From mboxrd@z Thu Jan 1 00:00:00 1970 From: Laxman Dewangan Subject: Re: [PATCH V2] dma: tegra: avoid channel lock up after free Date: Wed, 31 Oct 2012 20:28:52 +0530 Message-ID: <50913CAC.5090808@nvidia.com> References: <508EA04D.5050805@wwwdotorg.org> <1351552833-4132-1-git-send-email-digetx@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1351552833-4132-1-git-send-email-digetx@gmail.com> Sender: linux-kernel-owner@vger.kernel.org To: Dmitry Osipenko Cc: "swarren@wwwdotorg.org" , "vinod.koul@intel.com" , "linux-tegra@vger.kernel.org" , "linux-kernel@vger.kernel.org" List-Id: linux-tegra@vger.kernel.org On Tuesday 30 October 2012 04:50 AM, Dmitry Osipenko wrote: > Fixed channel "lock up" after free. > > Lock scenario: Channel 1 was allocated and prepared as slave_sg, used and freed. > Now preparation of cyclic dma on channel 1 will fail with err "DMA configuration > conflict" because tdc->isr_handler still selected to handle_once_dma_done. > > This happens because tegra_dma_abort_all() won't be called on channel freeing > if pending list is empty or channel not busy. We need to clear isr_handler > on channel freeing to avoid locking. Also I added small optimization to prepare > functions, so current channel type checked before making allocations. > > Signed-off-by: Dmitry Osipenko > --- Looks good to me. Acked-by: Laxman Dewangan