Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756745Ab2HXLwi (ORCPT ); Fri, 24 Aug 2012 07:52:38 -0400 Received: from hqemgate04.nvidia.com ([216.228.121.35]:6353 "EHLO hqemgate04.nvidia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756548Ab2HXLwb convert rfc822-to-8bit (ORCPT ); Fri, 24 Aug 2012 07:52:31 -0400 X-PGP-Universal: processed; by hqnvupgp05.nvidia.com on Fri, 24 Aug 2012 04:52:06 -0700 From: Hiroshi Doyu To: "konrad.wilk@oracle.com" CC: "m.szyprowski@samsung.com" , "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 , "subashrp@gmail.com" , "minchan@kernel.org" , "pullip.cho@samsung.com" Date: Fri, 24 Aug 2012 13:52:00 +0200 Subject: Re: [v3 1/4] ARM: dma-mapping: atomic_pool with struct page **pages Thread-Topic: [v3 1/4] ARM: dma-mapping: atomic_pool with struct page **pages Thread-Index: Ac2B7t/Rw3DAj1KmRFC3t/i1MGI/Mg== Message-ID: <20120824.145200.843951079622652894.hdoyu@nvidia.com> References: <1345796945-21115-1-git-send-email-hdoyu@nvidia.com><1345796945-21115-2-git-send-email-hdoyu@nvidia.com><20120824111323.GB11007@konrad-lan.dumpdata.com> In-Reply-To: <20120824111323.GB11007@konrad-lan.dumpdata.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: 2132 Lines: 54 Konrad Rzeszutek Wilk wrote @ Fri, 24 Aug 2012 13:13:23 +0200: > On Fri, Aug 24, 2012 at 11:29:02AM +0300, Hiroshi Doyu wrote: > > struct page **pages is necessary to align with non atomic path in > > __iommu_get_pages(). atomic_pool() has the intialized **pages instead > > of just *page. > > > > Signed-off-by: Hiroshi Doyu > > --- > > arch/arm/mm/dma-mapping.c | 17 +++++++++++++---- > > 1 files changed, 13 insertions(+), 4 deletions(-) > > > > diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c > > index 601da7a..b14ee64 100644 > > --- a/arch/arm/mm/dma-mapping.c > > +++ b/arch/arm/mm/dma-mapping.c > > @@ -296,7 +296,7 @@ struct dma_pool { > > unsigned long *bitmap; > > unsigned long nr_pages; > > void *vaddr; > > - struct page *page; > > + struct page **pages; > > }; > > > > static struct dma_pool atomic_pool = { > > @@ -335,12 +335,16 @@ static int __init atomic_pool_init(void) > > unsigned long nr_pages = pool->size >> PAGE_SHIFT; > > unsigned long *bitmap; > > struct page *page; > > + struct page **pages; > > void *ptr; > > int bitmap_size = BITS_TO_LONGS(nr_pages) * sizeof(long); > > + size_t size = nr_pages * sizeof(struct page *); > > > > - bitmap = kzalloc(bitmap_size, GFP_KERNEL); > > + size += bitmap_size; > > + bitmap = kzalloc(size, GFP_KERNEL); > > if (!bitmap) > > goto no_bitmap; > > + pages = (void *)bitmap + bitmap_size; > > So you stuck a bitmap field in front of the array then? > Why not just define a structure where this is clearly defined > instead of doing the casting. I just wanted to allocate only once for the members "pool->bitmap" and "pool->pages" at once. Since the size of a whole bitmap isn't known in advance, I couldn't find any fixed type for this bitmap, which pointer can be shifted without casting. IOW, they are variable length. -- 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/