On Mon, 17 Oct 2022 at 19:25, Dmitry Osipenko dmitry.osipenko@collabora.com wrote:
Move dma_buf_mmap() function to the dynamic locking specification by taking the reservation lock. Neither of the today's drivers take the reservation lock within the mmap() callback, hence it's safe to enforce the locking.
Acked-by: Sumit Semwal sumit.semwal@linaro.org Acked-by: Christian König christian.koenig@amd.com Signed-off-by: Dmitry Osipenko dmitry.osipenko@collabora.com
Just noticed this while reading code ... this patch seems to have missed dma_buf_mmap_internal()?
Might be good if at least some drivers gain a dma_resv_assert_held in that path to make sure we're not quite this bad, together with fixing this issue. -Daniel
drivers/dma-buf/dma-buf.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c index f54c649f922a..f149b384f4dd 100644 --- a/drivers/dma-buf/dma-buf.c +++ b/drivers/dma-buf/dma-buf.c @@ -1390,6 +1390,8 @@ EXPORT_SYMBOL_NS_GPL(dma_buf_end_cpu_access, DMA_BUF); int dma_buf_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma, unsigned long pgoff) {
int ret;if (WARN_ON(!dmabuf || !vma)) return -EINVAL;@@ -1410,7 +1412,11 @@ int dma_buf_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma, vma_set_file(vma, dmabuf->file); vma->vm_pgoff = pgoff;
return dmabuf->ops->mmap(dmabuf, vma);
dma_resv_lock(dmabuf->resv, NULL);ret = dmabuf->ops->mmap(dmabuf, vma);dma_resv_unlock(dmabuf->resv);return ret;} EXPORT_SYMBOL_NS_GPL(dma_buf_mmap, DMA_BUF);
-- 2.37.3