[PATCH 3.16.y-ckt 020/142] drm/radeon: use post-decrement in error handling

[Luis Henriques]

3.16.7-ckt26 -stable review patch.  If anyone has any objections, please let me 
know.

---8<------------------------------------------------------------

From: Rasmus Villemoes <li...@rasmusvillemoes.dk>

commit bc3f5d8c4ca01555820617eb3b6c0857e4df710d upstream.

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.koe...@amd.com>
Signed-off-by: Rasmus Villemoes <li...@rasmusvillemoes.dk>
Signed-off-by: Alex Deucher <alexander.deuc...@amd.com>
Signed-off-by: Luis Henriques <luis.henriq...@canonical.com>
---
 drivers/gpu/drm/radeon/radeon_ttm.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/radeon/radeon_ttm.c 
b/drivers/gpu/drm/radeon/radeon_ttm.c
index 7555349e30da..c4675b9729c9 100644
--- a/drivers/gpu/drm/radeon/radeon_ttm.c
+++ b/drivers/gpu/drm/radeon/radeon_ttm.c
@@ -629,7 +629,7 @@ static int radeon_ttm_tt_populate(struct ttm_tt *ttm)
                                                       0, PAGE_SIZE,
                                                       PCI_DMA_BIDIRECTIONAL);
                if (pci_dma_mapping_error(rdev->pdev, gtt->ttm.dma_address[i])) 
{
-                       while (--i) {
+                       while (i--) {
                                pci_unmap_page(rdev->pdev, 
gtt->ttm.dma_address[i],
                                               PAGE_SIZE, 
PCI_DMA_BIDIRECTIONAL);
                                gtt->ttm.dma_address[i] = 0;