| Message ID | 20211009024733.65676-1-guangming.cao@mediatek.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | dma-buf: remove restriction of IOCTL:DMA_BUF_SET_NAME | expand |
On 10/8/21 7:47 PM, guangming.cao@mediatek.com wrote: > 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 to be waiting 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 theoretically (yes, it was incorrect before this change.) > + * 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; > } > >
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; }