[PATCH 3/6] serial: sirf: fix endless loop bug in uart receive tasklet
From: Barry Song <hidden>
Date: 2015-05-14 06:45:23
Also in:
linux-serial
Subsystem:
the rest, tty layer and serial drivers · Maintainers:
Linus Torvalds, Greg Kroah-Hartman, Jiri Slaby
From: Qipan Li <redacted> In special condition, when cpu schedule into rx_tmo_process_tl or rx_dma_complete_tl and all the receive dma tasks have done, it will go into endless loop because no dma task cookie status be changed. Signed-off-by: Qipan Li <redacted> Signed-off-by: Barry Song <redacted> --- drivers/tty/serial/sirfsoc_uart.c | 9 +++++++++ 1 file changed, 9 insertions(+)
diff --git a/drivers/tty/serial/sirfsoc_uart.c b/drivers/tty/serial/sirfsoc_uart.c
index 48cceaf..ffeb766 100644
--- a/drivers/tty/serial/sirfsoc_uart.c
+++ b/drivers/tty/serial/sirfsoc_uart.c@@ -488,6 +488,7 @@ static void sirfsoc_rx_tmo_process_tl(unsigned long param) unsigned int count; struct dma_tx_state tx_state; unsigned long flags; + int i = 0; spin_lock_irqsave(&port->lock, flags); while (DMA_COMPLETE == dmaengine_tx_status(sirfport->rx_dma_chan,
@@ -497,6 +498,9 @@ static void sirfsoc_rx_tmo_process_tl(unsigned long param) SIRFSOC_RX_DMA_BUF_SIZE); sirfport->rx_completed++; sirfport->rx_completed %= SIRFSOC_RX_LOOP_BUF_CNT; + i++; + if (i > SIRFSOC_RX_LOOP_BUF_CNT) + break; } count = CIRC_CNT(sirfport->rx_dma_items[sirfport->rx_issued].xmit.head, sirfport->rx_dma_items[sirfport->rx_issued].xmit.tail,
@@ -713,6 +717,8 @@ static void sirfsoc_uart_rx_dma_complete_tl(unsigned long param) struct sirfsoc_int_en *uint_en = &sirfport->uart_reg->uart_int_en; struct dma_tx_state tx_state; unsigned long flags; + int i = 0; + spin_lock_irqsave(&port->lock, flags); while (DMA_COMPLETE == dmaengine_tx_status(sirfport->rx_dma_chan, sirfport->rx_dma_items[sirfport->rx_completed].cookie,
@@ -726,6 +732,9 @@ static void sirfsoc_uart_rx_dma_complete_tl(unsigned long param) else sirfport->rx_completed++; sirfport->rx_completed %= SIRFSOC_RX_LOOP_BUF_CNT; + i++; + if (i > SIRFSOC_RX_LOOP_BUF_CNT) + break; } spin_unlock_irqrestore(&port->lock, flags); tty_flip_buffer_push(&port->state->port);
--
2.3.5