[PATCH v4 1/5] seq_file: Introduce DEFINE_SHOW_STORE_ATTRIBUTE() helper macro

[Luo Jiaxing <luojiaxing@huawei.com>]

We already own DEFINE_SHOW_ATTRIBUTE() helper macro for defining attribute
for read-only file, but many of drivers want a helper macro for read-write
file too.

So we make one to decrease code duplication.

Signed-off-by: Luo Jiaxing <luojiaxing@huawei.com>
---
 include/linux/seq_file.h | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/include/linux/seq_file.h b/include/linux/seq_file.h
index 813614d..8a474c8 100644
--- a/include/linux/seq_file.h
+++ b/include/linux/seq_file.h
@@ -191,6 +191,21 @@ static const struct proc_ops __name ## _proc_ops = {			\
 	.proc_release	= single_release,				\
 }
 
+#define DEFINE_SHOW_STORE_ATTRIBUTE(__name)					\
+static int __name ## _open(struct inode *inode, struct file *file)	\
+{									\
+	return single_open(file, __name ## _show, inode->i_private);	\
+}									\
+									\
+static const struct file_operations __name ## _fops = {			\
+	.owner		= THIS_MODULE,					\
+	.open		= __name ## _open,				\
+	.read		= seq_read,					\
+	.write		= __name ## _write,				\
+	.llseek		= seq_lseek,					\
+	.release	= single_release,				\
+}
+
 static inline struct user_namespace *seq_user_ns(struct seq_file *seq)
 {
 #ifdef CONFIG_USER_NS
-- 
2.7.4