drm/omap: use dma_mapping_error in omap_gem_attach_pages

omap_gem_attach_pages() calls dma_map_page() but does not check the
possible error with dma_mapping_error(). If DMA-API debugging is
enabled, the debug layer will give a warning if dma_mapping_error() has
not been used.

This patch adds proper error handling to omap_gem_attach_pages().
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

drivers/gpu/drm/omapdrm/omap_gem.c

@@ -264,6 +264,19 @@ static int omap_gem_attach_pages(struct drm_gem_object *obj)
 		for (i = 0; i < npages; i++) {
 			addrs[i] = dma_map_page(dev->dev, pages[i],
 					0, PAGE_SIZE, DMA_BIDIRECTIONAL);
+
+			if (dma_mapping_error(dev->dev, addrs[i])) {
+				dev_warn(dev->dev,
+					"%s: failed to map page\n", __func__);
+
+				for (i = i - 1; i >= 0; --i) {
+					dma_unmap_page(dev->dev, addrs[i],
+						PAGE_SIZE, DMA_BIDIRECTIONAL);
+				}
+
+				ret = -ENOMEM;
+				goto free_addrs;
+			}
 		}
 	} else {
 		addrs = kzalloc(npages * sizeof(*addrs), GFP_KERNEL);
@@ -278,6 +291,8 @@ static int omap_gem_attach_pages(struct drm_gem_object *obj)
 
 	return 0;
 
+free_addrs:
+	kfree(addrs);
 free_pages:
 	drm_gem_put_pages(obj, pages, true, false);