serial: stm32: call stm32_transmit_chars locked

stm32_transmit_chars should be called under lock also in tx DMA callback.

Fixes: 3489187204eb ("serial: stm32: adding dma support")
Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com>
Signed-off-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
Link: https://lore.kernel.org/r/20210304162308.8984-10-erwan.leray@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c
index 74046ae3a41210f39f75e6c2fd11bb61ea9a0b1c..2bdd04a47f91723c9eccb1deac72283fb72d816a 100644 (file)
--- a/drivers/tty/serial/stm32-usart.c
+++ b/drivers/tty/serial/stm32-usart.c
@@ -291,13 +291,16 @@ static void stm32_usart_tx_dma_complete(void *arg)
        struct uart_port *port = arg;
        struct stm32_port *stm32port = to_stm32_port(port);
        const struct stm32_usart_offsets *ofs = &stm32port->info->ofs;
+       unsigned long flags;
 
        dmaengine_terminate_async(stm32port->tx_ch);
        stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_DMAT);
        stm32port->tx_dma_busy = false;
 
        /* Let's see if we have pending data to send */
+       spin_lock_irqsave(&port->lock, flags);
        stm32_usart_transmit_chars(port);
+       spin_unlock_irqrestore(&port->lock, flags);
 }
 
 static void stm32_usart_tx_interrupt_enable(struct uart_port *port)