From b8febd2f080de1f12e68cc233c68c7a39835a3c4 Mon Sep 17 00:00:00 2001
From: Greg Kurz <groug@kaod.org>
Date: Wed, 26 May 2021 09:03:51 -0400
Subject: [PATCH 11/15] virtio-blk: Fix rollback path in
 virtio_blk_data_plane_start()

RH-Author: Miroslav Rezanina <mrezanin@redhat.com>
RH-MergeRequest: 5: Synchronize RHEL-AV 8.5 release 18 to RHEL 9 Beta
RH-Commit: [8/12] 73d05400a537ce1847605dca58aff99e0a905919 (mrezanin/centos-src-qemu-kvm)
RH-Bugzilla: 1957194
RH-Acked-by: Danilo Cesar Lemes de Paula <ddepaula@redhat.com>
RH-Acked-by: Cornelia Huck <cohuck@redhat.com>
RH-Acked-by: Greg Kurz <gkurz@redhat.com>
RH-Acked-by: Laurent Vivier <lvivier@redhat.com>

When dataplane multiqueue support was added in QEMU 2.7, the path
that would rollback guest notifiers assignment in case of error
simply got dropped.

Later on, when Error was added to blk_set_aio_context() in QEMU 4.1,
another error path was introduced, but it ommits to rollback both
host and guest notifiers.

It seems cleaner to fix the rollback path in one go. The patch is
simple enough that it can be adjusted if backported to a pre-4.1
QEMU.

Fixes: 51b04ac5c6a6 ("virtio-blk: dataplane multiqueue support")
Cc: stefanha@redhat.com
Fixes: 97896a4887a0 ("block: Add Error to blk_set_aio_context()")
Cc: kwolf@redhat.com
Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20210407143501.244343-2-groug@kaod.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
(cherry picked from commit 570fe439e5d1b8626cf344c6bc97d90cfcaf0c79)
Signed-off-by: Greg Kurz <gkurz@redhat.com>
Signed-off-by: Danilo C. L. de Paula <ddepaula@redhat.com>
Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
---
 hw/block/dataplane/virtio-blk.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/hw/block/dataplane/virtio-blk.c b/hw/block/dataplane/virtio-blk.c
index e9050c8987..d7b5c95d26 100644
--- a/hw/block/dataplane/virtio-blk.c
+++ b/hw/block/dataplane/virtio-blk.c
@@ -207,7 +207,7 @@ int virtio_blk_data_plane_start(VirtIODevice *vdev)
                 virtio_bus_set_host_notifier(VIRTIO_BUS(qbus), i, false);
                 virtio_bus_cleanup_host_notifier(VIRTIO_BUS(qbus), i);
             }
-            goto fail_guest_notifiers;
+            goto fail_host_notifiers;
         }
     }
 
@@ -221,7 +221,7 @@ int virtio_blk_data_plane_start(VirtIODevice *vdev)
     aio_context_release(old_context);
     if (r < 0) {
         error_report_err(local_err);
-        goto fail_guest_notifiers;
+        goto fail_aio_context;
     }
 
     /* Process queued requests before the ones in vring */
@@ -245,6 +245,13 @@ int virtio_blk_data_plane_start(VirtIODevice *vdev)
     aio_context_release(s->ctx);
     return 0;
 
+  fail_aio_context:
+    for (i = 0; i < nvqs; i++) {
+        virtio_bus_set_host_notifier(VIRTIO_BUS(qbus), i, false);
+        virtio_bus_cleanup_host_notifier(VIRTIO_BUS(qbus), i);
+    }
+  fail_host_notifiers:
+    k->set_guest_notifiers(qbus->parent, nvqs, false);
   fail_guest_notifiers:
     /*
      * If we failed to set up the guest notifiers queued requests will be
-- 
2.27.0