From ad5351db89681515681c5d5659ddf4c69e3cc6f5 Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Fri, 7 Aug 2009 16:42:15 +0200 Subject: [PATCH] mac80211: allow DMA optimisation If we have a lot of frames to transmit at once, for instance with fragmentation, it can be an optimisation to only tell the DMA engine about them on the last fragment/frame to avoid banging the IO too much. This patch allows implementation such an optimisation by telling the driver when more frames can be expected. Currently, this is used by mac80211 only on fragmented frames, but could also be used in the future on other frames when the queue was full and there are multiple frames pending. Note that drivers need to be careful when using this flag, they need to kick their DMA engines not just when this flag is clear, but also when the queue gets full so that progress can be made. Signed-off-by: Johannes Berg Signed-off-by: John W. Linville --- include/net/mac80211.h | 5 +++++ net/mac80211/tx.c | 3 +++ 2 files changed, 8 insertions(+) diff --git a/include/net/mac80211.h b/include/net/mac80211.h index cd4eb20f98f5..76d43e12cc29 100644 --- a/include/net/mac80211.h +++ b/include/net/mac80211.h @@ -268,6 +268,10 @@ struct ieee80211_bss_conf { * @IEEE80211_TX_CTL_PSPOLL_RESPONSE: (internal?) * This frame is a response to a PS-poll frame and should be sent * although the station is in powersave mode. + * @IEEE80211_TX_CTL_MORE_FRAMES: More frames will be passed to the + * transmit function after the current frame, this can be used + * by drivers to kick the DMA queue only if unset or when the + * queue gets full. */ enum mac80211_tx_control_flags { IEEE80211_TX_CTL_REQ_TX_STATUS = BIT(0), @@ -288,6 +292,7 @@ enum mac80211_tx_control_flags { IEEE80211_TX_INTFL_RETRIED = BIT(15), IEEE80211_TX_INTFL_DONT_ENCRYPT = BIT(16), IEEE80211_TX_CTL_PSPOLL_RESPONSE = BIT(17), + IEEE80211_TX_CTL_MORE_FRAMES = BIT(18), }; /** diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c index 7cffaa046b33..7f2e4cdb8904 100644 --- a/net/mac80211/tx.c +++ b/net/mac80211/tx.c @@ -1154,6 +1154,9 @@ static int __ieee80211_tx(struct ieee80211_local *local, next = skb->next; len = skb->len; + if (next) + info->flags |= IEEE80211_TX_CTL_MORE_FRAMES; + sdata = vif_to_sdata(info->control.vif); switch (sdata->vif.type) { -- 2.20.1