Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932654Ab2HVOpN (ORCPT ); Wed, 22 Aug 2012 10:45:13 -0400 Received: from hqemgate04.nvidia.com ([216.228.121.35]:8218 "EHLO hqemgate04.nvidia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932467Ab2HVOpJ convert rfc822-to-8bit (ORCPT ); Wed, 22 Aug 2012 10:45:09 -0400 X-PGP-Universal: processed; by hqnvupgp07.nvidia.com on Wed, 22 Aug 2012 07:38:45 -0700 From: Hiroshi Doyu To: "m.szyprowski@samsung.com" CC: "linux-arm-kernel@lists.infradead.org" , "linaro-mm-sig@lists.linaro.org" , "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , "kyungmin.park@samsung.com" , "arnd@arndb.de" , "linux@arm.linux.org.uk" , "chunsang.jeong@linaro.org" , Krishna Reddy , "konrad.wilk@oracle.com" , "subashrp@gmail.com" , "minchan@kernel.org" Date: Wed, 22 Aug 2012 16:44:29 +0200 Subject: Re: [RFC 0/4] ARM: dma-mapping: IOMMU atomic allocation Thread-Topic: [RFC 0/4] ARM: dma-mapping: IOMMU atomic allocation Thread-Index: Ac2AdKQhZr6VE7kCRyelmQ2sRg33Kg== Message-ID: <20120822.174429.909991514856769456.hdoyu@nvidia.com> References: <1345630830-9586-1-git-send-email-hdoyu@nvidia.com><005901cd805e$4afd2e40$e0f78ac0$%szyprowski@samsung.com> In-Reply-To: <005901cd805e$4afd2e40$e0f78ac0$%szyprowski@samsung.com> Accept-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-nvconfidentiality: public acceptlanguage: en-US Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7BIT MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3095 Lines: 94 Hi Marek, Marek Szyprowski wrote @ Wed, 22 Aug 2012 14:04:26 +0200: > Hi Hiroshi, > > On Wednesday, August 22, 2012 12:20 PM Hiroshi Doyu wrote: > > > The commit e9da6e9 "ARM: dma-mapping: remove custom consistent dma > > region" breaks the compatibility with existing drivers. This causes > > the following kernel oops(*1). That driver has called dma_pool_alloc() > > to allocate memory from the interrupt context, and it hits > > BUG_ON(in_interrpt()) in "get_vm_area_caller()". This patch seris > > fixes this problem with making use of the pre-allocate atomic memory > > pool which DMA is using in the same way as DMA does now. > > > > Any comment would be really appreciated. > > I was working on the similar patches, but You were faster. ;-) Thank you for reviewing my patches. > Basically the patch no 1 and 2 are fine, but I don't like the changes proposed in > patch 3 and 4. You should not alter the attributes provided by the user nor make any > assumptions that such attributes has been provided - drivers are allowed to call > dma_alloc_attrs() directly. Please rework your patches to avoid such > approach. Sure. I'll send the series again later. Instead of making use of DMA_ATTR_NO_KERNEL_MAPPING, I use the following "__in_atomic_pool()" to see if buffer comes from atomic or not at freeing. >From cdf8621fd0876f3e56a55885c27e363893df2c98 Mon Sep 17 00:00:00 2001 From: Hiroshi Doyu Date: Wed, 22 Aug 2012 17:26:29 +0300 Subject: [PATCH 1/1] ARM: dma-mapping: Refactor out to introduce __in_atomic_pool Check the given range("start", "size") is included in "atomic_pool" or not. Signed-off-by: Hiroshi Doyu --- arch/arm/mm/dma-mapping.c | 20 +++++++++++++++----- 1 files changed, 15 insertions(+), 5 deletions(-) diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c index 30bef80..26080ef 100644 --- a/arch/arm/mm/dma-mapping.c +++ b/arch/arm/mm/dma-mapping.c @@ -450,20 +450,30 @@ static void *__alloc_from_pool(size_t size, struct page **ret_page) return ptr; } -static int __free_from_pool(void *start, size_t size) +static bool __in_atomic_pool(void *start, size_t size) { struct dma_pool *pool = &atomic_pool; - unsigned long pageno, count; - unsigned long flags; if (start < pool->vaddr || start > pool->vaddr + pool->size) - return 0; + return false; if (start + size > pool->vaddr + pool->size) { WARN(1, "freeing wrong coherent size from pool\n"); - return 0; + return false; } + return true; +} + +static int __free_from_pool(void *start, size_t size) +{ + struct dma_pool *pool = &atomic_pool; + unsigned long pageno, count; + unsigned long flags; + + if (!__in_atomic_pool(start, size)) + return 0; + pageno = (start - pool->vaddr) >> PAGE_SHIFT; count = size >> PAGE_SHIFT; -- 1.7.5.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/