From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Hellwig Subject: Re: use exact allocation for dma coherent memory Date: Thu, 20 Jun 2019 12:51:24 +0200 Message-ID: <20190620105124.GA25233@lst.de> References: <20190614134726.3827-1-hch@lst.de> <20190617082148.GF28859@kadam> <20190617083342.GA7883@lst.de> <20190619162903.GF9360@ziepe.ca> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Return-path: Content-Disposition: inline In-Reply-To: <20190619162903.GF9360@ziepe.ca> Sender: linux-kernel-owner@vger.kernel.org To: Jason Gunthorpe Cc: Christoph Hellwig , Potnuri Bharat Teja , Dan Carpenter , Maarten Lankhorst , Maxime Ripard , Sean Paul , David Airlie , Daniel Vetter , Jani Nikula , Joonas Lahtinen , Rodrigo Vivi , Ian Abbott , H Hartley Sweeten , devel@driverdev.osuosl.org, linux-s390@vger.kernel.org, Intel Linux Wireless , linux-rdma@vger.kernel.org, netdev@vger.kernel.org, intel-gfx@lists.freedesktop.org, linux-wireless@vger.kernel.org, linux-kernel@vger.kernel.or List-Id: linux-rdma@vger.kernel.org On Wed, Jun 19, 2019 at 01:29:03PM -0300, Jason Gunthorpe wrote: > > Yes. This will blow up badly on many platforms, as sq->queue > > might be vmapped, ioremapped, come from a pool without page backing. > > Gah, this addr gets fed into io_remap_pfn_range/remap_pfn_range too.. > > Potnuri, you should fix this.. > > You probably need to use dma_mmap_from_dev_coherent() in the mmap ? The function to use is dma_mmap_coherent, dma_mmap_from_dev_coherent is just an internal helper. That beiŋ said the drivers/infiniband code has a lot of *remap_pfn_range, and a lot of them look like they might be for DMA memory.