From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx172.postini.com [74.125.245.172]) by kanga.kvack.org (Postfix) with SMTP id 3FAB86B0068 for ; Fri, 24 Aug 2012 07:52:34 -0400 (EDT) From: Hiroshi Doyu Date: Fri, 24 Aug 2012 13:52:00 +0200 Subject: Re: [v3 1/4] ARM: dma-mapping: atomic_pool with struct page **pages 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> Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Sender: owner-linux-mm@kvack.org List-ID: 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" 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. > >=20 > > Signed-off-by: Hiroshi Doyu > > --- > > arch/arm/mm/dma-mapping.c | 17 +++++++++++++---- > > 1 files changed, 13 insertions(+), 4 deletions(-) > >=20 > > 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; > > }; > > =20 > > static struct dma_pool atomic_pool =3D { > > @@ -335,12 +335,16 @@ static int __init atomic_pool_init(void) > > unsigned long nr_pages =3D pool->size >> PAGE_SHIFT; > > unsigned long *bitmap; > > struct page *page; > > + struct page **pages; > > void *ptr; > > int bitmap_size =3D BITS_TO_LONGS(nr_pages) * sizeof(long); > > + size_t size =3D nr_pages * sizeof(struct page *); > > =20 > > - bitmap =3D kzalloc(bitmap_size, GFP_KERNEL); > > + size +=3D bitmap_size; > > + bitmap =3D kzalloc(size, GFP_KERNEL); > > if (!bitmap) > > goto no_bitmap; > > + pages =3D (void *)bitmap + bitmap_size; >=20 > 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, 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