[PATCH 3/4] wifi: ath12k: Decrease ath12k_sta_rc_update_wk() stack usage

Kalle Valo
2024-12-17T20:26:27Z

Currently when building ath12k with llvm-18.1.7-x86_64 the following warning is
observed:

drivers/net/wireless/ath/ath12k/mac.c:4946:13: warning: stack frame size (1112) exceeds limit (1024) in 'ath12k_sta_rc_update_wk' [-Wframe-larger-than]

A major contributor to the stack usage in this function is:

struct ath12k_wmi_peer_assoc_arg peer_arg;

Avoid the excess stack usage by dynamically allocating peer_arg
instead of declaring it on the stack.

Tested-on: QCN9274 hw2.0 PCI WLAN.WBE.1.3.1-00173-QCAHKSWPL_SILICONZ-1
Tested-on: WCN7850 hw2.0 PCI WLAN.HMT.1.0.c5-00481-QCAHMTSWPL_V1.0_V2.0_SILICONZ-3

Signed-off-by: Jeff Johnson <quic_jjohnson@quicinc.com>
Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>
---
drivers/net/wireless/ath/ath12k/mac.c | 14 +++++++++-----
1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/drivers/net/wireless/ath/ath12k/mac.c b/drivers/net/wireless/ath/ath12k/mac.c
index 2a30a11903c5..10293e9c1d49 100644
--- a/drivers/net/wireless/ath/ath12k/mac.c
+++ b/drivers/net/wireless/ath/ath12k/mac.c
@@ -4956,7 +4956,6 @@ static void ath12k_sta_rc_update_wk(struct wiphy *wiphy, struct wiphy_work *wk)
u32 changed, bw, nss, smps, bw_prev;
int err, num_vht_rates;
const struct cfg80211_bitrate_mask *mask;
- struct ath12k_wmi_peer_assoc_arg peer_arg;
enum wmi_phy_mode peer_phymode;
struct ath12k_link_sta *arsta;
struct ieee80211_vif *vif;
@@ -4992,9 +4991,14 @@ static void ath12k_sta_rc_update_wk(struct wiphy *wiphy, struct wiphy_work *wk)
nss = min(nss, max(ath12k_mac_max_ht_nss(ht_mcs_mask),
ath12k_mac_max_vht_nss(vht_mcs_mask)));

+ struct ath12k_wmi_peer_assoc_arg *peer_arg __free(kfree) =
+ kzalloc(sizeof(*peer_arg), GFP_KERNEL);
+ if (!peer_arg)
+ return;
+
if (changed & IEEE80211_RC_BW_CHANGED) {
- ath12k_peer_assoc_h_phymode(ar, arvif, arsta, &peer_arg);
- peer_phymode = peer_arg.peer_phymode;
+ ath12k_peer_assoc_h_phymode(ar, arvif, arsta, peer_arg);
+ peer_phymode = peer_arg->peer_phymode;

if (bw > bw_prev) {
/* Phymode shows maximum supported channel width, if we
@@ -5096,9 +5100,9 @@ static void ath12k_sta_rc_update_wk(struct wiphy *wiphy, struct wiphy_work *wk)
* other rates using peer_assoc command.
*/
ath12k_peer_assoc_prepare(ar, arvif, arsta,
- &peer_arg, true);
+ peer_arg, true);

- err = ath12k_wmi_send_peer_assoc_cmd(ar, &peer_arg);
+ err = ath12k_wmi_send_peer_assoc_cmd(ar, peer_arg);
if (err)
ath12k_warn(ar->ab, "failed to run peer assoc for STA %pM vdev %i: %d\n",
arsta->addr, arvif->vdev_id, err);
--
2.39.5