2015-07-30 12:14:53

by Felix Fietkau

Subject: [PATCH] mac80211: make local->tx_headroom a multiple of 4

This ensures that mac80211 generated management frames and beacons are
aligned before being passed to the driver

Signed-off-by: Felix Fietkau <[email protected]>
---
net/mac80211/main.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/net/mac80211/main.c b/net/mac80211/main.c
index ff79a13..e8b9224 100644
--- a/net/mac80211/main.c
+++ b/net/mac80211/main.c
@@ -1034,6 +1034,7 @@ int ieee80211_register_hw(struct ieee80211_hw *hw)
*/
local->tx_headroom = max_t(unsigned int , local->hw.extra_tx_headroom,
IEEE80211_TX_STATUS_HEADROOM);
+ local->tx_headroom = ALIGN(local->tx_headroom, 4);

debugfs_hw_add(local);

--
2.2.2

2015-08-13 09:17:51

by Johannes Berg

Subject: Re: [PATCH] mac80211: make local->tx_headroom a multiple of 4

On Thu, 2015-07-30 at 14:14 +0200, Felix Fietkau wrote:
> This ensures that mac80211 generated management frames and beacons
> are aligned before being passed to the driver
>
I'm not convinced this is appropriate. Drivers may or may not require
alignment, so I don't really see why we should in general enforce that?
Having less headroom requirement is better in general.

johannes