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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_sysfs.c | |
parent | ece95f7fefe3afae19e641e1b3f5e64b00d5b948 (diff) | |
download | kernel_samsung_smdk4412-027ea0416c955778ceca7ef82e48a1dd6b4617c9.zip kernel_samsung_smdk4412-027ea0416c955778ceca7ef82e48a1dd6b4617c9.tar.gz kernel_samsung_smdk4412-027ea0416c955778ceca7ef82e48a1dd6b4617c9.tar.bz2 |
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_sysfs.c')
-rw-r--r-- | drivers/net/bonding/bond_sysfs.c | 43 |
1 files changed, 16 insertions, 27 deletions
diff --git a/drivers/net/bonding/bond_sysfs.c b/drivers/net/bonding/bond_sysfs.c index bff4f2b..90a1f31 100644 --- a/drivers/net/bonding/bond_sysfs.c +++ b/drivers/net/bonding/bond_sysfs.c @@ -109,11 +109,10 @@ static ssize_t bonding_store_bonds(struct class *cls, const char *buffer, size_t { char command[IFNAMSIZ + 1] = {0, }; char *ifname; - int res = count; + int rv, res = count; struct bonding *bond; struct bonding *nxt; - down_write(&(bonding_rwsem)); sscanf(buffer, "%16s", command); /* IFNAMSIZ*/ ifname = command + 1; if ((strlen(command) <= 1) || @@ -121,39 +120,28 @@ static ssize_t bonding_store_bonds(struct class *cls, const char *buffer, size_t goto err_no_cmd; if (command[0] == '+') { - - /* 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, ifname, IFNAMSIZ) == 0) { - printk(KERN_ERR DRV_NAME - ": cannot add bond %s; it already exists\n", - ifname); - res = -EPERM; - goto out; - } - printk(KERN_INFO DRV_NAME ": %s is being created...\n", ifname); - if (bond_create(ifname, &bonding_defaults, &bond)) { - printk(KERN_INFO DRV_NAME - ": %s interface already exists. Bond creation failed.\n", - ifname); - res = -EPERM; + rv = bond_create(ifname, &bonding_defaults, &bond); + if (rv) { + printk(KERN_INFO DRV_NAME ": Bond creation failed.\n"); + res = rv; } goto out; } if (command[0] == '-') { + rtnl_lock(); + down_write(&bonding_rwsem); + list_for_each_entry_safe(bond, nxt, &bond_dev_list, bond_list) if (strnicmp(bond->dev->name, ifname, IFNAMSIZ) == 0) { - rtnl_lock(); /* check the ref count on the bond's kobject. * If it's > expected, then there's a file open, * and we have to fail. */ if (atomic_read(&bond->dev->dev.kobj.kref.refcount) > expected_refcount){ - rtnl_unlock(); printk(KERN_INFO DRV_NAME ": Unable remove bond %s due to open references.\n", ifname); @@ -164,6 +152,7 @@ static ssize_t bonding_store_bonds(struct class *cls, const char *buffer, size_t ": %s is being deleted...\n", bond->dev->name); bond_destroy(bond); + up_write(&bonding_rwsem); rtnl_unlock(); goto out; } @@ -171,6 +160,8 @@ static ssize_t bonding_store_bonds(struct class *cls, const char *buffer, size_t printk(KERN_ERR DRV_NAME ": unable to delete non-existent bond %s\n", ifname); res = -ENODEV; + up_write(&bonding_rwsem); + rtnl_unlock(); goto out; } @@ -183,7 +174,6 @@ err_no_cmd: * get called forever, which is bad. */ out: - up_write(&(bonding_rwsem)); return res; } /* class attribute for bond_masters file. This ends up in /sys/class/net */ @@ -271,6 +261,9 @@ static ssize_t bonding_store_slaves(struct device *d, /* Note: We can't hold bond->lock here, as bond_create grabs it. */ + rtnl_lock(); + down_write(&(bonding_rwsem)); + sscanf(buffer, "%16s", command); /* IFNAMSIZ*/ ifname = command + 1; if ((strlen(command) <= 1) || @@ -336,12 +329,10 @@ static ssize_t bonding_store_slaves(struct device *d, dev->mtu = bond->dev->mtu; } } - rtnl_lock(); res = bond_enslave(bond->dev, dev); bond_for_each_slave(bond, slave, i) if (strnicmp(slave->dev->name, ifname, IFNAMSIZ) == 0) slave->original_mtu = original_mtu; - rtnl_unlock(); if (res) { ret = res; } @@ -359,12 +350,10 @@ static ssize_t bonding_store_slaves(struct device *d, if (dev) { printk(KERN_INFO DRV_NAME ": %s: Removing slave %s\n", bond->dev->name, dev->name); - rtnl_lock(); if (bond->setup_by_slave) res = bond_release_and_destroy(bond->dev, dev); else res = bond_release(bond->dev, dev); - rtnl_unlock(); if (res) { ret = res; goto out; @@ -389,6 +378,8 @@ err_no_cmd: ret = -EPERM; out: + up_write(&(bonding_rwsem)); + rtnl_unlock(); return ret; } @@ -1423,8 +1414,6 @@ int bond_create_sysfs(void) int ret = 0; struct bonding *firstbond; - init_rwsem(&bonding_rwsem); - /* get the netdev class pointer */ firstbond = container_of(bond_dev_list.next, struct bonding, bond_list); if (!firstbond) |