[PATCH net-next v2] net: sched: don't disable bh when accessing action idr

From: Vlad Buslov
Date: Mon May 21 2018 - 15:08:43 EST


Initial net_device implementation used ingress_lock spinlock to synchronize
ingress path of device. This lock was used in both process and bh context.
In some code paths action map lock was obtained while holding ingress_lock.
Commit e1e992e52faa ("[NET_SCHED] protect action config/dump from irqs")
modified actions to always disable bh, while using action map lock, in
order to prevent deadlock on ingress_lock in softirq. This lock was removed
from net_device, so disabling bh, while accessing action map, is no longer
necessary.

Replace all action idr spinlock usage with regular calls that do not
disable bh.

Signed-off-by: Vlad Buslov <vladbu@xxxxxxxxxxxx>
---
net/sched/act_api.c | 20 ++++++++++----------
1 file changed, 10 insertions(+), 10 deletions(-)

diff --git a/net/sched/act_api.c b/net/sched/act_api.c
index 72251241665a..3f4cf930f809 100644
--- a/net/sched/act_api.c
+++ b/net/sched/act_api.c
@@ -77,9 +77,9 @@ static void free_tcf(struct tc_action *p)

static void tcf_idr_remove(struct tcf_idrinfo *idrinfo, struct tc_action *p)
{
- spin_lock_bh(&idrinfo->lock);
+ spin_lock(&idrinfo->lock);
idr_remove(&idrinfo->action_idr, p->tcfa_index);
- spin_unlock_bh(&idrinfo->lock);
+ spin_unlock(&idrinfo->lock);
gen_kill_estimator(&p->tcfa_rate_est);
free_tcf(p);
}
@@ -156,7 +156,7 @@ static int tcf_dump_walker(struct tcf_idrinfo *idrinfo, struct sk_buff *skb,
struct tc_action *p;
unsigned long id = 1;

- spin_lock_bh(&idrinfo->lock);
+ spin_lock(&idrinfo->lock);

s_i = cb->args[0];

@@ -191,7 +191,7 @@ static int tcf_dump_walker(struct tcf_idrinfo *idrinfo, struct sk_buff *skb,
if (index >= 0)
cb->args[0] = index + 1;

- spin_unlock_bh(&idrinfo->lock);
+ spin_unlock(&idrinfo->lock);
if (n_i) {
if (act_flags & TCA_FLAG_LARGE_DUMP_ON)
cb->args[1] = n_i;
@@ -261,9 +261,9 @@ static struct tc_action *tcf_idr_lookup(u32 index, struct tcf_idrinfo *idrinfo)
{
struct tc_action *p = NULL;

- spin_lock_bh(&idrinfo->lock);
+ spin_lock(&idrinfo->lock);
p = idr_find(&idrinfo->action_idr, index);
- spin_unlock_bh(&idrinfo->lock);
+ spin_unlock(&idrinfo->lock);

return p;
}
@@ -323,7 +323,7 @@ int tcf_idr_create(struct tc_action_net *tn, u32 index, struct nlattr *est,
}
spin_lock_init(&p->tcfa_lock);
idr_preload(GFP_KERNEL);
- spin_lock_bh(&idrinfo->lock);
+ spin_lock(&idrinfo->lock);
/* user doesn't specify an index */
if (!index) {
index = 1;
@@ -331,7 +331,7 @@ int tcf_idr_create(struct tc_action_net *tn, u32 index, struct nlattr *est,
} else {
err = idr_alloc_u32(idr, NULL, &index, index, GFP_ATOMIC);
}
- spin_unlock_bh(&idrinfo->lock);
+ spin_unlock(&idrinfo->lock);
idr_preload_end();
if (err)
goto err3;
@@ -369,9 +369,9 @@ void tcf_idr_insert(struct tc_action_net *tn, struct tc_action *a)
{
struct tcf_idrinfo *idrinfo = tn->idrinfo;

- spin_lock_bh(&idrinfo->lock);
+ spin_lock(&idrinfo->lock);
idr_replace(&idrinfo->action_idr, a, a->tcfa_index);
- spin_unlock_bh(&idrinfo->lock);
+ spin_unlock(&idrinfo->lock);
}
EXPORT_SYMBOL(tcf_idr_insert);

--
2.7.5