On Thu, 13 Sep 2018 16:12:54 +0900
Sergey Senozhatsky <sergey.senozhatsky.w...@gmail.com> wrote:
Signed-off-by: Sergey Senozhatsky <sergey.senozhat...@gmail.com>
> ---
>  include/linux/seq_buf.h | 35 +++++++++++++++++++++++++++++++
>  lib/seq_buf.c           | 46 +++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 81 insertions(+)
> 
> diff --git a/include/linux/seq_buf.h b/include/linux/seq_buf.h
> index aa5deb041c25..5e9a5ff9a440 100644
> --- a/include/linux/seq_buf.h
> +++ b/include/linux/seq_buf.h
> @@ -23,6 +23,36 @@ struct seq_buf {
>       loff_t                  readpos;
>  };
>  
> +#define __SEQ_BUF_INITIALIZER(buf, length) {                         \
> +     .buffer                 = (buf),                                \
> +     .size                   = (length),                             \
> +     .len                    = 0,                                    \
> +     .readpos                = 0, }

Nit, but the end bracket '}' should be on it's own line. Even when
part of a macro.

> +
> +#ifdef CONFIG_PRINTK
> +#define __PR_LINE_BUF_SZ     80
> +#else
> +#define __PR_LINE_BUF_SZ     0
> +#endif
> +
> +struct pr_line {
> +     struct seq_buf          sb;
> +     char                    *level;
> +};
> +
> +#define DEFINE_PR_LINE(lev, name)                                    \
> +     char            __line[__PR_LINE_BUF_SZ];                       \

To protect against name space collision could you use:

        char            __line_##name[__PR_LINE_BUF_SZ];

> +     struct pr_line  name = {                                        \
> +             .sb = __SEQ_BUF_INITIALIZER(__line, __PR_LINE_BUF_SZ),  \
> +             .level  = lev,                                          \
> +     }
> +
> +#define DEFINE_PR_LINE_BUF(lev, name, buf, sz)                               
> \
> +     struct pr_line  name = {                                        \
> +             .sb = __SEQ_BUF_INITIALIZER(buf, (sz)),         \
> +             .level  = lev,                                          \
> +     }
> +
>  static inline void seq_buf_clear(struct seq_buf *s)
>  {
>       s->len = 0;
> @@ -131,4 +161,9 @@ extern int
>  seq_buf_bprintf(struct seq_buf *s, const char *fmt, const u32 *binary);
>  #endif
>  
> +extern __printf(2, 0)
> +int vpr_line(struct pr_line *pl, const char *fmt, va_list args);
> +extern __printf(2, 3)
> +int pr_line(struct pr_line *pl, const char *fmt, ...);
> +extern void pr_line_flush(struct pr_line *pl);
>  #endif /* _LINUX_SEQ_BUF_H */
> diff --git a/lib/seq_buf.c b/lib/seq_buf.c
> index 11f2ae0f9099..29bc4f24b83e 100644
> --- a/lib/seq_buf.c
> +++ b/lib/seq_buf.c
> @@ -324,3 +324,49 @@ int seq_buf_to_user(struct seq_buf *s, char __user 
> *ubuf, int cnt)
>       s->readpos += cnt;
>       return cnt;
>  }
> +
> +int vpr_line(struct pr_line *pl, const char *fmt, va_list args)
> +{
> +     struct seq_buf *s = &pl->sb;
> +     int ret, len;
> +
> +     if (fmt[0] == '\n') {
> +             pr_line_flush(pl);
> +             return 0;
> +     }
> +
> +     ret = seq_buf_vprintf(s, fmt, args);
> +
> +     len = seq_buf_used(s);
> +     if (len && s->buffer[len - 1] == '\n')
> +             pr_line_flush(pl);
> +
> +     return ret;
> +}
> +EXPORT_SYMBOL(vpr_line);
> +
> +int pr_line(struct pr_line *pl, const char *fmt, ...)
> +{
> +     va_list ap;
> +     int ret;
> +
> +     va_start(ap, fmt);
> +     ret = vpr_line(pl, fmt, ap);
> +     va_end(ap);
> +
> +     return ret;
> +}
> +EXPORT_SYMBOL(pr_line);
> +
> +void pr_line_flush(struct pr_line *pl)
> +{
> +     struct seq_buf *s = &pl->sb;
> +     int len = seq_buf_used(s);
> +
> +     if (!len)
> +             return;
> +
> +     printk("%s%.*s", pl->level, len, s->buffer);
> +     seq_buf_clear(s);
> +}
> +EXPORT_SYMBOL(pr_line_flush);

The rest looks fine to me.

Acked-by: Steven Rostedt (VMware) <rost...@goodmis.org>

-- Steve

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