Re: [PATCH v1 1/2] Add FAT messages to printk index

Re: [PATCH v1 1/2] Add FAT messages to printk index

[OGAWA Hirofumi]

Jonathan Lassoff <jof@thejof.com> writes:

> In order for end users to quickly react to new issues that come up in
> production, it is proving useful to leverage the printk indexing system. This
> printk index enables kernel developers to use calls to printk() with changable
> ad-hoc format strings, while still enabling end users to detect changes and
> develop a semi-stable interface for detecting and parsing these messages.
>
> So that detailed FAT messages are captured by this printk index, this patch
> wraps fat_msg with a macro.
>
> PATCH v1 -- Fix indentation with tabs in fat_msg macro
>
> Signed-off-by: Jonathan Lassoff <jof@thejof.com>

Looks good. I prefer removing duplication of message prefix though, not
strong opinion.

e.g.
	#define FAT_MSG_PFX		"%sFAT-fs (%s): "
	printk_index_subsys_emit(FAT_MSG_PFX, level, fmt, ##args);\
	_printk(FAT_MSG_PFX "%pV\n", level, sb->s_id, &vaf);

Anyway, if this is same style with others, it is ok.

Acked-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>

> ---
>  fs/fat/fat.h  | 8 +++++++-
>  fs/fat/misc.c | 4 ++--
>  2 files changed, 9 insertions(+), 3 deletions(-)
>
> diff --git a/fs/fat/fat.h b/fs/fat/fat.h
> index 02d4d4234956..9b7f917dfe68 100644
> --- a/fs/fat/fat.h
> +++ b/fs/fat/fat.h
> @@ -433,8 +433,14 @@ void __fat_fs_error(struct super_block *sb, int report, const char *fmt, ...);
>  	__fat_fs_error(sb, 1, fmt , ## args)
>  #define fat_fs_error_ratelimit(sb, fmt, args...) \
>  	__fat_fs_error(sb, __ratelimit(&MSDOS_SB(sb)->ratelimit), fmt , ## args)
> +
> +#define fat_msg(sb, level, fmt, args...)				\
> +do {									\
> +	printk_index_subsys_emit("%sFAT-fs (%s): ", level, fmt, ##args);\
> +	_fat_msg(sb, level, fmt, ##args);				\
> +} while(0)
>  __printf(3, 4) __cold
> -void fat_msg(struct super_block *sb, const char *level, const char *fmt, ...);
> +void _fat_msg(struct super_block *sb, const char *level, const char *fmt, ...);
>  #define fat_msg_ratelimit(sb, level, fmt, args...)	\
>  	do {	\
>  			if (__ratelimit(&MSDOS_SB(sb)->ratelimit))	\
> diff --git a/fs/fat/misc.c b/fs/fat/misc.c
> index 91ca3c304211..b0808bb0c75f 100644
> --- a/fs/fat/misc.c
> +++ b/fs/fat/misc.c
> @@ -45,7 +45,7 @@ EXPORT_SYMBOL_GPL(__fat_fs_error);
>   * fat_msg() - print preformated FAT specific messages. Every thing what is
>   * not fat_fs_error() should be fat_msg().
>   */
> -void fat_msg(struct super_block *sb, const char *level, const char *fmt, ...)
> +void _fat_msg(struct super_block *sb, const char *level, const char *fmt, ...)
>  {
>  	struct va_format vaf;
>  	va_list args;
> @@ -53,7 +53,7 @@ void fat_msg(struct super_block *sb, const char *level, const char *fmt, ...)
>  	va_start(args, fmt);
>  	vaf.fmt = fmt;
>  	vaf.va = &args;
> -	printk("%sFAT-fs (%s): %pV\n", level, sb->s_id, &vaf);
> +	_printk("%sFAT-fs (%s): %pV\n", level, sb->s_id, &vaf);
>  	va_end(args);
>  }

-- 
OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>

Re: [PATCH v1 1/2] Add FAT messages to printk index

[Jonathan Lassoff]

On Thu, 17 Mar 2022 at 22:33, OGAWA Hirofumi
<hirofumi@mail.parknet.co.jp> wrote:

> Looks good. I prefer removing duplication of message prefix though, not
> strong opinion.
>
> e.g.
>         #define FAT_MSG_PFX             "%sFAT-fs (%s): "
>         printk_index_subsys_emit(FAT_MSG_PFX, level, fmt, ##args);\
>         _printk(FAT_MSG_PFX "%pV\n", level, sb->s_id, &vaf);
>
> Anyway, if this is same style with others, it is ok.

I would agree that defining a macro for the prefix may be useful. It
could be a nice hint to future developers that these things are
somewhat connected.

I can follow-up with a PATCH v2 to include what you suggest.

-- jof