md/raid6: move raid6 data processing to raid6_pq.ko

Move the raid6 data processing routines into a standalone module
(raid6_pq) to prepare them to be called from async_tx wrappers and other
non-md drivers/modules.  This precludes a circular dependency of raid456
needing the async modules for data processing while those modules in
turn depend on raid456 for the base level synchronous raid6 routines.

To support this move:
1/ The exportable definitions in raid6.h move to include/linux/raid/pq.h
2/ The raid6_call, recovery calls, and table symbols are exported
3/ Extra #ifdef __KERNEL__ statements to enable the userspace raid6test to
   compile

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: NeilBrown <neilb@suse.de>

1 files changed, 3 insertions, 1 deletions

diff --git a/drivers/md/Makefile b/drivers/md/Makefile
index 3b118da575ee..45cc5951d928 100644
--- a/drivers/md/Makefile
+++ b/drivers/md/Makefile
@@ -9,7 +9,8 @@ dm-snapshot-y	+= dm-snap.o dm-exception-store.o dm-snap-transient.o \
                     dm-snap-persistent.o
 dm-mirror-y     += dm-raid1.o
 md-mod-y        += md.o bitmap.o
-raid456-y       += raid5.o raid6algos.o raid6recov.o raid6tables.o \
+raid456-y       += raid5.o
+raid6_pq-y      += raid6algos.o raid6recov.o raid6tables.o \
                    raid6int1.o raid6int2.o raid6int4.o \
                    raid6int8.o raid6int16.o raid6int32.o \
                    raid6altivec1.o raid6altivec2.o raid6altivec4.o \
@@ -26,6 +27,7 @@ obj-$(CONFIG_MD_LINEAR)		+= linear.o
 obj-$(CONFIG_MD_RAID0)          += raid0.o
 obj-$(CONFIG_MD_RAID1)          += raid1.o
 obj-$(CONFIG_MD_RAID10)         += raid10.o
+obj-$(CONFIG_MD_RAID6_PQ)       += raid6_pq.o
 obj-$(CONFIG_MD_RAID456)        += raid456.o
 obj-$(CONFIG_MD_MULTIPATH)      += multipath.o
 obj-$(CONFIG_MD_FAULTY)         += faulty.o