On 1/11/2024 9:28 PM, Jason Wang wrote:
> On Fri, Jan 12, 2024 at 12:18 AM Mike Christie
> <michael.christie@xxxxxxxxxx> wrote:
>>
>> On 1/10/24 9:09 PM, Jason Wang wrote:
>>> On Thu, Jan 11, 2024 at 4:40 AM Steve Sistare <steven.sistare@xxxxxxxxxx> wrote:
>>>>
>>>> To pass ownership of a live vdpa device to a new process, the user
>>>> suspends the device, calls VHOST_NEW_OWNER to change the mm, and calls
>>>> VHOST_IOTLB_REMAP to change the user virtual addresses to match the new
>>>> mm. Flush workers in suspend to guarantee that no worker sees the new
>>>> mm and old VA in between.
>>>>
>>>> Signed-off-by: Steve Sistare <steven.sistare@xxxxxxxxxx>
>>>> ---
>>>> drivers/vhost/vdpa.c | 4 ++++
>>>> 1 file changed, 4 insertions(+)
>>>>
>>>> diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
>>>> index 8fe1562d24af..9673e8e20d11 100644
>>>> --- a/drivers/vhost/vdpa.c
>>>> +++ b/drivers/vhost/vdpa.c
>>>> @@ -591,10 +591,14 @@ static long vhost_vdpa_suspend(struct vhost_vdpa *v)
>>>> {
>>>> struct vdpa_device *vdpa = v->vdpa;
>>>> const struct vdpa_config_ops *ops = vdpa->config;
>>>> + struct vhost_dev *vdev = &v->vdev;
>>>>
>>>> if (!ops->suspend)
>>>> return -EOPNOTSUPP;
>>>>
>>>> + if (vdev->use_worker)
>>>> + vhost_dev_flush(vdev);
>>>
>>> It looks to me like it's better to check use_woker in vhost_dev_flush.
>>
>> You can now just call vhost_dev_flush and it will do the right thing.
>> The xa_for_each loop will only flush workers if they have been setup,
>> so for vdpa it will not find/flush anything.
Very good, I will drop this patch.
- Steve
