The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.4.y git checkout FETCH_HEAD git cherry-pick -x d5078509c8b06c5c472a60232815e41af81c6446 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2024012628-railcar-scrutiny-38b1@gregkh' --subject-prefix 'PATCH 5.4.y' HEAD^..

Possible dependencies:

d5078509c8b0 ("serial: sc16is7xx: improve do/while loop in sc16is7xx_irq()") 4409df5866b7 ("serial: sc16is7xx: change EFR lock to operate on each channels") 3837a0379533 ("serial: sc16is7xx: improve regmap debugfs by using one regmap per port") b4a778303ea0 ("serial: sc16is7xx: add missing support for rs485 devicetree properties") 049994292834 ("serial: sc16is7xx: fix regression with GPIO configuration") dabc54a45711 ("serial: sc16is7xx: remove obsolete out_thread label") c8f71b49ee4d ("serial: sc16is7xx: setup GPIO controller later in probe") 267913ecf737 ("serial: sc16is7xx: Fill in rs485_supported") 21144bab4f11 ("sc16is7xx: Handle modem status lines") cc4c1d05eb10 ("sc16is7xx: Properly resume TX after stop") d4ab5487cc77 ("Merge 5.17-rc6 into tty-next")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From d5078509c8b06c5c472a60232815e41af81c6446 Mon Sep 17 00:00:00 2001 From: Hugo Villeneuve hvilleneuve@dimonoff.com Date: Thu, 21 Dec 2023 18:18:12 -0500 Subject: [PATCH] serial: sc16is7xx: improve do/while loop in sc16is7xx_irq()

Simplify and improve readability by replacing while(1) loop with do {} while, and by using the keep_polling variable as the exit condition, making it more explicit.

Fixes: 834449872105 ("sc16is7xx: Fix for multi-channel stall") Cc: stable@vger.kernel.org Suggested-by: Andy Shevchenko andy.shevchenko@gmail.com Signed-off-by: Hugo Villeneuve hvilleneuve@dimonoff.com Link: https://lore.kernel.org/r/20231221231823.2327894-6-hugo@hugovil.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

diff --git a/drivers/tty/serial/sc16is7xx.c b/drivers/tty/serial/sc16is7xx.c index 44a11c89c949..8d257208cbf3 100644 --- a/drivers/tty/serial/sc16is7xx.c +++ b/drivers/tty/serial/sc16is7xx.c @@ -783,17 +783,18 @@ static bool sc16is7xx_port_irq(struct sc16is7xx_port *s, int portno)

static irqreturn_t sc16is7xx_irq(int irq, void *dev_id) { + bool keep_polling; + struct sc16is7xx_port *s = (struct sc16is7xx_port *)dev_id;

- while (1) { - bool keep_polling = false; + do { int i;

+ keep_polling = false; + for (i = 0; i < s->devtype->nr_uart; ++i) keep_polling |= sc16is7xx_port_irq(s, i); - if (!keep_polling) - break; - } + } while (keep_polling);

return IRQ_HANDLED; }