This is a note to let you know that I've just added the patch titled
TTY: sn_console: Replace spin_is_locked() with spin_trylock()
to my tty git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty.git
in the tty-testing branch.
The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)
The patch will be merged to the tty-next branch sometime soon,
after it passes testing, and the merge window is open.
If you have any questions about this process, please let me know.
>From 8ebfe885c65ec82a0b1e955cf99ed62664e84414 Mon Sep 17 00:00:00 2001
From: Lance Roy <ldr709@xxxxxxxxx>
Date: Thu, 4 Oct 2018 00:14:04 -0700
Subject: TTY: sn_console: Replace spin_is_locked() with spin_trylock()
sn_sal_console_write() used spin_is_locked() + spin_lock() to get
achieve the same thing as a spin_trylock(), so simplify it by using that
instead. This is also a step towards possibly removing spin_is_locked().
Signed-off-by: Lance Roy <ldr709@xxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: Jiri Slaby <jslaby@xxxxxxxx>
Cc: <linux-serial@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/tty/serial/sn_console.c | 15 ++++++---------
1 file changed, 6 insertions(+), 9 deletions(-)
diff --git a/drivers/tty/serial/sn_console.c b/drivers/tty/serial/sn_console.c
index 42b9aded4eb1..fe9170731c16 100644
--- a/drivers/tty/serial/sn_console.c
+++ b/drivers/tty/serial/sn_console.c
@@ -888,7 +888,7 @@ sn_sal_console_write(struct console *co, const char *s, unsigned count)
/* somebody really wants this output, might be an
* oops, kdb, panic, etc. make sure they get it. */
- if (spin_is_locked(&port->sc_port.lock)) {
+ if (!spin_trylock_irqsave(&port->sc_port.lock, flags)) {
int lhead = port->sc_port.state->xmit.head;
int ltail = port->sc_port.state->xmit.tail;
int counter, got_lock = 0;
@@ -905,13 +905,11 @@ sn_sal_console_write(struct console *co, const char *s, unsigned count)
*/
for (counter = 0; counter < 150; mdelay(125), counter++) {
- if (!spin_is_locked(&port->sc_port.lock)
- || stole_lock) {
- if (!stole_lock) {
- spin_lock_irqsave(&port->sc_port.lock,
- flags);
- got_lock = 1;
- }
+ if (stole_lock)
+ break;
+
+ if (spin_trylock_irqsave(&port->sc_port.lock, flags)) {
+ got_lock = 1;
break;
} else {
/* still locked */
@@ -938,7 +936,6 @@ sn_sal_console_write(struct console *co, const char *s, unsigned count)
puts_raw_fixed(port->sc_ops->sal_puts_raw, s, count);
} else {
stole_lock = 0;
- spin_lock_irqsave(&port->sc_port.lock, flags);
sn_transmit_chars(port, 1);
spin_unlock_irqrestore(&port->sc_port.lock, flags);
--
2.19.0
