Probably my previous emails went into the spam folder. Another friendly reminder using web version of my Gmail. Thank you.

On Mon, Mar 25, 2019 at 2:22 PM Yu Zhao yuzhao@google.com wrote:

dma_unmap_page() must be called with exactly the same dma address and size returned by dma_map_page(). Otherwise, the function may fail.

This is at least the case for debug_dma_unmap_page() and AMD iommu unmap_page callback.

Signed-off-by: Yu Zhao yuzhao@google.com

drivers/gpu/drm/ttm/ttm_page_alloc.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/ttm/ttm_page_alloc.c b/drivers/gpu/drm/ttm/ttm_page_alloc.c index f841accc2c00..c1636595f63c 100644 --- a/drivers/gpu/drm/ttm/ttm_page_alloc.c +++ b/drivers/gpu/drm/ttm/ttm_page_alloc.c @@ -1118,10 +1118,19 @@ int ttm_populate_and_map_pages(struct device *dev, struct ttm_dma_tt *tt, 0, num_pages * PAGE_SIZE, DMA_BIDIRECTIONAL); if (dma_mapping_error(dev, tt->dma_address[i])) {

•                   num_pages = 1;
                    while (i--) {
  

•                           if (i && tt->ttm.pages[i] -
  

•                                    tt->ttm.pages[i - 1] == 1) {
  

•                                   tt->dma_address[i] = 0;
  

•                                   num_pages++;
  

•                                   continue;
  

•                           }
                            dma_unmap_page(dev, tt->dma_address[i],
  

•                                          PAGE_SIZE,
  

DMA_BIDIRECTIONAL);

•                                          num_pages * PAGE_SIZE,
  

•                                          DMA_BIDIRECTIONAL);
                            tt->dma_address[i] = 0;
  

•                           num_pages = 1;
                    }
                    ttm_pool_unpopulate(&tt->ttm);
                    return -EFAULT;
  

-- 2.21.0.392.gf8f6787159e-goog