[PATCH AUTOSEL 4.14 16/36] mac80211: do not convert to A-MSDU if frag/subframe limited

From: Sasha Levin
Date: Mon Sep 24 2018 - 10:50:21 EST


From: Lorenzo Bianconi <lorenzo.bianconi@xxxxxxxxxx>

[ Upstream commit 1eb507903665442360a959136dfa3234c43db085 ]

Do not start to aggregate packets in a A-MSDU frame (converting the
first subframe to A-MSDU, adding the header) if max_tx_fragments or
max_amsdu_subframes limits are already exceeded by it. In particular,
this happens when drivers set the limit to 1 to avoid A-MSDUs at all.

Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@xxxxxxxxxx>
[reword commit message to be more precise]
Signed-off-by: Johannes Berg <johannes.berg@xxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
---
net/mac80211/tx.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index 2064234500cf..fd8dafe73aec 100644
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -3157,9 +3157,6 @@ static bool ieee80211_amsdu_aggregate(struct ieee80211_sub_if_data *sdata,
if (skb->len + head->len > max_amsdu_len)
goto out;

- if (!ieee80211_amsdu_prepare_head(sdata, fast_tx, head))
- goto out;
-
nfrags = 1 + skb_shinfo(skb)->nr_frags;
nfrags += 1 + skb_shinfo(head)->nr_frags;
frag_tail = &skb_shinfo(head)->frag_list;
@@ -3175,6 +3172,9 @@ static bool ieee80211_amsdu_aggregate(struct ieee80211_sub_if_data *sdata,
if (max_frags && nfrags > max_frags)
goto out;

+ if (!ieee80211_amsdu_prepare_head(sdata, fast_tx, head))
+ goto out;
+
/*
* Pad out the previous subframe to a multiple of 4 by adding the
* padding to the next one, that's being added. Note that head->len
--
2.17.1