2013-03-06 12:44:18

by Johannes Berg

Subject: [PATCH] mac80211: Call drv_set_tim only if there is a change

From: Ilan Peer <[email protected]>

It is possible that sta_info_recalc_tim() is called consecutively
without changing the station's tim bit. In such cases there is no
need to call the driver's set_tim() callback.

Signed-off-by: Ilan Peer <[email protected]>
Signed-off-by: Johannes Berg <[email protected]>
---
net/mac80211/sta_info.c | 13 +++++++++++++
1 file changed, 13 insertions(+)

diff --git a/net/mac80211/sta_info.c b/net/mac80211/sta_info.c
index 852bf45..a36ceed 100644
--- a/net/mac80211/sta_info.c
+++ b/net/mac80211/sta_info.c
@@ -556,6 +556,15 @@ static inline void __bss_tim_clear(u8 *tim, u16 id)
tim[id / 8] &= ~(1 << (id % 8));
}

+static inline bool __bss_tim_get(u8 *tim, u16 id)
+{
+ /*
+ * This format has been mandated by the IEEE specifications,
+ * so this line may not be changed to use the test_bit() format.
+ */
+ return tim[id / 8] & (1 << (id % 8));
+}
+
static unsigned long ieee80211_tids_for_ac(int ac)
{
/* If we ever support TIDs > 7, this obviously needs to be adjusted */
@@ -636,6 +645,9 @@ void sta_info_recalc_tim(struct sta_info *sta)
done:
spin_lock_bh(&local->tim_lock);

+ if (indicate_tim == __bss_tim_get(ps->tim, id))
+ goto out_unlock;
+
if (indicate_tim)
__bss_tim_set(ps->tim, id);
else
@@ -647,6 +659,7 @@ void sta_info_recalc_tim(struct sta_info *sta)
local->tim_in_locked_section = false;
}

+out_unlock:
spin_unlock_bh(&local->tim_lock);
}

--
1.8.0

2013-03-07 10:26:09

by Johannes Berg

Subject: Re: [PATCH] mac80211: Call drv_set_tim only if there is a change

On Wed, 2013-03-06 at 13:44 +0100, Johannes Berg wrote:
> From: Ilan Peer <[email protected]>
>
> It is possible that sta_info_recalc_tim() is called consecutively
> without changing the station's tim bit. In such cases there is no
> need to call the driver's set_tim() callback.

Applied.

johannes