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Message-ID: <20240328112856-mutt-send-email-mst@kernel.org>
Date: Thu, 28 Mar 2024 11:29:22 -0400
From: "Michael S. Tsirkin" <mst@...hat.com>
To: Simon Horman <horms@...nel.org>
Cc: Daniel Jurgens <danielj@...dia.com>, netdev@...r.kernel.org,
jasowang@...hat.com, xuanzhuo@...ux.alibaba.com,
virtualization@...ts.linux.dev, davem@...emloft.net,
edumazet@...gle.com, kuba@...nel.org, pabeni@...hat.com,
jiri@...dia.com
Subject: Re: [PATCH net-next 2/4] virtio_net: Remove command data from
control_buf
On Thu, Mar 28, 2024 at 01:35:16PM +0000, Simon Horman wrote:
> On Mon, Mar 25, 2024 at 04:49:09PM -0500, Daniel Jurgens wrote:
> > Allocate memory for the data when it's used. Ideally the could be on the
> > stack, but we can't DMA stack memory. With this change only the header
> > and status memory are shared between commands, which will allow using a
> > tighter lock than RTNL.
> >
> > Signed-off-by: Daniel Jurgens <danielj@...dia.com>
> > Reviewed-by: Jiri Pirko <jiri@...dia.com>
>
> ...
>
> > @@ -3893,10 +3925,16 @@ static int virtnet_restore_up(struct virtio_device *vdev)
> >
> > static int virtnet_set_guest_offloads(struct virtnet_info *vi, u64 offloads)
> > {
> > + u64 *_offloads __free(kfree) = NULL;
> > struct scatterlist sg;
> > - vi->ctrl->offloads = cpu_to_virtio64(vi->vdev, offloads);
> >
> > - sg_init_one(&sg, &vi->ctrl->offloads, sizeof(vi->ctrl->offloads));
> > + _offloads = kzalloc(sizeof(*_offloads), GFP_KERNEL);
> > + if (!_offloads)
> > + return -ENOMEM;
> > +
> > + *_offloads = cpu_to_virtio64(vi->vdev, offloads);
>
> Hi Daniel,
>
> There is a type mismatch between *_offloads and cpu_to_virtio64
> which is flagged by Sparse as follows:
>
> .../virtio_net.c:3978:20: warning: incorrect type in assignment (different base types)
> .../virtio_net.c:3978:20: expected unsigned long long [usertype]
> .../virtio_net.c:3978:20: got restricted __virtio64
>
> I think this can be addressed by changing the type of *_offloads to
> __virtio64 *.
Yes pls, endian-ness is easier to get right 1st time than fix
afterwards.
> > +
> > + sg_init_one(&sg, _offloads, sizeof(*_offloads));
> >
> > if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_GUEST_OFFLOADS,
> > VIRTIO_NET_CTRL_GUEST_OFFLOADS_SET, &sg)) {
> > --
> > 2.42.0
> >
> >
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