2020-09-17 12:52:13

by Felix Fietkau

Subject: [PATCH] mac80211: do not allow bigger VHT MPDUs than the hardware supports

Limit maximum VHT MPDU size by local capability

Signed-off-by: Felix Fietkau <[email protected]>
---
net/mac80211/vht.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/net/mac80211/vht.c b/net/mac80211/vht.c
index 7e601d067d53..fb0e3a657d2d 100644
--- a/net/mac80211/vht.c
+++ b/net/mac80211/vht.c
@@ -168,10 +168,7 @@ ieee80211_vht_cap_ie_to_sta_vht_cap(struct ieee80211_sub_if_data *sdata,
/* take some capabilities as-is */
cap_info = le32_to_cpu(vht_cap_ie->vht_cap_info);
vht_cap->cap = cap_info;
- vht_cap->cap &= IEEE80211_VHT_CAP_MAX_MPDU_LENGTH_3895 |
- IEEE80211_VHT_CAP_MAX_MPDU_LENGTH_7991 |
- IEEE80211_VHT_CAP_MAX_MPDU_LENGTH_11454 |
- IEEE80211_VHT_CAP_RXLDPC |
+ vht_cap->cap &= IEEE80211_VHT_CAP_RXLDPC |
IEEE80211_VHT_CAP_VHT_TXOP_PS |
IEEE80211_VHT_CAP_HTC_VHT |
IEEE80211_VHT_CAP_MAX_A_MPDU_LENGTH_EXPONENT_MASK |
@@ -180,6 +177,9 @@ ieee80211_vht_cap_ie_to_sta_vht_cap(struct ieee80211_sub_if_data *sdata,
IEEE80211_VHT_CAP_RX_ANTENNA_PATTERN |
IEEE80211_VHT_CAP_TX_ANTENNA_PATTERN;

+ vht_cap->cap |= min_t(u32, cap_info & IEEE80211_VHT_CAP_MAX_MPDU_MASK,
+ own_cap.cap & IEEE80211_VHT_CAP_MAX_MPDU_MASK);
+
/* and some based on our own capabilities */
switch (own_cap.cap & IEEE80211_VHT_CAP_SUPP_CHAN_WIDTH_MASK) {
case IEEE80211_VHT_CAP_SUPP_CHAN_WIDTH_160MHZ:
--
2.28.0

2021-01-05 08:59:00

by Shay Bar

Subject: Re: [PATCH] mac80211: do not allow bigger VHT MPDUs than the hardware supports

On 17/09/2020 15:50, Felix Fietkau wrote:
> Limit maximum VHT MPDU size by local capability
>
> Signed-off-by: Felix Fietkau <[email protected]>
> ---
> net/mac80211/vht.c | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/net/mac80211/vht.c b/net/mac80211/vht.c
> index 7e601d067d53..fb0e3a657d2d 100644
> --- a/net/mac80211/vht.c
> +++ b/net/mac80211/vht.c
> @@ -168,10 +168,7 @@ ieee80211_vht_cap_ie_to_sta_vht_cap(struct ieee80211_sub_if_data *sdata,
> /* take some capabilities as-is */
> cap_info = le32_to_cpu(vht_cap_ie->vht_cap_info);
> vht_cap->cap = cap_info;
> - vht_cap->cap &= IEEE80211_VHT_CAP_MAX_MPDU_LENGTH_3895 |
> - IEEE80211_VHT_CAP_MAX_MPDU_LENGTH_7991 |
> - IEEE80211_VHT_CAP_MAX_MPDU_LENGTH_11454 |
> - IEEE80211_VHT_CAP_RXLDPC |
> + vht_cap->cap &= IEEE80211_VHT_CAP_RXLDPC |
> IEEE80211_VHT_CAP_VHT_TXOP_PS |
> IEEE80211_VHT_CAP_HTC_VHT |
> IEEE80211_VHT_CAP_MAX_A_MPDU_LENGTH_EXPONENT_MASK |
> @@ -180,6 +177,9 @@ ieee80211_vht_cap_ie_to_sta_vht_cap(struct ieee80211_sub_if_data *sdata,
> IEEE80211_VHT_CAP_RX_ANTENNA_PATTERN |
> IEEE80211_VHT_CAP_TX_ANTENNA_PATTERN;
>
> + vht_cap->cap |= min_t(u32, cap_info & IEEE80211_VHT_CAP_MAX_MPDU_MASK,
> + own_cap.cap & IEEE80211_VHT_CAP_MAX_MPDU_MASK);
> +
> /* and some based on our own capabilities */
> switch (own_cap.cap & IEEE80211_VHT_CAP_SUPP_CHAN_WIDTH_MASK) {
> case IEEE80211_VHT_CAP_SUPP_CHAN_WIDTH_160MHZ:
>

The vht_cap->cap IEEE80211_VHT_CAP_MAX_MPDU* reflect the associated STA
_RX_ capabilities.

Why would you override the original STA _RX_ capabilities (vht_cap->cap)
with your own HW _RX_ size limitation ?

e.g. if HW support 11454 in TX and 3895 in RX, due to this change, you
limit your TX to your own _RX_ limitation (3895) while STA actually
reported 11454 RX.