Commit bf072af4 authored by Russell King - ARM Linux's avatar Russell King - ARM Linux Committed by Dan Williams
Browse files

ARM: PL08x: fix locking in tasklet 



Tasklets are run from an interruptible context.  The slave DMA functions
can be called from within IRQ handlers.  Taking the spinlock without
disabling interrupts allows an interrupt handler to run, which may try
to take the spinlock again, resulting in deadlock.  Fix this by using
the irqsave spinlocks.

Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
Acked-by: default avatarLinus Walleij <linus.walleij@stericsson.com>
Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
parent 91aa5fad

drivers/dma/amba-pl08x.c

+3 −2
Original line number Diff line number Diff line
@@ -1627,11 +1627,12 @@ static void pl08x_tasklet(unsigned long data) 
	struct pl08x_dma_chan *plchan = (struct pl08x_dma_chan *) data;

	struct pl08x_phy_chan *phychan = plchan->phychan;

	struct pl08x_driver_data *pl08x = plchan->host;

	unsigned long flags;



	if (!plchan)

		BUG();



	spin_lock(&plchan->lock);

	spin_lock_irqsave(&plchan->lock, flags);



	if (plchan->at) {

		dma_async_tx_callback callback =
@@ -1728,7 +1729,7 @@ static void pl08x_tasklet(unsigned long data) 
		}

	}



	spin_unlock(&plchan->lock);

	spin_unlock_irqrestore(&plchan->lock, flags);

}



static irqreturn_t pl08x_irq(int irq, void *dev)