From 0ac8382e9cfdd723445692fc97aaa4643929750d Mon Sep 17 00:00:00 2001 From: Yury Georgievskiy Date: Tue, 20 Jul 2010 15:26:50 -0700 Subject: [PATCH] serial: mcf: don't take spinlocks in already protected functions Don't take the port spinlock in uart functions where the serial core already takes care of locking/unlocking them. The code would actually lock up on architectures where spinlocks are implemented. Also protect calling mcf_rx_chars/mcf_tx_chars in the interrupt handler by the port spinlock and use IRQ_RETVAL to return from isr. [akpm@linux-foundation.org: make irq-handler return value more explicit] Signed-off-by: Yury Georgievskiy Cc: Alan Cox Acked-by: Greg Ungerer Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman --- drivers/serial/mcf.c | 31 +++++++++++++------------------ 1 file changed, 13 insertions(+), 18 deletions(-) diff --git a/drivers/serial/mcf.c b/drivers/serial/mcf.c index b5aaef965f24..3394b7cc1722 100644 --- a/drivers/serial/mcf.c +++ b/drivers/serial/mcf.c @@ -70,16 +70,14 @@ static unsigned int mcf_tx_empty(struct uart_port *port) static unsigned int mcf_get_mctrl(struct uart_port *port) { struct mcf_uart *pp = container_of(port, struct mcf_uart, port); - unsigned long flags; unsigned int sigs; - spin_lock_irqsave(&port->lock, flags); sigs = (readb(port->membase + MCFUART_UIPR) & MCFUART_UIPR_CTS) ? 0 : TIOCM_CTS; sigs |= (pp->sigs & TIOCM_RTS); sigs |= (mcf_getppdcd(port->line) ? TIOCM_CD : 0); sigs |= (mcf_getppdtr(port->line) ? TIOCM_DTR : 0); - spin_unlock_irqrestore(&port->lock, flags); + return sigs; } @@ -88,16 +86,13 @@ static unsigned int mcf_get_mctrl(struct uart_port *port) static void mcf_set_mctrl(struct uart_port *port, unsigned int sigs) { struct mcf_uart *pp = container_of(port, struct mcf_uart, port); - unsigned long flags; - spin_lock_irqsave(&port->lock, flags); pp->sigs = sigs; mcf_setppdtr(port->line, (sigs & TIOCM_DTR)); if (sigs & TIOCM_RTS) writeb(MCFUART_UOP_RTS, port->membase + MCFUART_UOP1); else writeb(MCFUART_UOP_RTS, port->membase + MCFUART_UOP0); - spin_unlock_irqrestore(&port->lock, flags); } /****************************************************************************/ @@ -105,12 +100,9 @@ static void mcf_set_mctrl(struct uart_port *port, unsigned int sigs) static void mcf_start_tx(struct uart_port *port) { struct mcf_uart *pp = container_of(port, struct mcf_uart, port); - unsigned long flags; - spin_lock_irqsave(&port->lock, flags); pp->imr |= MCFUART_UIR_TXREADY; writeb(pp->imr, port->membase + MCFUART_UIMR); - spin_unlock_irqrestore(&port->lock, flags); } /****************************************************************************/ @@ -118,12 +110,9 @@ static void mcf_start_tx(struct uart_port *port) static void mcf_stop_tx(struct uart_port *port) { struct mcf_uart *pp = container_of(port, struct mcf_uart, port); - unsigned long flags; - spin_lock_irqsave(&port->lock, flags); pp->imr &= ~MCFUART_UIR_TXREADY; writeb(pp->imr, port->membase + MCFUART_UIMR); - spin_unlock_irqrestore(&port->lock, flags); } /****************************************************************************/ @@ -131,12 +120,9 @@ static void mcf_stop_tx(struct uart_port *port) static void mcf_stop_rx(struct uart_port *port) { struct mcf_uart *pp = container_of(port, struct mcf_uart, port); - unsigned long flags; - spin_lock_irqsave(&port->lock, flags); pp->imr &= ~MCFUART_UIR_RXREADY; writeb(pp->imr, port->membase + MCFUART_UIMR); - spin_unlock_irqrestore(&port->lock, flags); } /****************************************************************************/ @@ -366,13 +352,22 @@ static irqreturn_t mcf_interrupt(int irq, void *data) struct uart_port *port = data; struct mcf_uart *pp = container_of(port, struct mcf_uart, port); unsigned int isr; + irqreturn_t ret = IRQ_NONE; isr = readb(port->membase + MCFUART_UISR) & pp->imr; - if (isr & MCFUART_UIR_RXREADY) + + spin_lock(&port->lock); + if (isr & MCFUART_UIR_RXREADY) { mcf_rx_chars(pp); - if (isr & MCFUART_UIR_TXREADY) + ret = IRQ_HANDLED; + } + if (isr & MCFUART_UIR_TXREADY) { mcf_tx_chars(pp); - return IRQ_HANDLED; + ret = IRQ_HANDLED; + } + spin_unlock(&port->lock); + + return ret; } /****************************************************************************/ -- 2.30.2