From: <guangming.cao@mediatek.com>
To: <christian.koenig@amd.com>, <sumit.semwal@linaro.org>
Cc: <dri-devel@lists.freedesktop.org>, <guangming.cao@mediatek.com>,
<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>,
Guangming Cao <Guangming.Cao@mediatek.com>
Subject: [PATCH v3] dma-buf: remove restriction of IOCTL:DMA_BUF_SET_NAME
Date: Thu, 14 Oct 2021 18:25:51 +0800 [thread overview]
Message-ID: <20211014102551.54983-1-guangming.cao@mediatek.com> (raw)
In-Reply-To: <20211012084109.176542-1-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>
---
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,
--
2.17.1
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next prev parent reply other threads:[~2021-10-14 10:31 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 ` guangming.cao [this message]
2021-10-14 10:35 ` [PATCH v3] " 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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