[Devel] [RFC PATCH vz9 v3 09/11] ploop: convert suspended_pios list to use lockless list

[Alexander Atanasov]

Signed-off-by: Alexander Atanasov <alexander.atanasov at virtuozzo.com>
---
 drivers/md/dm-ploop-cmd.c    | 13 +++++++++++--
 drivers/md/dm-ploop-map.c    |  2 +-
 drivers/md/dm-ploop-target.c |  2 +-
 drivers/md/dm-ploop.h        |  2 +-
 4 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/drivers/md/dm-ploop-cmd.c b/drivers/md/dm-ploop-cmd.c
index 61daaf8415c9..006495d95db3 100644
--- a/drivers/md/dm-ploop-cmd.c
+++ b/drivers/md/dm-ploop-cmd.c
@@ -124,14 +124,23 @@ ALLOW_ERROR_INJECTION(ploop_inflight_bios_ref_switch, ERRNO);
 static void ploop_resume_submitting_pios(struct ploop *ploop)
 {
 	LIST_HEAD(list);
+	struct llist_node *suspended_pending;
 
 	spin_lock_irq(&ploop->deferred_lock);
 	WARN_ON_ONCE(!ploop->stop_submitting_pios);
 	ploop->stop_submitting_pios = false;
-	list_splice_tail_init(&ploop->suspended_pios, &list);
 	spin_unlock_irq(&ploop->deferred_lock);
 
-	ploop_submit_embedded_pios(ploop, &list);
+	suspended_pending = llist_del_all(&ploop->llsuspended_pios);
+	if (suspended_pending) {
+		struct llist_node *pos, *t;
+		suspended_pending = llist_reverse_order(suspended_pending);
+		llist_for_each_safe(pos, t, suspended_pending) {
+			struct pio *pio = list_entry((struct list_head *)pos, typeof(*pio), list);
+			list_add(&pio->list, &list);
+		}
+		ploop_submit_embedded_pios(ploop, &list);
+	}
 }
 
 static int ploop_suspend_submitting_pios(struct ploop *ploop)
diff --git a/drivers/md/dm-ploop-map.c b/drivers/md/dm-ploop-map.c
index 4bd3e4c557f8..d93e96857d02 100644
--- a/drivers/md/dm-ploop-map.c
+++ b/drivers/md/dm-ploop-map.c
@@ -1870,7 +1870,7 @@ static void ploop_submit_embedded_pio(struct ploop *ploop, struct pio *pio)
 
 	spin_lock_irqsave(&ploop->deferred_lock, flags);
 	if (unlikely(ploop->stop_submitting_pios)) {
-		list_add_tail(&pio->list, &ploop->suspended_pios);
+		llist_add((struct llist_node *)(&pio->list), &ploop->llsuspended_pios);
 		queue = false;
 		goto unlock;
 	}
diff --git a/drivers/md/dm-ploop-target.c b/drivers/md/dm-ploop-target.c
index 3ac9e1f832f5..94d6f661f50c 100644
--- a/drivers/md/dm-ploop-target.c
+++ b/drivers/md/dm-ploop-target.c
@@ -370,7 +370,7 @@ static int ploop_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 	spin_lock_init(&ploop->inflight_lock);
 	spin_lock_init(&ploop->deferred_lock);
 
-	INIT_LIST_HEAD(&ploop->suspended_pios);
+	init_llist_head(&ploop->llsuspended_pios);
 
 	for (i = 0; i < PLOOP_LIST_COUNT; i++)
 		INIT_LIST_HEAD(&ploop->pios[i]);
diff --git a/drivers/md/dm-ploop.h b/drivers/md/dm-ploop.h
index f7d4a4af3381..7e7f82aa1402 100644
--- a/drivers/md/dm-ploop.h
+++ b/drivers/md/dm-ploop.h
@@ -190,7 +190,7 @@ struct ploop {
 	bool inflight_ref_comp_pending;
 	unsigned int inflight_bios_ref_index:1;
 
-	struct list_head suspended_pios;
+	struct llist_head llsuspended_pios;
 	bool stop_submitting_pios;
 
 	spinlock_t inflight_lock;
-- 
2.43.0