seq_file: add helper macro to define attribute for rw file

Patch series "Add helper macro DEFINE_SHOW_STORE_ATTRIBUTE() at
seq_file.c", v6.

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

So we add this helper macro to reduce duplicated code.


This patch (of 3):

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 add DEFINE_SHOW_STORE_ATTRIBUTE() helper to reduce duplicated code.

Link: https://lkml.kernel.org/r/[email protected]
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Luo Jiaxing <[email protected]>
Co-developed-by: Xingui Yang <[email protected]>
Signed-off-by: Xingui Yang <[email protected]>
Reviewed-by: Andy Shevchenko <[email protected]>
Cc: Al Viro <[email protected]>
Cc: Animesh Manna <[email protected]>
Cc: Anshuman Gupta <[email protected]>
Cc: Damien Le Moal <[email protected]>
Cc: Felipe Balbi <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: Himanshu Madhani <[email protected]>
Cc: James Bottomley <[email protected]>
Cc: John Garry <[email protected]>
Cc: Martin K. Petersen <[email protected]>
Cc: Uma Shankar <[email protected]>
Cc: Xiang Chen <[email protected]>
Cc: Zeng Tao <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

1 files changed, 15 insertions, 0 deletions

diff --git a/include/linux/seq_file.h b/include/linux/seq_file.h
index 386ab580b839..234bcdb1fba4 100644
--- a/include/linux/seq_file.h
+++ b/include/linux/seq_file.h
@@ -207,6 +207,21 @@ static const struct file_operations __name ## _fops = {			\
 	.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,				\
+}
+
 #define DEFINE_PROC_SHOW_ATTRIBUTE(__name)				\
 static int __name ## _open(struct inode *inode, struct file *file)	\
 {									\