[Devel] [PATCH RHEL7 COMMIT] ploop: push_backup cleanup

[Konstantin Khorenko]

The commit is pushed to "branch-rh7-3.10.0-327.10.1.vz7.12.x-ovz" and will appear at https://src.openvz.org/scm/ovz/vzkernel.git
after rh7-3.10.0-327.10.1.vz7.12.16
------>
commit 1f96fbdfe1efd72b1d18da09938bb638787f7b33
Author: Maxim Patlasov <mpatlasov at virtuozzo.com>
Date:   Mon May 2 18:40:42 2016 +0400

    ploop: push_backup cleanup
    
    ploop_pb_stop() is called either explicitly, when userspace makes
    ioctl(PLOOP_IOC_PUSH_BACKUP_STOP), or implicitly on ploop shutdown
    when userspace stops ploop device by ioctl(PLOOP_IOC_STOP).
    
    In both cases, it's useful to re-schedule all suspended preq-s. Otherwise,
    we won't be able to destroy ploop because some preq-s are still not
    completed.
    
    Signed-off-by: Maxim Patlasov <mpatlasov at virtuozzo.com>
    Acked-by: Dmitry Monakhov <dmonakhov at openvz.org>
---
 drivers/block/ploop/push_backup.c | 36 +++++++++++++++++++++++++++++++++++-
 1 file changed, 35 insertions(+), 1 deletion(-)

diff --git a/drivers/block/ploop/push_backup.c b/drivers/block/ploop/push_backup.c
index 488b8fb..05af67c 100644
--- a/drivers/block/ploop/push_backup.c
+++ b/drivers/block/ploop/push_backup.c
@@ -358,6 +358,12 @@ ploop_pb_get_first_req_from_pending(struct ploop_pushbackup_desc *pbd)
 }
 
 static struct ploop_request *
+ploop_pb_get_first_req_from_reported(struct ploop_pushbackup_desc *pbd)
+{
+	return ploop_pb_get_first_req_from_tree(&pbd->reported_tree);
+}
+
+static struct ploop_request *
 ploop_pb_get_req_from_pending(struct ploop_pushbackup_desc *pbd,
 			      cluster_t clu)
 {
@@ -400,16 +406,44 @@ int ploop_pb_preq_add_pending(struct ploop_pushbackup_desc *pbd,
 
 unsigned long ploop_pb_stop(struct ploop_pushbackup_desc *pbd)
 {
+	unsigned long ret = 0;
+	LIST_HEAD(drop_list);
+
 	if (pbd == NULL)
 		return 0;
 
 	spin_lock(&pbd->ppb_lock);
 
+	while (!RB_EMPTY_ROOT(&pbd->pending_tree)) {
+		struct ploop_request *preq =
+			ploop_pb_get_first_req_from_pending(pbd);
+		list_add(&preq->list, &drop_list);
+		ret++;
+	}
+
+	while (!RB_EMPTY_ROOT(&pbd->reported_tree)) {
+		struct ploop_request *preq =
+			ploop_pb_get_first_req_from_reported(pbd);
+		list_add(&preq->list, &drop_list);
+		ret++;
+	}
+
 	if (pbd->ppb_waiting)
 		complete(&pbd->ppb_comp);
 	spin_unlock(&pbd->ppb_lock);
 
-	return 0;
+	if (!list_empty(&drop_list)) {
+		struct ploop_device *plo = pbd->plo;
+
+		BUG_ON(!plo);
+		spin_lock_irq(&plo->lock);
+		list_splice_init(&drop_list, plo->ready_queue.prev);
+		if (test_bit(PLOOP_S_WAIT_PROCESS, &plo->state))
+			wake_up_interruptible(&plo->waitq);
+		spin_unlock_irq(&plo->lock);
+	}
+
+	return ret;
 }
 
 int ploop_pb_get_pending(struct ploop_pushbackup_desc *pbd,