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Commit 61f4146a authored by Gabriel Somlo's avatar Gabriel Somlo Committed by Greg Kroah-Hartman
Browse files

serial: altera_uart: fix locking in polling mode 



[ Upstream commit 1307c5d33cce8a41dd77c2571e4df65a5b627feb ]

Since altera_uart_interrupt() may also be called from
a poll timer in "serving_softirq" context, use
spin_[lock_irqsave|unlock_irqrestore] variants, which
are appropriate for both softirq and hardware interrupt
contexts.

Fixes: 2f8b9c15 ("altera_uart: Add support for polling mode (IRQ-less)")
Signed-off-by: default avatarGabriel Somlo <gsomlo@gmail.com>
Link: https://lore.kernel.org/r/20221122200426.888349-1-gsomlo@gmail.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent ce40c44e

drivers/tty/serial/altera_uart.c

+3 −2
Original line number Diff line number Diff line
@@ -280,16 +280,17 @@ static irqreturn_t altera_uart_interrupt(int irq, void *data) 
{

	struct uart_port *port = data;

	struct altera_uart *pp = container_of(port, struct altera_uart, port);

	unsigned long flags;

	unsigned int isr;



	isr = altera_uart_readl(port, ALTERA_UART_STATUS_REG) & pp->imr;



	spin_lock(&port->lock);

	spin_lock_irqsave(&port->lock, flags);

	if (isr & ALTERA_UART_STATUS_RRDY_MSK)

		altera_uart_rx_chars(port);

	if (isr & ALTERA_UART_STATUS_TRDY_MSK)

		altera_uart_tx_chars(port);

	spin_unlock(&port->lock);

	spin_unlock_irqrestore(&port->lock, flags);



	return IRQ_RETVAL(isr);

}