Re: [PATCH 1/3] seq_file: Introduce DEFINE_SEQ_ATTRIBUTE() helper macro

Re: [PATCH 1/3] seq_file: Introduce DEFINE_SEQ_ATTRIBUTE() helper macro

[Markus Elfring]

…
> +++ b/include/linux/seq_file.h
> @@ -145,6 +145,25 @@ void *__seq_open_private(struct file *, const struct seq_operations *, int);
> 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)	\
…

Can such a macro work also with an identifier which does not contain
double underscores?

Regards,
Markus

[PATCH 0/3] seq_file: Introduce DEFINE_SEQ_ATTRIBUTE() helper macro

[Kefeng Wang]

As discussion in https://lore.kernel.org/lkml/20191129222310.GA3712618@kroah.com/,
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 clean ups.

Kefeng Wang (3):
  seq_file: Introduce DEFINE_SEQ_ATTRIBUTE() helper macro
  mm: vmstat: Convert to use DEFINE_SEQ_ATTRIBUTE macro
  kernel: kprobes: Convert to use DEFINE_SEQ_ATTRIBUTE macro

 include/linux/seq_file.h | 19 +++++++++++++++++++
 kernel/kprobes.c         | 33 ++++++---------------------------
 mm/vmstat.c              | 32 ++++++--------------------------
 3 files changed, 31 insertions(+), 53 deletions(-)

-- 
2.26.2

[PATCH 1/3] seq_file: Introduce DEFINE_SEQ_ATTRIBUTE() helper macro

[Kefeng Wang]

Introduce DEFINE_SEQ_ATTRIBUTE() helper macro to decrease code duplication.

Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
---
 include/linux/seq_file.h | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/include/linux/seq_file.h b/include/linux/seq_file.h
index 1672cf6f7614..c77869cf7d10 100644
--- a/include/linux/seq_file.h
+++ b/include/linux/seq_file.h
@@ -145,6 +145,25 @@ void *__seq_open_private(struct file *, const struct seq_operations *, int);
 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)	\
 {									\
-- 
2.26.2