[PATCH] md: merge raid5 and raid6 code

There is a lot of commonality between raid5.c and raid6main.c.  This patches
merges both into one module called raid456.  This saves a lot of code, and
paves the way for online raid5->raid6 migrations.

There is still duplication, e.g.  between handle_stripe5 and handle_stripe6.
This will probably be cleaned up later.

Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 12 insertions, 26 deletions

diff --git a/drivers/md/Kconfig b/drivers/md/Kconfig
index ac25a48362ac..f657aa7ec78c 100644
--- a/drivers/md/Kconfig
+++ b/drivers/md/Kconfig
@@ -104,8 +104,8 @@ config MD_RAID10
 
           If unsure, say Y.
 
-config MD_RAID5
-        tristate "RAID-4/RAID-5 mode"
+config MD_RAID456
+        tristate "RAID-4/RAID-5/RAID-6 mode"
         depends on BLK_DEV_MD
         ---help---
           A RAID-5 set of N drives with a capacity of C MB per drive provides
@@ -116,14 +116,22 @@ config MD_RAID5
           while a RAID-5 set distributes the parity across the drives in one
           of the available parity distribution methods.
 
+          A RAID-6 set of N drives with a capacity of C MB per drive
+          provides the capacity of C * (N - 2) MB, and protects
+          against a failure of any two drives. For a given sector
+          (row) number, (N - 2) drives contain data sectors, and two
+          drives contains two independent redundancy syndromes.  Like
+          RAID-5, RAID-6 distributes the syndromes across the drives
+          in one of the available parity distribution methods.
+
           Information about Software RAID on Linux is contained in the
           Software-RAID mini-HOWTO, available from
           <http://www.tldp.org/docs.html#howto>. There you will also
           learn where to get the supporting user space utilities raidtools.
 
-          If you want to use such a RAID-4/RAID-5 set, say Y.  To
+          If you want to use such a RAID-4/RAID-5/RAID-6 set, say Y.  To
           compile this code as a module, choose M here: the module
-          will be called raid5.
+          will be called raid456.
 
           If unsure, say Y.
 
@@ -154,28 +162,6 @@ config MD_RAID5_RESHAPE
           There should be enough spares already present to make the new
           array workable.
 
-config MD_RAID6
-        tristate "RAID-6 mode"
-        depends on BLK_DEV_MD
-        ---help---
-          A RAID-6 set of N drives with a capacity of C MB per drive
-          provides the capacity of C * (N - 2) MB, and protects
-          against a failure of any two drives. For a given sector
-          (row) number, (N - 2) drives contain data sectors, and two
-          drives contains two independent redundancy syndromes.  Like
-          RAID-5, RAID-6 distributes the syndromes across the drives
-          in one of the available parity distribution methods.
-
-          RAID-6 requires mdadm-1.5.0 or later, available at:
-
-          ftp://ftp.kernel.org/pub/linux/utils/raid/mdadm/
-
-          If you want to use such a RAID-6 set, say Y.  To compile
-          this code as a module, choose M here: the module will be
-          called raid6.
-
-          If unsure, say Y.
-
 config MD_MULTIPATH
         tristate "Multipath I/O support"
         depends on BLK_DEV_MD