serial: 8250: Process sysrq at port unlock time

Let's take advantage of the new ("serial: core: Allow processing sysrq
at port unlock time") to handle sysrqs more cleanly.

Signed-off-by: Douglas Anderson <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/tty/serial/8250/8250_aspeed_vuart.c

···
  *    Copyright (C) 2016 Jeremy Kerr <[e-mail]>, IBM Corp.
  *    Copyright (C) 2006 Arnd Bergmann <[e-mail]>, IBM Corp.
  */
+#if defined(CONFIG_SERIAL_8250_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
+#define SUPPORT_SYSRQ
+#endif
+
 #include <linux/device.h>
 #include <linux/module.h>
 #include <linux/of_address.h>
···
 	if (lsr & UART_LSR_THRE)
 		serial8250_tx_chars(up);
 
-	spin_unlock_irqrestore(&port->lock, flags);
+	uart_unlock_and_check_sysrq(port, flags);
 
 	return 1;
 }

drivers/tty/serial/8250/8250_fsl.c

···
 // SPDX-License-Identifier: GPL-2.0
+#if defined(CONFIG_SERIAL_8250_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
+#define SUPPORT_SYSRQ
+#endif
+
 #include <linux/serial_reg.h>
 #include <linux/serial_8250.h>
 
···
 		serial8250_tx_chars(up);
 
 	up->lsr_saved_flags = orig_lsr;
-	spin_unlock_irqrestore(&up->port.lock, flags);
+	uart_unlock_and_check_sysrq(&up->port, flags);
 	return 1;
 }
 EXPORT_SYMBOL_GPL(fsl8250_handle_irq);

drivers/tty/serial/8250/8250_omap.c

···
  *
  */
 
+#if defined(CONFIG_SERIAL_8250_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
+#define SUPPORT_SYSRQ
+#endif
+
 #include <linux/device.h>
 #include <linux/io.h>
 #include <linux/module.h>
···
 		}
 	}
 
-	spin_unlock_irqrestore(&port->lock, flags);
+	uart_unlock_and_check_sysrq(port, flags);
 	serial8250_rpm_put(up);
 	return 1;
 }

drivers/tty/serial/8250/8250_port.c

···
 		else if (lsr & UART_LSR_FE)
 			flag = TTY_FRAME;
 	}
-	if (uart_handle_sysrq_char(port, ch))
+	if (uart_prepare_sysrq_char(port, ch))
 		return;
 
 	uart_insert_char(port, lsr, UART_LSR_OE, ch, flag);
···
 	if ((!up->dma || up->dma->tx_err) && (status & UART_LSR_THRE))
 		serial8250_tx_chars(up);
 
-	spin_unlock_irqrestore(&port->lock, flags);
+	uart_unlock_and_check_sysrq(port, flags);
 	return 1;
 }
 EXPORT_SYMBOL_GPL(serial8250_handle_irq);
···
 
 	serial8250_rpm_get(up);
 
-	if (port->sysrq)
-		locked = 0;
-	else if (oops_in_progress)
+	if (oops_in_progress)
 		locked = spin_trylock_irqsave(&port->lock, flags);
 	else
 		spin_lock_irqsave(&port->lock, flags);