From 1442577bf6da1a31ae6555212202be9a2cec5642 Mon Sep 17 00:00:00 2001
From: NeilBrown <neilb@suse.de>
Date: Fri, 16 Oct 2009 15:55:25 +1100
Subject: Revert "md: do not progress the resync process if the stripe was
 blocked"

This reverts commit df10cfbc4d7ab93260d997df754219d390d62a9d.

This patch was based on a misunderstanding and risks introducing a busy-wait loop.
So revert it.

Acked-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: NeilBrown <neilb@suse.de>
---
 drivers/md/raid5.c | 19 ++++++-------------
 1 file changed, 6 insertions(+), 13 deletions(-)

diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 94829804ab7f..ec14ff5b508a 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -2896,7 +2896,7 @@ static void handle_stripe_expansion(raid5_conf_t *conf, struct stripe_head *sh,
  *
  */
 
-static bool handle_stripe5(struct stripe_head *sh)
+static void handle_stripe5(struct stripe_head *sh)
 {
 	raid5_conf_t *conf = sh->raid_conf;
 	int disks = sh->disks, i;
@@ -3167,11 +3167,9 @@ static bool handle_stripe5(struct stripe_head *sh)
 	ops_run_io(sh, &s);
 
 	return_io(return_bi);
-
-	return blocked_rdev == NULL;
 }
 
-static bool handle_stripe6(struct stripe_head *sh)
+static void handle_stripe6(struct stripe_head *sh)
 {
 	raid5_conf_t *conf = sh->raid_conf;
 	int disks = sh->disks;
@@ -3455,17 +3453,14 @@ static bool handle_stripe6(struct stripe_head *sh)
 	ops_run_io(sh, &s);
 
 	return_io(return_bi);
-
-	return blocked_rdev == NULL;
 }
 
-/* returns true if the stripe was handled */
-static bool handle_stripe(struct stripe_head *sh)
+static void handle_stripe(struct stripe_head *sh)
 {
 	if (sh->raid_conf->level == 6)
-		return handle_stripe6(sh);
+		handle_stripe6(sh);
 	else
-		return handle_stripe5(sh);
+		handle_stripe5(sh);
 }
 
 static void raid5_activate_delayed(raid5_conf_t *conf)
@@ -4277,9 +4272,7 @@ static inline sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *ski
 	clear_bit(STRIPE_INSYNC, &sh->state);
 	spin_unlock(&sh->lock);
 
-	/* wait for any blocked device to be handled */
-	while (unlikely(!handle_stripe(sh)))
-		;
+	handle_stripe(sh);
 	release_stripe(sh);
 
 	return STRIPE_SECTORS;
-- 
cgit v1.2.3-59-g8ed1b


From 1d9d52416c0445019ccc1f0fddb9a227456eb61b Mon Sep 17 00:00:00 2001
From: NeilBrown <neilb@suse.de>
Date: Fri, 16 Oct 2009 15:55:32 +1100
Subject: md/raid1/raid10: add a cond_resched

During 'check' of a raid1 or raid10 it is possible for the management
thread to spend a lot of time running 'memcmp' on blocks from
different devices, so make sure the thread has a chance to schedule.
raid5d already has a cond_resched (in process_stripe).

Reported-By: Lee Howard <faxguy@howardsilvan.com>
Signed-off-by: NeilBrown <neilb@suse.de>
---
 drivers/md/raid1.c  | 1 +
 drivers/md/raid10.c | 1 +
 2 files changed, 2 insertions(+)

diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index d1b9bd5fd4f6..71a01a2e1938 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -1683,6 +1683,7 @@ static void raid1d(mddev_t *mddev)
 				generic_make_request(bio);
 			}
 		}
+		cond_resched();
 	}
 	if (unplug)
 		unplug_slaves(mddev);
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 51c4c5c4d87a..69fc76caa469 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -1632,6 +1632,7 @@ static void raid10d(mddev_t *mddev)
 				generic_make_request(bio);
 			}
 		}
+		cond_resched();
 	}
 	if (unplug)
 		unplug_slaves(mddev);
-- 
cgit v1.2.3-59-g8ed1b


From f5efd45ae597c96ed017afad5662b67d55b402a0 Mon Sep 17 00:00:00 2001
From: Dan Williams <dan.j.williams@intel.com>
Date: Fri, 16 Oct 2009 15:55:38 +1100
Subject: md/raid5: initialize conf->device_lock earlier

Deallocating a raid5_conf_t structure requires taking 'device_lock'.
Ensure it is initialized before it is used, i.e. initialize the lock
before attempting any further initializations that might fail.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: NeilBrown <neilb@suse.de>
---
 drivers/md/raid5.c | 25 ++++++++++++-------------
 1 file changed, 12 insertions(+), 13 deletions(-)

diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index ec14ff5b508a..c3e596778618 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -4715,6 +4715,18 @@ static raid5_conf_t *setup_conf(mddev_t *mddev)
 	conf = kzalloc(sizeof(raid5_conf_t), GFP_KERNEL);
 	if (conf == NULL)
 		goto abort;
+	spin_lock_init(&conf->device_lock);
+	init_waitqueue_head(&conf->wait_for_stripe);
+	init_waitqueue_head(&conf->wait_for_overlap);
+	INIT_LIST_HEAD(&conf->handle_list);
+	INIT_LIST_HEAD(&conf->hold_list);
+	INIT_LIST_HEAD(&conf->delayed_list);
+	INIT_LIST_HEAD(&conf->bitmap_list);
+	INIT_LIST_HEAD(&conf->inactive_list);
+	atomic_set(&conf->active_stripes, 0);
+	atomic_set(&conf->preread_active_stripes, 0);
+	atomic_set(&conf->active_aligned_reads, 0);
+	conf->bypass_threshold = BYPASS_THRESHOLD;
 
 	conf->raid_disks = mddev->raid_disks;
 	conf->scribble_len = scribble_len(conf->raid_disks);
@@ -4737,19 +4749,6 @@ static raid5_conf_t *setup_conf(mddev_t *mddev)
 	if (raid5_alloc_percpu(conf) != 0)
 		goto abort;
 
-	spin_lock_init(&conf->device_lock);
-	init_waitqueue_head(&conf->wait_for_stripe);
-	init_waitqueue_head(&conf->wait_for_overlap);
-	INIT_LIST_HEAD(&conf->handle_list);
-	INIT_LIST_HEAD(&conf->hold_list);
-	INIT_LIST_HEAD(&conf->delayed_list);
-	INIT_LIST_HEAD(&conf->bitmap_list);
-	INIT_LIST_HEAD(&conf->inactive_list);
-	atomic_set(&conf->active_stripes, 0);
-	atomic_set(&conf->preread_active_stripes, 0);
-	atomic_set(&conf->active_aligned_reads, 0);
-	conf->bypass_threshold = BYPASS_THRESHOLD;
-
 	pr_debug("raid5: run(%s) called.\n", mdname(mddev));
 
 	list_for_each_entry(rdev, &mddev->disks, same_set) {
-- 
cgit v1.2.3-59-g8ed1b


From ed9bfdf1a40952fd0f8094ec77f876b84ead69af Mon Sep 17 00:00:00 2001
From: NeilBrown <neilb@suse.de>
Date: Fri, 16 Oct 2009 15:55:44 +1100
Subject: md: raid1/raid10: handle allocation errors during array setup.

Both raid1 and raid10 create a mempool during startup.
If the 'alloc' function for this mempool fails, unplug_slaves
is called.
If that happens when the pool is being initialised, unplug_slaves
will try to use the 'conf' structure that isn't filled in yet, and
badness will happen.

So ensure that unplug_slaves doesn't get called unless we know
that the conf structure if fully initialised.

Signed-off-by: NeilBrown <neilb@suse.de>
---
 drivers/md/raid1.c  | 5 +++--
 drivers/md/raid10.c | 4 ++--
 2 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index 71a01a2e1938..a053423785c9 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -64,7 +64,7 @@ static void * r1bio_pool_alloc(gfp_t gfp_flags, void *data)
 
 	/* allocate a r1bio with room for raid_disks entries in the bios array */
 	r1_bio = kzalloc(size, gfp_flags);
-	if (!r1_bio)
+	if (!r1_bio && pi->mddev)
 		unplug_slaves(pi->mddev);
 
 	return r1_bio;
@@ -1979,13 +1979,14 @@ static int run(mddev_t *mddev)
 	conf->poolinfo = kmalloc(sizeof(*conf->poolinfo), GFP_KERNEL);
 	if (!conf->poolinfo)
 		goto out_no_mem;
-	conf->poolinfo->mddev = mddev;
+	conf->poolinfo->mddev = NULL;
 	conf->poolinfo->raid_disks = mddev->raid_disks;
 	conf->r1bio_pool = mempool_create(NR_RAID1_BIOS, r1bio_pool_alloc,
 					  r1bio_pool_free,
 					  conf->poolinfo);
 	if (!conf->r1bio_pool)
 		goto out_no_mem;
+	conf->poolinfo->mddev = mddev;
 
 	spin_lock_init(&conf->device_lock);
 	mddev->queue->queue_lock = &conf->device_lock;
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 69fc76caa469..c2cb7b87b440 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -68,7 +68,7 @@ static void * r10bio_pool_alloc(gfp_t gfp_flags, void *data)
 
 	/* allocate a r10bio with room for raid_disks entries in the bios array */
 	r10_bio = kzalloc(size, gfp_flags);
-	if (!r10_bio)
+	if (!r10_bio && conf->mddev)
 		unplug_slaves(conf->mddev);
 
 	return r10_bio;
@@ -2096,7 +2096,6 @@ static int run(mddev_t *mddev)
 	if (!conf->tmppage)
 		goto out_free_conf;
 
-	conf->mddev = mddev;
 	conf->raid_disks = mddev->raid_disks;
 	conf->near_copies = nc;
 	conf->far_copies = fc;
@@ -2133,6 +2132,7 @@ static int run(mddev_t *mddev)
 		goto out_free_conf;
 	}
 
+	conf->mddev = mddev;
 	spin_lock_init(&conf->device_lock);
 	mddev->queue->queue_lock = &conf->device_lock;
 
-- 
cgit v1.2.3-59-g8ed1b


From ae8fa2831bbc5092ee9d1b90e623af881cf27140 Mon Sep 17 00:00:00 2001
From: NeilBrown <neilb@suse.de>
Date: Fri, 16 Oct 2009 15:56:01 +1100
Subject: md: remove clumsy usage of do_sync_mapping_range from bitmap code

and replace with vfs_fsync which is much neater (but wasn't exported,
or even in existence at the time the code was written).

Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: NeilBrown <neilb@suse.de>
---
 drivers/md/bitmap.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/md/bitmap.c b/drivers/md/bitmap.c
index 6986b0059d23..60e2b322db11 100644
--- a/drivers/md/bitmap.c
+++ b/drivers/md/bitmap.c
@@ -1624,10 +1624,11 @@ int bitmap_create(mddev_t *mddev)
 	bitmap->offset = mddev->bitmap_offset;
 	if (file) {
 		get_file(file);
-		do_sync_mapping_range(file->f_mapping, 0, LLONG_MAX,
-				      SYNC_FILE_RANGE_WAIT_BEFORE |
-				      SYNC_FILE_RANGE_WRITE |
-				      SYNC_FILE_RANGE_WAIT_AFTER);
+		/* As future accesses to this file will use bmap,
+		 * and bypass the page cache, we must sync the file
+		 * first.
+		 */
+		vfs_fsync(file, file->f_dentry, 1);
 	}
 	/* read superblock from bitmap file (this sets bitmap->chunksize) */
 	err = bitmap_read_sb(bitmap);
-- 
cgit v1.2.3-59-g8ed1b


From dce3a7a42d585b74ce68081010b42afe81c8f4c4 Mon Sep 17 00:00:00 2001
From: Vladimir Dronnikov <dronnikov@gmail.com>
Date: Fri, 16 Oct 2009 16:25:19 +1100
Subject: md: drivers/md/unroll.pl replaced with awk analog

drivers/md/unroll.pl replaced by awk script to drop build-time
dependency on perl

Signed-off-by: Vladimir Dronnikov <dronnikov@gmail.com>
Signed-off-by: NeilBrown <neilb@suse.de>
---
 drivers/md/Makefile           | 22 +++++++++++-----------
 drivers/md/raid6altivec.uc    |  2 +-
 drivers/md/raid6int.uc        |  2 +-
 drivers/md/raid6test/Makefile | 42 +++++++++++++++++++++---------------------
 drivers/md/unroll.awk         | 20 ++++++++++++++++++++
 drivers/md/unroll.pl          | 24 ------------------------
 6 files changed, 54 insertions(+), 58 deletions(-)
 create mode 100644 drivers/md/unroll.awk
 delete mode 100644 drivers/md/unroll.pl

diff --git a/drivers/md/Makefile b/drivers/md/Makefile
index 1dc4185bd781..e355e7f6a536 100644
--- a/drivers/md/Makefile
+++ b/drivers/md/Makefile
@@ -46,7 +46,7 @@ obj-$(CONFIG_DM_LOG_USERSPACE)	+= dm-log-userspace.o
 obj-$(CONFIG_DM_ZERO)		+= dm-zero.o
 
 quiet_cmd_unroll = UNROLL  $@
-      cmd_unroll = $(PERL) $(srctree)/$(src)/unroll.pl $(UNROLL) \
+      cmd_unroll = $(AWK) -f$(srctree)/$(src)/unroll.awk -vN=$(UNROLL) \
                    < $< > $@ || ( rm -f $@ && exit 1 )
 
 ifeq ($(CONFIG_ALTIVEC),y)
@@ -59,56 +59,56 @@ endif
 
 targets += raid6int1.c
 $(obj)/raid6int1.c:   UNROLL := 1
-$(obj)/raid6int1.c:   $(src)/raid6int.uc $(src)/unroll.pl FORCE
+$(obj)/raid6int1.c:   $(src)/raid6int.uc $(src)/unroll.awk FORCE
 	$(call if_changed,unroll)
 
 targets += raid6int2.c
 $(obj)/raid6int2.c:   UNROLL := 2
-$(obj)/raid6int2.c:   $(src)/raid6int.uc $(src)/unroll.pl FORCE
+$(obj)/raid6int2.c:   $(src)/raid6int.uc $(src)/unroll.awk FORCE
 	$(call if_changed,unroll)
 
 targets += raid6int4.c
 $(obj)/raid6int4.c:   UNROLL := 4
-$(obj)/raid6int4.c:   $(src)/raid6int.uc $(src)/unroll.pl FORCE
+$(obj)/raid6int4.c:   $(src)/raid6int.uc $(src)/unroll.awk FORCE
 	$(call if_changed,unroll)
 
 targets += raid6int8.c
 $(obj)/raid6int8.c:   UNROLL := 8
-$(obj)/raid6int8.c:   $(src)/raid6int.uc $(src)/unroll.pl FORCE
+$(obj)/raid6int8.c:   $(src)/raid6int.uc $(src)/unroll.awk FORCE
 	$(call if_changed,unroll)
 
 targets += raid6int16.c
 $(obj)/raid6int16.c:  UNROLL := 16
-$(obj)/raid6int16.c:  $(src)/raid6int.uc $(src)/unroll.pl FORCE
+$(obj)/raid6int16.c:  $(src)/raid6int.uc $(src)/unroll.awk FORCE
 	$(call if_changed,unroll)
 
 targets += raid6int32.c
 $(obj)/raid6int32.c:  UNROLL := 32
-$(obj)/raid6int32.c:  $(src)/raid6int.uc $(src)/unroll.pl FORCE
+$(obj)/raid6int32.c:  $(src)/raid6int.uc $(src)/unroll.awk FORCE
 	$(call if_changed,unroll)
 
 CFLAGS_raid6altivec1.o += $(altivec_flags)
 targets += raid6altivec1.c
 $(obj)/raid6altivec1.c:   UNROLL := 1
-$(obj)/raid6altivec1.c:   $(src)/raid6altivec.uc $(src)/unroll.pl FORCE
+$(obj)/raid6altivec1.c:   $(src)/raid6altivec.uc $(src)/unroll.awk FORCE
 	$(call if_changed,unroll)
 
 CFLAGS_raid6altivec2.o += $(altivec_flags)
 targets += raid6altivec2.c
 $(obj)/raid6altivec2.c:   UNROLL := 2
-$(obj)/raid6altivec2.c:   $(src)/raid6altivec.uc $(src)/unroll.pl FORCE
+$(obj)/raid6altivec2.c:   $(src)/raid6altivec.uc $(src)/unroll.awk FORCE
 	$(call if_changed,unroll)
 
 CFLAGS_raid6altivec4.o += $(altivec_flags)
 targets += raid6altivec4.c
 $(obj)/raid6altivec4.c:   UNROLL := 4
-$(obj)/raid6altivec4.c:   $(src)/raid6altivec.uc $(src)/unroll.pl FORCE
+$(obj)/raid6altivec4.c:   $(src)/raid6altivec.uc $(src)/unroll.awk FORCE
 	$(call if_changed,unroll)
 
 CFLAGS_raid6altivec8.o += $(altivec_flags)
 targets += raid6altivec8.c
 $(obj)/raid6altivec8.c:   UNROLL := 8
-$(obj)/raid6altivec8.c:   $(src)/raid6altivec.uc $(src)/unroll.pl FORCE
+$(obj)/raid6altivec8.c:   $(src)/raid6altivec.uc $(src)/unroll.awk FORCE
 	$(call if_changed,unroll)
 
 quiet_cmd_mktable = TABLE   $@
diff --git a/drivers/md/raid6altivec.uc b/drivers/md/raid6altivec.uc
index 699dfeee4944..2654d5c854be 100644
--- a/drivers/md/raid6altivec.uc
+++ b/drivers/md/raid6altivec.uc
@@ -15,7 +15,7 @@
  *
  * $#-way unrolled portable integer math RAID-6 instruction set
  *
- * This file is postprocessed using unroll.pl
+ * This file is postprocessed using unroll.awk
  *
  * <benh> hpa: in process,
  * you can just "steal" the vec unit with enable_kernel_altivec() (but
diff --git a/drivers/md/raid6int.uc b/drivers/md/raid6int.uc
index f9bf9cba357f..d1e276a14fab 100644
--- a/drivers/md/raid6int.uc
+++ b/drivers/md/raid6int.uc
@@ -15,7 +15,7 @@
  *
  * $#-way unrolled portable integer math RAID-6 instruction set
  *
- * This file is postprocessed using unroll.pl
+ * This file is postprocessed using unroll.awk
  */
 
 #include <linux/raid/pq.h>
diff --git a/drivers/md/raid6test/Makefile b/drivers/md/raid6test/Makefile
index 58ffdf4f5161..2874cbef529d 100644
--- a/drivers/md/raid6test/Makefile
+++ b/drivers/md/raid6test/Makefile
@@ -7,7 +7,7 @@ CC	 = gcc
 OPTFLAGS = -O2			# Adjust as desired
 CFLAGS	 = -I.. -I ../../../include -g $(OPTFLAGS)
 LD	 = ld
-PERL	 = perl
+AWK	 = awk
 AR	 = ar
 RANLIB	 = ranlib
 
@@ -35,35 +35,35 @@ raid6.a: raid6int1.o raid6int2.o raid6int4.o raid6int8.o raid6int16.o \
 raid6test: test.c raid6.a
 	$(CC) $(CFLAGS) -o raid6test $^
 
-raid6altivec1.c: raid6altivec.uc ../unroll.pl
-	$(PERL) ../unroll.pl 1 < raid6altivec.uc > $@
+raid6altivec1.c: raid6altivec.uc ../unroll.awk
+	$(AWK) ../unroll.awk -vN=1 < raid6altivec.uc > $@
 
-raid6altivec2.c: raid6altivec.uc ../unroll.pl
-	$(PERL) ../unroll.pl 2 < raid6altivec.uc > $@
+raid6altivec2.c: raid6altivec.uc ../unroll.awk
+	$(AWK) ../unroll.awk -vN=2 < raid6altivec.uc > $@
 
-raid6altivec4.c: raid6altivec.uc ../unroll.pl
-	$(PERL) ../unroll.pl 4 < raid6altivec.uc > $@
+raid6altivec4.c: raid6altivec.uc ../unroll.awk
+	$(AWK) ../unroll.awk -vN=4 < raid6altivec.uc > $@
 
-raid6altivec8.c: raid6altivec.uc ../unroll.pl
-	$(PERL) ../unroll.pl 8 < raid6altivec.uc > $@
+raid6altivec8.c: raid6altivec.uc ../unroll.awk
+	$(AWK) ../unroll.awk -vN=8 < raid6altivec.uc > $@
 
-raid6int1.c: raid6int.uc ../unroll.pl
-	$(PERL) ../unroll.pl 1 < raid6int.uc > $@
+raid6int1.c: raid6int.uc ../unroll.awk
+	$(AWK) ../unroll.awk -vN=1 < raid6int.uc > $@
 
-raid6int2.c: raid6int.uc ../unroll.pl
-	$(PERL) ../unroll.pl 2 < raid6int.uc > $@
+raid6int2.c: raid6int.uc ../unroll.awk
+	$(AWK) ../unroll.awk -vN=2 < raid6int.uc > $@
 
-raid6int4.c: raid6int.uc ../unroll.pl
-	$(PERL) ../unroll.pl 4 < raid6int.uc > $@
+raid6int4.c: raid6int.uc ../unroll.awk
+	$(AWK) ../unroll.awk -vN=4 < raid6int.uc > $@
 
-raid6int8.c: raid6int.uc ../unroll.pl
-	$(PERL) ../unroll.pl 8 < raid6int.uc > $@
+raid6int8.c: raid6int.uc ../unroll.awk
+	$(AWK) ../unroll.awk -vN=8 < raid6int.uc > $@
 
-raid6int16.c: raid6int.uc ../unroll.pl
-	$(PERL) ../unroll.pl 16 < raid6int.uc > $@
+raid6int16.c: raid6int.uc ../unroll.awk
+	$(AWK) ../unroll.awk -vN=16 < raid6int.uc > $@
 
-raid6int32.c: raid6int.uc ../unroll.pl
-	$(PERL) ../unroll.pl 32 < raid6int.uc > $@
+raid6int32.c: raid6int.uc ../unroll.awk
+	$(AWK) ../unroll.awk -vN=32 < raid6int.uc > $@
 
 raid6tables.c: mktables
 	./mktables > raid6tables.c
diff --git a/drivers/md/unroll.awk b/drivers/md/unroll.awk
new file mode 100644
index 000000000000..c6aa03631df8
--- /dev/null
+++ b/drivers/md/unroll.awk
@@ -0,0 +1,20 @@
+
+# This filter requires one command line option of form -vN=n
+# where n must be a decimal number.
+#
+# Repeat each input line containing $$ n times, replacing $$ with 0...n-1.
+# Replace each $# with n, and each $* with a single $.
+
+BEGIN {
+	n = N + 0
+}
+{
+	if (/\$\$/) { rep = n } else { rep = 1 }
+	for (i = 0; i < rep; ++i) {
+		tmp = $0
+		gsub(/\$\$/, i, tmp)
+		gsub(/\$\#/, n, tmp)
+		gsub(/\$\*/, "$", tmp)
+		print tmp
+	}
+}
diff --git a/drivers/md/unroll.pl b/drivers/md/unroll.pl
deleted file mode 100644
index 3acc710a20ea..000000000000
--- a/drivers/md/unroll.pl
+++ /dev/null
@@ -1,24 +0,0 @@
-#!/usr/bin/perl
-#
-# Take a piece of C code and for each line which contains the sequence $$
-# repeat n times with $ replaced by 0...n-1; the sequence $# is replaced
-# by the unrolling factor, and $* with a single $
-#
-
-($n) = @ARGV;
-$n += 0;
-
-while ( defined($line = <STDIN>) ) {
-    if ( $line =~ /\$\$/ ) {
-	$rep = $n;
-    } else {
-	$rep = 1;
-    }
-    for ( $i = 0 ; $i < $rep ; $i++ ) {
-	$tmp = $line;
-	$tmp =~ s/\$\$/$i/g;
-	$tmp =~ s/\$\#/$n/g;
-	$tmp =~ s/\$\*/\$/g;
-	print $tmp;
-    }
-}
-- 
cgit v1.2.3-59-g8ed1b


From 417b8d4ac868cf58d6c68f52d72f7648413e0edc Mon Sep 17 00:00:00 2001
From: Dan Williams <dan.j.williams@intel.com>
Date: Fri, 16 Oct 2009 16:25:22 +1100
Subject: md/raid456: downlevel multicore operations to raid_run_ops

The percpu conversion allowed a straightforward handoff of stripe
processing to the async subsytem that initially showed some modest gains
(+4%).  However, this model is too simplistic and leads to stripes
bouncing between raid5d and the async thread pool for every invocation
of handle_stripe().  As reported by Holger this can fall into a
pathological situation severely impacting throughput (6x performance
loss).

By downleveling the parallelism to raid_run_ops the pathological
stripe_head bouncing is eliminated.  This version still exhibits an
average 11% throughput loss for:

	mdadm --create /dev/md0 /dev/sd[b-q] -n 16 -l 6
	echo 1024 > /sys/block/md0/md/stripe_cache_size
	dd if=/dev/zero of=/dev/md0 bs=1024k count=2048

...but the results are at least stable and can be used as a base for
further multicore experimentation.

Reported-by: Holger Kiehl <Holger.Kiehl@dwd.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: NeilBrown <neilb@suse.de>
---
 drivers/md/raid5.c | 75 +++++++++++++++++++++++++++++-------------------------
 drivers/md/raid5.h | 12 ++++++++-
 2 files changed, 51 insertions(+), 36 deletions(-)

diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index c3e596778618..25c3c29134d1 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -1139,7 +1139,7 @@ static void ops_run_check_pq(struct stripe_head *sh, struct raid5_percpu *percpu
 			   &sh->ops.zero_sum_result, percpu->spare_page, &submit);
 }
 
-static void raid_run_ops(struct stripe_head *sh, unsigned long ops_request)
+static void __raid_run_ops(struct stripe_head *sh, unsigned long ops_request)
 {
 	int overlap_clear = 0, i, disks = sh->disks;
 	struct dma_async_tx_descriptor *tx = NULL;
@@ -1204,6 +1204,36 @@ static void raid_run_ops(struct stripe_head *sh, unsigned long ops_request)
 	put_cpu();
 }
 
+#ifdef CONFIG_MULTICORE_RAID456
+static void async_run_ops(void *param, async_cookie_t cookie)
+{
+	struct stripe_head *sh = param;
+	unsigned long ops_request = sh->ops.request;
+
+	clear_bit_unlock(STRIPE_OPS_REQ_PENDING, &sh->state);
+	wake_up(&sh->ops.wait_for_ops);
+
+	__raid_run_ops(sh, ops_request);
+	release_stripe(sh);
+}
+
+static void raid_run_ops(struct stripe_head *sh, unsigned long ops_request)
+{
+	/* since handle_stripe can be called outside of raid5d context
+	 * we need to ensure sh->ops.request is de-staged before another
+	 * request arrives
+	 */
+	wait_event(sh->ops.wait_for_ops,
+		   !test_and_set_bit_lock(STRIPE_OPS_REQ_PENDING, &sh->state));
+	sh->ops.request = ops_request;
+
+	atomic_inc(&sh->count);
+	async_schedule(async_run_ops, sh);
+}
+#else
+#define raid_run_ops __raid_run_ops
+#endif
+
 static int grow_one_stripe(raid5_conf_t *conf)
 {
 	struct stripe_head *sh;
@@ -1213,6 +1243,9 @@ static int grow_one_stripe(raid5_conf_t *conf)
 	memset(sh, 0, sizeof(*sh) + (conf->raid_disks-1)*sizeof(struct r5dev));
 	sh->raid_conf = conf;
 	spin_lock_init(&sh->lock);
+	#ifdef CONFIG_MULTICORE_RAID456
+	init_waitqueue_head(&sh->ops.wait_for_ops);
+	#endif
 
 	if (grow_buffers(sh, conf->raid_disks)) {
 		shrink_buffers(sh, conf->raid_disks);
@@ -1329,6 +1362,9 @@ static int resize_stripes(raid5_conf_t *conf, int newsize)
 
 		nsh->raid_conf = conf;
 		spin_lock_init(&nsh->lock);
+		#ifdef CONFIG_MULTICORE_RAID456
+		init_waitqueue_head(&nsh->ops.wait_for_ops);
+		#endif
 
 		list_add(&nsh->lru, &newstripes);
 	}
@@ -4342,37 +4378,6 @@ static int  retry_aligned_read(raid5_conf_t *conf, struct bio *raid_bio)
 	return handled;
 }
 
-#ifdef CONFIG_MULTICORE_RAID456
-static void __process_stripe(void *param, async_cookie_t cookie)
-{
-	struct stripe_head *sh = param;
-
-	handle_stripe(sh);
-	release_stripe(sh);
-}
-
-static void process_stripe(struct stripe_head *sh, struct list_head *domain)
-{
-	async_schedule_domain(__process_stripe, sh, domain);
-}
-
-static void synchronize_stripe_processing(struct list_head *domain)
-{
-	async_synchronize_full_domain(domain);
-}
-#else
-static void process_stripe(struct stripe_head *sh, struct list_head *domain)
-{
-	handle_stripe(sh);
-	release_stripe(sh);
-	cond_resched();
-}
-
-static void synchronize_stripe_processing(struct list_head *domain)
-{
-}
-#endif
-
 
 /*
  * This is our raid5 kernel thread.
@@ -4386,7 +4391,6 @@ static void raid5d(mddev_t *mddev)
 	struct stripe_head *sh;
 	raid5_conf_t *conf = mddev->private;
 	int handled;
-	LIST_HEAD(raid_domain);
 
 	pr_debug("+++ raid5d active\n");
 
@@ -4423,7 +4427,9 @@ static void raid5d(mddev_t *mddev)
 		spin_unlock_irq(&conf->device_lock);
 		
 		handled++;
-		process_stripe(sh, &raid_domain);
+		handle_stripe(sh);
+		release_stripe(sh);
+		cond_resched();
 
 		spin_lock_irq(&conf->device_lock);
 	}
@@ -4431,7 +4437,6 @@ static void raid5d(mddev_t *mddev)
 
 	spin_unlock_irq(&conf->device_lock);
 
-	synchronize_stripe_processing(&raid_domain);
 	async_tx_issue_pending_all();
 	unplug_slaves(mddev);
 
diff --git a/drivers/md/raid5.h b/drivers/md/raid5.h
index 2390e0e83daf..dcefdc9629ee 100644
--- a/drivers/md/raid5.h
+++ b/drivers/md/raid5.h
@@ -214,12 +214,20 @@ struct stripe_head {
 	int			disks;		/* disks in stripe */
 	enum check_states	check_state;
 	enum reconstruct_states reconstruct_state;
-	/* stripe_operations
+	/**
+	 * struct stripe_operations
 	 * @target - STRIPE_OP_COMPUTE_BLK target
+	 * @target2 - 2nd compute target in the raid6 case
+	 * @zero_sum_result - P and Q verification flags
+	 * @request - async service request flags for raid_run_ops
 	 */
 	struct stripe_operations {
 		int 		     target, target2;
 		enum sum_check_flags zero_sum_result;
+		#ifdef CONFIG_MULTICORE_RAID456
+		unsigned long	     request;
+		wait_queue_head_t    wait_for_ops;
+		#endif
 	} ops;
 	struct r5dev {
 		struct bio	req;
@@ -294,6 +302,8 @@ struct r6_state {
 #define	STRIPE_FULL_WRITE	13 /* all blocks are set to be overwritten */
 #define	STRIPE_BIOFILL_RUN	14
 #define	STRIPE_COMPUTE_RUN	15
+#define	STRIPE_OPS_REQ_PENDING	16
+
 /*
  * Operation request flags
  */
-- 
cgit v1.2.3-59-g8ed1b


From e4424fee1815f996dccd36be44d68ca160ec3e1b Mon Sep 17 00:00:00 2001
From: NeilBrown <neilb@suse.de>
Date: Fri, 16 Oct 2009 16:27:34 +1100
Subject: md: fix problems with RAID6 calculations for DDF.

Signed-off-by: NeilBrown <neilb@suse.de>
---
 drivers/md/raid5.c | 20 +++++++++++++-------
 drivers/md/raid5.h |  2 +-
 2 files changed, 14 insertions(+), 8 deletions(-)

diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 25c3c29134d1..d4ce51b4d41b 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -158,11 +158,14 @@ static int raid6_idx_to_slot(int idx, struct stripe_head *sh,
 {
 	int slot;
 
+	if (sh->ddf_layout)
+		slot = (*count)++;
 	if (idx == sh->pd_idx)
 		return syndrome_disks;
 	if (idx == sh->qd_idx)
 		return syndrome_disks + 1;
-	slot = (*count)++;
+	if (!sh->ddf_layout)
+		slot = (*count)++;
 	return slot;
 }
 
@@ -727,9 +730,8 @@ static int set_syndrome_sources(struct page **srcs, struct stripe_head *sh)
 		srcs[slot] = sh->dev[i].page;
 		i = raid6_next_disk(i, disks);
 	} while (i != d0_idx);
-	BUG_ON(count != syndrome_disks);
 
-	return count;
+	return syndrome_disks;
 }
 
 static struct dma_async_tx_descriptor *
@@ -828,7 +830,6 @@ ops_run_compute6_2(struct stripe_head *sh, struct raid5_percpu *percpu)
 			failb = slot;
 		i = raid6_next_disk(i, disks);
 	} while (i != d0_idx);
-	BUG_ON(count != syndrome_disks);
 
 	BUG_ON(faila == failb);
 	if (failb < faila)
@@ -845,7 +846,7 @@ ops_run_compute6_2(struct stripe_head *sh, struct raid5_percpu *percpu)
 			init_async_submit(&submit, ASYNC_TX_FENCE, NULL,
 					  ops_complete_compute, sh,
 					  to_addr_conv(sh, percpu));
-			return async_gen_syndrome(blocks, 0, count+2,
+			return async_gen_syndrome(blocks, 0, syndrome_disks+2,
 						  STRIPE_SIZE, &submit);
 		} else {
 			struct page *dest;
@@ -1935,10 +1936,15 @@ static sector_t compute_blocknr(struct stripe_head *sh, int i, int previous)
 		case ALGORITHM_PARITY_N:
 			break;
 		case ALGORITHM_ROTATING_N_CONTINUE:
+			/* Like left_symmetric, but P is before Q */
 			if (sh->pd_idx == 0)
 				i--;	/* P D D D Q */
-			else if (i > sh->pd_idx)
-				i -= 2; /* D D Q P D */
+			else {
+				/* D D Q P D */
+				if (i < sh->pd_idx)
+					i += raid_disks;
+				i -= (sh->pd_idx + 1);
+			}
 			break;
 		case ALGORITHM_LEFT_ASYMMETRIC_6:
 		case ALGORITHM_RIGHT_ASYMMETRIC_6:
diff --git a/drivers/md/raid5.h b/drivers/md/raid5.h
index dcefdc9629ee..dd708359b451 100644
--- a/drivers/md/raid5.h
+++ b/drivers/md/raid5.h
@@ -488,7 +488,7 @@ static inline int algorithm_valid_raid6(int layout)
 {
 	return (layout >= 0 && layout <= 5)
 		||
-		(layout == 8 || layout == 10)
+		(layout >= 8 && layout <= 10)
 		||
 		(layout >= 16 && layout <= 20);
 }
-- 
cgit v1.2.3-59-g8ed1b


From 5e5e3e78ed9038b8f7112835d07084eefb9daa47 Mon Sep 17 00:00:00 2001
From: NeilBrown <neilb@suse.de>
Date: Fri, 16 Oct 2009 16:35:30 +1100
Subject: md: Fix handling of raid5 array which is being reshaped to fewer
 devices.

When a raid5 (or raid6) array is being reshaped to have fewer devices,
conf->raid_disks is the latter and hence smaller number of devices.
However sometimes we want to use a number which is the total number of
currently required devices - the larger of the 'old' and 'new' sizes.
Before we implemented reducing the number of devices, this was always
'new' i.e. ->raid_disks.
Now we need max(raid_disks, previous_raid_disks) in those places.

This particularly affects assembling an array that was shutdown while
in the middle of a reshape to fewer devices.

md.c needs a similar fix when interpreting the md metadata.

Signed-off-by: NeilBrown <neilb@suse.de>
---
 drivers/md/md.c    |  2 +-
 drivers/md/raid5.c | 37 ++++++++++++++++++-------------------
 2 files changed, 19 insertions(+), 20 deletions(-)

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 26ba42a79129..10eb1fce975e 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -2631,7 +2631,7 @@ static void analyze_sbs(mddev_t * mddev)
 			rdev->desc_nr = i++;
 			rdev->raid_disk = rdev->desc_nr;
 			set_bit(In_sync, &rdev->flags);
-		} else if (rdev->raid_disk >= mddev->raid_disks) {
+		} else if (rdev->raid_disk >= (mddev->raid_disks - min(0, mddev->delta_disks))) {
 			rdev->raid_disk = -1;
 			clear_bit(In_sync, &rdev->flags);
 		}
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index d4ce51b4d41b..c4366c9373c5 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -1238,22 +1238,22 @@ static void raid_run_ops(struct stripe_head *sh, unsigned long ops_request)
 static int grow_one_stripe(raid5_conf_t *conf)
 {
 	struct stripe_head *sh;
+	int disks = max(conf->raid_disks, conf->previous_raid_disks);
 	sh = kmem_cache_alloc(conf->slab_cache, GFP_KERNEL);
 	if (!sh)
 		return 0;
-	memset(sh, 0, sizeof(*sh) + (conf->raid_disks-1)*sizeof(struct r5dev));
+	memset(sh, 0, sizeof(*sh) + (disks-1)*sizeof(struct r5dev));
 	sh->raid_conf = conf;
 	spin_lock_init(&sh->lock);
 	#ifdef CONFIG_MULTICORE_RAID456
 	init_waitqueue_head(&sh->ops.wait_for_ops);
 	#endif
 
-	if (grow_buffers(sh, conf->raid_disks)) {
-		shrink_buffers(sh, conf->raid_disks);
+	if (grow_buffers(sh, disks)) {
+		shrink_buffers(sh, disks);
 		kmem_cache_free(conf->slab_cache, sh);
 		return 0;
 	}
-	sh->disks = conf->raid_disks;
 	/* we just created an active stripe so... */
 	atomic_set(&sh->count, 1);
 	atomic_inc(&conf->active_stripes);
@@ -1265,7 +1265,7 @@ static int grow_one_stripe(raid5_conf_t *conf)
 static int grow_stripes(raid5_conf_t *conf, int num)
 {
 	struct kmem_cache *sc;
-	int devs = conf->raid_disks;
+	int devs = max(conf->raid_disks, conf->previous_raid_disks);
 
 	sprintf(conf->cache_name[0],
 		"raid%d-%s", conf->level, mdname(conf->mddev));
@@ -3540,9 +3540,10 @@ static void unplug_slaves(mddev_t *mddev)
 {
 	raid5_conf_t *conf = mddev->private;
 	int i;
+	int devs = max(conf->raid_disks, conf->previous_raid_disks);
 
 	rcu_read_lock();
-	for (i = 0; i < conf->raid_disks; i++) {
+	for (i = 0; i < devs; i++) {
 		mdk_rdev_t *rdev = rcu_dereference(conf->disks[i].rdev);
 		if (rdev && !test_bit(Faulty, &rdev->flags) && atomic_read(&rdev->nr_pending)) {
 			struct request_queue *r_queue = bdev_get_queue(rdev->bdev);
@@ -4562,13 +4563,9 @@ raid5_size(mddev_t *mddev, sector_t sectors, int raid_disks)
 
 	if (!sectors)
 		sectors = mddev->dev_sectors;
-	if (!raid_disks) {
+	if (!raid_disks)
 		/* size is defined by the smallest of previous and new size */
-		if (conf->raid_disks < conf->previous_raid_disks)
-			raid_disks = conf->raid_disks;
-		else
-			raid_disks = conf->previous_raid_disks;
-	}
+		raid_disks = min(conf->raid_disks, conf->previous_raid_disks);
 
 	sectors &= ~((sector_t)mddev->chunk_sectors - 1);
 	sectors &= ~((sector_t)mddev->new_chunk_sectors - 1);
@@ -4669,7 +4666,7 @@ static int raid5_alloc_percpu(raid5_conf_t *conf)
 			}
 			per_cpu_ptr(conf->percpu, cpu)->spare_page = spare_page;
 		}
-		scribble = kmalloc(scribble_len(conf->raid_disks), GFP_KERNEL);
+		scribble = kmalloc(conf->scribble_len, GFP_KERNEL);
 		if (!scribble) {
 			err = -ENOMEM;
 			break;
@@ -4690,7 +4687,7 @@ static int raid5_alloc_percpu(raid5_conf_t *conf)
 static raid5_conf_t *setup_conf(mddev_t *mddev)
 {
 	raid5_conf_t *conf;
-	int raid_disk, memory;
+	int raid_disk, memory, max_disks;
 	mdk_rdev_t *rdev;
 	struct disk_info *disk;
 
@@ -4740,13 +4737,14 @@ static raid5_conf_t *setup_conf(mddev_t *mddev)
 	conf->bypass_threshold = BYPASS_THRESHOLD;
 
 	conf->raid_disks = mddev->raid_disks;
-	conf->scribble_len = scribble_len(conf->raid_disks);
 	if (mddev->reshape_position == MaxSector)
 		conf->previous_raid_disks = mddev->raid_disks;
 	else
 		conf->previous_raid_disks = mddev->raid_disks - mddev->delta_disks;
+	max_disks = max(conf->raid_disks, conf->previous_raid_disks);
+	conf->scribble_len = scribble_len(max_disks);
 
-	conf->disks = kzalloc(conf->raid_disks * sizeof(struct disk_info),
+	conf->disks = kzalloc(max_disks * sizeof(struct disk_info),
 			      GFP_KERNEL);
 	if (!conf->disks)
 		goto abort;
@@ -4764,7 +4762,7 @@ static raid5_conf_t *setup_conf(mddev_t *mddev)
 
 	list_for_each_entry(rdev, &mddev->disks, same_set) {
 		raid_disk = rdev->raid_disk;
-		if (raid_disk >= conf->raid_disks
+		if (raid_disk >= max_disks
 		    || raid_disk < 0)
 			continue;
 		disk = conf->disks + raid_disk;
@@ -4796,7 +4794,7 @@ static raid5_conf_t *setup_conf(mddev_t *mddev)
 	}
 
 	memory = conf->max_nr_stripes * (sizeof(struct stripe_head) +
-		 conf->raid_disks * ((sizeof(struct bio) + PAGE_SIZE))) / 1024;
+		 max_disks * ((sizeof(struct bio) + PAGE_SIZE))) / 1024;
 	if (grow_stripes(conf, conf->max_nr_stripes)) {
 		printk(KERN_ERR
 			"raid5: couldn't allocate %dkB for buffers\n", memory);
@@ -4921,7 +4919,8 @@ static int run(mddev_t *mddev)
 		    test_bit(In_sync, &rdev->flags))
 			working_disks++;
 
-	mddev->degraded = conf->raid_disks - working_disks;
+	mddev->degraded = (max(conf->raid_disks, conf->previous_raid_disks)
+			   - working_disks);
 
 	if (mddev->degraded > conf->max_degraded) {
 		printk(KERN_ERR "raid5: not enough operational devices for %s"
-- 
cgit v1.2.3-59-g8ed1b


From 5dd33c9a4c29015f6d87568d33521c98931a387e Mon Sep 17 00:00:00 2001
From: NeilBrown <neilb@suse.de>
Date: Fri, 16 Oct 2009 16:40:25 +1100
Subject: md/async: don't pass a memory pointer as a page pointer.

md/raid6 passes a list of 'struct page *' to the async_tx routines,
which then either DMA map them for offload, or take the page_address
for CPU based calculations.

For RAID6 we sometime leave 'blanks' in the list of pages.
For CPU based calcs, we want to treat theses as a page of zeros.
For offloaded calculations, we simply don't pass a page to the
hardware.

Currently the 'blanks' are encoded as a pointer to
raid6_empty_zero_page.  This is a 4096 byte memory region, not a
'struct page'.  This is mostly handled correctly but is rather ugly.

So change the code to pass and expect a NULL pointer for the blanks.
When taking page_address of a page, we need to check for a NULL and
in that case use raid6_empty_zero_page.

Signed-off-by: NeilBrown <neilb@suse.de>
---
 crypto/async_tx/async_pq.c          | 15 ++++-----------
 crypto/async_tx/async_raid6_recov.c | 16 +++++++++++-----
 drivers/md/raid5.c                  |  4 ++--
 3 files changed, 17 insertions(+), 18 deletions(-)

diff --git a/crypto/async_tx/async_pq.c b/crypto/async_tx/async_pq.c
index b88db6d1dc65..9ab1ce4af3cc 100644
--- a/crypto/async_tx/async_pq.c
+++ b/crypto/async_tx/async_pq.c
@@ -30,11 +30,6 @@
  */
 static struct page *scribble;
 
-static bool is_raid6_zero_block(struct page *p)
-{
-	return p == (void *) raid6_empty_zero_page;
-}
-
 /* the struct page *blocks[] parameter passed to async_gen_syndrome()
  * and async_syndrome_val() contains the 'P' destination address at
  * blocks[disks-2] and the 'Q' destination address at blocks[disks-1]
@@ -83,7 +78,7 @@ do_async_gen_syndrome(struct dma_chan *chan, struct page **blocks,
 	 * sources and update the coefficients accordingly
 	 */
 	for (i = 0, idx = 0; i < src_cnt; i++) {
-		if (is_raid6_zero_block(blocks[i]))
+		if (blocks[i] == NULL)
 			continue;
 		dma_src[idx] = dma_map_page(dma->dev, blocks[i], offset, len,
 					    DMA_TO_DEVICE);
@@ -160,9 +155,9 @@ do_sync_gen_syndrome(struct page **blocks, unsigned int offset, int disks,
 		srcs = (void **) blocks;
 
 	for (i = 0; i < disks; i++) {
-		if (is_raid6_zero_block(blocks[i])) {
+		if (blocks[i] == NULL) {
 			BUG_ON(i > disks - 3); /* P or Q can't be zero */
-			srcs[i] = blocks[i];
+			srcs[i] = (void*)raid6_empty_zero_page;
 		} else
 			srcs[i] = page_address(blocks[i]) + offset;
 	}
@@ -290,12 +285,10 @@ async_syndrome_val(struct page **blocks, unsigned int offset, int disks,
 		if (submit->flags & ASYNC_TX_FENCE)
 			dma_flags |= DMA_PREP_FENCE;
 		for (i = 0; i < disks; i++)
-			if (likely(blocks[i])) {
-				BUG_ON(is_raid6_zero_block(blocks[i]));
+			if (likely(blocks[i]))
 				dma_src[i] = dma_map_page(dev, blocks[i],
 							  offset, len,
 							  DMA_TO_DEVICE);
-			}
 
 		for (;;) {
 			tx = device->device_prep_dma_pq_val(chan, pq, dma_src,
diff --git a/crypto/async_tx/async_raid6_recov.c b/crypto/async_tx/async_raid6_recov.c
index 6d73dde4786d..8e30b6ed0789 100644
--- a/crypto/async_tx/async_raid6_recov.c
+++ b/crypto/async_tx/async_raid6_recov.c
@@ -263,10 +263,10 @@ __2data_recov_n(int disks, size_t bytes, int faila, int failb,
 	 * delta p and delta q
 	 */
 	dp = blocks[faila];
-	blocks[faila] = (void *)raid6_empty_zero_page;
+	blocks[faila] = NULL;
 	blocks[disks-2] = dp;
 	dq = blocks[failb];
-	blocks[failb] = (void *)raid6_empty_zero_page;
+	blocks[failb] = NULL;
 	blocks[disks-1] = dq;
 
 	init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL, scribble);
@@ -338,7 +338,10 @@ async_raid6_2data_recov(int disks, size_t bytes, int faila, int failb,
 
 		async_tx_quiesce(&submit->depend_tx);
 		for (i = 0; i < disks; i++)
-			ptrs[i] = page_address(blocks[i]);
+			if (blocks[i] == NULL)
+				ptrs[i] = (void*)raid6_empty_zero_page;
+			else
+				ptrs[i] = page_address(blocks[i]);
 
 		raid6_2data_recov(disks, bytes, faila, failb, ptrs);
 
@@ -398,7 +401,10 @@ async_raid6_datap_recov(int disks, size_t bytes, int faila,
 
 		async_tx_quiesce(&submit->depend_tx);
 		for (i = 0; i < disks; i++)
-			ptrs[i] = page_address(blocks[i]);
+			if (blocks[i] == NULL)
+				ptrs[i] = (void*)raid6_empty_zero_page;
+			else
+				ptrs[i] = page_address(blocks[i]);
 
 		raid6_datap_recov(disks, bytes, faila, ptrs);
 
@@ -414,7 +420,7 @@ async_raid6_datap_recov(int disks, size_t bytes, int faila,
 	 * Use the dead data page as temporary storage for delta q
 	 */
 	dq = blocks[faila];
-	blocks[faila] = (void *)raid6_empty_zero_page;
+	blocks[faila] = NULL;
 	blocks[disks-1] = dq;
 
 	/* in the 4 disk case we only need to perform a single source
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index c4366c9373c5..dcd9e659ed9d 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -720,7 +720,7 @@ static int set_syndrome_sources(struct page **srcs, struct stripe_head *sh)
 	int i;
 
 	for (i = 0; i < disks; i++)
-		srcs[i] = (void *)raid6_empty_zero_page;
+		srcs[i] = NULL;
 
 	count = 0;
 	i = d0_idx;
@@ -816,7 +816,7 @@ ops_run_compute6_2(struct stripe_head *sh, struct raid5_percpu *percpu)
 	 * slot number conversion for 'faila' and 'failb'
 	 */
 	for (i = 0; i < disks ; i++)
-		blocks[i] = (void *)raid6_empty_zero_page;
+		blocks[i] = NULL;
 	count = 0;
 	i = d0_idx;
 	do {
-- 
cgit v1.2.3-59-g8ed1b


From b2141e6951ad56c8f65e70547baeabd5698e390a Mon Sep 17 00:00:00 2001
From: NeilBrown <neilb@suse.de>
Date: Fri, 16 Oct 2009 16:40:34 +1100
Subject: raid6/async_tx: handle holes in block list in async_syndrome_val

async_syndrome_val check the P and Q blocks used for RAID6
calculations.
With DDF raid6, some of the data blocks might be NULL, so
this needs to be handled in the same way that async_gen_syndrome
handles it.

As async_syndrome_val calls async_xor, also enhance async_xor
to detect and skip NULL blocks in the list.

Signed-off-by: NeilBrown <neilb@suse.de>
---
 crypto/async_tx/async_pq.c  | 31 ++++++++++++++++++++++++-------
 crypto/async_tx/async_xor.c | 18 +++++++++++-------
 2 files changed, 35 insertions(+), 14 deletions(-)

diff --git a/crypto/async_tx/async_pq.c b/crypto/async_tx/async_pq.c
index 9ab1ce4af3cc..43b1436bd968 100644
--- a/crypto/async_tx/async_pq.c
+++ b/crypto/async_tx/async_pq.c
@@ -260,8 +260,10 @@ async_syndrome_val(struct page **blocks, unsigned int offset, int disks,
 						      len);
 	struct dma_device *device = chan ? chan->device : NULL;
 	struct dma_async_tx_descriptor *tx;
+	unsigned char coefs[disks-2];
 	enum dma_ctrl_flags dma_flags = submit->cb_fn ? DMA_PREP_INTERRUPT : 0;
 	dma_addr_t *dma_src = NULL;
+	int src_cnt = 0;
 
 	BUG_ON(disks < 4);
 
@@ -280,20 +282,35 @@ async_syndrome_val(struct page **blocks, unsigned int offset, int disks,
 			 __func__, disks, len);
 		if (!P(blocks, disks))
 			dma_flags |= DMA_PREP_PQ_DISABLE_P;
+		else
+			pq[0] = dma_map_page(dev, P(blocks,disks),
+					     offset, len,
+					     DMA_TO_DEVICE);
 		if (!Q(blocks, disks))
 			dma_flags |= DMA_PREP_PQ_DISABLE_Q;
+		else
+			pq[1] = dma_map_page(dev, Q(blocks,disks),
+					     offset, len,
+					     DMA_TO_DEVICE);
+
 		if (submit->flags & ASYNC_TX_FENCE)
 			dma_flags |= DMA_PREP_FENCE;
-		for (i = 0; i < disks; i++)
-			if (likely(blocks[i]))
-				dma_src[i] = dma_map_page(dev, blocks[i],
-							  offset, len,
-							  DMA_TO_DEVICE);
+		for (i = 0; i < disks-2; i++)
+			if (likely(blocks[i])) {
+				dma_src[src_cnt] = dma_map_page(dev, blocks[i],
+								offset, len,
+								DMA_TO_DEVICE);
+				coefs[src_cnt] = raid6_gfexp[i];
+				src_cnt++;
+			}
+		pq[1] = dma_map_page(dev, Q(blocks,disks),
+				     offset, len,
+				     DMA_TO_DEVICE);
 
 		for (;;) {
 			tx = device->device_prep_dma_pq_val(chan, pq, dma_src,
-							    disks - 2,
-							    raid6_gfexp,
+							    src_cnt,
+							    coefs,
 							    len, pqres,
 							    dma_flags);
 			if (likely(tx))
diff --git a/crypto/async_tx/async_xor.c b/crypto/async_tx/async_xor.c
index b459a9034aac..79182dcb91b7 100644
--- a/crypto/async_tx/async_xor.c
+++ b/crypto/async_tx/async_xor.c
@@ -44,20 +44,23 @@ do_async_xor(struct dma_chan *chan, struct page *dest, struct page **src_list,
 	void *cb_param_orig = submit->cb_param;
 	enum async_tx_flags flags_orig = submit->flags;
 	enum dma_ctrl_flags dma_flags;
-	int xor_src_cnt;
+	int xor_src_cnt = 0;
 	dma_addr_t dma_dest;
 
 	/* map the dest bidrectional in case it is re-used as a source */
 	dma_dest = dma_map_page(dma->dev, dest, offset, len, DMA_BIDIRECTIONAL);
 	for (i = 0; i < src_cnt; i++) {
 		/* only map the dest once */
+		if (!src_list[i])
+			continue;
 		if (unlikely(src_list[i] == dest)) {
-			dma_src[i] = dma_dest;
+			dma_src[xor_src_cnt++] = dma_dest;
 			continue;
 		}
-		dma_src[i] = dma_map_page(dma->dev, src_list[i], offset,
-					  len, DMA_TO_DEVICE);
+		dma_src[xor_src_cnt++] = dma_map_page(dma->dev, src_list[i], offset,
+						      len, DMA_TO_DEVICE);
 	}
+	src_cnt = xor_src_cnt;
 
 	while (src_cnt) {
 		submit->flags = flags_orig;
@@ -123,7 +126,7 @@ do_sync_xor(struct page *dest, struct page **src_list, unsigned int offset,
 	    int src_cnt, size_t len, struct async_submit_ctl *submit)
 {
 	int i;
-	int xor_src_cnt;
+	int xor_src_cnt = 0;
 	int src_off = 0;
 	void *dest_buf;
 	void **srcs;
@@ -135,8 +138,9 @@ do_sync_xor(struct page *dest, struct page **src_list, unsigned int offset,
 
 	/* convert to buffer pointers */
 	for (i = 0; i < src_cnt; i++)
-		srcs[i] = page_address(src_list[i]) + offset;
-
+		if (src_list[i])
+			srcs[xor_src_cnt++] = page_address(src_list[i]) + offset;
+	src_cnt = xor_src_cnt;
 	/* set destination address */
 	dest_buf = page_address(dest) + offset;
 
-- 
cgit v1.2.3-59-g8ed1b


From 6629542e79255e0dbef8ec82eaf644e1b2546c3c Mon Sep 17 00:00:00 2001
From: Dan Williams <dan.j.williams@intel.com>
Date: Mon, 19 Oct 2009 18:09:32 -0700
Subject: md/raid6: kill a gcc-4.0.1 'uninitialized variable' warning

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
 drivers/md/raid5.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index dcd9e659ed9d..81abefc172d9 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -156,16 +156,16 @@ static inline int raid6_next_disk(int disk, int raid_disks)
 static int raid6_idx_to_slot(int idx, struct stripe_head *sh,
 			     int *count, int syndrome_disks)
 {
-	int slot;
+	int slot = *count;
 
 	if (sh->ddf_layout)
-		slot = (*count)++;
+		(*count)++;
 	if (idx == sh->pd_idx)
 		return syndrome_disks;
 	if (idx == sh->qd_idx)
 		return syndrome_disks + 1;
 	if (!sh->ddf_layout)
-		slot = (*count)++;
+		(*count)++;
 	return slot;
 }
 
-- 
cgit v1.2.3-59-g8ed1b


From 5676470f06f783aebf545c8f17ca772911022068 Mon Sep 17 00:00:00 2001
From: Dan Williams <dan.j.williams@intel.com>
Date: Mon, 19 Oct 2009 18:09:32 -0700
Subject: async_pq: kill a stray dma_map() call and other cleanups

- update the kernel doc for async_syndrome to indicate what NULL in the
  source list means
- whitespace fixups

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
 crypto/async_tx/async_pq.c | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/crypto/async_tx/async_pq.c b/crypto/async_tx/async_pq.c
index 43b1436bd968..60476560e0b0 100644
--- a/crypto/async_tx/async_pq.c
+++ b/crypto/async_tx/async_pq.c
@@ -181,10 +181,14 @@ do_sync_gen_syndrome(struct page **blocks, unsigned int offset, int disks,
  * blocks[disks-1] to NULL.  When P or Q is omitted 'len' must be <=
  * PAGE_SIZE as a temporary buffer of this size is used in the
  * synchronous path.  'disks' always accounts for both destination
- * buffers.
+ * buffers.  If any source buffers (blocks[i] where i < disks - 2) are
+ * set to NULL those buffers will be replaced with the raid6_zero_page
+ * in the synchronous path and omitted in the hardware-asynchronous
+ * path.
  *
  * 'blocks' note: if submit->scribble is NULL then the contents of
- * 'blocks' may be overridden
+ * 'blocks' may be overwritten to perform address conversions
+ * (dma_map_page() or page_address()).
  */
 struct dma_async_tx_descriptor *
 async_gen_syndrome(struct page **blocks, unsigned int offset, int disks,
@@ -283,13 +287,13 @@ async_syndrome_val(struct page **blocks, unsigned int offset, int disks,
 		if (!P(blocks, disks))
 			dma_flags |= DMA_PREP_PQ_DISABLE_P;
 		else
-			pq[0] = dma_map_page(dev, P(blocks,disks),
+			pq[0] = dma_map_page(dev, P(blocks, disks),
 					     offset, len,
 					     DMA_TO_DEVICE);
 		if (!Q(blocks, disks))
 			dma_flags |= DMA_PREP_PQ_DISABLE_Q;
 		else
-			pq[1] = dma_map_page(dev, Q(blocks,disks),
+			pq[1] = dma_map_page(dev, Q(blocks, disks),
 					     offset, len,
 					     DMA_TO_DEVICE);
 
@@ -303,9 +307,6 @@ async_syndrome_val(struct page **blocks, unsigned int offset, int disks,
 				coefs[src_cnt] = raid6_gfexp[i];
 				src_cnt++;
 			}
-		pq[1] = dma_map_page(dev, Q(blocks,disks),
-				     offset, len,
-				     DMA_TO_DEVICE);
 
 		for (;;) {
 			tx = device->device_prep_dma_pq_val(chan, pq, dma_src,
-- 
cgit v1.2.3-59-g8ed1b


From 030b07720be0f3bfada12ff6bfa3c61a91212f32 Mon Sep 17 00:00:00 2001
From: Dan Williams <dan.j.williams@intel.com>
Date: Mon, 19 Oct 2009 18:09:32 -0700
Subject: async_pq: rename scribble page

The global scribble page is used as a temporary destination buffer when
disabling the P or Q result is requested.  The local scribble buffer
contains memory for performing address conversions.  Rename the global
variable to avoid confusion.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
 crypto/async_tx/async_pq.c | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/crypto/async_tx/async_pq.c b/crypto/async_tx/async_pq.c
index 60476560e0b0..6b5cc4fba59f 100644
--- a/crypto/async_tx/async_pq.c
+++ b/crypto/async_tx/async_pq.c
@@ -26,9 +26,10 @@
 #include <linux/async_tx.h>
 
 /**
- * scribble - space to hold throwaway P buffer for synchronous gen_syndrome
+ * pq_scribble_page - space to hold throwaway P or Q buffer for
+ * synchronous gen_syndrome
  */
-static struct page *scribble;
+static struct page *pq_scribble_page;
 
 /* the struct page *blocks[] parameter passed to async_gen_syndrome()
  * and async_syndrome_val() contains the 'P' destination address at
@@ -226,11 +227,11 @@ async_gen_syndrome(struct page **blocks, unsigned int offset, int disks,
 	async_tx_quiesce(&submit->depend_tx);
 
 	if (!P(blocks, disks)) {
-		P(blocks, disks) = scribble;
+		P(blocks, disks) = pq_scribble_page;
 		BUG_ON(len + offset > PAGE_SIZE);
 	}
 	if (!Q(blocks, disks)) {
-		Q(blocks, disks) = scribble;
+		Q(blocks, disks) = pq_scribble_page;
 		BUG_ON(len + offset > PAGE_SIZE);
 	}
 	do_sync_gen_syndrome(blocks, offset, disks, len, submit);
@@ -384,9 +385,9 @@ EXPORT_SYMBOL_GPL(async_syndrome_val);
 
 static int __init async_pq_init(void)
 {
-	scribble = alloc_page(GFP_KERNEL);
+	pq_scribble_page = alloc_page(GFP_KERNEL);
 
-	if (scribble)
+	if (pq_scribble_page)
 		return 0;
 
 	pr_err("%s: failed to allocate required spare page\n", __func__);
@@ -396,7 +397,7 @@ static int __init async_pq_init(void)
 
 static void __exit async_pq_exit(void)
 {
-	put_page(scribble);
+	put_page(pq_scribble_page);
 }
 
 module_init(async_pq_init);
-- 
cgit v1.2.3-59-g8ed1b


From da17bf4306fd3a52e938b121df82a7baa10eb282 Mon Sep 17 00:00:00 2001
From: Dan Williams <dan.j.williams@intel.com>
Date: Mon, 19 Oct 2009 14:05:12 -0700
Subject: async_tx: fix asynchronous raid6 recovery for ddf layouts

The raid6 recovery code currently requires special handling of the
4-disk and 5-disk recovery scenarios for the native layout.  Quoting
from commit 0a82a623:

     In these situations the default N-disk algorithm will present
     0-source or 1-source operations to dma devices.  To cover for
     dma devices where the minimum source count is 2 we implement
     4-disk and 5-disk handling in the recovery code.

The ddf layout presents disks=6 and disks=7 to the recovery code in
these situations.  Instead of looking at the number of disks count the
number of non-zero sources in the list and call the special case code
when the number of non-failed sources is 0 or 1.

[neilb@suse.de: replace 'ddf' flag with counting good sources]
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
 crypto/async_tx/async_raid6_recov.c | 86 ++++++++++++++++++++++++-------------
 1 file changed, 56 insertions(+), 30 deletions(-)

diff --git a/crypto/async_tx/async_raid6_recov.c b/crypto/async_tx/async_raid6_recov.c
index 8e30b6ed0789..943f2abac9b4 100644
--- a/crypto/async_tx/async_raid6_recov.c
+++ b/crypto/async_tx/async_raid6_recov.c
@@ -131,8 +131,8 @@ async_mult(struct page *dest, struct page *src, u8 coef, size_t len,
 }
 
 static struct dma_async_tx_descriptor *
-__2data_recov_4(size_t bytes, int faila, int failb, struct page **blocks,
-	      struct async_submit_ctl *submit)
+__2data_recov_4(int disks, size_t bytes, int faila, int failb,
+		struct page **blocks, struct async_submit_ctl *submit)
 {
 	struct dma_async_tx_descriptor *tx = NULL;
 	struct page *p, *q, *a, *b;
@@ -143,8 +143,8 @@ __2data_recov_4(size_t bytes, int faila, int failb, struct page **blocks,
 	void *cb_param = submit->cb_param;
 	void *scribble = submit->scribble;
 
-	p = blocks[4-2];
-	q = blocks[4-1];
+	p = blocks[disks-2];
+	q = blocks[disks-1];
 
 	a = blocks[faila];
 	b = blocks[failb];
@@ -170,8 +170,8 @@ __2data_recov_4(size_t bytes, int faila, int failb, struct page **blocks,
 }
 
 static struct dma_async_tx_descriptor *
-__2data_recov_5(size_t bytes, int faila, int failb, struct page **blocks,
-	      struct async_submit_ctl *submit)
+__2data_recov_5(int disks, size_t bytes, int faila, int failb,
+		struct page **blocks, struct async_submit_ctl *submit)
 {
 	struct dma_async_tx_descriptor *tx = NULL;
 	struct page *p, *q, *g, *dp, *dq;
@@ -181,21 +181,22 @@ __2data_recov_5(size_t bytes, int faila, int failb, struct page **blocks,
 	dma_async_tx_callback cb_fn = submit->cb_fn;
 	void *cb_param = submit->cb_param;
 	void *scribble = submit->scribble;
-	int uninitialized_var(good);
-	int i;
+	int good_srcs, good, i;
 
-	for (i = 0; i < 3; i++) {
+	good_srcs = 0;
+	good = -1;
+	for (i = 0; i < disks-2; i++) {
+		if (blocks[i] == NULL)
+			continue;
 		if (i == faila || i == failb)
 			continue;
-		else {
-			good = i;
-			break;
-		}
+		good = i;
+		good_srcs++;
 	}
-	BUG_ON(i >= 3);
+	BUG_ON(good_srcs > 1);
 
-	p = blocks[5-2];
-	q = blocks[5-1];
+	p = blocks[disks-2];
+	q = blocks[disks-1];
 	g = blocks[good];
 
 	/* Compute syndrome with zero for the missing data pages
@@ -323,6 +324,8 @@ struct dma_async_tx_descriptor *
 async_raid6_2data_recov(int disks, size_t bytes, int faila, int failb,
 			struct page **blocks, struct async_submit_ctl *submit)
 {
+	int non_zero_srcs, i;
+
 	BUG_ON(faila == failb);
 	if (failb < faila)
 		swap(faila, failb);
@@ -334,12 +337,11 @@ async_raid6_2data_recov(int disks, size_t bytes, int faila, int failb,
 	 */
 	if (!submit->scribble) {
 		void **ptrs = (void **) blocks;
-		int i;
 
 		async_tx_quiesce(&submit->depend_tx);
 		for (i = 0; i < disks; i++)
 			if (blocks[i] == NULL)
-				ptrs[i] = (void*)raid6_empty_zero_page;
+				ptrs[i] = (void *) raid6_empty_zero_page;
 			else
 				ptrs[i] = page_address(blocks[i]);
 
@@ -350,19 +352,30 @@ async_raid6_2data_recov(int disks, size_t bytes, int faila, int failb,
 		return NULL;
 	}
 
-	switch (disks) {
-	case 4:
+	non_zero_srcs = 0;
+	for (i = 0; i < disks-2 && non_zero_srcs < 4; i++)
+		if (blocks[i])
+			non_zero_srcs++;
+	switch (non_zero_srcs) {
+	case 0:
+	case 1:
+		/* There must be at least 2 sources - the failed devices. */
+		BUG();
+
+	case 2:
 		/* dma devices do not uniformly understand a zero source pq
 		 * operation (in contrast to the synchronous case), so
-		 * explicitly handle the 4 disk special case
+		 * explicitly handle the special case of a 4 disk array with
+		 * both data disks missing.
 		 */
-		return __2data_recov_4(bytes, faila, failb, blocks, submit);
-	case 5:
+		return __2data_recov_4(disks, bytes, faila, failb, blocks, submit);
+	case 3:
 		/* dma devices do not uniformly understand a single
 		 * source pq operation (in contrast to the synchronous
-		 * case), so explicitly handle the 5 disk special case
+		 * case), so explicitly handle the special case of a 5 disk
+		 * array with 2 of 3 data disks missing.
 		 */
-		return __2data_recov_5(bytes, faila, failb, blocks, submit);
+		return __2data_recov_5(disks, bytes, faila, failb, blocks, submit);
 	default:
 		return __2data_recov_n(disks, bytes, faila, failb, blocks, submit);
 	}
@@ -388,6 +401,7 @@ async_raid6_datap_recov(int disks, size_t bytes, int faila,
 	dma_async_tx_callback cb_fn = submit->cb_fn;
 	void *cb_param = submit->cb_param;
 	void *scribble = submit->scribble;
+	int good_srcs, good, i;
 	struct page *srcs[2];
 
 	pr_debug("%s: disks: %d len: %zu\n", __func__, disks, bytes);
@@ -397,7 +411,6 @@ async_raid6_datap_recov(int disks, size_t bytes, int faila,
 	 */
 	if (!scribble) {
 		void **ptrs = (void **) blocks;
-		int i;
 
 		async_tx_quiesce(&submit->depend_tx);
 		for (i = 0; i < disks; i++)
@@ -413,6 +426,20 @@ async_raid6_datap_recov(int disks, size_t bytes, int faila,
 		return NULL;
 	}
 
+	good_srcs = 0;
+	good = -1;
+	for (i = 0; i < disks-2; i++) {
+		if (i == faila)
+			continue;
+		if (blocks[i]) {
+			good = i;
+			good_srcs++;
+			if (good_srcs > 1)
+				break;
+		}
+	}
+	BUG_ON(good_srcs == 0);
+
 	p = blocks[disks-2];
 	q = blocks[disks-1];
 
@@ -423,11 +450,10 @@ async_raid6_datap_recov(int disks, size_t bytes, int faila,
 	blocks[faila] = NULL;
 	blocks[disks-1] = dq;
 
-	/* in the 4 disk case we only need to perform a single source
-	 * multiplication
+	/* in the 4-disk case we only need to perform a single source
+	 * multiplication with the one good data block.
 	 */
-	if (disks == 4) {
-		int good = faila == 0 ? 1 : 0;
+	if (good_srcs == 1) {
 		struct page *g = blocks[good];
 
 		init_async_submit(submit, ASYNC_TX_FENCE, tx, NULL, NULL,
-- 
cgit v1.2.3-59-g8ed1b