Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933481AbaGWUYF (ORCPT ); Wed, 23 Jul 2014 16:24:05 -0400 Received: from mail-we0-f171.google.com ([74.125.82.171]:53706 "EHLO mail-we0-f171.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933091AbaGWUYD (ORCPT ); Wed, 23 Jul 2014 16:24:03 -0400 MIME-Version: 1.0 In-Reply-To: References: Date: Wed, 23 Jul 2014 16:24:01 -0400 Message-ID: Subject: Re: staging: Unwritten function for ion_carveout_heap.c From: Nick Krause To: Colin Cross Cc: Greg KH , John Stultz , Rebecca Zavin , Laura Abbott , gioh.kim@lge.com, benjamin.gaignard@linaro.org, "devel@driverdev.osuosl.org" , "linux-kernel@vger.kernel.org" Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jul 23, 2014 at 4:10 PM, Colin Cross wrote: > On Wed, Jul 23, 2014 at 1:04 PM, Nick Krause wrote: >> Hey Greg and others. >> Sorry for another email but it seems the function, >> ion_carveout_heap_unmap_dma is >> just returning and not doing anything useful. Furthermore I am new so >> I don't known how >> to write this function but this may be causing some rather serious >> bugs as if the dma heap >> is not unmaped and we call this function a lot this will make the >> kernel not able to handle dma requests >> for this driver and other drivers that need this and in turn lead to >> a oops or even a kernel panic due to leaked >> dma allocated memory. I would recommend writing this function or >> helping me write it in >> other to avoid some rather serious bugs without a proper dma unmapping >> function for this driver :). >> Nick > > Look at ion_carveout_heap_map_dma - it doesn't do anything, it just > returns a pre-existing virtual address. That means there is nothing > to do in unmap. > > map_dma is actually a bit of a misnomer here, as the actual mapping is > done in ion_map_dma_buf. All ion_carveout_heap_map_dma does is return > the sg table for ion_map_dma_buf to pass to dma_map_sg. Very well then I guess this is closed then. Cheers Nick -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/