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pkt_sched: fq: do not hold qdisc lock while allocating memory

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Resizing fq hash table allocates memory while holding qdisc spinlock,
with BH disabled.

This is definitely not good, as allocation might sleep.

We can drop the lock and get it when needed, we hold RTNL so no other
changes can happen at the same time.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Fixes: afe4fd0624 ("pkt_sched: fq: Fair Queue packet scheduler")
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet 2014-03-06 22:57:52 -08:00 committed by David S. Miller
parent bc48bc8064
commit 2818fa0fa0
1 changed files with 15 additions and 6 deletions
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21
net/sched/sch_fq.c
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@ -601,6 +601,7 @@ static int fq_resize(struct Qdisc *sch, u32 log)
{ {
struct fq_sched_data *q = qdisc_priv(sch); struct fq_sched_data *q = qdisc_priv(sch);
struct rb_root *array; struct rb_root *array;
void *old_fq_root;
u32 idx; u32 idx;
if (q->fq_root && log == q->fq_trees_log) if (q->fq_root && log == q->fq_trees_log)
@ -615,13 +616,19 @@ static int fq_resize(struct Qdisc *sch, u32 log)
for (idx = 0; idx < (1U << log); idx++) for (idx = 0; idx < (1U << log); idx++)
array[idx] = RB_ROOT; array[idx] = RB_ROOT;
if (q->fq_root) { sch_tree_lock(sch);
fq_rehash(q, q->fq_root, q->fq_trees_log, array, log);
fq_free(q->fq_root); old_fq_root = q->fq_root;
} if (old_fq_root)
fq_rehash(q, old_fq_root, q->fq_trees_log, array, log);
q->fq_root = array; q->fq_root = array;
q->fq_trees_log = log; q->fq_trees_log = log;
sch_tree_unlock(sch);
fq_free(old_fq_root);
return 0; return 0;
} }
@ -697,9 +704,11 @@ static int fq_change(struct Qdisc *sch, struct nlattr *opt)
q->flow_refill_delay = usecs_to_jiffies(usecs_delay); q->flow_refill_delay = usecs_to_jiffies(usecs_delay);
} }
if (!err) if (!err) {
sch_tree_unlock(sch);
err = fq_resize(sch, fq_log); err = fq_resize(sch, fq_log);
sch_tree_lock(sch);
}
while (sch->q.qlen > sch->limit) { while (sch->q.qlen > sch->limit) {
struct sk_buff *skb = fq_dequeue(sch); struct sk_buff *skb = fq_dequeue(sch);