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netpoll: make __netpoll_cleanup non-block

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Like the previous patch, slave_disable_netpoll() and __netpoll_cleanup()
may be called with read_lock() held too, so we should make them
non-block, by moving the cleanup and kfree() to call_rcu_bh() callbacks.

Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Cong Wang <amwang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Amerigo Wang
2012-08-10 01:24:38 +00:00
committed by David S. Miller
parent 47be03a28c
commit 38e6bc185d
5 changed files with 39 additions and 24 deletions
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44
net/core/netpoll.c
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@@ -878,6 +878,24 @@ static int __init netpoll_init(void)
}
core_initcall(netpoll_init);
static void rcu_cleanup_netpoll_info(struct rcu_head *rcu_head)
{
struct netpoll_info *npinfo =
container_of(rcu_head, struct netpoll_info, rcu);
skb_queue_purge(&npinfo->arp_tx);
skb_queue_purge(&npinfo->txq);
/* we can't call cancel_delayed_work_sync here, as we are in softirq */
cancel_delayed_work(&npinfo->tx_work);
/* clean after last, unfinished work */
__skb_queue_purge(&npinfo->txq);
/* now cancel it again */
cancel_delayed_work(&npinfo->tx_work);
kfree(npinfo);
}
void __netpoll_cleanup(struct netpoll *np)
{
struct netpoll_info *npinfo;
@@ -903,21 +921,25 @@ void __netpoll_cleanup(struct netpoll *np)
ops->ndo_netpoll_cleanup(np->dev);
RCU_INIT_POINTER(np->dev->npinfo, NULL);
/* avoid racing with NAPI reading npinfo */
synchronize_rcu_bh();
skb_queue_purge(&npinfo->arp_tx);
skb_queue_purge(&npinfo->txq);
cancel_delayed_work_sync(&npinfo->tx_work);
/* clean after last, unfinished work */
__skb_queue_purge(&npinfo->txq);
kfree(npinfo);
call_rcu_bh(&npinfo->rcu, rcu_cleanup_netpoll_info);
}
}
EXPORT_SYMBOL_GPL(__netpoll_cleanup);
static void rcu_cleanup_netpoll(struct rcu_head *rcu_head)
{
struct netpoll *np = container_of(rcu_head, struct netpoll, rcu);
__netpoll_cleanup(np);
kfree(np);
}
void __netpoll_free_rcu(struct netpoll *np)
{
call_rcu_bh(&np->rcu, rcu_cleanup_netpoll);
}
EXPORT_SYMBOL_GPL(__netpoll_free_rcu);
void netpoll_cleanup(struct netpoll *np)
{
if (!np->dev)