tty/serial: Migrate mux to use has_sysrq

The SUPPORT_SYSRQ ifdeffery is not nice as:
- May create misunderstanding about sizeof(struct uart_port) between
  different objects
- Prevents moving functions from serial_core.h
- Reduces readability (well, it's ifdeffery - it's hard to follow)

In order to remove SUPPORT_SYSRQ, has_sysrq variable has been added.
Initialise it in driver's probe and remove ifdeffery.

Signed-off-by: Dmitry Safonov <dima@arista.com>
Link: https://lore.kernel.org/r/20191213000657.931618-27-dima@arista.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serial/mux.c b/drivers/tty/serial/mux.c
index 00ce31e..2a99532 100644 (file)
--- a/drivers/tty/serial/mux.c
+++ b/drivers/tty/serial/mux.c
@@ -25,11 +25,7 @@
 #include <asm/irq.h>
 #include <asm/parisc-device.h>
 
-#if defined(CONFIG_SERIAL_MUX_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
 #include <linux/sysrq.h>
-#define SUPPORT_SYSRQ
-#endif
-
 #include <linux/serial_core.h>
 
 #define MUX_OFFSET 0x800
@@ -483,6 +479,7 @@ static int __init mux_probe(struct parisc_device *dev)
                port->ops       = &mux_pops;
                port->flags     = UPF_BOOT_AUTOCONF;
                port->line      = port_cnt;
+               port->has_sysrq = IS_ENABLED(CONFIG_SERIAL_MUX_CONSOLE);
 
                /* The port->timeout needs to match what is present in
                 * uart_wait_until_sent in serial_core.c.  Otherwise