linux-kernel - [patch v2] [patch] staging: iio: ad799x: remove some unneeded IS

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Date:	Thu, 1 May 2014 00:05:29 +0300
From:	Dan Carpenter <dan.carpenter@...cle.com>
To:	Jonathan Cameron <jic23@...nel.org>
Cc:	Lars-Peter Clausen <lars@...afoo.de>,
	Hartmut Knaack <knaack.h@....de>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Randy Dunlap <rdunlap@...radead.org>,
	Aida Mynzhasova <ai.c.c0der@...il.com>,
	Masanari Iida <standby24x7@...il.com>,
	linux-iio@...r.kernel.org, linux-kernel@...r.kernel.org,
	kernel-janitors@...r.kernel.org
Subject: [patch v2] [patch] staging: iio: ad799x: remove some unneeded
 IS_ERR() checks

My static checker is upset that we check IS_ERR(t->reg) when we know it
is not an ERR_PTR.

Checking for IS_ERR() twice is often a sign of confusion and buggy code.
In this case, if the call to "ret = regulator_enable(st->vref);" fails,
then we call "regulator_disable(st->vref);" and that's a mistake because
"st->vref" is not enabled.

I fixed these problems and Hartmut Knaack pointed out a couple unneeded
IS_ERR() checks in ad799x_remove() so I have removed those as well.

Signed-off-by: Dan Carpenter <dan.carpenter@...cle.com>
---
v2: remove the unneeded checks in ad799x_remove() as well.  Updated the
    commit message to say that it's actually a small bug fix.

diff --git a/drivers/iio/adc/ad799x.c b/drivers/iio/adc/ad799x.c
index 16a8b14..39b4cb4 100644
--- a/drivers/iio/adc/ad799x.c
+++ b/drivers/iio/adc/ad799x.c
@@ -717,7 +717,7 @@ static int ad799x_probe(struct i2c_client *client,
 	ret = iio_triggered_buffer_setup(indio_dev, NULL,
 		&ad799x_trigger_handler, NULL);
 	if (ret)
-		goto error_disable_reg;
+		goto error_disable_vref;
 
 	if (client->irq > 0) {
 		ret = devm_request_threaded_irq(&client->dev,
@@ -739,11 +739,10 @@ static int ad799x_probe(struct i2c_client *client,
 
 error_cleanup_ring:
 	iio_triggered_buffer_cleanup(indio_dev);
+error_disable_vref:
+	regulator_disable(st->vref);
 error_disable_reg:
-	if (!IS_ERR(st->vref))
-		regulator_disable(st->vref);
-	if (!IS_ERR(st->reg))
-		regulator_disable(st->reg);
+	regulator_disable(st->reg);
 
 	return ret;
 }
@@ -756,10 +755,8 @@ static int ad799x_remove(struct i2c_client *client)
 	iio_device_unregister(indio_dev);
 
 	iio_triggered_buffer_cleanup(indio_dev);
-	if (!IS_ERR(st->vref))
-		regulator_disable(st->vref);
-	if (!IS_ERR(st->reg))
-		regulator_disable(st->reg);
+	regulator_disable(st->vref);
+	regulator_disable(st->reg);
 	kfree(st->rx_buf);
 
 	return 0;
--
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