On Thu, May 26, 2022 at 10:57:03AM +0200, Eugenio Perez Martin wrote:
On Wed, May 25, 2022 at 1:23 PM Dawar, Gautam <gautam.dawar@xxxxxxx> wrote:
[AMD Official Use Only - General]
-----Original Message-----
From: Eugenio Pérez <eperezma@xxxxxxxxxx>
Sent: Wednesday, May 25, 2022 4:29 PM
To: Michael S. Tsirkin <mst@xxxxxxxxxx>; netdev@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; kvm@xxxxxxxxxxxxxxx; virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx; Jason Wang <jasowang@xxxxxxxxxx>
Cc: Zhu Lingshan <lingshan.zhu@xxxxxxxxx>; martinh@xxxxxxxxxx; Stefano Garzarella <sgarzare@xxxxxxxxxx>; ecree.xilinx@xxxxxxxxx; Eli Cohen <elic@xxxxxxxxxx>; Dan Carpenter <dan.carpenter@xxxxxxxxxx>; Parav Pandit <parav@xxxxxxxxxx>; Wu Zongyong <wuzongyong@xxxxxxxxxxxxxxxxx>; dinang@xxxxxxxxxx; Christophe JAILLET <christophe.jaillet@xxxxxxxxxx>; Xie Yongji <xieyongji@xxxxxxxxxxxxx>; Dawar, Gautam <gautam.dawar@xxxxxxx>; lulu@xxxxxxxxxx; martinpo@xxxxxxxxxx; pabloc@xxxxxxxxxx; Longpeng <longpeng2@xxxxxxxxxx>; Piotr.Uminski@xxxxxxxxx; Kamde, Tanuj <tanuj.kamde@xxxxxxx>; Si-Wei Liu <si-wei.liu@xxxxxxxxxx>; habetsm.xilinx@xxxxxxxxx; lvivier@xxxxxxxxxx; Zhang Min <zhang.min9@xxxxxxxxxx>; hanand@xxxxxxxxxx
Subject: [PATCH v3 2/4] vhost-vdpa: introduce STOP backend feature bit
[CAUTION: External Email]
Userland knows if it can stop the device or not by checking this feature bit.
It's only offered if the vdpa driver backend implements the stop() operation callback, and try to set it if the backend does not offer that callback is an error.
Signed-off-by: Eugenio Pérez <eperezma@xxxxxxxxxx>
---
drivers/vhost/vdpa.c | 16 +++++++++++++++-
include/uapi/linux/vhost_types.h | 2 ++
2 files changed, 17 insertions(+), 1 deletion(-)
diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c index 1f1d1c425573..32713db5831d 100644
--- a/drivers/vhost/vdpa.c
+++ b/drivers/vhost/vdpa.c
@@ -347,6 +347,14 @@ static long vhost_vdpa_set_config(struct vhost_vdpa *v,
return 0;
}
+static bool vhost_vdpa_can_stop(const struct vhost_vdpa *v) {
+ struct vdpa_device *vdpa = v->vdpa;
+ const struct vdpa_config_ops *ops = vdpa->config;
+
+ return ops->stop;
[GD>>] Would it be better to explicitly return a bool to match the return type?
I'm not sure about the kernel code style regarding that casting. Maybe
it's better to return !!ops->stop here. The macros likely and unlikely
do that.
IIUC `ops->stop` is a function pointer, so what about
return ops->stop != NULL;
Thanks,
Stefano
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