This is a note to let you know that I've just added the patch titled
serial: stm32: Merge hard IRQ and threaded IRQ handling into single IRQ handler
to the 6.1-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:
serial-stm32-merge-hard-irq-and-threaded-irq-handling-into-single-irq-handler.patch
and it can be found in the queue-6.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 3f6c02fa712bd453871877fe1d1969625617471e Mon Sep 17 00:00:00 2001
From: Marek Vasut <marex@xxxxxxx>
Date: Fri, 20 Jan 2023 17:03:32 +0100
Subject: serial: stm32: Merge hard IRQ and threaded IRQ handling into single IRQ handler
From: Marek Vasut <marex@xxxxxxx>
commit 3f6c02fa712bd453871877fe1d1969625617471e upstream.
Requesting an interrupt with IRQF_ONESHOT will run the primary handler
in the hard-IRQ context even in the force-threaded mode. The
force-threaded mode is used by PREEMPT_RT in order to avoid acquiring
sleeping locks (spinlock_t) in hard-IRQ context. This combination
makes it impossible and leads to "sleeping while atomic" warnings.
Use one interrupt handler for both handlers (primary and secondary)
and drop the IRQF_ONESHOT flag which is not needed.
Fixes: e359b4411c283 ("serial: stm32: fix threaded interrupt handling")
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
Tested-by: Valentin Caron <valentin.caron@xxxxxxxxxxx> # V3
Signed-off-by: Marek Vasut <marex@xxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Link: https://lore.kernel.org/r/20230120160332.57930-1-marex@xxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/tty/serial/stm32-usart.c | 33 +++++----------------------------
1 file changed, 5 insertions(+), 28 deletions(-)
--- a/drivers/tty/serial/stm32-usart.c
+++ b/drivers/tty/serial/stm32-usart.c
@@ -798,25 +798,11 @@ static irqreturn_t stm32_usart_interrupt
spin_unlock(&port->lock);
}
- if (stm32_usart_rx_dma_enabled(port))
- return IRQ_WAKE_THREAD;
- else
- return IRQ_HANDLED;
-}
-
-static irqreturn_t stm32_usart_threaded_interrupt(int irq, void *ptr)
-{
- struct uart_port *port = ptr;
- struct tty_port *tport = &port->state->port;
- struct stm32_port *stm32_port = to_stm32_port(port);
- unsigned int size;
- unsigned long flags;
-
/* Receiver timeout irq for DMA RX */
- if (!stm32_port->throttled) {
- spin_lock_irqsave(&port->lock, flags);
+ if (stm32_usart_rx_dma_enabled(port) && !stm32_port->throttled) {
+ spin_lock(&port->lock);
size = stm32_usart_receive_chars(port, false);
- uart_unlock_and_check_sysrq_irqrestore(port, flags);
+ uart_unlock_and_check_sysrq(port);
if (size)
tty_flip_buffer_push(tport);
}
@@ -1016,10 +1002,8 @@ static int stm32_usart_startup(struct ua
u32 val;
int ret;
- ret = request_threaded_irq(port->irq, stm32_usart_interrupt,
- stm32_usart_threaded_interrupt,
- IRQF_ONESHOT | IRQF_NO_SUSPEND,
- name, port);
+ ret = request_irq(port->irq, stm32_usart_interrupt,
+ IRQF_NO_SUSPEND, name, port);
if (ret)
return ret;
@@ -1602,13 +1586,6 @@ static int stm32_usart_of_dma_rx_probe(s
struct dma_slave_config config;
int ret;
- /*
- * Using DMA and threaded handler for the console could lead to
- * deadlocks.
- */
- if (uart_console(port))
- return -ENODEV;
-
stm32port->rx_buf = dma_alloc_coherent(dev, RX_BUF_L,
&stm32port->rx_dma_buf,
GFP_KERNEL);
Patches currently in stable-queue which might be from marex@xxxxxxx are
queue-6.1/serial-stm32-merge-hard-irq-and-threaded-irq-handling-into-single-irq-handler.patch
