[PATCH ath-next 2/4] wifi: ath12k: use per-radio ab in ath12k_mac_hw_register()

[Baochen Qiang]

In ath12k_mac_hw_register() the local 'ab' is fetched once from the first
radio, i.e. ath12k_ah_to_ar(ah, 0)->ab. When an ath12k_hw spans more than
one ath12k_base, the radios walked by for_each_ar() may belong to
different ath12k_base instances. Using the function-scope 'ab' inside
that loop then refers to the first radio's device, which is stale with
respect to the ar being processed.

This is not a functional problem currently: the loop only dereferences the
stale 'ab' under hw_params->current_cc_support, which is set only for
WCN7850 and QCC2072. Both devices expose a single radio per ath12k_hw, so
'ab' and ar->ab always point to the same ath12k_base.

Still, relying on that is fragile. Cache ar->ab into a per-iteration
'this_ab' and use it for the country code programming and the log messages
so that each radio is handled against its own ath12k_base regardless of how
many radios an ath12k_hw spans.

Tested-on: WCN7850 hw2.0 PCI WLAN.HMT.1.1.c7-00108-QCAHMTSWPL_V1.0_V2.0_SILICONZ_UPSTREAM-3

Signed-off-by: Baochen Qiang <baochen.qiang at oss.qualcomm.com>
---
 drivers/net/wireless/ath/ath12k/mac.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/drivers/net/wireless/ath/ath12k/mac.c b/drivers/net/wireless/ath/ath12k/mac.c
index 54056dd37409..82cbb5b9cd11 100644
--- a/drivers/net/wireless/ath/ath12k/mac.c
+++ b/drivers/net/wireless/ath/ath12k/mac.c
@@ -15043,24 +15043,26 @@ static int ath12k_mac_hw_register(struct ath12k_hw *ah)
 		wiphy->interface_modes &= ~BIT(NL80211_IFTYPE_MONITOR);
 
 	for_each_ar(ah, ar, i) {
+		struct ath12k_base *this_ab = ar->ab;
+
 		/* Apply the regd received during initialization */
 		ret = ath12k_regd_update(ar, true);
 		if (ret) {
-			ath12k_err(ar->ab, "ath12k regd update failed: %d\n", ret);
+			ath12k_err(this_ab, "ath12k regd update failed: %d\n", ret);
 			goto err_unregister_hw;
 		}
 
-		if (ar->ab->hw_params->current_cc_support && ab->new_alpha2[0]) {
+		if (this_ab->hw_params->current_cc_support && this_ab->new_alpha2[0]) {
 			struct wmi_set_current_country_arg current_cc = {};
 
-			memcpy(&current_cc.alpha2, ab->new_alpha2, 2);
-			memcpy(&ar->alpha2, ab->new_alpha2, 2);
+			memcpy(&current_cc.alpha2, this_ab->new_alpha2, 2);
+			memcpy(&ar->alpha2, this_ab->new_alpha2, 2);
 
 			reinit_completion(&ar->regd_update_completed);
 
 			ret = ath12k_wmi_send_set_current_country_cmd(ar, &current_cc);
 			if (ret)
-				ath12k_warn(ar->ab,
+				ath12k_warn(this_ab,
 					    "failed set cc code for mac register: %d\n",
 					    ret);
 		}

-- 
2.25.1