async_tx: Fix DMA_PREP_FENCE usage in do_async_gen_syndrome()

The DMA_PREP_FENCE is to be used when preparing Tx descriptor if output
of Tx descriptor is to be used by next/dependent Tx descriptor.

The DMA_PREP_FENSE will not be set correctly in do_async_gen_syndrome()
when calling dma->device_prep_dma_pq() under following conditions:
1. ASYNC_TX_FENCE not set in submit->flags
2. DMA_PREP_FENCE not set in dma_flags
3. src_cnt (= (disks - 2)) is greater than dma_maxpq(dma, dma_flags)

This patch fixes DMA_PREP_FENCE usage in do_async_gen_syndrome() taking
inspiration from do_async_xor() implementation.

Signed-off-by: Anup Patel <anup.patel@broadcom.com>
Reviewed-by: Ray Jui <ray.jui@broadcom.com>
Reviewed-by: Scott Branden <scott.branden@broadcom.com>
Acked-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

1 files changed, 2 insertions, 3 deletions

diff --git a/crypto/async_tx/async_pq.c b/crypto/async_tx/async_pq.c
index f83de99d7d71..56bd612927ab 100644
--- a/crypto/async_tx/async_pq.c
+++ b/crypto/async_tx/async_pq.c
@@ -62,9 +62,6 @@ do_async_gen_syndrome(struct dma_chan *chan,
         dma_addr_t dma_dest[2];
         int src_off = 0;
 
-        if (submit->flags & ASYNC_TX_FENCE)
-                dma_flags |= DMA_PREP_FENCE;
-
         while (src_cnt > 0) {
                 submit->flags = flags_orig;
                 pq_src_cnt = min(src_cnt, dma_maxpq(dma, dma_flags));
@@ -83,6 +80,8 @@ do_async_gen_syndrome(struct dma_chan *chan,
                         if (cb_fn_orig)
                                 dma_flags |= DMA_PREP_INTERRUPT;
                 }
+                if (submit->flags & ASYNC_TX_FENCE)
+                        dma_flags |= DMA_PREP_FENCE;
 
                 /* Drivers force forward progress in case they can not provide
                  * a descriptor