From 93094c1874ab303b8dc1782172f24c10a42cd408 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Thu, 14 Sep 2023 20:43:24 +0206 Subject: [PATCH 033/196] serial: 8250_dma: Use port lock wrappers MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit When a serial port is used for kernel console output, then all modifications to the UART registers which are done from other contexts, e.g. getty, termios, are interference points for the kernel console. So far this has been ignored and the printk output is based on the principle of hope. The rework of the console infrastructure which aims to support threaded and atomic consoles, requires to mark sections which modify the UART registers as unsafe. This allows the atomic write function to make informed decisions and eventually to restore operational state. It also allows to prevent the regular UART code from modifying UART registers while printk output is in progress. All modifications of UART registers are guarded by the UART port lock, which provides an obvious synchronization point with the console infrastructure. To avoid adding this functionality to all UART drivers, wrap the spin_[un]lock*() invocations for uart_port::lock into helper functions which just contain the spin_[un]lock*() invocations for now. In a subsequent step these helpers will gain the console synchronization mechanisms. Converted with coccinelle. No functional change. Signed-off-by: Thomas Gleixner Reviewed-by: Ilpo Järvinen Signed-off-by: John Ogness Link: https://lore.kernel.org/r/20230914183831.587273-8-john.ogness@linutronix.de Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sebastian Andrzej Siewior --- drivers/tty/serial/8250/8250_dma.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/drivers/tty/serial/8250/8250_dma.c b/drivers/tty/serial/8250/8250_dma.c index 7fa66501792d..8b30ca8fdd3f 100644 --- a/drivers/tty/serial/8250/8250_dma.c +++ b/drivers/tty/serial/8250/8250_dma.c @@ -22,7 +22,7 @@ static void __dma_tx_complete(void *param) dma_sync_single_for_cpu(dma->txchan->device->dev, dma->tx_addr, UART_XMIT_SIZE, DMA_TO_DEVICE); - spin_lock_irqsave(&p->port.lock, flags); + uart_port_lock_irqsave(&p->port, &flags); dma->tx_running = 0; @@ -35,7 +35,7 @@ static void __dma_tx_complete(void *param) if (ret || !dma->tx_running) serial8250_set_THRI(p); - spin_unlock_irqrestore(&p->port.lock, flags); + uart_port_unlock_irqrestore(&p->port, flags); } static void __dma_rx_complete(struct uart_8250_port *p) @@ -70,7 +70,7 @@ static void dma_rx_complete(void *param) struct uart_8250_dma *dma = p->dma; unsigned long flags; - spin_lock_irqsave(&p->port.lock, flags); + uart_port_lock_irqsave(&p->port, &flags); if (dma->rx_running) __dma_rx_complete(p); @@ -80,7 +80,7 @@ static void dma_rx_complete(void *param) */ if (!dma->rx_running && (serial_lsr_in(p) & UART_LSR_DR)) p->dma->rx_dma(p); - spin_unlock_irqrestore(&p->port.lock, flags); + uart_port_unlock_irqrestore(&p->port, flags); } int serial8250_tx_dma(struct uart_8250_port *p) -- 2.43.2