Re: [PATCH net-next 02/10] bonding: use __dev_get_by_name instead of dev_get_by_name to find interface

Veaceslav Falico
2014-01-14T11:58:39Z

On Tue, Jan 14, 2014 at 03:41:01PM +0800, Ying Xue wrote:
>The following call chain indicates that bond_do_ioctl() is protected
>under rtnl_lock. If we use __dev_get_by_name() instead of
>dev_get_by_name() to find interface handler in it, this would
>help us avoid to change reference counter of interface once.
>
>dev_ioctl()
> rtnl_lock()
> dev_ifsioc()
> bond_do_ioctl()
> rtnl_unlock()
>
>Additionally we also change the coding style in bond_do_ioctl(),
>letting it more readable for us.
>
>Cc: Jay Vosburgh <fubar@us.ibm.com>
>Cc: Veaceslav Falico <vfalico@redhat.com>

Acked-by: Veaceslav Falico <vfalico@redhat.com>

>Signed-off-by: Ying Xue <ying.xue@windriver.com>
>---
> drivers/net/bonding/bond_main.c | 49 ++++++++++++++++++---------------------
> 1 file changed, 23 insertions(+), 26 deletions(-)
>
>diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
>index e06c445..a69afbf 100644
>--- a/drivers/net/bonding/bond_main.c
>+++ b/drivers/net/bonding/bond_main.c
>@@ -3213,37 +3213,34 @@ static int bond_do_ioctl(struct net_device *bond_dev, struct ifreq *ifr, int cmd
> if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
> return -EPERM;
>
>- slave_dev = dev_get_by_name(net, ifr->ifr_slave);
>+ slave_dev = __dev_get_by_name(net, ifr->ifr_slave);
>
> pr_debug("slave_dev=%p:\n", slave_dev);
>
> if (!slave_dev)
>- res = -ENODEV;
>- else {
>- pr_debug("slave_dev->name=%s:\n", slave_dev->name);
>- switch (cmd) {
>- case BOND_ENSLAVE_OLD:
>- case SIOCBONDENSLAVE:
>- res = bond_enslave(bond_dev, slave_dev);
>- break;
>- case BOND_RELEASE_OLD:
>- case SIOCBONDRELEASE:
>- res = bond_release(bond_dev, slave_dev);
>- break;
>- case BOND_SETHWADDR_OLD:
>- case SIOCBONDSETHWADDR:
>- bond_set_dev_addr(bond_dev, slave_dev);
>- res = 0;
>- break;
>- case BOND_CHANGE_ACTIVE_OLD:
>- case SIOCBONDCHANGEACTIVE:
>- res = bond_option_active_slave_set(bond, slave_dev);
>- break;
>- default:
>- res = -EOPNOTSUPP;
>- }
>+ return -ENODEV;
>
>- dev_put(slave_dev);
>+ pr_debug("slave_dev->name=%s:\n", slave_dev->name);
>+ switch (cmd) {
>+ case BOND_ENSLAVE_OLD:
>+ case SIOCBONDENSLAVE:
>+ res = bond_enslave(bond_dev, slave_dev);
>+ break;
>+ case BOND_RELEASE_OLD:
>+ case SIOCBONDRELEASE:
>+ res = bond_release(bond_dev, slave_dev);
>+ break;
>+ case BOND_SETHWADDR_OLD:
>+ case SIOCBONDSETHWADDR:
>+ bond_set_dev_addr(bond_dev, slave_dev);
>+ res = 0;
>+ break;
>+ case BOND_CHANGE_ACTIVE_OLD:
>+ case SIOCBONDCHANGEACTIVE:
>+ res = bond_option_active_slave_set(bond, slave_dev);
>+ break;
>+ default:
>+ res = -EOPNOTSUPP;
> }
>
> return res;
>--
>1.7.9.5
>