drm/nouveau: use post-decrement in error handling

We need to use post-decrement to get the dma_map_page undone also for
i==0, and to avoid some very unpleasant behaviour if dma_map_page
failed already at i==0.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Reviewed-by: Ben Skeggs <bskeggs@redhat.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/drivers/gpu/drm/nouveau/nouveau_bo.c b/drivers/gpu/drm/nouveau/nouveau_bo.c
index 78f520d05de9..e3acc35e3805 100644
--- a/drivers/gpu/drm/nouveau/nouveau_bo.c
+++ b/drivers/gpu/drm/nouveau/nouveau_bo.c
@@ -1520,7 +1520,7 @@ nouveau_ttm_tt_populate(struct ttm_tt *ttm)
                                     DMA_BIDIRECTIONAL);
 
                 if (dma_mapping_error(pdev, addr)) {
-                        while (--i) {
+                        while (i--) {
                                 dma_unmap_page(pdev, ttm_dma->dma_address[i],
                                                PAGE_SIZE, DMA_BIDIRECTIONAL);
                                 ttm_dma->dma_address[i] = 0;