ioat3: specify valid address for disabled-Q or disabled-P

Although disabled, hardware still checks address validity, so duplicate
the known address.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>

drivers/dma/ioat/dma_v3.c

@@ -736,10 +736,16 @@ ioat3_prep_pq(struct dma_chan *chan, dma_addr_t *dst, dma_addr_t *src,
 	      unsigned int src_cnt, const unsigned char *scf, size_t len,
 	      unsigned long flags)
 {
+	/* specify valid address for disabled result */
+	if (flags & DMA_PREP_PQ_DISABLE_P)
+		dst[0] = dst[1];
+	if (flags & DMA_PREP_PQ_DISABLE_Q)
+		dst[1] = dst[0];
+
 	/* handle the single source multiply case from the raid6
 	 * recovery path
 	 */
-	if (unlikely((flags & DMA_PREP_PQ_DISABLE_P) && src_cnt == 1)) {
+	if ((flags & DMA_PREP_PQ_DISABLE_P) && src_cnt == 1) {
 		dma_addr_t single_source[2];
 		unsigned char single_source_coef[2];
 
@@ -761,6 +767,12 @@ ioat3_prep_pq_val(struct dma_chan *chan, dma_addr_t *pq, dma_addr_t *src,
 		  unsigned int src_cnt, const unsigned char *scf, size_t len,
 		  enum sum_check_flags *pqres, unsigned long flags)
 {
+	/* specify valid address for disabled result */
+	if (flags & DMA_PREP_PQ_DISABLE_P)
+		pq[0] = pq[1];
+	if (flags & DMA_PREP_PQ_DISABLE_Q)
+		pq[1] = pq[0];
+
 	/* the cleanup routine only sets bits on validate failure, it
 	 * does not clear bits on validate success... so clear it here
 	 */
@@ -778,9 +790,9 @@ ioat3_prep_pqxor(struct dma_chan *chan, dma_addr_t dst, dma_addr_t *src,
 	dma_addr_t pq[2];
 
 	memset(scf, 0, src_cnt);
-	flags |= DMA_PREP_PQ_DISABLE_Q;
 	pq[0] = dst;
-	pq[1] = ~0;
+	flags |= DMA_PREP_PQ_DISABLE_Q;
+	pq[1] = dst; /* specify valid address for disabled result */
 
 	return __ioat3_prep_pq_lock(chan, NULL, pq, src, src_cnt, scf, len,
 				    flags);
@@ -800,9 +812,9 @@ ioat3_prep_pqxor_val(struct dma_chan *chan, dma_addr_t *src,
 	*result = 0;
 
 	memset(scf, 0, src_cnt);
-	flags |= DMA_PREP_PQ_DISABLE_Q;
 	pq[0] = src[0];
-	pq[1] = ~0;
+	flags |= DMA_PREP_PQ_DISABLE_Q;
+	pq[1] = pq[0]; /* specify valid address for disabled result */
 
 	return __ioat3_prep_pq_lock(chan, result, pq, &src[1], src_cnt - 1, scf,
 				    len, flags);