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Subject[PATCH] batman-adv: Axe 'aggr_list_lock'
Date
'aggr_list.lock' can safely be used in place of another explicit spinlock
when access to 'aggr_list' has to be guarded.

This avoids to take 2 locks, knowing that the 2nd one is always successful.

Now that the 'aggr_list.lock' is handled explicitly, the lock-free
__sbk_something() variants should be used when dealing with 'aggr_list'.

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
---
Compile tested only.
---
net/batman-adv/bat_v.c | 1 -
net/batman-adv/bat_v_ogm.c | 30 +++++++++++++++---------------
net/batman-adv/types.h | 3 ---
3 files changed, 15 insertions(+), 19 deletions(-)

diff --git a/net/batman-adv/bat_v.c b/net/batman-adv/bat_v.c
index 64054edc2e3c..4ff6cf1ecae7 100644
--- a/net/batman-adv/bat_v.c
+++ b/net/batman-adv/bat_v.c
@@ -1085,7 +1085,6 @@ void batadv_v_hardif_init(struct batadv_hard_iface *hard_iface)

hard_iface->bat_v.aggr_len = 0;
skb_queue_head_init(&hard_iface->bat_v.aggr_list);
- spin_lock_init(&hard_iface->bat_v.aggr_list_lock);
INIT_DELAYED_WORK(&hard_iface->bat_v.aggr_wq,
batadv_v_ogm_aggr_work);
}
diff --git a/net/batman-adv/bat_v_ogm.c b/net/batman-adv/bat_v_ogm.c
index b841c83d9c3b..c9a00100f199 100644
--- a/net/batman-adv/bat_v_ogm.c
+++ b/net/batman-adv/bat_v_ogm.c
@@ -151,7 +151,7 @@ static unsigned int batadv_v_ogm_len(struct sk_buff *skb)
* @skb: the OGM to check
* @hard_iface: the interface to use to send the OGM
*
- * Caller needs to hold the hard_iface->bat_v.aggr_list_lock.
+ * Caller needs to hold the hard_iface->bat_v.aggr_list.lock.
*
* Return: True, if the given OGMv2 packet still fits, false otherwise.
*/
@@ -162,7 +162,7 @@ static bool batadv_v_ogm_queue_left(struct sk_buff *skb,
BATADV_MAX_AGGREGATION_BYTES);
unsigned int ogm_len = batadv_v_ogm_len(skb);

- lockdep_assert_held(&hard_iface->bat_v.aggr_list_lock);
+ lockdep_assert_held(&hard_iface->bat_v.aggr_list.lock);

return hard_iface->bat_v.aggr_len + ogm_len <= max;
}
@@ -173,13 +173,13 @@ static bool batadv_v_ogm_queue_left(struct sk_buff *skb,
*
* Empties the OGMv2 aggregation queue and frees all the skbs it contained.
*
- * Caller needs to hold the hard_iface->bat_v.aggr_list_lock.
+ * Caller needs to hold the hard_iface->bat_v.aggr_list.lock.
*/
static void batadv_v_ogm_aggr_list_free(struct batadv_hard_iface *hard_iface)
{
- lockdep_assert_held(&hard_iface->bat_v.aggr_list_lock);
+ lockdep_assert_held(&hard_iface->bat_v.aggr_list.lock);

- skb_queue_purge(&hard_iface->bat_v.aggr_list);
+ __skb_queue_purge(&hard_iface->bat_v.aggr_list);
hard_iface->bat_v.aggr_len = 0;
}

@@ -192,7 +192,7 @@ static void batadv_v_ogm_aggr_list_free(struct batadv_hard_iface *hard_iface)
*
* The aggregation queue is empty after this call.
*
- * Caller needs to hold the hard_iface->bat_v.aggr_list_lock.
+ * Caller needs to hold the hard_iface->bat_v.aggr_list.lock.
*/
static void batadv_v_ogm_aggr_send(struct batadv_hard_iface *hard_iface)
{
@@ -201,7 +201,7 @@ static void batadv_v_ogm_aggr_send(struct batadv_hard_iface *hard_iface)
unsigned int ogm_len;
struct sk_buff *skb;

- lockdep_assert_held(&hard_iface->bat_v.aggr_list_lock);
+ lockdep_assert_held(&hard_iface->bat_v.aggr_list.lock);

if (!aggr_len)
return;
@@ -215,7 +215,7 @@ static void batadv_v_ogm_aggr_send(struct batadv_hard_iface *hard_iface)
skb_reserve(skb_aggr, ETH_HLEN + NET_IP_ALIGN);
skb_reset_network_header(skb_aggr);

- while ((skb = skb_dequeue(&hard_iface->bat_v.aggr_list))) {
+ while ((skb = __skb_dequeue(&hard_iface->bat_v.aggr_list))) {
hard_iface->bat_v.aggr_len -= batadv_v_ogm_len(skb);

ogm_len = batadv_v_ogm_len(skb);
@@ -242,13 +242,13 @@ static void batadv_v_ogm_queue_on_if(struct sk_buff *skb,
return;
}

- spin_lock_bh(&hard_iface->bat_v.aggr_list_lock);
+ spin_lock_bh(&hard_iface->bat_v.aggr_list.lock);
if (!batadv_v_ogm_queue_left(skb, hard_iface))
batadv_v_ogm_aggr_send(hard_iface);

hard_iface->bat_v.aggr_len += batadv_v_ogm_len(skb);
- skb_queue_tail(&hard_iface->bat_v.aggr_list, skb);
- spin_unlock_bh(&hard_iface->bat_v.aggr_list_lock);
+ __skb_queue_tail(&hard_iface->bat_v.aggr_list, skb);
+ spin_unlock_bh(&hard_iface->bat_v.aggr_list.lock);
}

/**
@@ -373,9 +373,9 @@ void batadv_v_ogm_aggr_work(struct work_struct *work)
batv = container_of(work, struct batadv_hard_iface_bat_v, aggr_wq.work);
hard_iface = container_of(batv, struct batadv_hard_iface, bat_v);

- spin_lock_bh(&hard_iface->bat_v.aggr_list_lock);
+ spin_lock_bh(&hard_iface->bat_v.aggr_list.lock);
batadv_v_ogm_aggr_send(hard_iface);
- spin_unlock_bh(&hard_iface->bat_v.aggr_list_lock);
+ spin_unlock_bh(&hard_iface->bat_v.aggr_list.lock);

batadv_v_ogm_start_queue_timer(hard_iface);
}
@@ -406,9 +406,9 @@ void batadv_v_ogm_iface_disable(struct batadv_hard_iface *hard_iface)
{
cancel_delayed_work_sync(&hard_iface->bat_v.aggr_wq);

- spin_lock_bh(&hard_iface->bat_v.aggr_list_lock);
+ spin_lock_bh(&hard_iface->bat_v.aggr_list.lock);
batadv_v_ogm_aggr_list_free(hard_iface);
- spin_unlock_bh(&hard_iface->bat_v.aggr_list_lock);
+ spin_unlock_bh(&hard_iface->bat_v.aggr_list.lock);
}

/**
diff --git a/net/batman-adv/types.h b/net/batman-adv/types.h
index be7c02aa91e2..75a72d6676ec 100644
--- a/net/batman-adv/types.h
+++ b/net/batman-adv/types.h
@@ -126,9 +126,6 @@ struct batadv_hard_iface_bat_v {
/** @aggr_len: size of the OGM aggregate (excluding ethernet header) */
unsigned int aggr_len;

- /** @aggr_list_lock: protects aggr_list */
- spinlock_t aggr_list_lock;
-
/**
* @throughput_override: throughput override to disable link
* auto-detection
--
2.20.1
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