serial: earlycon: Skip parse_options() if empty string

Earlycon param strings of the form
   earlycon=<name>
are rejected from parse_options() with an error (which, in turn,
results in a NULL argument for the setup() method options parameter).

Only pass non-empty string to parse_options(); this will enable
handling actual parse errors differently than expected and allow
formats.

Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serial/earlycon.c b/drivers/tty/serial/earlycon.c
index da5e8c8c4ad4ff122f56e246431aeb7517f15747..025ea01408968f045a1375b7975c9870db14d7f7 100644 (file)
--- a/drivers/tty/serial/earlycon.c
+++ b/drivers/tty/serial/earlycon.c
@@ -109,13 +109,16 @@ int __init setup_earlycon(char *buf, const char *match,
        len = strlen(match);
        if (strncmp(buf, match, len))
                return 0;
-       if (buf[len] && (buf[len] != ','))
-               return 0;
 
-       buf += len + 1;
+       if (buf[len]) {
+               if (buf[len] != ',')
+                       return 0;
+               buf += len + 1;
+       } else
+               buf = NULL;
 
        /* On parsing error, pass the options buf to the setup function */
-       if (!parse_options(&early_console_dev, buf))
+       if (buf && !parse_options(&early_console_dev, buf))
                buf = NULL;
 
        port->uartclk = BASE_BAUD * 16;