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John David Anglin f8dae00684 parisc: Ensure full cache coherency for kmap/kunmap
Helge Deller noted a few weeks ago problems with the AIO support on
parisc. This change is the result of numerous iterations on how best to
deal with this problem.

The solution adopted here is to provide full cache coherency in a
uniform manner on all parisc systems. This involves calling
flush_dcache_page() on kmap operations and flush_kernel_dcache_page() on
kunmap operations. As a result, the copy_user_page() and
clear_user_page() functions can be removed and the overall code is
simpler.

The change ensures that both userspace and kernel aliases to a mapped
page are invalidated and flushed. This is necessary for the correct
operation of PA8800 and PA8900 based systems which do not support
inequivalent aliases.

With this change, I have observed no cache related issues on c8000 and
rp3440. It is now possible for example to do kernel builds with "-j64"
on four way systems.

On systems using XFS file systems, the patch recently posted by Mikulas
Patocka to "fix crash using XFS on loopback" is needed to avoid a hang
caused by an uninitialized lock passed to flush_dcache_page() in the
page struct.

Signed-off-by: John David Anglin <dave.anglin@bell.net>
Cc: stable@vger.kernel.org # v3.9+
Signed-off-by: Helge Deller <deller@gmx.de>
2014-01-08 23:02:57 +01:00
..
configs parisc: update 64bit defconfigs and use SIL680 instead of SIIMAGE driver 2013-12-03 23:23:35 +01:00
hpux [readdir] constify ->actor 2013-06-29 12:57:05 +04:00
include parisc: Ensure full cache coherency for kmap/kunmap 2014-01-08 23:02:57 +01:00
kernel parisc: Ensure full cache coherency for kmap/kunmap 2014-01-08 23:02:57 +01:00
lib parisc: size_t is unsigned, so comparison size < 0 doesn't make sense. 2013-11-20 00:09:42 +01:00
math-emu parisc: remove duplicate define 2013-11-07 22:28:15 +01:00
mm parisc: fix kernel memory layout in vmlinux.ld.S 2013-11-30 22:09:21 +01:00
oprofile oprofile: more whitespace fixes 2008-10-15 20:55:51 +02:00
Kconfig Kconfig cleanups for v3.13 2013-11-15 14:05:15 -08:00
Kconfig.debug consolidate per-arch stack overflow debugging options 2013-07-04 11:25:39 -07:00
Makefile parisc: make "make install" not depend on vmlinux 2013-11-07 22:28:06 +01:00
defpalo.conf parisc: switch to gzip-compressed vmlinuz kernel 2013-07-09 22:09:20 +02:00
install.sh parisc: make "make install" not depend on vmlinux 2013-11-07 22:28:06 +01:00
nm Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00