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@xxxxxxxxx>
---
v2: add missing do { } while (0)
include/linux/usb/serial.h | 15 +++++++++++++++
1 files changed, 15 insertions(+), 0 deletions(-)
diff --git a/include/linux/usb/serial.h b/include/linux/usb/serial.h
index 4267a9c..0cd7814 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 */
--
1.7.8.4
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