staging: wfx: standardize the error when vif does not exist

Smatch complains:

   drivers/staging/wfx/hif_rx.c:177 hif_scan_complete_indication() warn: potential NULL parameter dereference 'wvif'
   drivers/staging/wfx/data_tx.c:576 wfx_flush() warn: potential NULL parameter dereference 'wvif'

Indeed, if the vif id returned by the device does not exist anymore,
wdev_to_wvif() could return NULL.

In add, the error is not handled uniformly in the code, sometime a
WARN() is displayed but code continue, sometime a dev_warn() is
displayed, sometime it is just not tested, ...

This patch standardize that.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Jérôme Pouiller <jerome.pouiller@silabs.com>
Link: https://lore.kernel.org/r/20201009171307.864608-4-Jerome.Pouiller@silabs.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: jerome-pouiller

drivers/staging/wfx/data_tx.c

@@ -431,7 +431,10 @@ static void wfx_skb_dtor(struct wfx_vif *wvif, struct sk_buff *skb)
 			      sizeof(struct hif_req_tx) +
 			      req->fc_offset;
 
-	WARN_ON(!wvif);
+	if (!wvif) {
+		pr_warn("%s: vif associated with the skb does not exist anymore\n", __func__);
+		return;
+	}
 	wfx_tx_policy_put(wvif, req->retry_policy_index);
 	skb_pull(skb, offset);
 	ieee80211_tx_status_irqsafe(wvif->wdev->hw, skb);

drivers/staging/wfx/hif_rx.c

@@ -110,9 +110,9 @@ static int hif_receive_indication(struct wfx_dev *wdev,
 	const struct hif_ind_rx *body = buf;
 
 	if (!wvif) {
-		dev_warn(wdev->dev, "ignore rx data for non-existent vif %d\n",
-			 hif->interface);
-		return 0;
+		dev_warn(wdev->dev, "%s: ignore rx data for non-existent vif %d\n",
+			 __func__, hif->interface);
+		return -EIO;
 	}
 	skb_pull(skb, sizeof(struct hif_msg) + sizeof(struct hif_ind_rx));
 	wfx_rx_cb(wvif, body, skb);
@@ -128,8 +128,8 @@ static int hif_event_indication(struct wfx_dev *wdev,
 	int type = le32_to_cpu(body->event_id);
 
 	if (!wvif) {
-		dev_warn(wdev->dev, "received event for non-existent vif\n");
-		return 0;
+		dev_warn(wdev->dev, "%s: received event for non-existent vif\n", __func__);
+		return -EIO;
 	}
 
 	switch (type) {
@@ -161,7 +161,10 @@ static int hif_pm_mode_complete_indication(struct wfx_dev *wdev,
 {
 	struct wfx_vif *wvif = wdev_to_wvif(wdev, hif->interface);
 
-	WARN_ON(!wvif);
+	if (!wvif) {
+		dev_warn(wdev->dev, "%s: received event for non-existent vif\n", __func__);
+		return -EIO;
+	}
 	complete(&wvif->set_pm_mode_complete);
 
 	return 0;
@@ -173,7 +176,11 @@ static int hif_scan_complete_indication(struct wfx_dev *wdev,
 {
 	struct wfx_vif *wvif = wdev_to_wvif(wdev, hif->interface);
 
-	WARN_ON(!wvif);
+	if (!wvif) {
+		dev_warn(wdev->dev, "%s: received event for non-existent vif\n", __func__);
+		return -EIO;
+	}
+
 	wfx_scan_complete(wvif);
 
 	return 0;
@@ -185,7 +192,10 @@ static int hif_join_complete_indication(struct wfx_dev *wdev,
 {
 	struct wfx_vif *wvif = wdev_to_wvif(wdev, hif->interface);
 
-	WARN_ON(!wvif);
+	if (!wvif) {
+		dev_warn(wdev->dev, "%s: received event for non-existent vif\n", __func__);
+		return -EIO;
+	}
 	dev_warn(wdev->dev, "unattended JoinCompleteInd\n");
 
 	return 0;
@@ -195,11 +205,15 @@ static int hif_suspend_resume_indication(struct wfx_dev *wdev,
 					 const struct hif_msg *hif,
 					 const void *buf)
 {
-	struct wfx_vif *wvif = wdev_to_wvif(wdev, hif->interface);
 	const struct hif_ind_suspend_resume_tx *body = buf;
+	struct wfx_vif *wvif;
 
 	if (body->bc_mc_only) {
-		WARN_ON(!wvif);
+		wvif = wdev_to_wvif(wdev, hif->interface);
+		if (!wvif) {
+			dev_warn(wdev->dev, "%s: received event for non-existent vif\n", __func__);
+			return -EIO;
+		}
 		if (body->resume)
 			wfx_suspend_resume_mc(wvif, STA_NOTIFY_AWAKE);
 		else

drivers/staging/wfx/sta.c

@@ -619,6 +619,10 @@ int wfx_set_tim(struct ieee80211_hw *hw, struct ieee80211_sta *sta, bool set)
 	struct wfx_sta_priv *sta_dev = (struct wfx_sta_priv *)&sta->drv_priv;
 	struct wfx_vif *wvif = wdev_to_wvif(wdev, sta_dev->vif_id);
 
+	if (!wvif) {
+		dev_warn(wdev->dev, "%s: received event for non-existent vif\n", __func__);
+		return -EIO;
+	}
 	schedule_work(&wvif->update_tim_work);
 	return 0;
 }