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Date:   Wed, 6 May 2020 13:33:39 -0700
From:   Ira Weiny <ira.weiny@intel.com>
To:     Christoph Hellwig <hch@infradead.org>
Cc:     linux-kernel@vger.kernel.org,
        Andrew Morton <akpm@linux-foundation.org>,
        Christian Koenig <christian.koenig@amd.com>,
        Huang Rui <ray.huang@amd.com>,
        Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
        "James E.J. Bottomley" <James.Bottomley@hansenpartnership.com>,
        Helge Deller <deller@gmx.de>,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Paul Mackerras <paulus@samba.org>,
        "David S. Miller" <davem@davemloft.net>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        Andy Lutomirski <luto@kernel.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Chris Zankel <chris@zankel.net>,
        Max Filippov <jcmvbkbc@gmail.com>,
        Dan Williams <dan.j.williams@intel.com>,
        linux-snps-arc@lists.infradead.org,
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        linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org,
        linuxppc-dev@lists.ozlabs.org, sparclinux@vger.kernel.org,
        linux-xtensa@linux-xtensa.org, dri-devel@lists.freedesktop.org
Subject: Re: [PATCH V2 08/11] arch/kmap: Ensure kmap_prot visibility
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 <20200504010912.982044-9-ira.weiny@intel.com>
 <20200506061326.GD5192@infradead.org>
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On Tue, May 05, 2020 at 11:13:26PM -0700, Christoph Hellwig wrote:
> On Sun, May 03, 2020 at 06:09:09PM -0700, ira.weiny@intel.com wrote:
> > From: Ira Weiny <ira.weiny@intel.com>
> > 
> > We want to support kmap_atomic_prot() on all architectures and it makes
> > sense to define kmap_atomic() to use the default kmap_prot.
> > 
> > So we ensure all arch's have a globally available kmap_prot either as a
> > define or exported symbol.
> 
> FYI, I still think a
> 
> #ifndef kmap_prot
> #define kmap_prot PAGE_KERNEL
> #endif
> 
> in linux/highmem.h would be nicer.  Then only xtensa and sparc need
> to override it and clearly stand out.

That would be nice...  But...  in this particular patch kmap_prot needs to be
in arch/microblaze/include/asm/highmem.h to preserve bisect-ability.

So there would be an inversion with this define and the core #ifndef...

I like the change but I'm going to add this change as a follow on patch because
at the end of the series microblaze no longer needs this.

If this is reasonable could I get a review on this patch to add to the next
series?

Ira