From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Hellwig Subject: Re: [PATCH] dma-direct: reject highmem pages from dma_alloc_from_contiguous Date: Mon, 22 Oct 2018 11:41:48 +0200 Message-ID: <20181022094148.GA20099@lst.de> References: <20181014181447.22783-1-hch@lst.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20181014181447.22783-1-hch@lst.de> Sender: linux-kernel-owner@vger.kernel.org To: iommu@lists.linux-foundation.org Cc: linux-kernel@vger.kernel.org List-Id: iommu@lists.linux-foundation.org Any comments? On Sun, Oct 14, 2018 at 08:14:47PM +0200, Christoph Hellwig wrote: > dma_alloc_from_contiguous can return highmem pages depending on the > setup, which a plain non-remapping DMA allocator can't handle. Detect > this case and try the normal page allocator instead. > > Signed-off-by: Christoph Hellwig > --- > kernel/dma/direct.c | 12 ++++++++++++ > 1 file changed, 12 insertions(+) > > diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c > index 87a6bc2a96c0..46fbaa49125b 100644 > --- a/kernel/dma/direct.c > +++ b/kernel/dma/direct.c > @@ -126,6 +126,18 @@ void *dma_direct_alloc_pages(struct device *dev, size_t size, > if (gfpflags_allow_blocking(gfp)) { > page = dma_alloc_from_contiguous(dev, count, page_order, > gfp & __GFP_NOWARN); > + if (page && PageHighMem(page)) { > + /* > + * Depending on the cma= arguments and per-arch setup > + * dma_alloc_from_contiguous could return highmem > + * pages. Without remapping there is no way to return > + * them here, so log an error and fail. > + */ > + dev_info(dev, "Ignoring highmem page from CMA.\n"); > + dma_release_from_contiguous(dev, page, count); > + page = NULL; > + } > + > if (page && !dma_coherent_ok(dev, page_to_phys(page), size)) { > dma_release_from_contiguous(dev, page, count); > page = NULL; > -- > 2.19.1 > > _______________________________________________ > iommu mailing list > iommu@lists.linux-foundation.org > https://lists.linuxfoundation.org/mailman/listinfo/iommu ---end quoted text---