linux-kernel - [PATCH 2/2] iio: buffer: Move a sanity check at the beginning of 'iio_scan_mask

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Message-Id: <98a351adda1908c306e981b9cc86d3dbc79eb5ec.1626261211.git.christophe.jaillet@wanadoo.fr>
Date:   Wed, 14 Jul 2021 13:14:51 +0200
From:   Christophe JAILLET <christophe.jaillet@...adoo.fr>
To:     jic23@...nel.org, lars@...afoo.de
Cc:     linux-iio@...r.kernel.org, linux-kernel@...r.kernel.org,
        kernel-janitors@...r.kernel.org,
        Christophe JAILLET <christophe.jaillet@...adoo.fr>
Subject: [PATCH 2/2] iio: buffer: Move a sanity check at the beginning of 'iio_scan_mask_set()'

This is more standard to have sanity checks at the entry of a function,
instead of allocating some memory first and having to free it if a
condition is not met.

Shuffle code a bit to check 'masklength' before calling 'bitmap_alloc()'

Signed-off-by: Christophe JAILLET <christophe.jaillet@...adoo.fr>
---
 drivers/iio/industrialio-buffer.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/iio/industrialio-buffer.c b/drivers/iio/industrialio-buffer.c
index 6d4776a7f002..a95cc2da56be 100644
--- a/drivers/iio/industrialio-buffer.c
+++ b/drivers/iio/industrialio-buffer.c
@@ -354,13 +354,14 @@ static int iio_scan_mask_set(struct iio_dev *indio_dev,
 	const unsigned long *mask;
 	unsigned long *trialmask;
 
-	trialmask = bitmap_alloc(indio_dev->masklength, GFP_KERNEL);
-	if (!trialmask)
-		return -ENOMEM;
 	if (!indio_dev->masklength) {
 		WARN(1, "Trying to set scanmask prior to registering buffer\n");
-		goto err_invalid_mask;
+		return -EINVAL;
 	}
+
+	trialmask = bitmap_alloc(indio_dev->masklength, GFP_KERNEL);
+	if (!trialmask)
+		return -ENOMEM;
 	bitmap_copy(trialmask, buffer->scan_mask, indio_dev->masklength);
 	set_bit(bit, trialmask);
 
-- 
2.30.2