linux-kernel - [PATCH] staging: greybus: codecs: fix type confusion with dedicated list iterator variable

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Message-Id: <20220319202058.2518847-1-jakobkoschel@gmail.com>
Date:   Sat, 19 Mar 2022 21:20:58 +0100
From:   Jakob Koschel <jakobkoschel@...il.com>
To:     Vaibhav Agarwal <vaibhav.sr@...il.com>
Cc:     Jakob Koschel <jakobkoschel@...il.com>,
        linux-kernel@...r.kernel.org, greybus-dev@...ts.linaro.org,
        linux-staging@...ts.linux.dev, Mark Greer <mgreer@...malcreek.com>,
        Johan Hovold <johan@...nel.org>, Alex Elder <elder@...nel.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Mike Rapoport <rppt@...nel.org>,
        "Brian Johannesmeyer" <bjohannesmeyer@...il.com>,
        Cristiano Giuffrida <c.giuffrida@...nl>,
        "Bos, H.J." <h.j.bos@...nl>
Subject: [PATCH] staging: greybus: codecs: fix type confusion with dedicated list iterator variable

If the list does not exit early then data == NULL and 'module' does not
point to a valid list element.
Using 'module' in such a case is not valid and was therefore removed.

In preparation to limit the scope of the list iterator to the list
traversal loop, use a dedicated pointer pointing to the found element [1].

Link: https://lore.kernel.org/all/YhdfEIwI4EdtHdym@kroah.com/
Signed-off-by: Jakob Koschel <jakobkoschel@...il.com>
---
 drivers/staging/greybus/audio_codec.c | 24 ++++++++++++++----------
 1 file changed, 14 insertions(+), 10 deletions(-)

diff --git a/drivers/staging/greybus/audio_codec.c b/drivers/staging/greybus/audio_codec.c
index b589cf6b1d03..0f50d1e51e2c 100644
--- a/drivers/staging/greybus/audio_codec.c
+++ b/drivers/staging/greybus/audio_codec.c
@@ -497,7 +497,7 @@ static int gbcodec_prepare(struct snd_pcm_substream *substream,
 			   struct snd_soc_dai *dai)
 {
 	int ret;
-	struct gbaudio_module_info *module;
+	struct gbaudio_module_info *module = NULL, *iter;
 	struct gbaudio_data_connection *data;
 	struct gb_bundle *bundle;
 	struct gbaudio_codec_info *codec = dev_get_drvdata(dai->dev);
@@ -511,11 +511,13 @@ static int gbcodec_prepare(struct snd_pcm_substream *substream,
 		return -ENODEV;
 	}

-	list_for_each_entry(module, &codec->module_list, list) {
+	list_for_each_entry(iter, &codec->module_list, list) {
 		/* find the dai */
-		data = find_data(module, dai->id);
-		if (data)
+		data = find_data(iter, dai->id);
+		if (data) {
+			module = iter;
 			break;
+		}
 	}
 	if (!data) {
 		dev_err(dai->dev, "DATA connection missing\n");
@@ -563,7 +565,7 @@ static int gbcodec_mute_stream(struct snd_soc_dai *dai, int mute, int stream)
 {
 	int ret;
 	struct gbaudio_data_connection *data;
-	struct gbaudio_module_info *module;
+	struct gbaudio_module_info *module = NULL, *iter;
 	struct gb_bundle *bundle;
 	struct gbaudio_codec_info *codec = dev_get_drvdata(dai->dev);
 	struct gbaudio_stream_params *params;
@@ -592,15 +594,17 @@ static int gbcodec_mute_stream(struct snd_soc_dai *dai, int mute, int stream)
 		return ret;
 	}

-	list_for_each_entry(module, &codec->module_list, list) {
+	list_for_each_entry(iter, &codec->module_list, list) {
 		/* find the dai */
-		data = find_data(module, dai->id);
-		if (data)
+		data = find_data(iter, dai->id);
+		if (data) {
+			module = iter;
 			break;
+		}
 	}
 	if (!data) {
-		dev_err(dai->dev, "%s:%s DATA connection missing\n",
-			dai->name, module->name);
+		dev_err(dai->dev, "%s DATA connection missing\n",
+			dai->name);
 		mutex_unlock(&codec->lock);
 		return -ENODEV;
 	}

base-commit: 34e047aa16c0123bbae8e2f6df33e5ecc1f56601
--
2.25.1