[PATCH 06/19] raid5: move the reconstruct write expansion operation to a workqueue

[Dan Williams]

From: Dan Williams <dan.j.williams@xxxxxxxxx>

Enable handle_stripe5 to use the reconstruct write operations capability
for expansion operations.  

However this does not move the copy operation associated with an expand to
the workqueue.  First, it was difficult to find a clean way to pass the
parameters of this operation to the queue.  Second, this section of code is
a good candidate for performing the copies with inline calls to the dma
routines.

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

 drivers/md/raid5.c |   36 +++++++++++++++++++++++++++---------
 1 files changed, 27 insertions(+), 9 deletions(-)

diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 1a8dfd2..a07b52b 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -2053,6 +2053,7 @@ #endif
 	 * completed
 	 */
 	if (test_bit(STRIPE_OP_RCW, &sh->state) &&
+		!test_bit(STRIPE_OP_RCW_Expand, &sh->ops.state) &&
 		test_bit(STRIPE_OP_RCW_Done, &sh->ops.state)) {
 		clear_bit(STRIPE_OP_RCW, &sh->state);
 		clear_bit(STRIPE_OP_RCW_Done, &sh->ops.state);
@@ -2226,6 +2227,7 @@ #endif
 				}
 			}
 		}
+
 		if (test_bit(STRIPE_OP_COMPUTE_Done, &sh->ops.state) &&
 			test_bit(STRIPE_OP_COMPUTE_Recover_pd, &sh->ops.state)) {
 			clear_bit(STRIPE_OP_COMPUTE, &sh->state);
@@ -2282,18 +2284,28 @@ #endif
 		}
 	}
 
-	if (expanded && test_bit(STRIPE_EXPANDING, &sh->state)) {
+	/* Finish 'rcw' operations initiated by the expansion
+	 * process
+	 */
+	if (test_bit(STRIPE_OP_RCW, &sh->state) &&
+		test_bit(STRIPE_OP_RCW_Expand, &sh->ops.state) &&
+		test_bit(STRIPE_OP_RCW_Done, &sh->ops.state)) {
+		clear_bit(STRIPE_OP_RCW, &sh->state);
+		clear_bit(STRIPE_OP_RCW_Done, &sh->ops.state);
+		clear_bit(STRIPE_OP_RCW_Expand, &sh->ops.state);
+		clear_bit(STRIPE_EXPANDING, &sh->state);
+		for (i= conf->raid_disks; i--;)
+			set_bit(R5_Wantwrite, &sh->dev[i].flags);
+	}
+
+	if (expanded && test_bit(STRIPE_EXPANDING, &sh->state) &&
+		!test_bit(STRIPE_OP_RCW, &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);
-		for (i= conf->raid_disks; i--;) {
-			set_bit(R5_LOCKED, &sh->dev[i].flags);
-			locked++;
-			set_bit(R5_Wantwrite, &sh->dev[i].flags);
-		}
-		clear_bit(STRIPE_EXPANDING, &sh->state);
-	} else if (expanded) {
+		set_bit(STRIPE_OP_RCW_Expand, &sh->ops.state);
+		locked += handle_write_operations5(sh, 0);
+	} else if (expanded && !test_bit(STRIPE_OP_RCW, &sh->state)) {
 		clear_bit(STRIPE_EXPAND_READY, &sh->state);
 		atomic_dec(&conf->reshape_stripes);
 		wake_up(&conf->wait_for_overlap);
@@ -2327,9 +2339,15 @@ #endif
 					release_stripe(sh2);
 					continue;
 				}
+				/* to do: perform these operations with a dma engine
+				 * inline (rather than pushing to the workqueue)
+				 */
+				/*#ifdef CONFIG_RAID5_DMA*/
+				/*#else*/
 				memcpy(page_address(sh2->dev[dd_idx].page),
 				       page_address(sh->dev[i].page),
 				       STRIPE_SIZE);
+				/*#endif*/
 				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++)
-
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