linux-kernel - Re: [PATCH 01/10] virtio_console: drop unused config fields

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Message-ID: <ae2107ec-9c4e-3638-fabb-4edc73896ccf@redhat.com>
Date:   Wed, 7 Dec 2016 12:12:49 +0800
From:   Jason Wang <jasowang@...hat.com>
To:     "Michael S. Tsirkin" <mst@...hat.com>, linux-kernel@...r.kernel.org
Cc:     Arnd Bergmann <arnd@...db.de>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Amit Shah <amit.shah@...hat.com>,
        virtualization@...ts.linux-foundation.org
Subject: Re: [PATCH 01/10] virtio_console: drop unused config fields



On 2016年12月06日 23:40, Michael S. Tsirkin wrote:
> struct ports_device includes a config field including the whole
> virtio_console_config, but only max_nr_ports in there is ever updated or
> used. The rest is unused and in fact does not even mirror the
> device config. Drop everything except max_nr_ports,
> saving some memory.
>
> Signed-off-by: Michael S. Tsirkin <mst@...hat.com>
> ---
>   drivers/char/virtio_console.c | 14 +++++++-------
>   1 file changed, 7 insertions(+), 7 deletions(-)

Reviewed-by: Jason Wang <jasowang@...hat.com>

>
> diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c
> index 5649234..8b00e79 100644
> --- a/drivers/char/virtio_console.c
> +++ b/drivers/char/virtio_console.c
> @@ -152,8 +152,8 @@ struct ports_device {
>   	spinlock_t c_ivq_lock;
>   	spinlock_t c_ovq_lock;
>   
> -	/* The current config space is stored here */
> -	struct virtio_console_config config;
> +	/* max. number of ports this device can hold */
> +	u32 max_nr_ports;
>   
>   	/* The virtio device we're associated with */
>   	struct virtio_device *vdev;
> @@ -1649,11 +1649,11 @@ static void handle_control_message(struct virtio_device *vdev,
>   			break;
>   		}
>   		if (virtio32_to_cpu(vdev, cpkt->id) >=
> -		    portdev->config.max_nr_ports) {
> +		    portdev->max_nr_ports) {
>   			dev_warn(&portdev->vdev->dev,
>   				"Request for adding port with "
>   				"out-of-bound id %u, max. supported id: %u\n",
> -				cpkt->id, portdev->config.max_nr_ports - 1);
> +				cpkt->id, portdev->max_nr_ports - 1);
>   			break;
>   		}
>   		add_port(portdev, virtio32_to_cpu(vdev, cpkt->id));
> @@ -1894,7 +1894,7 @@ static int init_vqs(struct ports_device *portdev)
>   	u32 i, j, nr_ports, nr_queues;
>   	int err;
>   
> -	nr_ports = portdev->config.max_nr_ports;
> +	nr_ports = portdev->max_nr_ports;
>   	nr_queues = use_multiport(portdev) ? (nr_ports + 1) * 2 : 2;
>   
>   	vqs = kmalloc(nr_queues * sizeof(struct virtqueue *), GFP_KERNEL);
> @@ -2047,13 +2047,13 @@ static int virtcons_probe(struct virtio_device *vdev)
>   	}
>   
>   	multiport = false;
> -	portdev->config.max_nr_ports = 1;
> +	portdev->max_nr_ports = 1;
>   
>   	/* Don't test MULTIPORT at all if we're rproc: not a valid feature! */
>   	if (!is_rproc_serial(vdev) &&
>   	    virtio_cread_feature(vdev, VIRTIO_CONSOLE_F_MULTIPORT,
>   				 struct virtio_console_config, max_nr_ports,
> -				 &portdev->config.max_nr_ports) == 0) {
> +				 &portdev->max_nr_ports) == 0) {
>   		multiport = true;
>   	}
>