serial: bfin-uart: avoid dead lock in rx irq handler in smp kernel (9642dbe7) · Commits · 戴 / test

Disabing dma irq and lock bottom half in smp kernel doesn't ensure exclusive uart access. Call spin_lock_irqsave() instead. Signed-off-by:

drivers/tty/serial/bfin_uart.c

+3 −4

Original line number	Diff line number	Diff line
		@@ -477,9 +477,9 @@ static void bfin_serial_dma_rx_chars(struct bfin_serial_port *uart)
		void bfin_serial_rx_dma_timeout(struct bfin_serial_port *uart)
		{
		int x_pos, pos;
		unsigned long flags;

		dma_disable_irq_nosync(uart->rx_dma_channel);
		spin_lock_bh(&uart->rx_lock);
		spin_lock_irqsave(&uart->rx_lock, flags);

		/* 2D DMA RX buffer ring is used. Because curr_y_count and
		* curr_x_count can't be read as an atomic operation,
		@@ -510,8 +510,7 @@ void bfin_serial_rx_dma_timeout(struct bfin_serial_port *uart)
		uart->rx_dma_buf.tail = uart->rx_dma_buf.head;
		}

		spin_unlock_bh(&uart->rx_lock);
		dma_enable_irq(uart->rx_dma_channel);
		spin_unlock_irqrestore(&uart->rx_lock, flags);

		mod_timer(&(uart->rx_dma_timer), jiffies + DMA_RX_FLUSH_JIFFIES);
		}