serial: fix device name reporting when minor space is shared between drivers

The multiple drivers share the minor space occupied by a particular major
number, the actual index within the device name's space is indicated by
the tty_driver->name_base + uart_port->line

Another usable formula is (uart_driver->minor - MINOR_BASE) + port->line

Use those to print the device names properly in such situations in
serial_core.c and 8250.c

Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 15 insertions, 7 deletions

diff --git a/drivers/serial/8250.c b/drivers/serial/8250.c
index db2cdc103c88..d4104a3bbe87 100644
--- a/drivers/serial/8250.c
+++ b/drivers/serial/8250.c
@@ -57,6 +57,13 @@ static unsigned int share_irqs = SERIAL8250_SHARE_IRQS;
 
 static unsigned int nr_uarts = CONFIG_SERIAL_8250_RUNTIME_UARTS;
 
+static struct uart_driver serial8250_reg;
+
+static int serial_index(struct uart_port *port)
+{
+        return (serial8250_reg.minor - 64) + port->line;
+}
+
 /*
  * Debugging.
  */
@@ -997,7 +1004,7 @@ static void autoconfig(struct uart_8250_port *up, unsigned int probeflags)
                 return;
 
         DEBUG_AUTOCONF("ttyS%d: autoconf (0x%04x, 0x%p): ",
-                        up->port.line, up->port.iobase, up->port.membase);
+                       serial_index(&up->port), up->port.iobase, up->port.membase);
 
         /*
          * We really do need global IRQs disabled here - we're going to
@@ -1132,8 +1139,8 @@ static void autoconfig(struct uart_8250_port *up, unsigned int probeflags)
         if (up->capabilities != uart_config[up->port.type].flags) {
                 printk(KERN_WARNING
                        "ttyS%d: detected caps %08x should be %08x\n",
-                        up->port.line, up->capabilities,
-                        uart_config[up->port.type].flags);
+                       serial_index(&up->port), up->capabilities,
+                       uart_config[up->port.type].flags);
         }
 
         up->port.fifosize = uart_config[up->port.type].fifo_size;
@@ -1857,7 +1864,8 @@ static int serial8250_startup(struct uart_port *port)
          */
         if (!(up->port.flags & UPF_BUGGY_UART) &&
             (serial_inp(up, UART_LSR) == 0xff)) {
-                printk("ttyS%d: LSR safety check engaged!\n", up->port.line);
+                printk(KERN_INFO "ttyS%d: LSR safety check engaged!\n",
+                       serial_index(&up->port));
                 return -ENODEV;
         }
 
@@ -1912,7 +1920,8 @@ static int serial8250_startup(struct uart_port *port)
                  */
                 if (!(iir1 & UART_IIR_NO_INT) && (iir & UART_IIR_NO_INT)) {
                         up->bugs |= UART_BUG_THRE;
-                        pr_debug("ttyS%d - using backup timer\n", port->line);
+                        pr_debug("ttyS%d - using backup timer\n",
+                                 serial_index(port));
                 }
         }
 
@@ -1972,7 +1981,7 @@ static int serial8250_startup(struct uart_port *port)
                 if (!(up->bugs & UART_BUG_TXEN)) {
                         up->bugs |= UART_BUG_TXEN;
                         pr_debug("ttyS%d - enabling bad tx status workarounds\n",
-                                 port->line);
+                                 serial_index(port));
                 }
         } else {
                 up->bugs &= ~UART_BUG_TXEN;
@@ -2633,7 +2642,6 @@ static int serial8250_console_early_setup(void)
         return serial8250_find_port_for_earlycon();
 }
 
-static struct uart_driver serial8250_reg;
 static struct console serial8250_console = {
         .name           = "ttyS",
         .write          = serial8250_console_write,