Re: Adding kmap_atomic_prot_pfn

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From: Ingo Molnar
Date: Friday, October 24, 2008 - 2:32 am

* Thomas Hellström <thomas@tungstengraphics.com> wrote:


okay, then just to put this question to rest: i wrote the original 
32-bit highmem code ~10 years ago. I wrote the first version of fixmap 
support - in fact i coined the term. I wrote the first version of the 
atomic-kmap facility as well.

All of that code is licensed under the GPLv2. So if anyone wants to make 
any copyright claims about highmem/kmap/fixmap derivative works, 
consider it in that light.

Regarding this new API variant that Keith wrote: it would be silly and 
dangerous to export it anywhere but to in-kernel drivers. The API 
disables preemption on 32-bit and rummages deep in the guts of the 
kernel as well, uses up a precious resource (fixmap slots), etc. It's 
internal and we eventually might want to deprecate forms of it and 
concentrate on the good 64-bit performance side.

	Ingo
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Messages in current thread:
[git pull] drm patches for 2.6.27-rc1, Dave Airlie, (Fri Oct 17, 2:29 pm)
Re: [git pull] drm patches for 2.6.27-rc1, Linus Torvalds, (Fri Oct 17, 3:43 pm)
Re: [git pull] drm patches for 2.6.27-rc1, Nick Piggin, (Fri Oct 17, 6:37 pm)
Re: [git pull] drm patches for 2.6.27-rc1, Eric Anholt, (Fri Oct 17, 7:10 pm)
Re: [git pull] drm patches for 2.6.27-rc1, Linus Torvalds, (Fri Oct 17, 7:47 pm)
Re: [git pull] drm patches for 2.6.27-rc1, Keith Packard, (Fri Oct 17, 8:49 pm)
Re: [git pull] drm patches for 2.6.27-rc1, Corbin Simpson, (Fri Oct 17, 11:44 pm)
Re: [git pull] drm patches for 2.6.27-rc1, Eric Anholt, (Sat Oct 18, 12:49 am)
Re: [git pull] drm patches for 2.6.27-rc1, Dave Airlie, (Sat Oct 18, 2:11 am)
Re: [git pull] drm patches for 2.6.27-rc1, Keith Packard, (Sat Oct 18, 12:11 pm)
Re: [git pull] drm patches for 2.6.27-rc1, Linus Torvalds, (Sat Oct 18, 12:31 pm)
Re: [git pull] drm patches for 2.6.27-rc1, Thomas Hellström, (Sat Oct 18, 1:07 pm)
Re: [git pull] drm patches for 2.6.27-rc1, Keith Packard, (Sat Oct 18, 1:20 pm)
Re: [git pull] drm patches for 2.6.27-rc1, Ingo Molnar, (Sat Oct 18, 1:37 pm)
Re: [git pull] drm patches for 2.6.27-rc1, Keith Packard, (Sat Oct 18, 2:51 pm)
Re: [git pull] drm patches for 2.6.27-rc1, Ingo Molnar, (Sat Oct 18, 3:32 pm)
Re: [git pull] drm patches for 2.6.27-rc1, Jon Smirl, (Sat Oct 18, 3:47 pm)
Re: [git pull] drm patches for 2.6.27-rc1, Linus Torvalds, (Sat Oct 18, 3:53 pm)
Re: [git pull] drm patches for 2.6.27-rc1, Keith Packard, (Sat Oct 18, 5:38 pm)
Re: [git pull] drm patches for 2.6.27-rc1, Arjan van de Ven, (Sat Oct 18, 6:06 pm)
Re: [git pull] drm patches for 2.6.27-rc1, Keith Packard, (Sat Oct 18, 6:15 pm)
Re: [git pull] drm patches for 2.6.27-rc1, Nick Piggin, (Sat Oct 18, 8:14 pm)
Re: [git pull] drm patches for 2.6.27-rc1, Keith Packard, (Sat Oct 18, 9:14 pm)
Re: [git pull] drm patches for 2.6.27-rc1, Yinghai Lu, (Sat Oct 18, 9:28 pm)
Re: [git pull] drm patches for 2.6.27-rc1, Keith Packard, (Sat Oct 18, 11:41 pm)
Re: [git pull] drm patches for 2.6.27-rc1, Peter Zijlstra, (Sun Oct 19, 10:52 am)
Re: io resources and cached mappings (was: [git pull] drm ..., Arjan van de Ven, (Sun Oct 19, 11:00 am)
Re: [git pull] drm patches for 2.6.27-rc1, Steven J Newbury, (Sun Oct 19, 9:17 pm)
Re: [git pull] drm patches for 2.6.27-rc1, Ingo Molnar, (Mon Oct 20, 3:01 am)
Re: [git pull] drm patches for 2.6.27-rc1, Linus Torvalds, (Mon Oct 20, 9:31 am)
Re: [git pull] drm patches for 2.6.27-rc1, Jesse Barnes, (Mon Oct 20, 1:04 pm)
Re: Adding kmap_atomic_prot_pfn (was: [git pull] drm patc ..., Benjamin Herrenschmidt, (Thu Oct 23, 8:21 pm)
Re: Adding kmap_atomic_prot_pfn (was: [git pull] drm patc ..., Benjamin Herrenschmidt, (Thu Oct 23, 8:24 pm)
Re: Adding kmap_atomic_prot_pfn , Thomas Hellström, (Fri Oct 24, 12:33 am)
Re: Adding kmap_atomic_prot_pfn, Ingo Molnar, (Fri Oct 24, 1:38 am)
Re: Adding kmap_atomic_prot_pfn, Thomas Hellström, (Fri Oct 24, 2:19 am)
Re: Adding kmap_atomic_prot_pfn, Ingo Molnar, (Fri Oct 24, 2:32 am)
Re: Adding kmap_atomic_prot_pfn, Thomas Hellström, (Fri Oct 24, 3:18 am)
Re: Adding kmap_atomic_prot_pfn, Thomas Hellström, (Fri Oct 24, 4:04 am)
Re: Adding kmap_atomic_prot_pfn, Keith Packard, (Fri Oct 24, 8:48 am)
[git pull] IO mappings, #2, Ingo Molnar, (Mon Nov 3, 10:29 am)
Re: [git pull] IO mappings, #2, Jonathan Corbet, (Tue Nov 4, 3:36 pm)
Re: [git pull] IO mappings, #2, Ingo Molnar, (Wed Nov 5, 2:01 am)