[PATCH v2] hw/core/qdev-properties-system: Add missing return in set_drive_helper()

[Fiona Ebner <f.ebner@proxmox.com>]

Currently, changing the 'drive' property of e.g. a scsi-hd object will
result in an assertion failure if the aio context of the block node
it's replaced with doesn't match the current aio context:

> bdrv_replace_child_noperm: Assertion `bdrv_get_aio_context(old_bs) ==
> bdrv_get_aio_context(new_bs)' failed.

The problematic scenario is already detected, but a 'return' statement
was missing.

Cc: qemu-stable@nongnu.org
Fixes: d1a58c176a ("qdev: allow setting drive property for realized device")
Signed-off-by: Fiona Ebner <f.ebner@proxmox.com>
---

Changes in v2:
* Add missing condition in commit message, sorry for the noise!

Reproducer:

#!/bin/bash
rm /tmp/disk0.raw
rm /tmp/disk1.raw
./qemu-img create -f raw /tmp/disk0.raw 1G
./qemu-img create -f raw /tmp/disk1.raw 1G
./qemu-system-x86_64 --qmp stdio \
--blockdev file,node-name=node0,filename=/tmp/disk0.raw \
--blockdev file,node-name=node1,filename=/tmp/disk1.raw \
--nodefaults \
--object 'iothread,id=iothread0' \
--device 'virtio-scsi-pci,id=virtioscsi0,bus=pci.0,addr=0x3,iothread=iothread0' \
--device 'scsi-hd,bus=virtioscsi0.0,scsi-id=1,drive=node0,id=scsi0' \
<<EOF
{"execute": "qmp_capabilities"}
{"execute": "qom-set", "arguments": { "path": "/machine/peripheral/scsi0", "property": "drive", "value": "node1" } }
{"execute": "quit"}
EOF

 hw/core/qdev-properties-system.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/hw/core/qdev-properties-system.c b/hw/core/qdev-properties-system.c
index 8e11e6388b..24e145d870 100644
--- a/hw/core/qdev-properties-system.c
+++ b/hw/core/qdev-properties-system.c
@@ -145,6 +145,7 @@ static void set_drive_helper(Object *obj, Visitor *v, const char *name,
         if (ctx != bdrv_get_aio_context(bs)) {
             error_setg(errp, "Different aio context is not supported for new "
                        "node");
+            return;
         }
 
         blk_replace_bs(blk, bs, errp);
-- 
2.39.5