Date: Mon, 4 Apr 2016 17:05:58 +0200
From: Boris Brezillon <boris.brezillon@free-electrons.com>
To: Vignesh R <vigneshr@ti.com>
Cc: David Woodhouse <dwmw2@infradead.org>,
        Brian Norris <computersforpeace@gmail.com>,
        <linux-mtd@lists.infradead.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Dave Gordon <david.s.gordon@intel.com>,
        Mark Brown <broonie@kernel.org>, <linux-spi@vger.kernel.org>,
        <linux-arm-kernel@lists.infradead.org>,
        Vinod Koul <vinod.koul@intel.com>,
        Dan Williams <dan.j.williams@intel.com>, <dmaengine@vger.kernel.org>,
        Mauro Carvalho Chehab <m.chehab@samsung.com>,
        Hans Verkuil <hans.verkuil@cisco.com>,
        Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
        <linux-media@vger.kernel.org>, Richard Weinberger <richard@nod.at>,
        Herbert Xu <herbert@gondor.apana.org.au>,
        "David S. Miller" <davem@davemloft.net>,
        <linux-crypto@vger.kernel.org>, <linux-mm@kvack.org>,
        Joerg Roedel <joro@8bytes.org>, <iommu@lists.linux-foundation.org>,
        <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 1/4] mm: add is_highmem_addr() helper
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On Mon, 4 Apr 2016 13:44:11 +0530
Vignesh R <vigneshr@ti.com> wrote:

> Hi,
> 
> On 03/31/2016 05:59 PM, Boris Brezillon wrote:
> > Add an helper to check if a virtual address is in the highmem region.
> > 
> > Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
> > ---
> >  include/linux/highmem.h | 13 +++++++++++++
> >  1 file changed, 13 insertions(+)
> > 
> > diff --git a/include/linux/highmem.h b/include/linux/highmem.h
> > index bb3f329..13dff37 100644
> > --- a/include/linux/highmem.h
> > +++ b/include/linux/highmem.h
> > @@ -41,6 +41,14 @@ void kmap_flush_unused(void);
> >  
> >  struct page *kmap_to_page(void *addr);
> >  
> > +static inline bool is_highmem_addr(const void *x)
> > +{
> > +	unsigned long vaddr = (unsigned long)x;
> > +
> > +	return vaddr >=  PKMAP_BASE &&
> > +	       vaddr < ((PKMAP_BASE + LAST_PKMAP) * PAGE_SIZE);
> 
> 
> Shouldn't this be:
> 		vaddr < (PKMAP_BASE + (LAST_PKMAP * PAGE_SIZE)) ?

Oops, yes indeed.

Anyway, given Russell's feedback I don't think I'm gonna follow up on
this series.

Sorry.

Boris

-- 
Boris Brezillon, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com