[PATCH] ALSA: core: Fix signedness issue in info read callback

[Sreeraj S Kurup]

The read callback returns ssize_t, which allows it to return
either the number of bytes read or a negative error code.

However, snd_info_entry_read() stores the callback result in a
size_t variable. This converts negative error codes into large
unsigned values.

Use a separate ssize_t variable to store the callback result.
This preserves negative error codes and ensures that the file
position is updated only when the callback returns a positive
number of bytes.

This prevents callback errors from being incorrectly reported
as successful reads.

Signed-off-by: Sreeraj S Kurup <sreekuttan2156239@xxxxxxxxx>
---
 sound/core/info.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/sound/core/info.c b/sound/core/info.c
index c4d57d0809ad..35aaa8bd6d56 100644
--- a/sound/core/info.c
+++ b/sound/core/info.c
@@ -144,6 +144,7 @@ static ssize_t snd_info_entry_read(struct file *file, char __user *buffer,
 	struct snd_info_private_data *data = file->private_data;
 	struct snd_info_entry *entry = data->entry;
 	size_t size;
+	ssize_t ret;
 	loff_t pos;
 
 	pos = *offset;
@@ -153,11 +154,11 @@ static ssize_t snd_info_entry_read(struct file *file, char __user *buffer,
 		return 0;
 	size = entry->size - pos;
 	size = min(count, size);
-	size = entry->c.ops->read(entry, data->file_private_data,
+	ret = entry->c.ops->read(entry, data->file_private_data,
 				  file, buffer, size, pos);
-	if ((ssize_t) size > 0)
-		*offset = pos + size;
-	return size;
+	if (ret > 0)
+		*offset = pos + ret;
+	return ret;
 }
 
 static ssize_t snd_info_entry_write(struct file *file, const char __user *buffer,
-- 
2.55.0