Hi John, Suren,
On Wed, 20 Jan 2021 at 02:15, John Stultz <[email protected]> wrote: > > We shouldn't vunmap more then we vmap, but if we do, make > sure we complain loudly. I was checking the general usage of vunmap in the kernel, and I couldn't find many instances where we need to WARN_ON for the vunmap count more than vmap count. Is there a specific need for this in the heaps? Best, Sumit. > > Cc: Sumit Semwal <[email protected]> > Cc: Liam Mark <[email protected]> > Cc: Laura Abbott <[email protected]> > Cc: Brian Starkey <[email protected]> > Cc: Hridya Valsaraju <[email protected]> > Cc: Suren Baghdasaryan <[email protected]> > Cc: Sandeep Patil <[email protected]> > Cc: Daniel Mentz <[email protected]> > Cc: Chris Goldsworthy <[email protected]> > Cc: Ørjan Eide <[email protected]> > Cc: Robin Murphy <[email protected]> > Cc: Ezequiel Garcia <[email protected]> > Cc: Simon Ser <[email protected]> > Cc: James Jones <[email protected]> > Cc: [email protected] > Cc: [email protected] > Suggested-by: Suren Baghdasaryan <[email protected]> > Signed-off-by: John Stultz <[email protected]> > --- > drivers/dma-buf/heaps/cma_heap.c | 1 + > drivers/dma-buf/heaps/system_heap.c | 1 + > 2 files changed, 2 insertions(+) > > diff --git a/drivers/dma-buf/heaps/cma_heap.c > b/drivers/dma-buf/heaps/cma_heap.c > index 364fc2f3e499..0c76cbc3fb11 100644 > --- a/drivers/dma-buf/heaps/cma_heap.c > +++ b/drivers/dma-buf/heaps/cma_heap.c > @@ -232,6 +232,7 @@ static void cma_heap_vunmap(struct dma_buf *dmabuf, > struct dma_buf_map *map) > struct cma_heap_buffer *buffer = dmabuf->priv; > > mutex_lock(&buffer->lock); > + WARN_ON(buffer->vmap_cnt == 0); > if (!--buffer->vmap_cnt) { > vunmap(buffer->vaddr); > buffer->vaddr = NULL; > diff --git a/drivers/dma-buf/heaps/system_heap.c > b/drivers/dma-buf/heaps/system_heap.c > index 405351aad2a8..2321c91891f6 100644 > --- a/drivers/dma-buf/heaps/system_heap.c > +++ b/drivers/dma-buf/heaps/system_heap.c > @@ -273,6 +273,7 @@ static void system_heap_vunmap(struct dma_buf *dmabuf, > struct dma_buf_map *map) > struct system_heap_buffer *buffer = dmabuf->priv; > > mutex_lock(&buffer->lock); > + WARN_ON(buffer->vmap_cnt == 0); > if (!--buffer->vmap_cnt) { > vunmap(buffer->vaddr); > buffer->vaddr = NULL; > -- > 2.17.1 >
