diff options
Diffstat (limited to 'net/sched')
| -rw-r--r-- | net/sched/act_api.c | 76 | ||||
| -rw-r--r-- | net/sched/cls_api.c | 2 |
2 files changed, 50 insertions, 28 deletions
diff --git a/net/sched/act_api.c b/net/sched/act_api.c index 6611f292b6cb..3a7770eff52d 100644 --- a/net/sched/act_api.c +++ b/net/sched/act_api.c @@ -816,6 +816,9 @@ EXPORT_SYMBOL(tcf_idr_cleanup); * its reference and bind counters, and return 1. Otherwise insert temporary * error pointer (to prevent concurrent users from inserting actions with same * index) and return 0. + * + * May return -EAGAIN for binding actions in case of a parallel add/delete on + * the requested index. */ int tcf_idr_check_alloc(struct tc_action_net *tn, u32 *index, @@ -824,43 +827,61 @@ int tcf_idr_check_alloc(struct tc_action_net *tn, u32 *index, struct tcf_idrinfo *idrinfo = tn->idrinfo; struct tc_action *p; int ret; + u32 max; -again: - mutex_lock(&idrinfo->lock); if (*index) { +again: + rcu_read_lock(); p = idr_find(&idrinfo->action_idr, *index); + if (IS_ERR(p)) { /* This means that another process allocated * index but did not assign the pointer yet. */ - mutex_unlock(&idrinfo->lock); + rcu_read_unlock(); goto again; } - if (p) { - refcount_inc(&p->tcfa_refcnt); - if (bind) - atomic_inc(&p->tcfa_bindcnt); - *a = p; - ret = 1; - } else { - *a = NULL; - ret = idr_alloc_u32(&idrinfo->action_idr, NULL, index, - *index, GFP_KERNEL); - if (!ret) - idr_replace(&idrinfo->action_idr, - ERR_PTR(-EBUSY), *index); + if (!p) { + /* Empty slot, try to allocate it */ + max = *index; + rcu_read_unlock(); + goto new; } + + if (!refcount_inc_not_zero(&p->tcfa_refcnt)) { + /* Action was deleted in parallel */ + rcu_read_unlock(); + return -EAGAIN; + } + + if (bind) + atomic_inc(&p->tcfa_bindcnt); + *a = p; + + rcu_read_unlock(); + + return 1; } else { + /* Find a slot */ *index = 1; - *a = NULL; - ret = idr_alloc_u32(&idrinfo->action_idr, NULL, index, - UINT_MAX, GFP_KERNEL); - if (!ret) - idr_replace(&idrinfo->action_idr, ERR_PTR(-EBUSY), - *index); + max = UINT_MAX; } + +new: + *a = NULL; + + mutex_lock(&idrinfo->lock); + ret = idr_alloc_u32(&idrinfo->action_idr, ERR_PTR(-EBUSY), index, max, + GFP_KERNEL); mutex_unlock(&idrinfo->lock); + + /* N binds raced for action allocation, + * retry for all the ones that failed. + */ + if (ret == -ENOSPC && *index == max) + ret = -EAGAIN; + return ret; } EXPORT_SYMBOL(tcf_idr_check_alloc); @@ -1283,7 +1304,7 @@ static const struct nla_policy tcf_action_policy[TCA_ACT_MAX + 1] = { [TCA_ACT_HW_STATS] = NLA_POLICY_BITFIELD32(TCA_ACT_HW_STATS_ANY), }; -void tcf_idr_insert_many(struct tc_action *actions[]) +void tcf_idr_insert_many(struct tc_action *actions[], int init_res[]) { struct tc_action *a; int i; @@ -1291,11 +1312,12 @@ void tcf_idr_insert_many(struct tc_action *actions[]) tcf_act_for_each_action(i, a, actions) { struct tcf_idrinfo *idrinfo; + if (init_res[i] == 0) /* Bound */ + continue; + idrinfo = a->idrinfo; mutex_lock(&idrinfo->lock); - /* Replace ERR_PTR(-EBUSY) allocated by tcf_idr_check_alloc if - * it is just created, otherwise this is just a nop. - */ + /* Replace ERR_PTR(-EBUSY) allocated by tcf_idr_check_alloc */ idr_replace(&idrinfo->action_idr, a, a->tcfa_index); mutex_unlock(&idrinfo->lock); } @@ -1495,7 +1517,7 @@ int tcf_action_init(struct net *net, struct tcf_proto *tp, struct nlattr *nla, /* We have to commit them all together, because if any error happened in * between, we could not handle the failure gracefully. */ - tcf_idr_insert_many(actions); + tcf_idr_insert_many(actions, init_res); *attr_size = tcf_action_full_attrs_size(sz); err = i - 1; diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c index 437daebc1fc4..dc1c19a25882 100644 --- a/net/sched/cls_api.c +++ b/net/sched/cls_api.c @@ -3313,7 +3313,7 @@ int tcf_exts_validate_ex(struct net *net, struct tcf_proto *tp, struct nlattr ** act->type = exts->type = TCA_OLD_COMPAT; exts->actions[0] = act; exts->nr_actions = 1; - tcf_idr_insert_many(exts->actions); + tcf_idr_insert_many(exts->actions, init_res); } else if (exts->action && tb[exts->action]) { int err; |