Re: [PATCH] drm/ttm: properly unmap dma page upon failure

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