From d92576f1167cacf7844e5993f343eed4a6d8a147 Mon Sep 17 00:00:00 2001
From: Matthew Wilcox <matthew.r.wilcox@intel.com>
Date: Mon, 16 Feb 2015 15:59:44 -0800
Subject: dax: does not work correctly with virtual aliasing caches

The DAX code accesses the underlying storage through the kernel's linear
mapping, which may not be cache-coherent with user mappings on ARM, MIPS
or SPARC.  Temporarily disable the DAX code until this problem is
resolved.

The original XIP code also had this problem, but it was never noticed.

Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>
Cc: Andreas Dilger <andreas.dilger@intel.com>
Cc: Boaz Harrosh <boaz@plexistor.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
 fs/Kconfig | 1 +
 1 file changed, 1 insertion(+)

(limited to 'fs/Kconfig')

diff --git a/fs/Kconfig b/fs/Kconfig
index 5331497d5b25..ec35851e5b71 100644
--- a/fs/Kconfig
+++ b/fs/Kconfig
@@ -36,6 +36,7 @@ source "fs/nilfs2/Kconfig"
 config FS_DAX
 	bool "Direct Access (DAX) support"
 	depends on MMU
+	depends on !(ARM || MIPS || SPARC)
 	help
 	  Direct Access (DAX) can be used on memory-backed block devices.
 	  If the block device supports DAX and the filesystem supports DAX,
-- 
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