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Subject[PATCH v3 2/5] net: ethernet: ti: davinci_cpdma: fix locking while ctrl_stop
Date
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():

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.

Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>
---
drivers/net/ethernet/ti/davinci_cpdma.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/drivers/net/ethernet/ti/davinci_cpdma.c b/drivers/net/ethernet/ti/davinci_cpdma.c
index 167fd65..ffb32af 100644
--- a/drivers/net/ethernet/ti/davinci_cpdma.c
+++ b/drivers/net/ethernet/ti/davinci_cpdma.c
@@ -334,12 +334,14 @@ int cpdma_ctlr_stop(struct cpdma_ctlr *ctlr)
}

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

for (i = 0; i < ARRAY_SIZE(ctlr->channels); i++) {
if (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_TXINTMASKCLEAR, 0xffffffff);

--
1.9.1
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