Messages in this thread | | | Date | Fri, 13 Sep 2013 14:36:15 +0200 | Subject | Re: [GIT PULL] Btrfs | From | Geert Uytterhoeven <> |
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On Fri, Sep 13, 2013 at 2:15 PM, Russell King <rmk@arm.linux.org.uk> wrote: > On Fri, Sep 13, 2013 at 07:53:21AM -0400, Josh Boyer wrote: >> I'm not an ARM expert, so I don't know if ARM should use the >> asm-generic implementations, or just use __get_user/__put_user in all >> cases. I've CC'd rmk. > > Why do we have uaccess-unaligned.h ? Normally, these kinds of things > are spawned by architectures which have problems with unaligned accesses, > ARM being one of them, but afaik we've never need this. > > With the kernel-side trapping of unaligned accesses on older hardware, > we've always dealt with the normal accessor faulting. > > From what I can tell in the git history, these unaligned put_user and > get_user have existed all the way back to the dawn of git use. > > Can someone enlighten me why we have them?
You removed the answer when trimming the quoted part:
| "Btrfs is the first user of __put_user_unaligned() outside the compat code,
__put_user_unaligned() is used in fs/compat.c, presumably because alignment restrictions may differ between 32- and 64-bit versions of the same CPU family.
No one seems to actully use __get_user_unaligned().
Gr{oetje,eeting}s,
Geert
-- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
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