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bonding: fix __get_first_agg RCU usage

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Currently, the RCU read lock usage is just wrong - it gets the slave struct
under RCU and continues to use it when RCU lock is released.

However, it's still safe to do this cause we didn't need the
rcu_read_lock() initially - all of the __get_first_agg() callers are either
holding RCU read lock or the RTNL lock, so that we can't sync while in it.

Fixes: be79bd048 ("bonding: add RCU for bond_3ad_state_machine_handler()")
CC: dingtianhong@huawei.com
CC: Jay Vosburgh <fubar@us.ibm.com>
CC: Andy Gospodarek <andy@greyhouse.net>
Signed-off-by: Veaceslav Falico <vfalico@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Veaceslav Falico 2014-01-10 11:59:44 +01:00 committed by David S. Miller
parent c1bc9644ec
commit 768b954922
1 changed files with 4 additions and 1 deletions
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5
drivers/net/bonding/bond_3ad.c
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@ -143,11 +143,13 @@ static inline struct bonding *__get_bond_by_port(struct port *port)
* *
* Return the aggregator of the first slave in @bond, or %NULL if it can't be * Return the aggregator of the first slave in @bond, or %NULL if it can't be
* found. * found.
* The caller must hold RCU or RTNL lock.
*/ */
static inline struct aggregator *__get_first_agg(struct port *port) static inline struct aggregator *__get_first_agg(struct port *port)
{ {
struct bonding *bond = __get_bond_by_port(port); struct bonding *bond = __get_bond_by_port(port);
struct slave *first_slave; struct slave *first_slave;
struct aggregator *agg;
/* If there's no bond for this port, or bond has no slaves */ /* If there's no bond for this port, or bond has no slaves */
if (bond == NULL) if (bond == NULL)
@ -155,9 +157,10 @@ static inline struct aggregator *__get_first_agg(struct port *port)
rcu_read_lock(); rcu_read_lock();
first_slave = bond_first_slave_rcu(bond); first_slave = bond_first_slave_rcu(bond);
agg = first_slave ? &(SLAVE_AD_INFO(first_slave).aggregator) : NULL;
rcu_read_unlock(); rcu_read_unlock();
return first_slave ? &(SLAVE_AD_INFO(first_slave).aggregator) : NULL; return agg;
} }
/** /**