[PATCH 2/2] ASoC: SOF: sof-client-probes: cleanup tokenize_input()

[Dan Carpenter]

The tokenize_input() function is cleaner if it uses strndup_user()
instead of simple_write_to_buffer().  The way it's written now, if
*ppos is non-zero then it returns -EIO but normally we would return
0 in that case.  It's easier to handle that in the callers.

Signed-off-by: Dan Carpenter <dan.carpenter at oracle.com>
---
 sound/soc/sof/sof-client-probes.c | 27 +++++++++++++--------------
 1 file changed, 13 insertions(+), 14 deletions(-)

diff --git a/sound/soc/sof/sof-client-probes.c b/sound/soc/sof/sof-client-probes.c
index 679bc7d371fc..6c922b683f67 100644
--- a/sound/soc/sof/sof-client-probes.c
+++ b/sound/soc/sof/sof-client-probes.c
@@ -461,24 +461,17 @@ static int strsplit_u32(char *buf, const char *delim, u32 **tkns, size_t *num_tk
 }
 
 static int tokenize_input(const char __user *from, size_t count,
-			  loff_t *ppos, u32 **tkns, size_t *num_tkns)
+			  u32 **tkns, size_t *num_tkns)
 {
 	char *buf;
 	int ret;
 
-	buf = kmalloc(count + 1, GFP_KERNEL);
-	if (!buf)
-		return -ENOMEM;
-
-	ret = simple_write_to_buffer(buf, count, ppos, from, count);
-	if (ret != count) {
-		ret = ret >= 0 ? -EIO : ret;
-		goto exit;
-	}
+	buf = strndup_user(from, count + 1);
+	if (IS_ERR(buf))
+		return PTR_ERR(buf);
 
-	buf[count] = '\0';
 	ret = strsplit_u32(buf, ",", tkns, num_tkns);
-exit:
+
 	kfree(buf);
 	return ret;
 }
@@ -552,12 +545,15 @@ sof_probes_dfs_points_write(struct file *file, const char __user *from,
 	u32 *tkns;
 	int ret, err;
 
+	if (*ppos)
+		return 0;
+
 	if (priv->extractor_stream_tag == SOF_PROBES_INVALID_NODE_ID) {
 		dev_warn(dev, "no extractor stream running\n");
 		return -ENOENT;
 	}
 
-	ret = tokenize_input(from, count, ppos, &tkns, &num_tkns);
+	ret = tokenize_input(from, count, &tkns, &num_tkns);
 	if (ret < 0)
 		return ret;
 	bytes = sizeof(*tkns) * num_tkns;
@@ -607,12 +603,15 @@ sof_probes_dfs_points_remove_write(struct file *file, const char __user *from,
 	u32 *tkns;
 	int ret, err;
 
+	if (*ppos)
+		return 0;
+
 	if (priv->extractor_stream_tag == SOF_PROBES_INVALID_NODE_ID) {
 		dev_warn(dev, "no extractor stream running\n");
 		return -ENOENT;
 	}
 
-	ret = tokenize_input(from, count, ppos, &tkns, &num_tkns);
+	ret = tokenize_input(from, count, &tkns, &num_tkns);
 	if (ret < 0)
 		return ret;
 	if (!num_tkns) {
-- 
2.35.1