1 files changed, 44 insertions, 31 deletions

diff --git a/sound/core/info.c b/sound/core/info.c
index d749a0d394a7..b70564ed8b37 100644
--- a/sound/core/info.c
+++ b/sound/core/info.c
@@ -22,6 +22,7 @@
 #include <linux/init.h>
 #include <linux/time.h>
 #include <linux/mm.h>
+#include <linux/slab.h>
 #include <linux/smp_lock.h>
 #include <linux/string.h>
 #include <sound/core.h>
@@ -163,40 +164,44 @@ static loff_t snd_info_entry_llseek(struct file *file, loff_t offset, int orig)
 {
         struct snd_info_private_data *data;
         struct snd_info_entry *entry;
-        loff_t ret;
+        loff_t ret = -EINVAL, size;
 
         data = file->private_data;
         entry = data->entry;
-        lock_kernel();
-        switch (entry->content) {
-        case SNDRV_INFO_CONTENT_TEXT:
-                switch (orig) {
-                case SEEK_SET:
-                        file->f_pos = offset;
-                        ret = file->f_pos;
-                        goto out;
-                case SEEK_CUR:
-                        file->f_pos += offset;
-                        ret = file->f_pos;
-                        goto out;
-                case SEEK_END:
-                default:
-                        ret = -EINVAL;
-                        goto out;
-                }
+        mutex_lock(&entry->access);
+        if (entry->content == SNDRV_INFO_CONTENT_DATA &&
+            entry->c.ops->llseek) {
+                offset = entry->c.ops->llseek(entry,
+                                              data->file_private_data,
+                                              file, offset, orig);
+                goto out;
+        }
+        if (entry->content == SNDRV_INFO_CONTENT_DATA)
+                size = entry->size;
+        else
+                size = 0;
+        switch (orig) {
+        case SEEK_SET:
                 break;
-        case SNDRV_INFO_CONTENT_DATA:
-                if (entry->c.ops->llseek) {
-                        ret = entry->c.ops->llseek(entry,
-                                                    data->file_private_data,
-                                                    file, offset, orig);
+        case SEEK_CUR:
+                offset += file->f_pos;
+                break;
+        case SEEK_END:
+                if (!size)
                         goto out;
-                }
+                offset += size;
                 break;
-        }
-        ret = -ENXIO;
-out:
-        unlock_kernel();
+        default:
+                goto out;
+        }
+        if (offset < 0)
+                goto out;
+        if (size && offset > size)
+                offset = size;
+        file->f_pos = offset;
+        ret = offset;
+ out:
+        mutex_unlock(&entry->access);
         return ret;
 }
 
@@ -231,10 +236,15 @@ static ssize_t snd_info_entry_read(struct file *file, char __user *buffer,
                         return -EFAULT;
                 break;
         case SNDRV_INFO_CONTENT_DATA:
-                if (entry->c.ops->read)
+                if (pos >= entry->size)
+                        return 0;
+                if (entry->c.ops->read) {
+                        size = entry->size - pos;
+                        size = min(count, size);
                         size = entry->c.ops->read(entry,
                                                   data->file_private_data,
-                                                  file, buffer, count, pos);
+                                                  file, buffer, size, pos);
+                }
                 break;
         }
         if ((ssize_t) size > 0)
@@ -281,10 +291,13 @@ static ssize_t snd_info_entry_write(struct file *file, const char __user *buffer
                 size = count;
                 break;
         case SNDRV_INFO_CONTENT_DATA:
-                if (entry->c.ops->write)
+                if (entry->c.ops->write && count > 0) {
+                        size_t maxsize = entry->size - pos;
+                        count = min(count, maxsize);
                         size = entry->c.ops->write(entry,
                                                    data->file_private_data,
                                                    file, buffer, count, pos);
+                }
                 break;
         }
         if ((ssize_t) size > 0)