[patch 23/47] serial: fix serial_match_port() for dynamic majortty-device numbers

[Greg KH]

2.6.25-stable review patch.  If anyone has any objections, please let us
know.

------------------
From: Guennadi Liakhovetski <g.liakhovetski@xxxxxx>

commit 7ca796f492a11f9408e661c8f22cd8c4f486b8e5 upstream

As reported by Vipul Gandhi, the current serial_match_port() doesn't work
for tty-devices using dynamic major number allocation.  Fix it.

It oopses if you suspend a serial port with _dynamic_ major number.  ATM,
I think, there's only the drivers/serial/jsm/jsm_driver.c driver, that
does it in-tree.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@xxxxxx>
Tested-by: Vipul Gandhi <vcgandhi1@xxxxxxx>
Cc: Alan Cox <alan@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
 drivers/serial/serial_core.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

--- a/drivers/serial/serial_core.c
+++ b/drivers/serial/serial_core.c
@@ -1950,7 +1950,9 @@ struct uart_match {
 static int serial_match_port(struct device *dev, void *data)
 {
 	struct uart_match *match = data;
-	dev_t devt = MKDEV(match->driver->major, match->driver->minor) + match->port->line;
+	struct tty_driver *tty_drv = match->driver->tty_driver;
+	dev_t devt = MKDEV(tty_drv->major, tty_drv->minor_start) +
+		match->port->line;
 
 	return dev->devt == devt; /* Actually, only one tty per port */
 }

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