linux-kernel - [PATCH v3] iio: move 'indio_dev->info' null check first in __iio_device

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Message-ID: <20200407150743.8144-1-alexandru.ardelean@analog.com>
Date:   Tue, 7 Apr 2020 18:07:43 +0300
From:   Alexandru Ardelean <alexandru.ardelean@...log.com>
To:     <linux-iio@...r.kernel.org>, <linux-kernel@...r.kernel.org>
CC:     <jic23@...nel.org>,
        Alexandru Ardelean <alexandru.ardelean@...log.com>
Subject: [PATCH v3] iio: move 'indio_dev->info' null check first in __iio_device_register()

Moves this to be the first check, as it's very simple and fails the
registration earlier, instead of potentially initializing the
'indio_dev->label' and checking for duplicate indexes, and then failing
with this simple-check.

This is a minor optimization, since '__iio_device_register()' will waste
fewer validation cycles in case 'indio_dev->info' is NULL.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@...log.com>
---

Changelog v1 -> v2:
* fixed typo 'regitration' -> 'registration'

Changelog v2 -> v3:
* title update to include __iio_device_register()
* dropped 'Doesn't fix anything.' 
* added sentence about the minor optimization

 drivers/iio/industrialio-core.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c
index 157d95a24faa..56ff24d7a174 100644
--- a/drivers/iio/industrialio-core.c
+++ b/drivers/iio/industrialio-core.c
@@ -1711,6 +1711,9 @@ int __iio_device_register(struct iio_dev *indio_dev, struct module *this_mod)
 {
 	int ret;
 
+	if (!indio_dev->info)
+		return -EINVAL;
+
 	indio_dev->driver_module = this_mod;
 	/* If the calling driver did not initialize of_node, do it here */
 	if (!indio_dev->dev.of_node && indio_dev->dev.parent)
@@ -1723,9 +1726,6 @@ int __iio_device_register(struct iio_dev *indio_dev, struct module *this_mod)
 	if (ret < 0)
 		return ret;
 
-	if (!indio_dev->info)
-		return -EINVAL;
-
 	/* configure elements for the chrdev */
 	indio_dev->dev.devt = MKDEV(MAJOR(iio_devt), indio_dev->id);
 
-- 
2.17.1