Merge branch 'for-linus' of git://neil.brown.name/md

* 'for-linus' of git://neil.brown.name/md:
  async_tx: fix asynchronous raid6 recovery for ddf layouts
  async_pq: rename scribble page
  async_pq: kill a stray dma_map() call and other cleanups
  md/raid6: kill a gcc-4.0.1 'uninitialized variable' warning
  raid6/async_tx: handle holes in block list in async_syndrome_val
  md/async: don't pass a memory pointer as a page pointer.
  md: Fix handling of raid5 array which is being reshaped to fewer devices.
  md: fix problems with RAID6 calculations for DDF.
  md/raid456: downlevel multicore operations to raid_run_ops
  md: drivers/md/unroll.pl replaced with awk analog
  md: remove clumsy usage of do_sync_mapping_range from bitmap code
  md: raid1/raid10: handle allocation errors during array setup.
  md/raid5: initialize conf->device_lock earlier
  md/raid1/raid10: add a cond_resched
  Revert "md: do not progress the resync process if the stripe was blocked"

15 files changed, 284 insertions, 224 deletions

diff --git a/crypto/async_tx/async_pq.c b/crypto/async_tx/async_pq.c
index b88db6d1dc65..6b5cc4fba59f 100644
--- a/crypto/async_tx/async_pq.c
+++ b/crypto/async_tx/async_pq.c
@@ -26,14 +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 bool is_raid6_zero_block(struct page *p)
-{
-        return p == (void *) raid6_empty_zero_page;
-}
+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
@@ -83,7 +79,7 @@ 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 +156,9 @@ 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;
         }
@@ -186,10 +182,14 @@ 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,
@@ -227,11 +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);
@@ -265,8 +265,10 @@ 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);
 
@@ -285,22 +287,32 @@ 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++)
+                for (i = 0; i < disks-2; i++)
                         if (likely(blocks[i])) {
-                                BUG_ON(is_raid6_zero_block(blocks[i]));
-                                dma_src[i] = dma_map_page(dev, blocks[i],
-                                                          offset, len,
-                                                          DMA_TO_DEVICE);
+                                dma_src[src_cnt] = dma_map_page(dev, blocks[i],
+                                                                offset, len,
+                                                                DMA_TO_DEVICE);
+                                coefs[src_cnt] = raid6_gfexp[i];
+                                src_cnt++;
                         }
 
                 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))
@@ -373,9 +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__);
@@ -385,7 +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);
diff --git a/crypto/async_tx/async_raid6_recov.c b/crypto/async_tx/async_raid6_recov.c
index 6d73dde4786d..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
@@ -263,10 +264,10 @@ __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);
@@ -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);
@@ -334,11 +337,13 @@ 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++)
-                        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);
 
@@ -347,19 +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);
         }
@@ -385,6 +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);
@@ -394,11 +411,13 @@ 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++)
-                        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);
 
@@ -407,6 +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];
 
@@ -414,14 +447,13 @@ 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
-         * 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,
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;
 
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/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);
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/raid1.c b/drivers/md/raid1.c
index d1b9bd5fd4f6..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;
@@ -1683,6 +1683,7 @@ static void raid1d(mddev_t *mddev)
                                 generic_make_request(bio);
                         }
                 }
+                cond_resched();
         }
         if (unplug)
                 unplug_slaves(mddev);
@@ -1978,13 +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 51c4c5c4d87a..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;
@@ -1632,6 +1632,7 @@ static void raid10d(mddev_t *mddev)
                                 generic_make_request(bio);
                         }
                 }
+                cond_resched();
         }
         if (unplug)
                 unplug_slaves(mddev);
@@ -2095,7 +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;
@@ -2132,6 +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;
 
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 94829804ab7f..81abefc172d9 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -156,13 +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)
+                (*count)++;
         if (idx == sh->pd_idx)
                 return syndrome_disks;
         if (idx == sh->qd_idx)
                 return syndrome_disks + 1;
-        slot = (*count)++;
+        if (!sh->ddf_layout)
+                (*count)++;
         return slot;
 }
 
@@ -717,7 +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;
@@ -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 *
@@ -814,7 +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 {
@@ -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;
@@ -1139,7 +1140,7 @@ 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;
@@ -1204,22 +1205,55 @@ 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;
+        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);
@@ -1231,7 +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));
@@ -1329,6 +1363,9 @@ 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);
         }
@@ -1899,10 +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:
@@ -2896,7 +2938,7 @@ 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 +3209,9 @@ 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 +3495,14 @@ 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)
@@ -3503,9 +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);
@@ -4277,9 +4315,7 @@ 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;
@@ -4349,37 +4385,6 @@ 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.
@@ -4393,7 +4398,6 @@ 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");
 
@@ -4430,7 +4434,9 @@ 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);
         }
@@ -4438,7 +4444,6 @@ 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);
 
@@ -4558,13 +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);
@@ -4665,7 +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;
@@ -4686,7 +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;
 
@@ -4722,15 +4723,28 @@ 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);
         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;
@@ -4744,24 +4758,11 @@ 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) {
                 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;
@@ -4793,7 +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);
@@ -4918,7 +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"
diff --git a/drivers/md/raid5.h b/drivers/md/raid5.h
index 2390e0e83daf..dd708359b451 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
  */
@@ -478,7 +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);
 }
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;
-    }
-}