[PATCH 1/2] vdpa: Track device suspended state

[Dragos Tatulea]

Set vdpa device suspended state on successful suspend. Clear it on
successful resume and reset.

The state will be locked by the vhost_vdpa mutex. The mutex is taken
during suspend, resume and reset in vhost_vdpa_unlocked_ioctl. The
exception is vhost_vdpa_open which does a device reset but that should
be safe because it can only happen before the other ops.

Signed-off-by: Dragos Tatulea <dtatu...@nvidia.com>
Suggested-by: Eugenio Pérez <epere...@redhat.com>
---
 drivers/vhost/vdpa.c | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
index da7ec77cdaff..4c422be7d1e7 100644
--- a/drivers/vhost/vdpa.c
+++ b/drivers/vhost/vdpa.c
@@ -59,6 +59,7 @@ struct vhost_vdpa {
        int in_batch;
        struct vdpa_iova_range range;
        u32 batch_asid;
+       bool suspended;
 };
 
 static DEFINE_IDA(vhost_vdpa_ida);
@@ -232,6 +233,8 @@ static int _compat_vdpa_reset(struct vhost_vdpa *v)
        struct vdpa_device *vdpa = v->vdpa;
        u32 flags = 0;
 
+       v->suspended = false;
+
        if (v->vdev.vqs) {
                flags |= !vhost_backend_has_feature(v->vdev.vqs[0],
                                                    
VHOST_BACKEND_F_IOTLB_PERSIST) ?
@@ -590,11 +593,16 @@ static long vhost_vdpa_suspend(struct vhost_vdpa *v)
 {
        struct vdpa_device *vdpa = v->vdpa;
        const struct vdpa_config_ops *ops = vdpa->config;
+       int ret;
 
        if (!ops->suspend)
                return -EOPNOTSUPP;
 
-       return ops->suspend(vdpa);
+       ret = ops->suspend(vdpa);
+       if (!ret)
+               v->suspended = true;
+
+       return ret;
 }
 
 /* After a successful return of this ioctl the device resumes processing
@@ -605,11 +613,16 @@ static long vhost_vdpa_resume(struct vhost_vdpa *v)
 {
        struct vdpa_device *vdpa = v->vdpa;
        const struct vdpa_config_ops *ops = vdpa->config;
+       int ret;
 
        if (!ops->resume)
                return -EOPNOTSUPP;
 
-       return ops->resume(vdpa);
+       ret = ops->resume(vdpa);
+       if (!ret)
+               v->suspended = false;
+
+       return ret;
 }
 
 static long vhost_vdpa_vring_ioctl(struct vhost_vdpa *v, unsigned int cmd,
-- 
2.43.0