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; }