[093/127] include/linux/seq_file.h: introduce DEFINE_SEQ_ATTRIBUTE() helper macro

Commit Message

Andrew Morton June 4, 2020, 11:51 p.m. UTC

From: Kefeng Wang <[e-mail]>
Subject: include/linux/seq_file.h: introduce DEFINE_SEQ_ATTRIBUTE() helper macro

Patch series "seq_file: Introduce DEFINE_SEQ_ATTRIBUTE() helper macro".

As discussed in
https://lore.kernel.org/lkml/[e-mail]/, we could
introduce a new helper macro to reduce losts of boilerplate code, vmstat
and kprobes is the example which covert to use it, if this is accepted, I
will send out more cleanups.


This patch (of 3):

Introduce DEFINE_SEQ_ATTRIBUTE() helper macro to decrease code duplication.

[[e-mail]: coding style fixes]
Link: http://lkml.kernel.org/r/[e-mail]
Link: http://lkml.kernel.org/r/[e-mail]
Signed-off-by: Kefeng Wang <[e-mail]>
Cc: Greg KH <[e-mail]>
Cc: Ingo Molnar <[e-mail]>
Cc: Kefeng Wang <[e-mail]>
Cc: Anil S Keshavamurthy <[e-mail]>
Cc: "David S. Miller" <[e-mail]>
Cc: Masami Hiramatsu <[e-mail]>
Cc: Al Viro <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
---

 include/linux/seq_file.h |   19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

Patch

--- a/include/linux/seq_file.h~seq_file-introduce-define_seq_attribute-helper-macro
+++ a/include/linux/seq_file.h
@@ -145,6 +145,25 @@  void *__seq_open_private(struct file *,
 int seq_open_private(struct file *, const struct seq_operations *, int);
 int seq_release_private(struct inode *, struct file *);
 
+#define DEFINE_SEQ_ATTRIBUTE(__name)					\
+static int __name ## _open(struct inode *inode, struct file *file)	\
+{									\
+	int ret = seq_open(file, &__name ## _sops);			\
+	if (!ret && inode->i_private) {					\
+		struct seq_file *seq_f = file->private_data;		\
+		seq_f->private = inode->i_private;			\
+	}								\
+	return ret;							\
+}									\
+									\
+static const struct file_operations __name ## _fops = {			\
+	.owner		= THIS_MODULE,					\
+	.open		= __name ## _open,				\
+	.read		= seq_read,					\
+	.llseek		= seq_lseek,					\
+	.release	= seq_release,					\
+}
+
 #define DEFINE_SHOW_ATTRIBUTE(__name)					\
 static int __name ## _open(struct inode *inode, struct file *file)	\
 {									\