Re: dio_get_page() lockdep complaints

From: Martin Schwidefsky
Date: Mon Nov 12 2007 - 03:46:19 EST


On Sun, 2007-11-11 at 20:49 +0100, Peter Zijlstra wrote:
> Right, which gets us into all kinds of trouble because some sites need
> mmap_sem to resolve some races, notably s390 31-bit and shm.

You are refering to the mmap_sem use in compat_linux.c:do_mmap2, aren't
you? That check for adresses > 2GB after the call to do_mmap_pgoff can
be removed since arch_get_unmapped_area already checks against
TASK_SIZE. The result of the do_mmap_pgoff call will never be out of
range. This check is a left-over from the early days of the s390 compat
code.

--
blue skies,
Martin.

"Reality continues to ruin my life." - Calvin.


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