Merge tag 'tty-4.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty

Pull tty/serial driver updates from Greg KH:
 "Here is the big tty and serial driver pull request for 4.19-rc1.

  It's not all that big, just a number of small serial driver updates
  and fixes, along with some better vt handling for unicode characters
  for those using braille terminals.

  All of these patches have been in linux-next for a long time with no
  reported issues"

* tag 'tty-4.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (73 commits)
  tty: serial: 8250: Revert NXP SC16C2552 workaround
  serial: 8250_exar: Read INT0 from slave device, too
  tty: rocket: Fix possible buffer overwrite on register_PCI
  serial: 8250_dw: Add ACPI support for uart on Broadcom SoC
  serial: 8250_dw: always set baud rate in dw8250_set_termios
  dt-bindings: serial: Add binding for uartlite
  tty: serial: uartlite: Add support for suspend and resume
  tty: serial: uartlite: Add clock adaptation
  tty: serial: uartlite: Add structure for private data
  serial: sh-sci: Improve support for separate TEI and DRI interrupts
  serial: sh-sci: Remove SCIx_RZ_SCIFA_REGTYPE
  serial: sh-sci: Allow for compressed SCIF address
  serial: sh-sci: Improve interrupts description
  serial: 8250: Use cached port name directly in messages
  serial: 8250_exar: Drop unused variable in pci_xr17v35x_setup()
  vt: drop unused struct vt_struct
  vt: avoid a VLA in the unicode screen scroll function
  vt: add /dev/vcsu* to devices.txt
  vt: coherence validation code for the unicode screen buffer
  vt: selection: take screen contents from uniscr if available
  ...

1 files changed, 12 insertions, 5 deletions

diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index 9c14a453f73c..80bb56facfb6 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -182,6 +182,7 @@ static int uart_port_startup(struct tty_struct *tty, struct uart_state *state,
 {
 	struct uart_port *uport = uart_port_check(state);
 	unsigned long page;
+	unsigned long flags = 0;
 	int retval = 0;
 
 	if (uport->type == PORT_UNKNOWN)
@@ -196,15 +197,18 @@ static int uart_port_startup(struct tty_struct *tty, struct uart_state *state,
 	 * Initialise and allocate the transmit and temporary
 	 * buffer.
 	 */
-	if (!state->xmit.buf) {
-		/* This is protected by the per port mutex */
-		page = get_zeroed_page(GFP_KERNEL);
-		if (!page)
-			return -ENOMEM;
+	page = get_zeroed_page(GFP_KERNEL);
+	if (!page)
+		return -ENOMEM;
 
+	uart_port_lock(state, flags);
+	if (!state->xmit.buf) {
 		state->xmit.buf = (unsigned char *) page;
 		uart_circ_clear(&state->xmit);
+	} else {
+		free_page(page);
 	}
+	uart_port_unlock(uport, flags);
 
 	retval = uport->ops->startup(uport);
 	if (retval == 0) {
@@ -263,6 +267,7 @@ static void uart_shutdown(struct tty_struct *tty, struct uart_state *state)
 {
 	struct uart_port *uport = uart_port_check(state);
 	struct tty_port *port = &state->port;
+	unsigned long flags = 0;
 
 	/*
 	 * Set the TTY IO error marker
@@ -295,10 +300,12 @@ static void uart_shutdown(struct tty_struct *tty, struct uart_state *state)
 	/*
 	 * Free the transmit buffer page.
 	 */
+	uart_port_lock(state, flags);
 	if (state->xmit.buf) {
 		free_page((unsigned long)state->xmit.buf);
 		state->xmit.buf = NULL;
 	}
+	uart_port_unlock(uport, flags);
 }
 
 /**