From: Guangming Cao <Guangming.Cao@xxxxxxxxxxxx> On Tue, 2021-10-26 at 13:18 +0200, Christian König wrote: > Am 14.10.21 um 12:25 schrieb guangming.cao@xxxxxxxxxxxx: > > From: Guangming Cao <Guangming.Cao@xxxxxxxxxxxx> > > > > 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@xxxxxxxxxxxx> > > We could now cleanup the return value from dma_buf_set_name() into a > void since that function can't fail any more as far as I can see. > > But that isn't mandatory I think, patch is Reviewed-by: Christian > König > <christian.koenig@xxxxxxx> > So, here is no need to check return value of 'strndup_user', just return without error code if the almost impossible error occurs? Guangming. > Regards, > Christian. > > > --- > > 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, > >
