[PATCH 10/12] md: use async_tx and raid5_run_ops for raid5 expansion operations

[Dan Williams <dan.j.williams@intel.com>]

From: Dan Williams <dan.j.williams@intel.com>

handle_stripe sets STRIPE_OP_POSTXOR without setting STRIPE_OP_BIODRAIN to
carry out the postxor operation required by the expansion process.  This
distinction is needed since all blocks will need to be written back to disk
even though none of the blocks will have their 'written' pointer set.

The bulk copy operation to the new stripe is handled by async_tx.

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

 drivers/md/raid5.c |   48 ++++++++++++++++++++++++++++++++++++------------
 1 files changed, 36 insertions(+), 12 deletions(-)

diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 3c793dc..8b36611 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -2582,18 +2582,32 @@ #endif
 		}
 	}
 
-	if (expanded && test_bit(STRIPE_EXPANDING, &sh->state)) {
-		/* Need to write out all blocks after computing parity */
-		sh->disks = conf->raid_disks;
-		sh->pd_idx = stripe_to_pdidx(sh->sector, conf, conf->raid_disks);
-		compute_parity5(sh, RECONSTRUCT_WRITE);
+	/* Finish postxor operations initiated by the expansion
+	 * process
+	 */
+	if (test_bit(STRIPE_OP_POSTXOR, &sh->ops.complete) &&
+		!test_bit(STRIPE_OP_BIODRAIN, &sh->ops.pending)) {
+
+		clear_bit(STRIPE_EXPANDING, &sh->state);
+
+		clear_bit(STRIPE_OP_POSTXOR, &sh->ops.pending);
+		clear_bit(STRIPE_OP_POSTXOR, &sh->ops.ack);
+		clear_bit(STRIPE_OP_POSTXOR, &sh->ops.complete);
+
 		for (i= conf->raid_disks; i--;) {
-			set_bit(R5_LOCKED, &sh->dev[i].flags);
-			locked++;
 			set_bit(R5_Wantwrite, &sh->dev[i].flags);
+			if (!test_and_set_bit(STRIPE_OP_IO, &sh->ops.pending))
+				sh->ops.count++;
 		}
-		clear_bit(STRIPE_EXPANDING, &sh->state);
-	} else if (expanded) {
+	}
+
+	if (expanded && test_bit(STRIPE_EXPANDING, &sh->state) &&
+		!test_bit(STRIPE_OP_POSTXOR, &sh->ops.pending)) {
+		/* Need to write out all blocks after computing parity */
+		sh->disks = conf->raid_disks;
+		sh->pd_idx = stripe_to_pdidx(sh->sector, conf, conf->raid_disks);
+		locked += handle_write_operations5(sh, 0, 1);
+	} else if (expanded && !test_bit(STRIPE_OP_POSTXOR, &sh->ops.pending)) {
 		clear_bit(STRIPE_EXPAND_READY, &sh->state);
 		atomic_dec(&conf->reshape_stripes);
 		wake_up(&conf->wait_for_overlap);
@@ -2604,6 +2618,7 @@ #endif
 		/* We have read all the blocks in this stripe and now we need to
 		 * copy some of them into a target stripe for expand.
 		 */
+		struct dma_async_tx_descriptor *tx = NULL;
 		clear_bit(STRIPE_EXPAND_SOURCE, &sh->state);
 		for (i=0; i< sh->disks; i++)
 			if (i != sh->pd_idx) {
@@ -2627,9 +2642,12 @@ #endif
 					release_stripe(sh2);
 					continue;
 				}
-				memcpy(page_address(sh2->dev[dd_idx].page),
-				       page_address(sh->dev[i].page),
-				       STRIPE_SIZE);
+
+				/* place all the copies on one channel */
+				tx = async_memcpy(sh2->dev[dd_idx].page,
+					sh->dev[i].page, 0, 0, STRIPE_SIZE,
+					ASYNC_TX_DEP_ACK, tx, NULL, NULL);
+
 				set_bit(R5_Expanded, &sh2->dev[dd_idx].flags);
 				set_bit(R5_UPTODATE, &sh2->dev[dd_idx].flags);
 				for (j=0; j<conf->raid_disks; j++)
@@ -2641,6 +2659,12 @@ #endif
 					set_bit(STRIPE_HANDLE, &sh2->state);
 				}
 				release_stripe(sh2);
+
+				/* done submitting copies, wait for them to complete */
+				if (i + 1 >= sh->disks) {
+					async_tx_ack(tx);
+					dma_wait_for_async_tx(tx);
+				}
 			}
 	}