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mxser: extract TX empty check from mxser_wait_until_sent()

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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>
This commit is contained in:
Jiri Slaby 2021-11-18 08:31:17 +01:00 committed by Greg Kroah-Hartman
parent c7ec012f6c
commit 239ef19ef0
1 changed files with 13 additions and 7 deletions
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20
drivers/tty/mxser.c
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@ -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);
}