From 98838f90d92f6f0abf6d6a99880c0ff3127633b8 Mon Sep 17 00:00:00 2001 From: Russell King - ARM Linux Date: Mon, 3 Jan 2011 22:32:26 +0000 Subject: [PATCH] ARM: PL08x: fix deadlock in terminate_all Trying to disable a tasklet while holding a spinlock which the tasklet will take is a recipe for deadlock - tasklet_disable() will wait for the tasklet to finish running, which it will never do. In any case, there is not a corresponding tasklet_enable(), so once the tasklet is disabled, it will never run again until reboot. It's safe to just remove the tasklet_disable() as we remove all current and pending descriptors before releasing this spinlock. This means that the tasklet will find no remaining work if it subsequently runs. The only remaining issue is that the callback for an already submitted txd may be in progress, or even called after terminate_all() returns. There's not much that can be done about that as waiting for the callback to complete before returning will also lead to deadlocks. Signed-off-by: Russell King Acked-by: Linus Walleij Signed-off-by: Dan Williams --- drivers/dma/amba-pl08x.c | 2 -- 1 file changed, 2 deletions(-) diff --git a/drivers/dma/amba-pl08x.c b/drivers/dma/amba-pl08x.c index 9a8d44504c6..4ca1eb122e0 100644 --- a/drivers/dma/amba-pl08x.c +++ b/drivers/dma/amba-pl08x.c @@ -1560,8 +1560,6 @@ static int pl08x_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd, pl08x_put_phy_channel(pl08x, plchan->phychan); plchan->phychan = NULL; } - /* Stop any pending tasklet */ - tasklet_disable(&plchan->tasklet); /* Dequeue jobs and free LLIs */ if (plchan->at) { pl08x_free_txd(pl08x, plchan->at); -- 2.20.1