Re: [PATCH] mac80211: do not aggregate frames if max_frags is set to one
> On Tue, 2018-08-28 at 23:41 +0200, Lorenzo Bianconi wrote: > > > Assuming the A-MSDU subframe is composed by two packets, the last one > > must not contain padding, is my understanding correct? > > Yes. More generally, assuming the A-MSDU subframe is composed of *any > number of* packets, the last one must not contain padding :) > > > > My colleague Sara (CC'ed now) has a patch to fix all of this (we just > > > did that this morning). I'll send it out tomorrow morning. Can I bother > > > you to try that? > > > > > > > Sure, no worries :) > > Thanks, patch coming up in a second. > > > > We'd have to fix the first point independently though, or I guess we can > > > roll that into our bugfix too, which would you prefer? > > > > > > johannes > > > > > > > If the patch is already done I can add the fix for the first point on > > top of it, does it sound good? > > Perfect. Ok, I will apply it on top of Sara's patch and send it later today. Regards, Lorenzo > > johannes
Re: [PATCH] mac80211: do not aggregate frames if max_frags is set to one
On Tue, 2018-08-28 at 23:41 +0200, Lorenzo Bianconi wrote: > Assuming the A-MSDU subframe is composed by two packets, the last one > must not contain padding, is my understanding correct? Yes. More generally, assuming the A-MSDU subframe is composed of *any number of* packets, the last one must not contain padding :) > > My colleague Sara (CC'ed now) has a patch to fix all of this (we just > > did that this morning). I'll send it out tomorrow morning. Can I bother > > you to try that? > > > > Sure, no worries :) Thanks, patch coming up in a second. > > We'd have to fix the first point independently though, or I guess we can > > roll that into our bugfix too, which would you prefer? > > > > johannes > > > > If the patch is already done I can add the fix for the first point on > top of it, does it sound good? Perfect. johannes
Re: [PATCH] mac80211: do not aggregate frames if max_frags is set to one
> > On Tue, 2018-08-28 at 23:07 +0200, Lorenzo Bianconi wrote: > > Do not try to aggregate packets in a A-MSDU frame if max_tx_fragments > > or max_amsdu_subframes is set to 1. > > Yeah that seems valid. > > > Moreover take into account > > tail padding added on the first frame into flow backlog if > > ieee80211_amsdu_realloc_pad routine on the second frame fails. > > That's not really right - the padding shouldn't have been added to the > first subframe in the first place as the last one shouldn't have padding > at all. There's also a separate bug in that the A-MSDU subframe length > should NOT include the padding. > Assuming the A-MSDU subframe is composed by two packets, the last one must not contain padding, is my understanding correct? > My colleague Sara (CC'ed now) has a patch to fix all of this (we just > did that this morning). I'll send it out tomorrow morning. Can I bother > you to try that? > Sure, no worries :) > We'd have to fix the first point independently though, or I guess we can > roll that into our bugfix too, which would you prefer? > > johannes > If the patch is already done I can add the fix for the first point on top of it, does it sound good? Regards, Lorenzo
Re: [PATCH] mac80211: do not aggregate frames if max_frags is set to one
On Tue, 2018-08-28 at 23:07 +0200, Lorenzo Bianconi wrote: > Do not try to aggregate packets in a A-MSDU frame if max_tx_fragments > or max_amsdu_subframes is set to 1. Yeah that seems valid. > Moreover take into account > tail padding added on the first frame into flow backlog if > ieee80211_amsdu_realloc_pad routine on the second frame fails. That's not really right - the padding shouldn't have been added to the first subframe in the first place as the last one shouldn't have padding at all. There's also a separate bug in that the A-MSDU subframe length should NOT include the padding. My colleague Sara (CC'ed now) has a patch to fix all of this (we just did that this morning). I'll send it out tomorrow morning. Can I bother you to try that? We'd have to fix the first point independently though, or I guess we can roll that into our bugfix too, which would you prefer? johannes
[PATCH] mac80211: do not aggregate frames if max_frags is set to one
Do not try to aggregate packets in a A-MSDU frame if max_tx_fragments
or max_amsdu_subframes is set to 1. Moreover take into account
tail padding added on the first frame into flow backlog if
ieee80211_amsdu_realloc_pad routine on the second frame fails.
This patch fixes a kernel freeze that occasionally occurs running
iperf tests using mt76 driver
Fixes: 6e0456b54545 ("mac80211: add A-MSDU tx support")
Signed-off-by: Lorenzo Bianconi
---
net/mac80211/tx.c | 25 +++--
1 file changed, 15 insertions(+), 10 deletions(-)
diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index 093108077edc..a5701573c83b 100644
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -3185,11 +3185,11 @@ static bool ieee80211_amsdu_aggregate(struct
ieee80211_sub_if_data *sdata,
u8 max_subframes = sta->sta.max_amsdu_subframes;
int max_frags = local->hw.max_tx_fragments;
int max_amsdu_len = sta->sta.max_amsdu_len;
+ int n = 1, nfrags, delta;
__be16 len;
void *data;
bool ret = false;
unsigned int orig_len;
- int n = 1, nfrags;
if (!ieee80211_hw_check(&local->hw, TX_AMSDU))
return false;
@@ -3222,9 +3222,6 @@ 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;
@@ -3240,10 +3237,15 @@ static bool ieee80211_amsdu_aggregate(struct
ieee80211_sub_if_data *sdata,
if (max_frags && nfrags > max_frags)
goto out;
- if (!ieee80211_amsdu_realloc_pad(local, skb, sizeof(rfc1042_header) + 2,
-&subframe_len))
+ if (!ieee80211_amsdu_prepare_head(sdata, fast_tx, head))
goto out;
+ if (!ieee80211_amsdu_realloc_pad(local, skb, sizeof(rfc1042_header) + 2,
+&subframe_len)) {
+ delta = head->len - orig_len;
+ goto update_backlog;
+ }
+
ret = true;
data = skb_push(skb, ETH_ALEN + 2);
memmove(data, data + ETH_ALEN + 2, 2 * ETH_ALEN);
@@ -3256,11 +3258,14 @@ static bool ieee80211_amsdu_aggregate(struct
ieee80211_sub_if_data *sdata,
head->len += skb->len;
head->data_len += skb->len;
*frag_tail = skb;
+ delta = head->len - orig_len;
- flow->backlog += head->len - orig_len;
- tin->backlog_bytes += head->len - orig_len;
-
- fq_recalc_backlog(fq, tin, flow);
+update_backlog:
+ if (delta > 0) {
+ flow->backlog += delta;
+ tin->backlog_bytes += delta;
+ fq_recalc_backlog(fq, tin, flow);
+ }
out:
spin_unlock_bh(&fq->lock);
--
2.17.1
