Commit e73c317e authored by Guangming Cao's avatar Guangming Cao Committed by Christian König
Browse files

dma-buf: remove restriction of IOCTL:DMA_BUF_SET_NAME 

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: default avatarGuangming Cao <Guangming.Cao@mediatek.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211014102551.54983-1-guangming.cao@mediatek.com


Reviewed-by: default avatarChristian König <christian.koenig@amd.com>
Signed-off-by: default avatarChristian König <christian.koenig@amd.com>
parent 099afadc

drivers/dma-buf/dma-buf.c

+3 −14
Original line number Diff line number Diff line
@@ -293,10 +293,8 @@ 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
@@ -309,25 +307,16 @@ 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,