Re: [patch v2] [patch] staging: iio: ad799x: remove some unneeded IS_ERR() checks

From: Jonathan Cameron
Date: Sat May 03 2014 - 06:15:39 EST


On 30/04/14 22:52, Hartmut Knaack wrote:
Dan Carpenter schrieb:
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@xxxxxxxxxx>
Acked-by: Hartmut Knaack <knaack.h@xxxxxx>
Thanks to both of you for this.

Applied to the togreg branch of iio.git as the cleanup that caused
this was most likely part of a series that is only in staging-next at
the moment.

Jonathan

---
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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