From 6fc5a520429e29ae84cb9ce8e8c584166a54a1ee Mon Sep 17 00:00:00 2001 From: Takatoshi Akiyama Date: Mon, 7 Nov 2016 16:56:50 +0100 Subject: [PATCH] serial: sh-sci: Fix deadlock caused by serial output request While spin is already locked, serial output request causes the deadlock, because serial output process also tries to lock the spin. This patch removes serial output with spin locked. Signed-off-by: Takatoshi Akiyama Signed-off-by: Takeshi Kihara Signed-off-by: Simon Horman Reviewed-by: Geert Uytterhoeven Acked-by: Wolfram Sang Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/sh-sci.c | 20 +++++--------------- 1 file changed, 5 insertions(+), 15 deletions(-) diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c index 4b26252c2885..91e7dddbf72c 100644 --- a/drivers/tty/serial/sh-sci.c +++ b/drivers/tty/serial/sh-sci.c @@ -1142,11 +1142,8 @@ static int sci_dma_rx_push(struct sci_port *s, void *buf, size_t count) int copied; copied = tty_insert_flip_string(tport, buf, count); - if (copied < count) { - dev_warn(port->dev, "Rx overrun: dropping %zu bytes\n", - count - copied); + if (copied < count) port->icount.buf_overrun++; - } port->icount.rx += copied; @@ -1161,8 +1158,6 @@ static int sci_dma_rx_find_active(struct sci_port *s) if (s->active_rx == s->cookie_rx[i]) return i; - dev_err(s->port.dev, "%s: Rx cookie %d not found!\n", __func__, - s->active_rx); return -1; } @@ -1223,9 +1218,9 @@ static void sci_dma_rx_complete(void *arg) dma_async_issue_pending(chan); + spin_unlock_irqrestore(&port->lock, flags); dev_dbg(port->dev, "%s: cookie %d #%d, new active cookie %d\n", __func__, s->cookie_rx[active], active, s->active_rx); - spin_unlock_irqrestore(&port->lock, flags); return; fail: @@ -1273,8 +1268,6 @@ static void sci_submit_rx(struct sci_port *s) if (dma_submit_error(s->cookie_rx[i])) goto fail; - dev_dbg(s->port.dev, "%s(): cookie %d to #%d\n", __func__, - s->cookie_rx[i], i); } s->active_rx = s->cookie_rx[0]; @@ -1288,7 +1281,6 @@ fail: for (i = 0; i < 2; i++) s->cookie_rx[i] = -EINVAL; s->active_rx = -EINVAL; - dev_warn(s->port.dev, "Failed to re-start Rx DMA, using PIO\n"); sci_rx_dma_release(s, true); } @@ -1358,10 +1350,10 @@ static void rx_timer_fn(unsigned long arg) int active, count; u16 scr; - spin_lock_irqsave(&port->lock, flags); - dev_dbg(port->dev, "DMA Rx timed out\n"); + spin_lock_irqsave(&port->lock, flags); + active = sci_dma_rx_find_active(s); if (active < 0) { spin_unlock_irqrestore(&port->lock, flags); @@ -1370,9 +1362,9 @@ static void rx_timer_fn(unsigned long arg) status = dmaengine_tx_status(s->chan_rx, s->active_rx, &state); if (status == DMA_COMPLETE) { + spin_unlock_irqrestore(&port->lock, flags); dev_dbg(port->dev, "Cookie %d #%d has already completed\n", s->active_rx, active); - spin_unlock_irqrestore(&port->lock, flags); /* Let packet complete handler take care of the packet */ return; @@ -1396,8 +1388,6 @@ static void rx_timer_fn(unsigned long arg) /* Handle incomplete DMA receive */ dmaengine_terminate_all(s->chan_rx); read = sg_dma_len(&s->sg_rx[active]) - state.residue; - dev_dbg(port->dev, "Read %u bytes with cookie %d\n", read, - s->active_rx); if (read) { count = sci_dma_rx_push(s, s->rx_buf[active], read); -- 2.20.1