From 9a2225f2a7214cc04a03a09768b19215a3fe4c16 Mon Sep 17 00:00:00 2001 From: "Jiri Slaby (SUSE)" Date: Thu, 14 Aug 2025 09:24:50 +0200 Subject: [PATCH] serial: 8250_core: use guard() in serial_unlink_irq_chain() Having all the new guards, use them in the 8250 code. This improves readability, makes error handling easier, and marks locked portions of code explicit. serial_unlink_irq_chain() is done separately here because with the guard() used, those BUG_ON()s can be switched WARN_ON()s as we can actually handle the conditions and return (despite something went really wrong). Signed-off-by: "Jiri Slaby (SUSE)" Link: https://lore.kernel.org/r/20250814072456.182853-11-jirislaby@kernel.org Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/8250/8250_core.c | 20 +++++++++++--------- 1 file changed, 11 insertions(+), 9 deletions(-) diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c index 82c3636451e5..7d931693b311 100644 --- a/drivers/tty/serial/8250/8250_core.c +++ b/drivers/tty/serial/8250/8250_core.c @@ -178,20 +178,22 @@ static void serial_unlink_irq_chain(struct uart_8250_port *up) { struct irq_info *i; - mutex_lock(&hash_mutex); + guard(mutex)(&hash_mutex); hash_for_each_possible(irq_lists, i, node, up->port.irq) - if (i->irq == up->port.irq) - break; + if (i->irq == up->port.irq) { + if (WARN_ON(i->head == NULL)) + return; - BUG_ON(i == NULL); - BUG_ON(i->head == NULL); + if (list_empty(i->head)) + free_irq(up->port.irq, i); - if (list_empty(i->head)) - free_irq(up->port.irq, i); + serial_do_unlink(i, up); + + return; + } - serial_do_unlink(i, up); - mutex_unlock(&hash_mutex); + WARN_ON(1); } /* -- 2.47.3