ath10k: skip fw stats debugfs interface if device is down

If the device is not running then there may be no
FW at all to send the query to. If the FW is
already there it might still trigger a crash if
the command is sent before the device is fully
initialized.
Signed-off-by: Michal Kazior <michal.kazior@tieto.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>

drivers/net/wireless/ath/ath10k/debug.c

@@ -161,7 +161,7 @@ void ath10k_debug_read_target_stats(struct ath10k *ar,
 	struct wmi_pdev_stats *ps;
 	int i;
 
-	mutex_lock(&ar->conf_mutex);
+	spin_lock_bh(&ar->data_lock);
 
 	stats = &ar->debug.target_stats;
 
@@ -259,6 +259,7 @@ void ath10k_debug_read_target_stats(struct ath10k *ar,
 		}
 	}
 
+	spin_unlock_bh(&ar->data_lock);
 	mutex_unlock(&ar->conf_mutex);
 	complete(&ar->debug.event_stats_compl);
 }
@@ -268,35 +269,35 @@ static ssize_t ath10k_read_fw_stats(struct file *file, char __user *user_buf,
 {
 	struct ath10k *ar = file->private_data;
 	struct ath10k_target_stats *fw_stats;
-	char *buf;
+	char *buf = NULL;
 	unsigned int len = 0, buf_len = 2500;
-	ssize_t ret_cnt;
+	ssize_t ret_cnt = 0;
 	long left;
 	int i;
 	int ret;
 
 	fw_stats = &ar->debug.target_stats;
 
+	mutex_lock(&ar->conf_mutex);
+
+	if (ar->state != ATH10K_STATE_ON)
+		goto exit;
+
 	buf = kzalloc(buf_len, GFP_KERNEL);
 	if (!buf)
-		return -ENOMEM;
+		goto exit;
 
 	ret = ath10k_wmi_request_stats(ar, WMI_REQUEST_PEER_STAT);
 	if (ret) {
 		ath10k_warn("could not request stats (%d)\n", ret);
-		kfree(buf);
-		return -EIO;
+		goto exit;
 	}
 
 	left = wait_for_completion_timeout(&ar->debug.event_stats_compl, 1*HZ);
+	if (left <= 0)
+		goto exit;
 
-	if (left <= 0) {
-		kfree(buf);
-		return -ETIMEDOUT;
-	}
-
-	mutex_lock(&ar->conf_mutex);
-
+	spin_lock_bh(&ar->data_lock);
 	len += scnprintf(buf + len, buf_len - len, "\n");
 	len += scnprintf(buf + len, buf_len - len, "%30s\n",
 			 "ath10k PDEV stats");
@@ -424,14 +425,15 @@ static ssize_t ath10k_read_fw_stats(struct file *file, char __user *user_buf,
 				 fw_stats->peer_stat[i].peer_tx_rate);
 		len += scnprintf(buf + len, buf_len - len, "\n");
 	}
+	spin_unlock_bh(&ar->data_lock);
 
 	if (len > buf_len)
 		len = buf_len;
 
 	ret_cnt = simple_read_from_buffer(user_buf, count, ppos, buf, len);
 
+exit:
 	mutex_unlock(&ar->conf_mutex);
-
 	kfree(buf);
 	return ret_cnt;
 }