mxser: extract TX empty check from mxser_wait_until_sent()

And move it to new mxser_tx_empty(), because:
1) it simplifies the code (esp. the locking), and
2) serial_core needs such a hook anyway, so have it ready.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20211118073125.12283-12-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/mxser.c b/drivers/tty/mxser.c
index 6ab8899ada9c60940a6b37dee89463a6c7665fb7..fb26670b5a0bf94942c0f654364d90bac8dcf766 100644 (file)
--- a/drivers/tty/mxser.c
+++ b/drivers/tty/mxser.c
@@ -1402,6 +1402,18 @@ static void mxser_set_termios(struct tty_struct *tty, struct ktermios *old_termi
        }
 }
 
+static bool mxser_tx_empty(struct mxser_port *info)
+{
+       unsigned long flags;
+       u8 lsr;
+
+       spin_lock_irqsave(&info->slock, flags);
+       lsr = inb(info->ioaddr + UART_LSR);
+       spin_unlock_irqrestore(&info->slock, flags);
+
+       return !(lsr & UART_LSR_TEMT);
+}
+
 /*
  * mxser_wait_until_sent() --- wait until the transmitter is empty
  */
@@ -1409,8 +1421,6 @@ static void mxser_wait_until_sent(struct tty_struct *tty, int timeout)
 {
        struct mxser_port *info = tty->driver_data;
        unsigned long orig_jiffies, char_time;
-       unsigned long flags;
-       int lsr;
 
        if (info->type == PORT_UNKNOWN)
                return;
@@ -1445,17 +1455,13 @@ static void mxser_wait_until_sent(struct tty_struct *tty, int timeout)
        if (!timeout || timeout > 2 * info->timeout)
                timeout = 2 * info->timeout;
 
-       spin_lock_irqsave(&info->slock, flags);
-       while (!((lsr = inb(info->ioaddr + UART_LSR)) & UART_LSR_TEMT)) {
-               spin_unlock_irqrestore(&info->slock, flags);
+       while (mxser_tx_empty(info)) {
                schedule_timeout_interruptible(char_time);
-               spin_lock_irqsave(&info->slock, flags);
                if (signal_pending(current))
                        break;
                if (timeout && time_after(jiffies, orig_jiffies + timeout))
                        break;
        }
-       spin_unlock_irqrestore(&info->slock, flags);
        set_current_state(TASK_RUNNING);
 }