2021-11-10 16:06:43

by Karthikeyan Periyasamy

Subject: [PATCH] ath11k: avoid unnecessary BH disable lock in STA kickout event

In STA kickout event processing, the peer object is protected
under spin lock BH. Release this lock after picking up the vdev_id
from the peer object instead after ieee80211_report_low_ack().
This will minimize the lock hold period which will improve
performance since base_lock is used across the data path.
This was found in code review.

Tested-on: IPQ8074 hw2.0 AHB WLAN.HK.2.5.0.1-00729-QCAHKSWPL_SILICONZ-3 v2

Signed-off-by: Karthikeyan Periyasamy <[email protected]>
---
drivers/net/wireless/ath/ath11k/wmi.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/net/wireless/ath/ath11k/wmi.c b/drivers/net/wireless/ath/ath11k/wmi.c
index 5ae2ef4..60de539 100644
--- a/drivers/net/wireless/ath/ath11k/wmi.c
+++ b/drivers/net/wireless/ath/ath11k/wmi.c
@@ -6398,6 +6398,7 @@ static void ath11k_peer_sta_kickout_event(struct ath11k_base *ab, struct sk_buff
struct ieee80211_sta *sta;
struct ath11k_peer *peer;
struct ath11k *ar;
+ u32 vdev_id;

if (ath11k_pull_peer_sta_kickout_ev(ab, skb, &arg) != 0) {
ath11k_warn(ab, "failed to extract peer sta kickout event");
@@ -6413,10 +6414,15 @@ static void ath11k_peer_sta_kickout_event(struct ath11k_base *ab, struct sk_buff
if (!peer) {
ath11k_warn(ab, "peer not found %pM\n",
arg.mac_addr);
+ spin_unlock_bh(&ab->base_lock);
goto exit;
}

- ar = ath11k_mac_get_ar_by_vdev_id(ab, peer->vdev_id);
+ vdev_id = peer->vdev_id;
+
+ spin_unlock_bh(&ab->base_lock);
+
+ ar = ath11k_mac_get_ar_by_vdev_id(ab, vdev_id);
if (!ar) {
ath11k_warn(ab, "invalid vdev id in peer sta kickout ev %d",
peer->vdev_id);
@@ -6437,7 +6443,6 @@ static void ath11k_peer_sta_kickout_event(struct ath11k_base *ab, struct sk_buff
ieee80211_report_low_ack(sta, 10);

exit:
- spin_unlock_bh(&ab->base_lock);
rcu_read_unlock();
}

--
2.7.4

2021-11-15 09:16:30

by Kalle Valo

Subject: Re: [PATCH] ath11k: avoid unnecessary BH disable lock in STA kickout event

Karthikeyan Periyasamy <[email protected]> wrote:

> In STA kickout event processing, the peer object is protected
> under spin lock BH. Release this lock after picking up the vdev_id
> from the peer object instead after ieee80211_report_low_ack().
> This will minimize the lock hold period which will improve
> performance since base_lock is used across the data path.
> This was found in code review.
>
> Tested-on: IPQ8074 hw2.0 AHB WLAN.HK.2.5.0.1-00729-QCAHKSWPL_SILICONZ-3 v2
>
> Signed-off-by: Karthikeyan Periyasamy <[email protected]>
> Signed-off-by: Kalle Valo <[email protected]>

Patch applied to ath-next branch of ath.git, thanks.

4c375743c5fe ath11k: avoid unnecessary BH disable lock in STA kickout event

--
https://patchwork.kernel.org/project/linux-wireless/patch/[email protected]/

https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches