[PATCH] dma-buf: Fix SET_NAME ioctl uapi

[Sumit Semwal]

Thanks Daniel, Martin,

On Thu, 23 Apr 2020 at 20:21, Martin Liu <liumartin at google.com> wrote:
>
> On Thu, Apr 09, 2020 at 09:28:16AM +0530, Sumit Semwal wrote:
> > Thanks for the patch, Daniel!
> >
> >
> > On Tue, 7 Apr 2020 at 19:00, Daniel Vetter <daniel.vetter at ffwll.ch> wrote:
> > >
> > > The uapi is the same on 32 and 64 bit, but the number isnt. Everyone
> > > who botched this please re-read:
> > >
> > > https://www.kernel.org/doc/html/v5.4-preprc-cpu/ioctl/botching-up-ioctls.html
> > >
> > > Also, the type argument for the ioctl macros is for the type the void
> > > __user *arg pointer points at, which in this case would be the
> > > variable-sized char[] of a 0 terminated string. So this was botched in
> > > more than just the usual ways.
> >
> > Yes, it shouldn't have passed through the cracks; my apologies!
> >
> > >
> > > Cc: Sumit Semwal <sumit.semwal at linaro.org>
> > > Cc: Chenbo Feng <fengc at google.com>
> > > Cc: Greg Hackmann <ghackmann at google.com>
> > > Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
> > > Cc: linux-media at vger.kernel.org
> > > Cc: linaro-mm-sig at lists.linaro.org
> > > Cc: minchan at kernel.org
> > > Cc: surenb at google.com
> > > Cc: jenhaochen at google.com
> > > Cc: Martin Liu <liumartin at google.com>
> >
> > Martin,
> > Could I request you to test this one with the 4 combinations of 32-bit
> > / 64-bit userspace and kernel, and let us know that all 4 are working
> > alright? If yes, please consider giving your tested-by here.
> >
> Hi Sumit, Daniel,
> Sorry for being late to the tests. I finished the tests on 32/64 apps
> with 64 bit kernel and they were fine. Unfortunately, I couldn't have a 32
> bit kernel to run the tests somehow. However, this should work from the
> code logic. Hope this is okay to you and thanks for Todd's help.
>
> Tested-by: Martin Liu <liumartin at google.com>
> Reviewed-by: Martin Liu <liumartin at google.com>

Applied to drm-misc-fixes.
>
> > > Signed-off-by: Daniel Vetter <daniel.vetter at intel.com>
> > > ---
> > >  drivers/dma-buf/dma-buf.c    | 3 ++-
> > >  include/uapi/linux/dma-buf.h | 4 ++++
> > >  2 files changed, 6 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c
> > > index 570c923023e6..1d923b8e4c59 100644
> > > --- a/drivers/dma-buf/dma-buf.c
> > > +++ b/drivers/dma-buf/dma-buf.c
> > > @@ -388,7 +388,8 @@ static long dma_buf_ioctl(struct file *file,
> > >
> > >                 return ret;
> > >
> > > -       case DMA_BUF_SET_NAME:
> > > +       case DMA_BUF_SET_NAME_A:
> > > +       case DMA_BUF_SET_NAME_B:
> > >                 return dma_buf_set_name(dmabuf, (const char __user *)arg);
> > >
> > >         default:
> > > diff --git a/include/uapi/linux/dma-buf.h b/include/uapi/linux/dma-buf.h
> > > index dbc7092e04b5..21dfac815dc0 100644
> > > --- a/include/uapi/linux/dma-buf.h
> > > +++ b/include/uapi/linux/dma-buf.h
> > > @@ -39,6 +39,10 @@ struct dma_buf_sync {
> > >
> > >  #define DMA_BUF_BASE           'b'
> > >  #define DMA_BUF_IOCTL_SYNC     _IOW(DMA_BUF_BASE, 0, struct dma_buf_sync)
> > > +/* 32/64bitness of this uapi was botched in android, there's no difference
> > > + * between them in actual uapi, they're just different numbers. */
> > >  #define DMA_BUF_SET_NAME       _IOW(DMA_BUF_BASE, 1, const char *)
> > > +#define DMA_BUF_SET_NAME_A     _IOW(DMA_BUF_BASE, 1, u32)
> > > +#define DMA_BUF_SET_NAME_B     _IOW(DMA_BUF_BASE, 1, u64)
> > >
> > >  #endif
> > > --
> > > 2.25.1
> > >
> > Best,
> > Sumit.
Best,
Sumit.