From: Johan Hovold <jhovold@gmail.com>
Date: Mon, 6 Feb 2012 18:22:19 +0000 (+0100)
Subject: USB: serial: add macro for console error reporting
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=e688355bfeadf17ef522b1e62cc12f8e88e69667;p=linux-beck.git

USB: serial: add macro for console error reporting

Add macro which prints an error message only once if port is used a
console.

Reporting errors in a write path when port is used as a console could
otherwise result in an infinite loop.

Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/include/linux/usb/serial.h b/include/linux/usb/serial.h
index 4267a9c717ba..10cb74d2ad1d 100644
--- a/include/linux/usb/serial.h
+++ b/include/linux/usb/serial.h
@@ -389,5 +389,20 @@ do {									\
 		printk(KERN_DEBUG "%s: " format "\n", __FILE__, ##arg);	\
 } while (0)
 
+/*
+ * Macro for reporting errors in write path to avoid inifinite loop
+ * when port is used as a console.
+ */
+#define dev_err_console(usport, fmt, ...)				\
+do {									\
+	static bool __print_once;					\
+	struct usb_serial_port *__port = (usport);			\
+									\
+	if (!__port->port.console || !__print_once) {			\
+		__print_once = true;					\
+		dev_err(&__port->dev, fmt, ##__VA_ARGS__);		\
+	}								\
+} while (0)
+
 #endif /* __LINUX_USB_SERIAL_H */