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)