> From: Christian König <christian.koe...@amd.com> > Sent: Wednesday, August 18, 2021 2:10 PM > To: Sa, Nuno <nuno...@analog.com>; linaro-mm-...@lists.linaro.org; > dri-devel@lists.freedesktop.org; linux-me...@vger.kernel.org > Cc: Rob Clark <r...@ti.com>; Sumit Semwal > <sumit.sem...@linaro.org> > Subject: Re: [PATCH] dma-buf: return -EINVAL if dmabuf object is > NULL > > [External] > > To be honest I think the if(WARN_ON(!dmabuf)) return -EINVAL > handling > here is misleading in the first place. > > Returning -EINVAL on a hard coding error is not good practice and > should > probably be removed from the DMA-buf subsystem in general.
Would you say to just return 0 then? I don't think that having the dereference is also good.. I used -EINVAL to be coherent with the rest of the code. - Nuno Sá > Christian. > > Am 18.08.21 um 13:58 schrieb Nuno Sá: > > On top of warning about a NULL object, we also want to return with a > > proper error code (as done in 'dma_buf_begin_cpu_access()'). > Otherwise, > > we will get a NULL pointer dereference. > > > > Fixes: fc13020e086b ("dma-buf: add support for kernel cpu access") > > Signed-off-by: Nuno Sá <nuno...@analog.com> > > --- > > drivers/dma-buf/dma-buf.c | 3 ++- > > 1 file changed, 2 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma- > buf.c > > index 63d32261b63f..8ec7876dd523 100644 > > --- a/drivers/dma-buf/dma-buf.c > > +++ b/drivers/dma-buf/dma-buf.c > > @@ -1231,7 +1231,8 @@ int dma_buf_end_cpu_access(struct > dma_buf *dmabuf, > > { > > int ret = 0; > > > > - WARN_ON(!dmabuf); > > + if (WARN_ON(!dmabuf)) > > + return -EINVAL; > > > > might_lock(&dmabuf->resv->lock.base); > >