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>

1 files changed, 24 insertions, 7 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))