This is a note to let you know that I've just added the patch titled
mxser: keep only !tty test in ISR
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
mxser-keep-only-tty-test-in-isr.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 82c5fe27ac4f267345d3f38e14d1ff5f1c154d9f
Author: Jiri Slaby <jslaby@xxxxxxx>
Date: Thu Nov 18 08:31:09 2021 +0100
mxser: keep only !tty test in ISR
[ Upstream commit 274ab58dc2b460cc474ffc7ccfcede4b2be1a3f5 ]
The others are superfluous with tty refcounting in place now. And they
are racy in fact:
* tty_port_initialized() reports false for a small moment after
interrupts are enabled.
* closing is 1 while the port is still alive.
The queues are flushed later during close anyway. So there is no need
for this special handling. Actually, the ISR should not flush the
queues. It should behave as every other driver, just queue the chars
into tty buffer and go on. But this will be changed later. There is
still a lot code depending on having tty in ISR (and not only tty_port).
Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
Link: https://lore.kernel.org/r/20211118073125.12283-4-jslaby@xxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/tty/mxser.c b/drivers/tty/mxser.c
index 1216f3985e18e..da375851af4e6 100644
--- a/drivers/tty/mxser.c
+++ b/drivers/tty/mxser.c
@@ -261,7 +261,6 @@ struct mxser_port {
unsigned int xmit_head;
unsigned int xmit_tail;
unsigned int xmit_cnt;
- int closing;
spinlock_t slock;
};
@@ -923,7 +922,6 @@ static void mxser_close(struct tty_struct *tty, struct file *filp)
return;
if (tty_port_close_start(port, tty, filp) == 0)
return;
- info->closing = 1;
mutex_lock(&port->mutex);
mxser_close_port(port);
mxser_flush_buffer(tty);
@@ -932,7 +930,6 @@ static void mxser_close(struct tty_struct *tty, struct file *filp)
mxser_shutdown_port(port);
tty_port_set_initialized(port, 0);
mutex_unlock(&port->mutex);
- info->closing = 0;
/* Right now the tty_port set is done outside of the close_end helper
as we don't yet have everyone using refcounts */
tty_port_close_end(port, tty);
@@ -1693,7 +1690,7 @@ static bool mxser_port_isr(struct mxser_port *port)
iir &= MOXA_MUST_IIR_MASK;
tty = tty_port_tty_get(&port->port);
- if (!tty || port->closing || !tty_port_initialized(&port->port)) {
+ if (!tty) {
status = inb(port->ioaddr + UART_LSR);
outb(MOXA_MUST_FCR_GDA_MODE_ENABLE | UART_FCR_ENABLE_FIFO |
UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT,
