[PATCH 4.19 241/422] net: socionext: Fix two sleep-in-atomic-context bugs in ave_rxfifo_reset()

[Greg Kroah-Hartman]

From: Jia-Ju Bai <baijiaju1990@xxxxxxxxx>

[ Upstream commit 0020f5c807ef67954d9210eea0ba17a6134cdf7d ]

The driver may sleep with holding a spinlock.
The function call paths (from bottom to top) in Linux-4.17 are:

[FUNC] usleep_range
drivers/net/ethernet/socionext/sni_ave.c, 892:
	usleep_range in ave_rxfifo_reset
drivers/net/ethernet/socionext/sni_ave.c, 932:
	ave_rxfifo_reset in ave_irq_handler

[FUNC] usleep_range
drivers/net/ethernet/socionext/sni_ave.c, 888:
	usleep_range in ave_rxfifo_reset
drivers/net/ethernet/socionext/sni_ave.c, 932:
	ave_rxfifo_reset in ave_irq_handler

To fix these bugs, usleep_range() is replaced with udelay().

These bugs are found by my static analysis tool DSAC.

Signed-off-by: Jia-Ju Bai <baijiaju1990@xxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/net/ethernet/socionext/sni_ave.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/socionext/sni_ave.c b/drivers/net/ethernet/socionext/sni_ave.c
index f27d67a4d3045..09d25b87cf7c0 100644
--- a/drivers/net/ethernet/socionext/sni_ave.c
+++ b/drivers/net/ethernet/socionext/sni_ave.c
@@ -906,11 +906,11 @@ static void ave_rxfifo_reset(struct net_device *ndev)
 
 	/* assert reset */
 	writel(AVE_GRR_RXFFR, priv->base + AVE_GRR);
-	usleep_range(40, 50);
+	udelay(50);
 
 	/* negate reset */
 	writel(0, priv->base + AVE_GRR);
-	usleep_range(10, 20);
+	udelay(20);
 
 	/* negate interrupt status */
 	writel(AVE_GI_RXOVF, priv->base + AVE_GISR);
-- 
2.20.1