ALSA: info - Check file position validity in common layer

Check the validity of the file position in the common info layer before
calling read or write callbacks in assumption that entry->size is set up
properly to indicate the max file size.

Removed the redundant checks from the callbacks as well.

Signed-off-by: Takashi Iwai <tiwai@suse.de>

1 files changed, 6 insertions, 18 deletions

diff --git a/sound/pci/cs4281.c b/sound/pci/cs4281.c
index b0bba2e86b12..6772070ed492 100644
--- a/sound/pci/cs4281.c
+++ b/sound/pci/cs4281.c
@@ -1144,17 +1144,11 @@ static ssize_t snd_cs4281_BA0_read(struct snd_info_entry *entry,
                                    struct file *file, char __user *buf,
                                    size_t count, loff_t pos)
 {
-        long size;
         struct cs4281 *chip = entry->private_data;
         
-        size = count;
-        if (pos + size > CS4281_BA0_SIZE)
-                size = (long)CS4281_BA0_SIZE - pos;
-        if (size > 0) {
-                if (copy_to_user_fromio(buf, chip->ba0 + pos, size))
-                        return -EFAULT;
-        }
-        return size;
+        if (copy_to_user_fromio(buf, chip->ba0 + pos, count))
+                return -EFAULT;
+        return count;
 }
 
 static ssize_t snd_cs4281_BA1_read(struct snd_info_entry *entry,
@@ -1162,17 +1156,11 @@ static ssize_t snd_cs4281_BA1_read(struct snd_info_entry *entry,
                                    struct file *file, char __user *buf,
                                    size_t count, loff_t pos)
 {
-        long size;
         struct cs4281 *chip = entry->private_data;
         
-        size = count;
-        if (pos + size > CS4281_BA1_SIZE)
-                size = (long)CS4281_BA1_SIZE - pos;
-        if (size > 0) {
-                if (copy_to_user_fromio(buf, chip->ba1 + pos, size))
-                        return -EFAULT;
-        }
-        return size;
+        if (copy_to_user_fromio(buf, chip->ba1 + pos, count))
+                return -EFAULT;
+        return count;
 }
 
 static struct snd_info_entry_ops snd_cs4281_proc_ops_BA0 = {