From: "Christian König" <christian.koenig@amd.com>
To: guangming.cao@mediatek.com, sumit.semwal@linaro.org
Cc: dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, linux-media@vger.kernel.org,
linux-mediatek@lists.infradead.org, matthias.bgg@gmail.com,
rdunlap@infradead.org, wsd_upstream@mediatek.com
Subject: Re: [PATCH v3] dma-buf: remove restriction of IOCTL:DMA_BUF_SET_NAME
Date: Tue, 26 Oct 2021 13:18:53 +0200 [thread overview]
Message-ID: <0e062f12-7e79-5a05-1e7b-10dda8e353b7@amd.com> (raw)
In-Reply-To: <20211014102551.54983-1-guangming.cao@mediatek.com>
Am 14.10.21 um 12:25 schrieb guangming.cao@mediatek.com:
> From: Guangming Cao <Guangming.Cao@mediatek.com>
>
> In this patch(https://patchwork.freedesktop.org/patch/310349),
> it add a new IOCTL to support dma-buf user to set debug name.
>
> But it also added a limitation of this IOCTL, it needs the
> attachments of dmabuf should be empty, otherwise it will fail.
>
> For the original series, the idea was that allowing name change
> mid-use could confuse the users about the dma-buf.
> However, the rest of the series also makes sure each dma-buf have a unique
> inode(https://patchwork.freedesktop.org/patch/310387/), and any accounting
> should probably use that, without relying on the name as much.
>
> So, removing this restriction will let dma-buf userspace users to use it
> more comfortably and without any side effect.
>
> Signed-off-by: Guangming Cao <Guangming.Cao@mediatek.com>
We could now cleanup the return value from dma_buf_set_name() into a
void since that function can't fail any more as far as I can see.
But that isn't mandatory I think, patch is Reviewed-by: Christian König
<christian.koenig@amd.com>
Regards,
Christian.
> ---
> drivers/dma-buf/dma-buf.c | 17 +++--------------
> 1 file changed, 3 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c
> index 511fe0d217a0..5fbb3a2068a3 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 support changing the name of the dma-buf if the same
> + * 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
> @@ -341,25 +339,16 @@ static __poll_t dma_buf_poll(struct file *file, poll_table *poll)
> static long dma_buf_set_name(struct dma_buf *dmabuf, const char __user *buf)
> {
> char *name = strndup_user(buf, DMA_BUF_NAME_LEN);
> - long ret = 0;
>
> 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;
> + return 0;
> }
>
> static long dma_buf_ioctl(struct file *file,
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2021-10-26 11:20 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
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 [this message]
2021-10-26 11:52 ` guangming.cao
2021-10-28 11:35 ` Christian König
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=0e062f12-7e79-5a05-1e7b-10dda8e353b7@amd.com \
--to=christian.koenig@amd.com \
--cc=dri-devel@lists.freedesktop.org \
--cc=guangming.cao@mediatek.com \
--cc=linaro-mm-sig@lists.linaro.org \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-media@vger.kernel.org \
--cc=linux-mediatek@lists.infradead.org \
--cc=matthias.bgg@gmail.com \
--cc=rdunlap@infradead.org \
--cc=sumit.semwal@linaro.org \
--cc=wsd_upstream@mediatek.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).