Commit 30db4451 authored by Thomas Mühlbacher's avatar Thomas Mühlbacher Committed by Marc Kleine-Budde
Browse files

can: sja1000: fix max irq loop handling 



Reading the interrupt register `SJA1000_IR` causes all of its bits to be
reset. If we ever reach the condition of handling more than
`SJA1000_MAX_IRQ` IRQs, we will have read the register and reset all its
bits but without actually handling the interrupt inside of the loop
body.

This may, among other issues, cause us to never `netif_wake_queue()`
again after a transmission interrupt.

Fixes: 429da1cc ("can: Driver for the SJA1000 CAN controller")
Cc: stable@vger.kernel.org
Signed-off-by: default avatarThomas Mühlbacher <tmuehlbacher@posteo.net>
Acked-by: default avatarOliver Hartkopp <socketcan@hartkopp.net>
Link: https://patch.msgid.link/20251115153437.11419-1-tmuehlbacher@posteo.net


Signed-off-by: default avatarMarc Kleine-Budde <mkl@pengutronix.de>
parent 0c73772c

drivers/net/can/sja1000/sja1000.c

+2 −2
Original line number Diff line number Diff line
@@ -548,8 +548,8 @@ irqreturn_t sja1000_interrupt(int irq, void *dev_id) 
	if (priv->read_reg(priv, SJA1000_IER) == IRQ_OFF)

		goto out;



	while ((isrc = priv->read_reg(priv, SJA1000_IR)) &&

	       (n < SJA1000_MAX_IRQ)) {

	while ((n < SJA1000_MAX_IRQ) &&

	       (isrc = priv->read_reg(priv, SJA1000_IR))) {



		status = priv->read_reg(priv, SJA1000_SR);

		/* check for absent controller due to hw unplug */