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>

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;