From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qg0-f49.google.com (mail-qg0-f49.google.com [209.85.192.49]) by kanga.kvack.org (Postfix) with ESMTP id C241A828DF for ; Fri, 15 Jan 2016 11:59:02 -0500 (EST) Received: by mail-qg0-f49.google.com with SMTP id 6so433326998qgy.1 for ; Fri, 15 Jan 2016 08:59:02 -0800 (PST) Received: from mail-qk0-x244.google.com (mail-qk0-x244.google.com. [2607:f8b0:400d:c09::244]) by mx.google.com with ESMTPS id k9si14149425qge.20.2016.01.15.08.59.01 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 15 Jan 2016 08:59:02 -0800 (PST) Received: by mail-qk0-x244.google.com with SMTP id y67so4649237qkc.1 for ; Fri, 15 Jan 2016 08:59:01 -0800 (PST) MIME-Version: 1.0 In-Reply-To: <5693A77E.4020809@linux.intel.com> References: <1447247184-27939-1-git-send-email-sakari.ailus@linux.intel.com> <20151202162558.d0465f11746ff94114c5d987@linux-foundation.org> <5693A77E.4020809@linux.intel.com> Date: Fri, 15 Jan 2016 08:59:01 -0800 Message-ID: Subject: Re: [PATCH 1/1] mm: EXPORT_SYMBOL_GPL(find_vm_area); From: Dan Williams Content-Type: text/plain; charset=UTF-8 Sender: owner-linux-mm@kvack.org List-ID: To: Sakari Ailus Cc: Andrew Morton , linux-mm On Mon, Jan 11, 2016 at 5:00 AM, Sakari Ailus wrote: > Hi Andrew, > > Andrew Morton wrote: >> On Wed, 11 Nov 2015 15:06:24 +0200 Sakari Ailus wrote: >> >>> find_vm_area() is needed in implementing the DMA mapping API as a module. >>> Device specific IOMMUs with associated DMA mapping implementations should be >>> buildable as modules. >>> >>> ... >>> >>> --- a/mm/vmalloc.c >>> +++ b/mm/vmalloc.c >>> @@ -1416,6 +1416,7 @@ struct vm_struct *find_vm_area(const void *addr) >>> >>> return NULL; >>> } >>> +EXPORT_SYMBOL_GPL(find_vm_area); >> >> Confused. Who is setting CONFIG_HAS_DMA=m? >> > > Apologies for the late reply --- CONFIG_HAS_DMA isn't configured as a > module, but some devices are not DMA coherent even on x86. The existing > x86 DMA mapping implementation doesn't quite work for those at the > moment, and nothing prevents using another one (and as a module, in > which case this patch is required). Why not teach the DMA mapping api how to do cache management for such devices? Why would you need find_vm_area() exported? -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org