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;