From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752271AbbJYVrN (ORCPT ); Sun, 25 Oct 2015 17:47:13 -0400 Received: from smtp1.it.da.ut.ee ([193.40.5.66]:53779 "EHLO smtp1.it.da.ut.ee" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751705AbbJYVrM convert rfc822-to-8bit (ORCPT ); Sun, 25 Oct 2015 17:47:12 -0400 Date: Sun, 25 Oct 2015 23:46:56 +0200 (EET) From: Meelis Roos To: =?ISO-8859-15?Q?Ville_Syrj=E4l=E4?= cc: Linux Kernel list , Christoph Hellwig , Ingo Molnar , Thomas Gleixner , "H. Peter Anvin" Subject: Re: [PATCH] x86: dma-mapping: Fix arch_dma_alloc_attrs() oops with NULL dev In-Reply-To: <1445807503-8920-1-git-send-email-ville.syrjala@linux.intel.com> Message-ID: References: <1445807503-8920-1-git-send-email-ville.syrjala@linux.intel.com> User-Agent: Alpine 2.20 (LRH 67 2015-01-07) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > From: Ville Syrjälä > > Commit 6894258eda2f ("dma-mapping: consolidate dma_{alloc,free}_{attrs,coherent}") > broke drivers that pass NULL as the device for dma_alloc. > Fix things by moving the ISA DMA fallback dev assignment earlier. > > A quick search suggest that Meelis Roos has hit this with sb16, and I > caught it with smsc-ircc2. Here's the oops I got: [...] The patch also fixes my SB16 issue, thank you! > diff --git a/arch/x86/kernel/pci-dma.c b/arch/x86/kernel/pci-dma.c > index 1b55de1..cd99433 100644 > --- a/arch/x86/kernel/pci-dma.c > +++ b/arch/x86/kernel/pci-dma.c > @@ -131,11 +131,12 @@ void dma_generic_free_coherent(struct device *dev, size_t size, void *vaddr, > > bool arch_dma_alloc_attrs(struct device **dev, gfp_t *gfp) > { > + if (!*dev) > + *dev = &x86_dma_fallback_dev; > + > *gfp &= ~(__GFP_DMA | __GFP_HIGHMEM | __GFP_DMA32); > *gfp = dma_alloc_coherent_gfp_flags(*dev, *gfp); > > - if (!*dev) > - *dev = &x86_dma_fallback_dev; > if (!is_device_dma_capable(*dev)) > return false; > return true; > -- Meelis Roos (mroos@linux.ee)