2009-04-27 15:57:21

by Alex Williamson

Subject: [PATCH] virtio_net: Cleanup command queue scatterlist usage

We were avoiding calling sg_init* on scatterlists passed
into virtnet_send_command to prevent extraneous end markers.
This caused build warnings for uninitialized variables.
Cleanup the code to create proper scatterlists.

Signed-off-by: Alex Williamson <[email protected]>
---

drivers/net/virtio_net.c | 16 ++++++++++------
1 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 0718558..ed70df4 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -616,10 +616,11 @@ static int virtnet_open(struct net_device *dev)
static bool virtnet_send_command(struct virtnet_info *vi, u8 class, u8 cmd,
struct scatterlist *data, int out, int in)
{
- struct scatterlist sg[VIRTNET_SEND_COMMAND_SG_MAX + 2];
+ struct scatterlist *s, sg[VIRTNET_SEND_COMMAND_SG_MAX + 2];
struct virtio_net_ctrl_hdr ctrl;
virtio_net_ctrl_ack status = ~0;
unsigned int tmp;
+ int i;

/* Caller should know better */
BUG_ON(!virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ) ||
@@ -634,7 +635,8 @@ static bool virtnet_send_command(struct virtnet_info *vi, u8 class, u8 cmd,
sg_init_table(sg, out + in);

sg_set_buf(&sg[0], &ctrl, sizeof(ctrl));
- memcpy(&sg[1], data, sizeof(struct scatterlist) * (out + in - 2));
+ for_each_sg(data, s, out + in - 2, i)
+ sg_set_buf(&sg[i + 1], sg_virt(s), s->length);
sg_set_buf(&sg[out + in - 1], &status, sizeof(status));

BUG_ON(vi->cvq->vq_ops->add_buf(vi->cvq, sg, out, in, vi));
@@ -688,7 +690,7 @@ static void virtnet_set_rx_mode(struct net_device *dev)
promisc = ((dev->flags & IFF_PROMISC) != 0);
allmulti = ((dev->flags & IFF_ALLMULTI) != 0);

- sg_set_buf(sg, &promisc, sizeof(promisc));
+ sg_init_one(sg, &promisc, sizeof(promisc));

if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_RX,
VIRTIO_NET_CTRL_RX_PROMISC,
@@ -696,7 +698,7 @@ static void virtnet_set_rx_mode(struct net_device *dev)
dev_warn(&dev->dev, "Failed to %sable promisc mode.\n",
promisc ? "en" : "dis");

- sg_set_buf(sg, &allmulti, sizeof(allmulti));
+ sg_init_one(sg, &allmulti, sizeof(allmulti));

if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_RX,
VIRTIO_NET_CTRL_RX_ALLMULTI,
@@ -712,6 +714,8 @@ static void virtnet_set_rx_mode(struct net_device *dev)
return;
}

+ sg_init_table(sg, 2);
+
/* Store the unicast list and count in the front of the buffer */
mac_data->entries = dev->uc_count;
addr = dev->uc_list;
@@ -745,7 +749,7 @@ static void virnet_vlan_rx_add_vid(struct net_device *dev, u16 vid)
struct virtnet_info *vi = netdev_priv(dev);
struct scatterlist sg;

- sg_set_buf(&sg, &vid, sizeof(vid));
+ sg_init_one(&sg, &vid, sizeof(vid));

if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_VLAN,
VIRTIO_NET_CTRL_VLAN_ADD, &sg, 1, 0))
@@ -757,7 +761,7 @@ static void virnet_vlan_rx_kill_vid(struct net_device *dev, u16 vid)
struct virtnet_info *vi = netdev_priv(dev);
struct scatterlist sg;

- sg_set_buf(&sg, &vid, sizeof(vid));
+ sg_init_one(&sg, &vid, sizeof(vid));

if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_VLAN,
VIRTIO_NET_CTRL_VLAN_DEL, &sg, 1, 0))

2009-04-28 09:31:24

by David Miller

Subject: Re: [PATCH] virtio_net: Cleanup command queue scatterlist usage

From: Alex Williamson <[email protected]>
Date: Mon, 27 Apr 2009 09:50:03 -0600

> We were avoiding calling sg_init* on scatterlists passed
> into virtnet_send_command to prevent extraneous end markers.
> This caused build warnings for uninitialized variables.
> Cleanup the code to create proper scatterlists.
>
> Signed-off-by: Alex Williamson <[email protected]>

Looks good to me, what say you Rusty?