From 2818fa0fa068bcbc87d6bd9064e3c1f72d6fcc2a Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Thu, 6 Mar 2014 22:57:52 -0800 Subject: [PATCH] pkt_sched: fq: do not hold qdisc lock while allocating memory 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 Fixes: afe4fd062416 ("pkt_sched: fq: Fair Queue packet scheduler") Signed-off-by: David S. Miller --- net/sched/sch_fq.c | 21 +++++++++++++++------ 1 file changed, 15 insertions(+), 6 deletions(-) diff --git a/net/sched/sch_fq.c b/net/sched/sch_fq.c index 08ef7a42c0e4..21e251766eb1 100644 --- a/net/sched/sch_fq.c +++ b/net/sched/sch_fq.c @@ -601,6 +601,7 @@ static int fq_resize(struct Qdisc *sch, u32 log) { struct fq_sched_data *q = qdisc_priv(sch); struct rb_root *array; + void *old_fq_root; u32 idx; 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++) array[idx] = RB_ROOT; - if (q->fq_root) { - fq_rehash(q, q->fq_root, q->fq_trees_log, array, log); - fq_free(q->fq_root); - } + sch_tree_lock(sch); + + 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_trees_log = log; + sch_tree_unlock(sch); + + fq_free(old_fq_root); + 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); } - if (!err) + if (!err) { + sch_tree_unlock(sch); err = fq_resize(sch, fq_log); - + sch_tree_lock(sch); + } while (sch->q.qlen > sch->limit) { struct sk_buff *skb = fq_dequeue(sch); -- 2.39.5