From 02ca144fa4891035b43770e96d51468c94aa8391 Mon Sep 17 00:00:00 2001 From: Johan Hovold Date: Wed, 21 Apr 2021 11:54:44 +0200 Subject: tty: mxser: drop low-latency workaround Commit 67d2bc58afdd ("Char: mxser_new, fix recursive locking") worked around the infamous low_latency behaviour of tty_flip_buffer_push() by simply dropping and reacquiring the port lock in the interrupt handler. Since commit a9c3f68f3cd8 ("tty: Fix low_latency BUG"), tty_flip_buffer_push() always schedules a work item to push data to the line discipline and there's no need to keep any low_latency hacks around. Link: https://lore.kernel.org/lkml/3018694794025219@wsc.cz/T/#m06b04c640a7b6f41afb3d34a4cf29b1df4935d3a Reviewed-by: Jiri Slaby Signed-off-by: Johan Hovold Link: https://lore.kernel.org/r/20210421095509.3024-2-johan@kernel.org Signed-off-by: Greg Kroah-Hartman --- drivers/tty/mxser.c | 7 ------- 1 file changed, 7 deletions(-) (limited to 'drivers/tty') diff --git a/drivers/tty/mxser.c b/drivers/tty/mxser.c index 2d8e76263a25..16a852ecbe8a 100644 --- a/drivers/tty/mxser.c +++ b/drivers/tty/mxser.c @@ -2155,14 +2155,7 @@ end_intr: port->mon_data.rxcnt += cnt; port->mon_data.up_rxcnt += cnt; - /* - * We are called from an interrupt context with &port->slock - * being held. Drop it temporarily in order to prevent - * recursive locking. - */ - spin_unlock(&port->slock); tty_flip_buffer_push(&port->port); - spin_lock(&port->slock); } static void mxser_transmit_chars(struct tty_struct *tty, struct mxser_port *port) -- cgit v1.2.3-70-g09d2