Re: [PATCH 11/33] drm/omap: use dma_mapping_error in omap_gem_attach_pages

On 24/02/16 00:10, Laurent Pinchart wrote:

Hi Tomi,

Thank you for the patch.

On Friday 19 February 2016 11:47:46 Tomi Valkeinen wrote:

...

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

drivers/gpu/drm/omapdrm/omap_gem.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+)

diff --git a/drivers/gpu/drm/omapdrm/omap_gem.c b/drivers/gpu/drm/omapdrm/omap_gem.c index 8495a1a4b617..7098190815f1 100644 --- a/drivers/gpu/drm/omapdrm/omap_gem.c +++ b/drivers/gpu/drm/omapdrm/omap_gem.c @@ -264,6 +264,18 @@ 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, "omap_gem_attach_pages: dma_map_page 
  

failed\n");

Using dev_warn(dev->dev, "%s: failed to map page\n", __func__); and proper line breaks you'll have no trouble complying with the 80 characters per line limit :-)

Ok.

...

• 		for (i = i - 1; i >= 0; --i) {
  

Maybe i-- instead of i = i - 1 ?

Hmm I don't know... I do like assignment in the initializer more than i--. And why i--? Why not --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);

@@ -277,6 +289,8 @@ static int omap_gem_attach_pages(struct drm_gem_object *obj) omap_obj->pages = pages;

return 0; +free_addrs:

• kfree(addrs);

I'd move this blank line before free_addrs.

Yes, that makes it cleaner.

Tomi