Commit 080d5c5a authored Aug 22, 2016 by Ivan Khoronzhuk Committed by David S. Miller Aug 23, 2016

net: ethernet: ti: davinci_cpdma: fix locking while ctrl_stop



The interrupts shouldn't be disabled while receiving skb, but while
ctrl_stop, the channels are stopped and all remaining packets are
handled with netif_receive_skb(), it can cause WARN_ONCE when ctrl
is stopping while not all packets were handled with NAPIs:

lock_irq_save
    cpdma_ctlr_stop
       cpdma_chan_top
           __cpdma_chan_free
               cpsw_rx_handler
                   netif_receive_skb

So, split locking while ctrl stop thus interrupts are still
enabled while skbs handling. It can cause WARN_ONCE in rare
cases when ctrl is stopping while not all packets were handled
with NAPIs.

Reviewed-by: Mugunthan V N <mugunthanvnm@ti.com>
Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 3802dce1

drivers/net/ethernet/ti/davinci_cpdma.c

+2 −0

Original line number	Original line	Diff line number	Diff line
	@@ -334,12 +334,14 @@ int cpdma_ctlr_stop(struct cpdma_ctlr *ctlr)
	}		}

	ctlr->state = CPDMA_STATE_TEARDOWN;		ctlr->state = CPDMA_STATE_TEARDOWN;
			spin_unlock_irqrestore(&ctlr->lock, flags);

	for (i = 0; i < ARRAY_SIZE(ctlr->channels); i++) {		for (i = 0; i < ARRAY_SIZE(ctlr->channels); i++) {
	if (ctlr->channels[i])		if (ctlr->channels[i])
	cpdma_chan_stop(ctlr->channels[i]);		cpdma_chan_stop(ctlr->channels[i]);
	}		}

			spin_lock_irqsave(&ctlr->lock, flags);
	dma_reg_write(ctlr, CPDMA_RXINTMASKCLEAR, 0xffffffff);		dma_reg_write(ctlr, CPDMA_RXINTMASKCLEAR, 0xffffffff);
	dma_reg_write(ctlr, CPDMA_TXINTMASKCLEAR, 0xffffffff);		dma_reg_write(ctlr, CPDMA_TXINTMASKCLEAR, 0xffffffff);