wifi: mt76: mt7915: check return value before accessing free_block_num

Check return value of mt7915_mcu_get_eeprom_free_block() first before
accessing free_block_num.

Fixes: bbc1d415 ("mt76: mt7915: add default calibrated data support")
Signed-off-by: Ryder Lee <ryder.lee@mediatek.com>
Signed-off-by: Felix Fietkau <nbd@nbd.name>

drivers/net/wireless/mediatek/mt76/mt7915/eeprom.c

@@ -110,18 +110,23 @@ static int mt7915_eeprom_load(struct mt7915_dev *dev)
 	} else {
 		u8 free_block_num;
 		u32 block_num, i;
+		u32 eeprom_blk_size = MT7915_EEPROM_BLOCK_SIZE;
 
-		mt7915_mcu_get_eeprom_free_block(dev, &free_block_num);
-		/* efuse info not enough */
+		ret = mt7915_mcu_get_eeprom_free_block(dev, &free_block_num);
+		if (ret < 0)
+			return ret;
+
+		/* efuse info isn't enough */
 		if (free_block_num >= 29)
 			return -EINVAL;
 
 		/* read eeprom data from efuse */
-		block_num = DIV_ROUND_UP(eeprom_size,
-					 MT7915_EEPROM_BLOCK_SIZE);
-		for (i = 0; i < block_num; i++)
-			mt7915_mcu_get_eeprom(dev,
-					      i * MT7915_EEPROM_BLOCK_SIZE);
+		block_num = DIV_ROUND_UP(eeprom_size, eeprom_blk_size);
+		for (i = 0; i < block_num; i++) {
+			ret = mt7915_mcu_get_eeprom(dev, i * eeprom_blk_size);
+			if (ret < 0)
+				return ret;
+		}
 	}
 
 	return mt7915_check_eeprom(dev);

drivers/net/wireless/mediatek/mt76/mt7915/mcu.c

@@ -2792,8 +2792,9 @@ int mt7915_mcu_get_eeprom(struct mt7915_dev *dev, u32 offset)
 	int ret;
 	u8 *buf;
 
-	ret = mt76_mcu_send_and_get_msg(&dev->mt76, MCU_EXT_QUERY(EFUSE_ACCESS), &req,
-				sizeof(req), true, &skb);
+	ret = mt76_mcu_send_and_get_msg(&dev->mt76,
+					MCU_EXT_QUERY(EFUSE_ACCESS),
+					&req, sizeof(req), true, &skb);
 	if (ret)
 		return ret;
 
@@ -2818,8 +2819,9 @@ int mt7915_mcu_get_eeprom_free_block(struct mt7915_dev *dev, u8 *block_num)
 	struct sk_buff *skb;
 	int ret;
 
-	ret = mt76_mcu_send_and_get_msg(&dev->mt76, MCU_EXT_QUERY(EFUSE_FREE_BLOCK), &req,
-					sizeof(req), true, &skb);
+	ret = mt76_mcu_send_and_get_msg(&dev->mt76,
+					MCU_EXT_QUERY(EFUSE_FREE_BLOCK),
+					&req, sizeof(req), true, &skb);
 	if (ret)
 		return ret;