wifi: ath12k: Fix uninitialized variable access in ath12k_mac_allocate() function

Currently, the uninitialized variable 'ab' is accessed in the
ath12k_mac_allocate() function. Initialize 'ab' with the first radio device
present in the hardware abstraction handle (ah). Additionally, move the
default setting procedure from the pdev mapping iteration to the total
radio calculating iteration for better code readability. Perform the
maximum radio validation check for total_radio to ensure that both num_hw
and radio_per_hw are validated indirectly, as these variables are derived
from total_radio. This also fixes the below Smatch static checker warning.

Smatch warning:
ath12k_mac_allocate() error: uninitialized symbol 'ab'

Tested-on: QCN9274 hw2.0 PCI WLAN.WBE.1.3.1-00173-QCAHKSWPL_SILICONZ-1

Fixes: a343d97 ("wifi: ath12k: move struct ath12k_hw from per device to group")
Signed-off-by: Karthikeyan Periyasamy <[email protected]>
Acked-by: Jeff Johnson <[email protected]>
Acked-by: Kalle Valo <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jeff Johnson <[email protected]>

Author: Karthikeyan Periyasamy

drivers/net/wireless/ath/ath12k/mac.c

@@ -11383,8 +11383,20 @@ int ath12k_mac_allocate(struct ath12k_hw_group *ag)
 	u8 radio_per_hw;
 
 	total_radio = 0;
-	for (i = 0; i < ag->num_devices; i++)
-		total_radio += ag->ab[i]->num_radios;
+	for (i = 0; i < ag->num_devices; i++) {
+		ab = ag->ab[i];
+		if (!ab)
+			continue;
+
+		ath12k_mac_set_device_defaults(ab);
+		total_radio += ab->num_radios;
+	}
+
+	if (!total_radio)
+		return -EINVAL;
+
+	if (WARN_ON(total_radio > ATH12K_GROUP_MAX_RADIO))
+		return -ENOSPC;
 
 	/* All pdev get combined and register as single wiphy based on
 	 * hardware group which participate in multi-link operation else
@@ -11397,14 +11409,16 @@ int ath12k_mac_allocate(struct ath12k_hw_group *ag)
 
 	num_hw = total_radio / radio_per_hw;
 
-	if (WARN_ON(num_hw >= ATH12K_GROUP_MAX_RADIO))
-		return -ENOSPC;
-
 	ag->num_hw = 0;
 	device_id = 0;
 	mac_id = 0;
 	for (i = 0; i < num_hw; i++) {
 		for (j = 0; j < radio_per_hw; j++) {
+			if (device_id >= ag->num_devices || !ag->ab[device_id]) {
+				ret = -ENOSPC;
+				goto err;
+			}
+
 			ab = ag->ab[device_id];
 			pdev_map[j].ab = ab;
 			pdev_map[j].pdev_idx = mac_id;
@@ -11416,10 +11430,11 @@ int ath12k_mac_allocate(struct ath12k_hw_group *ag)
 			if (mac_id >= ab->num_radios) {
 				mac_id = 0;
 				device_id++;
-				ath12k_mac_set_device_defaults(ab);
 			}
 		}
 
+		ab = pdev_map->ab;
+
 		ah = ath12k_mac_hw_allocate(ag, pdev_map, radio_per_hw);
 		if (!ah) {
 			ath12k_warn(ab, "failed to allocate mac80211 hw device for hw_idx %d\n",