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netpoll: Allow netpoll_setup/cleanup recursion
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This patch adds the functions __netpoll_setup/__netpoll_cleanup
which is designed to be called recursively through ndo_netpoll_seutp.

They must be called with RTNL held, and the caller must initialise
np->dev and ensure that it has a valid reference count.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Herbert Xu authored and David S. Miller committed Jun 15, 2010
1 parent 4247e16 commit 8fdd95e
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Showing 2 changed files with 99 additions and 79 deletions.
2 changes: 2 additions & 0 deletions include/linux/netpoll.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -46,9 +46,11 @@ void netpoll_poll(struct netpoll *np);
void netpoll_send_udp(struct netpoll *np, const char *msg, int len);
void netpoll_print_options(struct netpoll *np);
int netpoll_parse_options(struct netpoll *np, char *opt);
int __netpoll_setup(struct netpoll *np);
int netpoll_setup(struct netpoll *np);
int netpoll_trap(void);
void netpoll_set_trap(int trap);
void __netpoll_cleanup(struct netpoll *np);
void netpoll_cleanup(struct netpoll *np);
int __netpoll_rx(struct sk_buff *skb);
void netpoll_send_skb(struct netpoll *np, struct sk_buff *skb);
Expand Down
176 changes: 97 additions & 79 deletions net/core/netpoll.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -693,15 +693,78 @@ int netpoll_parse_options(struct netpoll *np, char *opt)
return -1;
}

int netpoll_setup(struct netpoll *np)
int __netpoll_setup(struct netpoll *np)
{
struct net_device *ndev = NULL;
struct in_device *in_dev;
struct net_device *ndev = np->dev;
struct netpoll_info *npinfo;
const struct net_device_ops *ops;
unsigned long flags;
int err;

if ((ndev->priv_flags & IFF_DISABLE_NETPOLL) ||
!ndev->netdev_ops->ndo_poll_controller) {
printk(KERN_ERR "%s: %s doesn't support polling, aborting.\n",
np->name, np->dev_name);
err = -ENOTSUPP;
goto out;
}

if (!ndev->npinfo) {
npinfo = kmalloc(sizeof(*npinfo), GFP_KERNEL);
if (!npinfo) {
err = -ENOMEM;
goto out;
}

npinfo->rx_flags = 0;
INIT_LIST_HEAD(&npinfo->rx_np);

spin_lock_init(&npinfo->rx_lock);
skb_queue_head_init(&npinfo->arp_tx);
skb_queue_head_init(&npinfo->txq);
INIT_DELAYED_WORK(&npinfo->tx_work, queue_process);

atomic_set(&npinfo->refcnt, 1);

ops = np->dev->netdev_ops;
if (ops->ndo_netpoll_setup) {
err = ops->ndo_netpoll_setup(ndev, npinfo);
if (err)
goto free_npinfo;
}
} else {
npinfo = ndev->npinfo;
atomic_inc(&npinfo->refcnt);
}

npinfo->netpoll = np;

if (np->rx_hook) {
spin_lock_irqsave(&npinfo->rx_lock, flags);
npinfo->rx_flags |= NETPOLL_RX_ENABLED;
list_add_tail(&np->rx, &npinfo->rx_np);
spin_unlock_irqrestore(&npinfo->rx_lock, flags);
}

/* last thing to do is link it to the net device structure */
rcu_assign_pointer(ndev->npinfo, npinfo);
rtnl_unlock();

return 0;

free_npinfo:
kfree(npinfo);
out:
return err;
}
EXPORT_SYMBOL_GPL(__netpoll_setup);

int netpoll_setup(struct netpoll *np)
{
struct net_device *ndev = NULL;
struct in_device *in_dev;
int err;

if (np->dev_name)
ndev = dev_get_by_name(&init_net, np->dev_name);
if (!ndev) {
Expand Down Expand Up @@ -774,61 +837,14 @@ int netpoll_setup(struct netpoll *np)
refill_skbs();

rtnl_lock();
if ((ndev->priv_flags & IFF_DISABLE_NETPOLL) ||
!ndev->netdev_ops->ndo_poll_controller) {
printk(KERN_ERR "%s: %s doesn't support polling, aborting.\n",
np->name, np->dev_name);
err = -ENOTSUPP;
goto unlock;
}

if (!ndev->npinfo) {
npinfo = kmalloc(sizeof(*npinfo), GFP_KERNEL);
if (!npinfo) {
err = -ENOMEM;
goto unlock;
}

npinfo->rx_flags = 0;
INIT_LIST_HEAD(&npinfo->rx_np);

spin_lock_init(&npinfo->rx_lock);
skb_queue_head_init(&npinfo->arp_tx);
skb_queue_head_init(&npinfo->txq);
INIT_DELAYED_WORK(&npinfo->tx_work, queue_process);

atomic_set(&npinfo->refcnt, 1);

ops = np->dev->netdev_ops;
if (ops->ndo_netpoll_setup) {
err = ops->ndo_netpoll_setup(ndev, npinfo);
if (err)
goto free_npinfo;
}
} else {
npinfo = ndev->npinfo;
atomic_inc(&npinfo->refcnt);
}

npinfo->netpoll = np;

if (np->rx_hook) {
spin_lock_irqsave(&npinfo->rx_lock, flags);
npinfo->rx_flags |= NETPOLL_RX_ENABLED;
list_add_tail(&np->rx, &npinfo->rx_np);
spin_unlock_irqrestore(&npinfo->rx_lock, flags);
}

/* last thing to do is link it to the net device structure */
rcu_assign_pointer(ndev->npinfo, npinfo);
err = __netpoll_setup(np);
rtnl_unlock();

if (err)
goto put;

return 0;

free_npinfo:
kfree(npinfo);
unlock:
rtnl_unlock();
put:
dev_put(ndev);
return err;
Expand All @@ -841,40 +857,32 @@ static int __init netpoll_init(void)
}
core_initcall(netpoll_init);

void netpoll_cleanup(struct netpoll *np)
void __netpoll_cleanup(struct netpoll *np)
{
struct netpoll_info *npinfo;
unsigned long flags;
int free = 0;

if (!np->dev)
npinfo = np->dev->npinfo;
if (!npinfo)
return;

rtnl_lock();
npinfo = np->dev->npinfo;
if (npinfo) {
if (!list_empty(&npinfo->rx_np)) {
spin_lock_irqsave(&npinfo->rx_lock, flags);
list_del(&np->rx);
if (list_empty(&npinfo->rx_np))
npinfo->rx_flags &= ~NETPOLL_RX_ENABLED;
spin_unlock_irqrestore(&npinfo->rx_lock, flags);
}
if (!list_empty(&npinfo->rx_np)) {
spin_lock_irqsave(&npinfo->rx_lock, flags);
list_del(&np->rx);
if (list_empty(&npinfo->rx_np))
npinfo->rx_flags &= ~NETPOLL_RX_ENABLED;
spin_unlock_irqrestore(&npinfo->rx_lock, flags);
}

free = atomic_dec_and_test(&npinfo->refcnt);
if (free) {
const struct net_device_ops *ops;
if (atomic_dec_and_test(&npinfo->refcnt)) {
const struct net_device_ops *ops;

ops = np->dev->netdev_ops;
if (ops->ndo_netpoll_cleanup)
ops->ndo_netpoll_cleanup(np->dev);
ops = np->dev->netdev_ops;
if (ops->ndo_netpoll_cleanup)
ops->ndo_netpoll_cleanup(np->dev);

rcu_assign_pointer(np->dev->npinfo, NULL);
}
}
rtnl_unlock();
rcu_assign_pointer(np->dev->npinfo, NULL);

if (free) {
/* avoid racing with NAPI reading npinfo */
synchronize_rcu_bh();

Expand All @@ -886,9 +894,19 @@ void netpoll_cleanup(struct netpoll *np)
__skb_queue_purge(&npinfo->txq);
kfree(npinfo);
}
}
EXPORT_SYMBOL_GPL(__netpoll_cleanup);

dev_put(np->dev);
void netpoll_cleanup(struct netpoll *np)
{
if (!np->dev)
return;

rtnl_lock();
__netpoll_cleanup(np);
rtnl_unlock();

dev_put(np->dev);
np->dev = NULL;
}

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