linux-kernel - [PATCH] ata: sata_mv: Replace mdelay with usleep_range in mv_reset

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Message-Id: <1516876013-12653-1-git-send-email-baijiaju1990@gmail.com>
Date:   Thu, 25 Jan 2018 18:26:52 +0800
From:   Jia-Ju Bai <baijiaju1990@...il.com>
To:     tj@...nel.org, mlord@...ox.com
Cc:     linux-ide@...r.kernel.org, linux-kernel@...r.kernel.org,
        Jia-Ju Bai <baijiaju1990@...il.com>
Subject: [PATCH] ata: sata_mv: Replace mdelay with usleep_range in mv_reset_channel

After checking all possible call chains to mv_reset_channel here,
my tool finds that mv_reset_channel is never called in atomic context, 
namely never in an interrupt handler or holding a spinlock.
Thus mdelay can be replaced with usleep_range to avoid busy wait.

This is found by a static analysis tool named DCNS written by myself.

Signed-off-by: Jia-Ju Bai <baijiaju1990@...il.com>
---
 drivers/ata/sata_mv.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/ata/sata_mv.c b/drivers/ata/sata_mv.c
index cc208b7..42d4589 100644
--- a/drivers/ata/sata_mv.c
+++ b/drivers/ata/sata_mv.c
@@ -3596,7 +3596,7 @@ static void mv_reset_channel(struct mv_host_priv *hpriv, void __iomem *mmio,
 	hpriv->ops->phy_errata(hpriv, mmio, port_no);
 
 	if (IS_GEN_I(hpriv))
-		mdelay(1);
+		usleep_range(500, 1000);
 }
 
 static void mv_pmp_select(struct ata_port *ap, int pmp)
-- 
1.7.9.5