2 files changed, 33 insertions, 20 deletions

diff --git a/fs/debugfs/file.c b/fs/debugfs/file.c
index fa6b7f7ff914..fddffe4851f5 100644
--- a/fs/debugfs/file.c
+++ b/fs/debugfs/file.c
@@ -56,13 +56,15 @@ const struct inode_operations debugfs_link_operations = {
         .follow_link    = debugfs_follow_link,
 };
 
-static void debugfs_u8_set(void *data, u64 val)
+static int debugfs_u8_set(void *data, u64 val)
 {
         *(u8 *)data = val;
+        return 0;
 }
-static u64 debugfs_u8_get(void *data)
+static int debugfs_u8_get(void *data, u64 *val)
 {
-        return *(u8 *)data;
+        *val = *(u8 *)data;
+        return 0;
 }
 DEFINE_SIMPLE_ATTRIBUTE(fops_u8, debugfs_u8_get, debugfs_u8_set, "%llu\n");
 
@@ -97,13 +99,15 @@ struct dentry *debugfs_create_u8(const char *name, mode_t mode,
 }
 EXPORT_SYMBOL_GPL(debugfs_create_u8);
 
-static void debugfs_u16_set(void *data, u64 val)
+static int debugfs_u16_set(void *data, u64 val)
 {
         *(u16 *)data = val;
+        return 0;
 }
-static u64 debugfs_u16_get(void *data)
+static int debugfs_u16_get(void *data, u64 *val)
 {
-        return *(u16 *)data;
+        *val = *(u16 *)data;
+        return 0;
 }
 DEFINE_SIMPLE_ATTRIBUTE(fops_u16, debugfs_u16_get, debugfs_u16_set, "%llu\n");
 
@@ -138,13 +142,15 @@ struct dentry *debugfs_create_u16(const char *name, mode_t mode,
 }
 EXPORT_SYMBOL_GPL(debugfs_create_u16);
 
-static void debugfs_u32_set(void *data, u64 val)
+static int debugfs_u32_set(void *data, u64 val)
 {
         *(u32 *)data = val;
+        return 0;
 }
-static u64 debugfs_u32_get(void *data)
+static int debugfs_u32_get(void *data, u64 *val)
 {
-        return *(u32 *)data;
+        *val = *(u32 *)data;
+        return 0;
 }
 DEFINE_SIMPLE_ATTRIBUTE(fops_u32, debugfs_u32_get, debugfs_u32_set, "%llu\n");
 
@@ -179,14 +185,16 @@ struct dentry *debugfs_create_u32(const char *name, mode_t mode,
 }
 EXPORT_SYMBOL_GPL(debugfs_create_u32);
 
-static void debugfs_u64_set(void *data, u64 val)
+static int debugfs_u64_set(void *data, u64 val)
 {
         *(u64 *)data = val;
+        return 0;
 }
 
-static u64 debugfs_u64_get(void *data)
+static int debugfs_u64_get(void *data, u64 *val)
 {
-        return *(u64 *)data;
+        *val = *(u64 *)data;
+        return 0;
 }
 DEFINE_SIMPLE_ATTRIBUTE(fops_u64, debugfs_u64_get, debugfs_u64_set, "%llu\n");
 
diff --git a/fs/libfs.c b/fs/libfs.c
index 5523bde96387..2319415ddb5e 100644
--- a/fs/libfs.c
+++ b/fs/libfs.c
@@ -583,8 +583,8 @@ int simple_transaction_release(struct inode *inode, struct file *file)
 /* Simple attribute files */
 
 struct simple_attr {
-        u64 (*get)(void *);
-        void (*set)(void *, u64);
+        int (*get)(void *, u64 *);
+        int (*set)(void *, u64);
         char get_buf[24];       /* enough to store a u64 and "\n\0" */
         char set_buf[24];
         void *data;
@@ -595,7 +595,7 @@ struct simple_attr {
 /* simple_attr_open is called by an actual attribute open file operation
  * to set the attribute specific access operations. */
 int simple_attr_open(struct inode *inode, struct file *file,
-                     u64 (*get)(void *), void (*set)(void *, u64),
+                     int (*get)(void *, u64 *), int (*set)(void *, u64),
                      const char *fmt)
 {
         struct simple_attr *attr;
@@ -635,14 +635,20 @@ ssize_t simple_attr_read(struct file *file, char __user *buf,
                 return -EACCES;
 
         mutex_lock(&attr->mutex);
-        if (*ppos) /* continued read */
+        if (*ppos) {            /* continued read */
                 size = strlen(attr->get_buf);
-        else      /* first read */
+        } else {                /* first read */
+                u64 val;
+                ret = attr->get(attr->data, &val);
+                if (ret)
+                        goto out;
+
                 size = scnprintf(attr->get_buf, sizeof(attr->get_buf),
-                                 attr->fmt,
-                                 (unsigned long long)attr->get(attr->data));
+                                 attr->fmt, (unsigned long long)val);
+        }
 
         ret = simple_read_from_buffer(buf, len, ppos, attr->get_buf, size);
+out:
         mutex_unlock(&attr->mutex);
         return ret;
 }
@@ -657,7 +663,6 @@ ssize_t simple_attr_write(struct file *file, const char __user *buf,
         ssize_t ret;
 
         attr = file->private_data;
-
         if (!attr->set)
                 return -EACCES;