diff options
| author | Jay Vosburgh <fubar@us.ibm.com> | 2008-01-17 16:25:02 -0800 |
|---|---|---|
| committer | Jeff Garzik <jeff@garzik.org> | 2008-01-18 14:38:39 -0500 |
| commit | 027ea0416c955778ceca7ef82e48a1dd6b4617c9 (patch) | |
| tree | ad823fb28b414d948fc372a08c8c15cee31bd8e1 /drivers/net/bonding/bond_main.c | |
| parent | ece95f7fefe3afae19e641e1b3f5e64b00d5b948 (diff) | |
bonding: fix lock ordering for rtnl and bonding_rwsem
Fix the handling of rtnl and the bonding_rwsem to always be acquired
in a consistent order (rtnl, then bonding_rwsem).
The existing code sometimes acquired them in this order, and sometimes
in the opposite order, which opens a window for deadlock between ifenslave
and sysfs.
Signed-off-by: Jay Vosburgh <fubar@us.ibm.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
Diffstat (limited to 'drivers/net/bonding/bond_main.c')
| -rw-r--r-- | drivers/net/bonding/bond_main.c | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c index 379c5d87c80..2c6da496938 100644 --- a/drivers/net/bonding/bond_main.c +++ b/drivers/net/bonding/bond_main.c @@ -4874,9 +4874,22 @@ static struct lock_class_key bonding_netdev_xmit_lock_key; int bond_create(char *name, struct bond_params *params, struct bonding **newbond) { struct net_device *bond_dev; + struct bonding *bond, *nxt; int res; rtnl_lock(); + down_write(&bonding_rwsem); + + /* Check to see if the bond already exists. */ + list_for_each_entry_safe(bond, nxt, &bond_dev_list, bond_list) + if (strnicmp(bond->dev->name, name, IFNAMSIZ) == 0) { + printk(KERN_ERR DRV_NAME + ": cannot add bond %s; it already exists\n", + name); + res = -EPERM; + goto out_rtnl; + } + bond_dev = alloc_netdev(sizeof(struct bonding), name ? name : "", ether_setup); if (!bond_dev) { @@ -4915,10 +4928,12 @@ int bond_create(char *name, struct bond_params *params, struct bonding **newbond netif_carrier_off(bond_dev); + up_write(&bonding_rwsem); rtnl_unlock(); /* allows sysfs registration of net device */ res = bond_create_sysfs_entry(bond_dev->priv); if (res < 0) { rtnl_lock(); + down_write(&bonding_rwsem); goto out_bond; } @@ -4929,6 +4944,7 @@ out_bond: out_netdev: free_netdev(bond_dev); out_rtnl: + up_write(&bonding_rwsem); rtnl_unlock(); return res; } @@ -4949,6 +4965,9 @@ static int __init bonding_init(void) #ifdef CONFIG_PROC_FS bond_create_proc_dir(); #endif + + init_rwsem(&bonding_rwsem); + for (i = 0; i < max_bonds; i++) { res = bond_create(NULL, &bonding_defaults, NULL); if (res) |