From: Randy Dunlap <rdunlap@infradead.org>
To: guangming.cao@mediatek.com,
"Sumit Semwal" <sumit.semwal@linaro.org>,
"Christian König" <christian.koenig@amd.com>,
"Matthias Brugger" <matthias.bgg@gmail.com>,
"open list:DMA BUFFER SHARING FRAMEWORK"
<linux-media@vger.kernel.org>,
"open list:DMA BUFFER SHARING FRAMEWORK"
<dri-devel@lists.freedesktop.org>,
"moderated list:DMA BUFFER SHARING FRAMEWORK"
<linaro-mm-sig@lists.linaro.org>,
"open list" <linux-kernel@vger.kernel.org>,
"moderated list:ARM/Mediatek SoC support"
<linux-arm-kernel@lists.infradead.org>,
"moderated list:ARM/Mediatek SoC support"
<linux-mediatek@lists.infradead.org>
Cc: wsd_upstream@mediatek.com
Subject: Re: [PATCH] dma-buf: remove restriction of IOCTL:DMA_BUF_SET_NAME
Date: Fri, 8 Oct 2021 21:41:04 -0700 [thread overview]
Message-ID: <c23181a5-b75b-c04b-7cc4-020f2b2b44c1@infradead.org> (raw)
In-Reply-To: <20211009024733.65676-1-guangming.cao@mediatek.com>
On 10/8/21 7:47 PM, guangming.cao@mediatek.com wrote:
> From: Guangming Cao <Guangming.Cao@mediatek.com>
>
> If dma-buf don't want userspace users to touch the dmabuf buffer,
> it seems we should add this restriction into dma_buf_ops.mmap,
> not in this IOCTL:DMA_BUF_SET_NAME.
>
> With this restriction, we can only know the kernel users of the dmabuf
> by attachments.
> However, for many userspace users, such as userpsace users of dma_heap,
> they also need to mark the usage of dma-buf, and they don't care about
> who attached to this dmabuf, and seems it's no meaning to waitting for
to be waiting for
> IOCTL:DMA_BUF_SET_NAME rather than mmap.
>
> Signed-off-by: Guangming Cao <Guangming.Cao@mediatek.com>
> ---
> drivers/dma-buf/dma-buf.c | 14 ++------------
> 1 file changed, 2 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c
> index 511fe0d217a0..afbd0a226639 100644
> --- a/drivers/dma-buf/dma-buf.c
> +++ b/drivers/dma-buf/dma-buf.c
> @@ -325,10 +325,8 @@ static __poll_t dma_buf_poll(struct file *file, poll_table *poll)
>
> /**
> * dma_buf_set_name - Set a name to a specific dma_buf to track the usage.
> - * The name of the dma-buf buffer can only be set when the dma-buf is not
> - * attached to any devices. It could theoritically support changing the
> - * name of the dma-buf if the same piece of memory is used for multiple
> - * purpose between different devices.
> + * It could theoritically support changing the name of the dma-buf if the same
theoretically
(yes, it was incorrect before this change.)
> + * piece of memory is used for multiple purpose between different devices.
> *
> * @dmabuf: [in] dmabuf buffer that will be renamed.
> * @buf: [in] A piece of userspace memory that contains the name of
> @@ -346,19 +344,11 @@ static long dma_buf_set_name(struct dma_buf *dmabuf, const char __user *buf)
> if (IS_ERR(name))
> return PTR_ERR(name);
>
> - dma_resv_lock(dmabuf->resv, NULL);
> - if (!list_empty(&dmabuf->attachments)) {
> - ret = -EBUSY;
> - kfree(name);
> - goto out_unlock;
> - }
> spin_lock(&dmabuf->name_lock);
> kfree(dmabuf->name);
> dmabuf->name = name;
> spin_unlock(&dmabuf->name_lock);
>
> -out_unlock:
> - dma_resv_unlock(dmabuf->resv);
> return ret;
> }
>
>
--
~Randy
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next prev parent reply other threads:[~2021-10-09 4:42 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-09 2:47 [PATCH] dma-buf: remove restriction of IOCTL:DMA_BUF_SET_NAME guangming.cao
2021-10-09 4:41 ` Randy Dunlap [this message]
2021-10-09 5:55 ` [PATCH v2] " guangming.cao
2021-10-11 8:20 ` Christian König
2021-10-12 8:41 ` guangming.cao
2021-10-14 10:25 ` [PATCH v3] " guangming.cao
2021-10-14 10:35 ` guangming.cao
2021-10-26 8:04 ` guangming.cao
2021-10-26 11:18 ` Christian König
2021-10-26 11:52 ` guangming.cao
2021-10-28 11:35 ` Christian König
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