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serial: altera_uart: fix locking in polling mode

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[ 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: 2f8b9c15cd ("altera_uart: Add support for polling mode (IRQ-less)")
Signed-off-by: Gabriel Somlo <gsomlo@gmail.com>
Link: https://lore.kernel.org/r/20221122200426.888349-1-gsomlo@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Gabriel Somlo 2022-11-22 15:04:26 -05:00 committed by Greg Kroah-Hartman
parent ce40c44e62
commit 61f4146a7e
1 changed files with 3 additions and 2 deletions
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5
drivers/tty/serial/altera_uart.c
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@ -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);
}