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pkt_sched: Make qdisc grafting locking more specific.

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Lock the root of the qdisc being operated upon.

All explicit references to qdisc_tree_lock() are now gone.
The only remaining uses are via the sch_tree_{lock,unlock}()
and tcf_tree_{lock,unlock}() macros.

Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David S. Miller 2008-07-16 03:00:19 -07:00
parent ead81cc5fc
commit 53049978df
1 changed files with 29 additions and 12 deletions
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41
net/sched/sch_api.c
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@ -441,15 +441,29 @@ static struct Qdisc *
dev_graft_qdisc(struct net_device *dev, struct Qdisc *qdisc)
{
struct netdev_queue *dev_queue;
spinlock_t *root_lock;
struct Qdisc *oqdisc;
int ingress;
if (dev->flags & IFF_UP)
dev_deactivate(dev);
qdisc_lock_tree(dev);
if (qdisc && qdisc->flags&TCQ_F_INGRESS) {
ingress = 0;
if (qdisc && qdisc->flags&TCQ_F_INGRESS)
ingress = 1;
if (ingress) {
dev_queue = &dev->rx_queue;
oqdisc = dev_queue->qdisc;
} else {
dev_queue = netdev_get_tx_queue(dev, 0);
oqdisc = dev_queue->qdisc_sleeping;
}
root_lock = qdisc_root_lock(oqdisc);
spin_lock_bh(root_lock);
if (ingress) {
/* Prune old scheduler */
if (oqdisc && atomic_read(&oqdisc->refcnt) <= 1) {
/* delete */
@ -460,9 +474,6 @@ dev_graft_qdisc(struct net_device *dev, struct Qdisc *qdisc)
}
} else {
dev_queue = netdev_get_tx_queue(dev, 0);
oqdisc = dev_queue->qdisc_sleeping;
/* Prune old scheduler */
if (oqdisc && atomic_read(&oqdisc->refcnt) <= 1)
qdisc_reset(oqdisc);
@ -474,7 +485,7 @@ dev_graft_qdisc(struct net_device *dev, struct Qdisc *qdisc)
dev_queue->qdisc = &noop_qdisc;
}
qdisc_unlock_tree(dev);
spin_unlock_bh(root_lock);
if (dev->flags & IFF_UP)
dev_activate(dev);
@ -765,10 +776,12 @@ static int tc_get_qdisc(struct sk_buff *skb, struct nlmsghdr *n, void *arg)
if ((err = qdisc_graft(dev, p, clid, NULL, &q)) != 0)
return err;
if (q) {
spinlock_t *root_lock = qdisc_root_lock(q);
qdisc_notify(skb, n, clid, q, NULL);
qdisc_lock_tree(dev);
spin_unlock_bh(root_lock);
qdisc_destroy(q);
qdisc_unlock_tree(dev);
spin_unlock_bh(root_lock);
}
} else {
qdisc_notify(skb, n, clid, NULL, q);
@ -911,20 +924,24 @@ create_n_graft:
graft:
if (1) {
struct Qdisc *old_q = NULL;
spinlock_t *root_lock;
err = qdisc_graft(dev, p, clid, q, &old_q);
if (err) {
if (q) {
qdisc_lock_tree(dev);
root_lock = qdisc_root_lock(q);
spin_lock_bh(root_lock);
qdisc_destroy(q);
qdisc_unlock_tree(dev);
spin_unlock_bh(root_lock);
}
return err;
}
qdisc_notify(skb, n, clid, old_q, q);
if (old_q) {
qdisc_lock_tree(dev);
root_lock = qdisc_root_lock(old_q);
spin_lock_bh(root_lock);
qdisc_destroy(old_q);
qdisc_unlock_tree(dev);
spin_unlock_bh(root_lock);
}
}
return 0;