netdev - [PATCH 1/2] net: davinci_cpdma: reduce time holding ctlr->lock in cpdma_control

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Message-Id: <1469534545-14478-2-git-send-email-u.kleine-koenig@pengutronix.de>
Date:	Tue, 26 Jul 2016 14:02:24 +0200
From:	Uwe Kleine-König 
	<u.kleine-koenig@...gutronix.de>
To:	Mugunthan V N <mugunthanvnm@...com>,
	Grygorii Strashko <grygorii.strashko@...com>
Cc:	linux-omap@...r.kernel.org, netdev@...r.kernel.org,
	kernel@...gutronix.de
Subject: [PATCH 1/2] net: davinci_cpdma: reduce time holding ctlr->lock in cpdma_control_set

The only user of cpdma_control_set (i.e. cpsw_ndo_open) doesn't check
the return code, so it doesn't matter, which error triggers. So the
checks that are independant of the fields protected by ctlr->lock can be
moved out of the critical section.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@...gutronix.de>
---
 drivers/net/ethernet/ti/davinci_cpdma.c | 20 +++++++++-----------
 1 file changed, 9 insertions(+), 11 deletions(-)

diff --git a/drivers/net/ethernet/ti/davinci_cpdma.c b/drivers/net/ethernet/ti/davinci_cpdma.c
index 73638f7a55d4..5ffa04a306c6 100644
--- a/drivers/net/ethernet/ti/davinci_cpdma.c
+++ b/drivers/net/ethernet/ti/davinci_cpdma.c
@@ -877,23 +877,21 @@ int cpdma_control_set(struct cpdma_ctlr *ctlr, int control, int value)
 	int ret;
 	u32 val;
 
-	spin_lock_irqsave(&ctlr->lock, flags);
-
-	ret = -ENOTSUPP;
 	if (!ctlr->params.has_ext_regs)
-		goto unlock_ret;
+		return -ENOTSUPP;
 
-	ret = -EINVAL;
-	if (ctlr->state != CPDMA_STATE_ACTIVE)
-		goto unlock_ret;
-
-	ret = -ENOENT;
 	if (control < 0 || control >= ARRAY_SIZE(controls))
-		goto unlock_ret;
+		return -ENOENT;
 
-	ret = -EPERM;
 	if ((info->access & ACCESS_WO) != ACCESS_WO)
+		return -EPERM;
+
+	spin_lock_irqsave(&ctlr->lock, flags);
+
+	if (ctlr->state != CPDMA_STATE_ACTIVE) {
+		ret = -EINVAL;
 		goto unlock_ret;
+	}
 
 	val  = dma_reg_read(ctlr, info->reg);
 	val &= ~(info->mask << info->shift);
-- 
2.8.1