Re: [PATCH for-next v1] RDMA/irdma: Implement egress VLAN priority

[Jason Gunthorpe <jgg@nvidia.com>]

On Fri, Jun 02, 2023 at 06:02:57PM -0500, Shiraz Saleem wrote:
> From: Mustafa Ismail <mustafa.ismail@intel.com>
> 
> When a VLAN interface is in use, get and use the VLAN
> egress mapping.
> 
> Signed-off-by: Mustafa Ismail <mustafa.ismail@intel.com>
> Signed-off-by: Shiraz Saleem <shiraz.saleem@intel.com>
> ---
> v0-->v1:
> Use rcu_dereference on GID attribute __rcu pointer
> vs the function arg in irdma_roce_get_vlan_prio
> 
>  drivers/infiniband/hw/irdma/cm.c    | 50 +++++++++++++++++++++++++++++++++++--
>  drivers/infiniband/hw/irdma/verbs.c | 45 ++++++++++++++++++++++++++-------
>  2 files changed, 84 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/infiniband/hw/irdma/cm.c b/drivers/infiniband/hw/irdma/cm.c
> index 70009b9..926823f 100644
> --- a/drivers/infiniband/hw/irdma/cm.c
> +++ b/drivers/infiniband/hw/irdma/cm.c
> @@ -1555,6 +1555,26 @@ static int irdma_del_multiple_qhash(struct irdma_device *iwdev,
>  	return ret;
>  }
>  
> +static u8 irdma_iw_get_vlan_prio(u32 *loc_addr, u8 prio, bool ipv4)
> +{
> +	struct net_device *ndev;
> +
> +	if (ipv4)
> +		ndev = ip_dev_find(&init_net, htonl(loc_addr[0]));
> +	else
> +		ndev = irdma_netdev_vlan_ipv6(loc_addr, NULL, NULL);
> +
> +	if (!ndev)
> +		return prio;
> +	if (is_vlan_dev(ndev))
> +		prio = (vlan_dev_get_egress_qos_mask(ndev, prio) & VLAN_PRIO_MASK)
> +			>> VLAN_PRIO_SHIFT;
> +	if (ipv4)
> +		dev_put(ndev);

Huuuuh??

struct net_device *irdma_netdev_vlan_ipv6(u32 *addr, u16 *vlan_id, u8 *mac)
{
	struct net_device *ip_dev = NULL;
	struct in6_addr laddr6;

	if (!IS_ENABLED(CONFIG_IPV6))
		return NULL;

	irdma_copy_ip_htonl(laddr6.in6_u.u6_addr32, addr);
	if (vlan_id)
		*vlan_id = 0xFFFF;	/* Match rdma_vlan_dev_vlan_id() */
	if (mac)
		eth_zero_addr(mac);

	rcu_read_lock();
	for_each_netdev_rcu (&init_net, ip_dev) {
		if (ipv6_chk_addr(&init_net, &laddr6, ip_dev, 1)) {
			if (vlan_id)
				*vlan_id = rdma_vlan_dev_vlan_id(ip_dev);
			if (ip_dev->dev_addr && mac)
				ether_addr_copy(mac, ip_dev->dev_addr);
			break;
		}
	}
	rcu_read_unlock();

	return ip_dev;

You can't take ip_dev out of the rcu

Jason