.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Alexey Gladkov <gladkov.alexey@gmail.com>,
        Michel Lespinasse <walken@google.com>,
        Bernd Edlinger <bernd.edlinger@hotmail.de>,
        Andrei Vagin <avagin@gmail.com>,
        Yafang Shao <laoar.shao@gmail.com>,
        Christian Brauner <christian.brauner@ubuntu.com>,
        linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org,
        linaro-mm-sig@lists.linaro.org, linux-kernel@vger.kernel.org,
        linux-fsdevel@vger.kernel.org
References: <20210204232854.451676-1-kaleshsingh@google.com>
 <20210204232854.451676-2-kaleshsingh@google.com>
From:   Randy Dunlap <rdunlap@infradead.org>
Message-ID: <4e71615b-bdc9-bd5f-ffe3-25f50ce5b882@infradead.org>
Date:   Thu, 4 Feb 2021 16:15:17 -0800
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On 2/4/21 3:28 PM, Kalesh Singh wrote:
> If a FD refers to a DMA buffer add the DMA buffer inode number to
> /proc/<pid>/fdinfo/<FD> and /proc/<pid>/task/<tid>/fdindo/<FD>.
> 
> The dmabuf inode number allows userspace to uniquely identify the buffer
> and avoids a dependency on /proc/<pid>/fd/* when accounting per-process
> DMA buffer sizes.
> 
> Signed-off-by: Kalesh Singh <kaleshsingh@google.com>
> ---

Hi,
Please document this change in
Documentation/filesystems/proc.rst.

Thanks.

> 
> Changes in v2: 
>   - Update patch desciption
> 
>  drivers/dma-buf/dma-buf.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c
> index 9ad6397aaa97..d869099ede83 100644
> --- a/drivers/dma-buf/dma-buf.c
> +++ b/drivers/dma-buf/dma-buf.c
> @@ -414,6 +414,7 @@ static void dma_buf_show_fdinfo(struct seq_file *m, struct file *file)
>  {
>  	struct dma_buf *dmabuf = file->private_data;
>  
> +	seq_printf(m, "dmabuf_inode_no:\t%lu\n", file_inode(file)->i_ino);
>  	seq_printf(m, "size:\t%zu\n", dmabuf->size);
>  	/* Don't count the temporary reference taken inside procfs seq_show */
>  	seq_printf(m, "count:\t%ld\n", file_count(dmabuf->file) - 1);
> 


-- 
~Randy