drm/amdgpu: use post-decrement in error handling
We need to use post-decrement to get the pci_map_page undone also for
i==0, and to avoid some very unpleasant behaviour if pci_map_page
failed already at i==0.
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
index 6442a06..1cbb16e 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
@@ -712,7 +712,7 @@
0, PAGE_SIZE,
PCI_DMA_BIDIRECTIONAL);
if (pci_dma_mapping_error(adev->pdev, gtt->ttm.dma_address[i])) {
- while (--i) {
+ while (i--) {
pci_unmap_page(adev->pdev, gtt->ttm.dma_address[i],
PAGE_SIZE, PCI_DMA_BIDIRECTIONAL);
gtt->ttm.dma_address[i] = 0;