[QEMU HCI-8.0 PATCH v4 1/5] vhost-blk: improve vhost_blk_device_realize cleanup

[Andrey Zhadchenko <andrey.zhadchenko@virtuozzo.com>]

vhost_dev_init() does a lot of unexpected things:
 - closes the backend fd on failure
 - memsets dev as 0 (thus clearing dev->vqs)

Cleanup properly: don't double-close vhostfd, factor out vqs
so we do not leak it during cleanup.

Fixes: 0ff3cb5ff2 ("block: add vhost-blk backend")
https://virtuozzo.atlassian.net/browse/VSTOR-143437
Reviewed-by: Andrey Drobyshev <andrey.drobyshev@virtuozzo.com>
Signed-off-by: Andrey Zhadchenko <andrey.zhadchenko@virtuozzo.com>
---
v2:
 - old patch dropped

v3:
 - extend the double-close fix to preserve and free vqs after
vhost_dev_init() clears dev

 hw/block/vhost-blk.c | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/hw/block/vhost-blk.c b/hw/block/vhost-blk.c
index c52851fcf8..20c2f41691 100644
--- a/hw/block/vhost-blk.c
+++ b/hw/block/vhost-blk.c
@@ -237,6 +237,7 @@ static void vhost_blk_device_realize(DeviceState *dev, Error **errp)
     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
     VHostBlk *s = VHOST_BLK(vdev);
     VhostBlkConf *conf = &s->conf;
+    struct vhost_virtqueue *vqs;
     int i, ret;
 
     if (!conf->conf.blk) {
@@ -289,7 +290,8 @@ static void vhost_blk_device_realize(DeviceState *dev, Error **errp)
 
     s->dev.nvqs = conf->num_queues;
     s->dev.max_queues = conf->num_queues;
-    s->dev.vqs = g_new0(struct vhost_virtqueue, s->dev.nvqs);
+    vqs = g_new0(struct vhost_virtqueue, s->dev.nvqs);
+    s->dev.vqs = vqs;
     s->dev.vq_index = 0;
 
     virtio_init(vdev, VIRTIO_ID_BLOCK, sizeof(struct virtio_blk_config));
@@ -318,6 +320,8 @@ static void vhost_blk_device_realize(DeviceState *dev, Error **errp)
     if (ret < 0) {
         error_setg(errp, "vhost-blk: vhost initialization failed: %s",
                 strerror(-ret));
+        /* vhost_dev_init() closes vhostfd on failure */
+        s->vhostfd = -1;
         goto cleanup;
     }
 
@@ -327,8 +331,11 @@ cleanup:
     if (s->mighand) {
             qemu_del_vm_change_state_handler(s->mighand);
     }
-    g_free(s->dev.vqs);
-    close(s->vhostfd);
+    g_free(vqs);
+    if (s->vhostfd >= 0) {
+        close(s->vhostfd);
+        s->vhostfd = -1;
+    }
     for (i = 0; i < conf->num_queues; i++) {
         virtio_del_queue(vdev, i);
     }
@@ -470,6 +477,7 @@ static void vhost_blk_instance_init(Object *obj)
 {
     VHostBlk *s = VHOST_BLK(obj);
 
+    s->vhostfd = -1;
     device_add_bootindex_property(obj, &s->conf.conf.bootindex,
                                   "bootindex", "/disk@0,0",
                                   DEVICE(obj));
-- 
2.43.5