linux-kernel - Re: Adding kmap_atomic_prot

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Message-ID: <49017A2C.5010504@tungstengraphics.com>
Date:	Fri, 24 Oct 2008 09:33:00 +0200
From:	Thomas Hellström <thomas@...gstengraphics.com>
To:	Keith Packard <keithp@...thp.com>
CC:	Linus Torvalds <torvalds@...ux-foundation.org>,
	nickpiggin@...oo.com.au, airlied@...ux.ie, dri-devel@...ts.sf.net,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	jbarnes@...tuousgeek.org, Peter Anvin <hpa@...or.com>,
	Andrew Morton <akpm@...ux-foundation.org>, yinghai@...nel.org,
	Ingo Molnar <mingo@...e.hu>
Subject: Re: Adding kmap_atomic_prot_pfn 

Keith,

What you actually are doing here is claiming copyright on code that 
other people have written, and tighten the export restrictions. 
kmap_atomic_prot_pfn() appeared long ago in drm git with identical code 
and purpose, but with different authors, and iounmap_atomic is identical 
to kunmap_atomic.

Pls fix.

/Thomas

Keith Packard wrote:
>
> diff --git a/arch/x86/mm/iomap_32.c b/arch/x86/mm/iomap_32.c
> new file mode 100644
> index 0000000..c559599
> --- /dev/null
> +++ b/arch/x86/mm/iomap_32.c
> @@ -0,0 +1,59 @@
> +/*
> + * Copyright © 2008 Keith Packard <keithp@...thp.com>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful, but
> + * WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> + * General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License along
> + * with this program; if not, write to the Free Software Foundation, Inc.,
> + * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
> + */
> +
> +#include <asm/iomap.h>
> +#include <linux/module.h>
> +
> +/* Map 'pfn' using fixed map 'type' and protections 'prot'
> + */
> +void *
> +iomap_atomic_prot_pfn(unsigned long pfn, enum km_type type, pgprot_t prot)
> +{
> +	enum fixed_addresses idx;
> +	unsigned long vaddr;
> +
> +	pagefault_disable();
> +
> +	idx = type + KM_TYPE_NR*smp_processor_id();
> +	vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
> +	set_pte(kmap_pte-idx, pfn_pte(pfn, prot));
> +	arch_flush_lazy_mmu_mode();
> +
> +	return (void*) vaddr;
> +}
> +EXPORT_SYMBOL_GPL(iomap_atomic_prot_pfn);
> +
> +void
> +iounmap_atomic(void *kvaddr, enum km_type type)
> +{
> +	unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
> +	enum fixed_addresses idx = type + KM_TYPE_NR*smp_processor_id();
> +
> +	/*
> +	 * Force other mappings to Oops if they'll try to access this pte
> +	 * without first remap it.  Keeping stale mappings around is a bad idea
> +	 * also, in case the page changes cacheability attributes or becomes
> +	 * a protected page in a hypervisor.
> +	 */
> +	if (vaddr == __fix_to_virt(FIX_KMAP_BEGIN+idx))
> +		kpte_clear_flush(kmap_pte-idx, vaddr);
> +
> +	arch_flush_lazy_mmu_mode();
> +	pagefault_enable();
> +}
> +EXPORT_SYMBOL_GPL(iounmap_atomic);
>   



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