From: <guangming.cao@mediatek.com>
To: "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>, Guangming Cao <Guangming.Cao@mediatek.com>
Subject: [PATCH] dma-buf: remove restriction of IOCTL:DMA_BUF_SET_NAME
Date: Sat, 9 Oct 2021 10:47:33 +0800 [thread overview]
Message-ID: <20211009024733.65676-1-guangming.cao@mediatek.com> (raw)
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
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
+ * 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;
}
--
2.17.1
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next reply other threads:[~2021-10-09 3:23 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-09 2:47 guangming.cao [this message]
2021-10-09 4:41 ` [PATCH] dma-buf: remove restriction of IOCTL:DMA_BUF_SET_NAME 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
2021-10-26 11:52 ` guangming.cao
2021-10-28 11:35 ` Christian König
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