usb: device: Fix transfer slot leak without callback

Log transfer status and release transfer semaphore regardless if user
provided transfer completion callback or not. This fixes transfer slot
leak when transfer without callback completes.

Signed-off-by: Tomasz Moń <[email protected]>

Author: tmon-nordic

subsys/usb/device/usb_transfer.c

@@ -131,7 +131,7 @@ static void usb_transfer_work(struct k_work *item)
 	}
 
 done:
-	if (trans->status != -EBUSY && trans->cb) { /* Transfer complete */
+	if (trans->status != -EBUSY) { /* Transfer complete */
 		usb_transfer_callback cb = trans->cb;
 		int tsize = trans->tsize;
 		void *priv = trans->priv;
@@ -149,7 +149,9 @@ static void usb_transfer_work(struct k_work *item)
 		k_sem_give(&trans->sem);
 
 		/* Transfer completion callback */
-		cb(ep, tsize, priv);
+		if (cb) {
+			cb(ep, tsize, priv);
+		}
 	}
 }