Re: [PATCH] xfs: define printk_once variants for xfs messages

[Brian Foster <bfoster@redhat.com>]

On Wed, Apr 22, 2020 at 09:36:34PM -0500, Eric Sandeen wrote:
> There are a couple places where we directly call printk_once() and one
> of them doesn't follow the standard xfs subsystem printk format as a
> result.
> 
> #define printk_once variants to go with our existing printk_ratelimited
> #defines so we can do one-shot printks in a consistent manner.
> 
> Signed-off-by: Eric Sandeen <sandeen@redhat.com>
> ---

LGTM:

Reviewed-by: Brian Foster <bfoster@redhat.com>

> 
> diff --git a/fs/xfs/xfs_message.h b/fs/xfs/xfs_message.h
> index 0b05e10995a0..802a96190d22 100644
> --- a/fs/xfs/xfs_message.h
> +++ b/fs/xfs/xfs_message.h
> @@ -31,15 +31,27 @@ void xfs_debug(const struct xfs_mount *mp, const char *fmt, ...)
>  }
>  #endif
>  
> -#define xfs_printk_ratelimited(func, dev, fmt, ...)		\
> +#define xfs_printk_ratelimited(func, dev, fmt, ...)			\
>  do {									\
>  	static DEFINE_RATELIMIT_STATE(_rs,				\
>  				      DEFAULT_RATELIMIT_INTERVAL,	\
>  				      DEFAULT_RATELIMIT_BURST);		\
>  	if (__ratelimit(&_rs))						\
> -		func(dev, fmt, ##__VA_ARGS__);			\
> +		func(dev, fmt, ##__VA_ARGS__);				\
>  } while (0)
>  
> +#define xfs_printk_once(func, dev, fmt, ...)			\
> +({								\
> +	static bool __section(.data.once) __print_once;		\
> +	bool __ret_print_once = !__print_once; 			\
> +								\
> +	if (!__print_once) {					\
> +		__print_once = true;				\
> +		func(dev, fmt, ##__VA_ARGS__);			\
> +	}							\
> +	unlikely(__ret_print_once);				\
> +})
> +
>  #define xfs_emerg_ratelimited(dev, fmt, ...)				\
>  	xfs_printk_ratelimited(xfs_emerg, dev, fmt, ##__VA_ARGS__)
>  #define xfs_alert_ratelimited(dev, fmt, ...)				\
> @@ -57,6 +69,11 @@ do {									\
>  #define xfs_debug_ratelimited(dev, fmt, ...)				\
>  	xfs_printk_ratelimited(xfs_debug, dev, fmt, ##__VA_ARGS__)
>  
> +#define xfs_warn_once(dev, fmt, ...)				\
> +	xfs_printk_once(xfs_warn, dev, fmt, ##__VA_ARGS__)
> +#define xfs_notice_once(dev, fmt, ...)				\
> +	xfs_printk_once(xfs_notice, dev, fmt, ##__VA_ARGS__)
> +
>  void assfail(struct xfs_mount *mp, char *expr, char *f, int l);
>  void asswarn(struct xfs_mount *mp, char *expr, char *f, int l);
>  
> diff --git a/fs/xfs/xfs_mount.c b/fs/xfs/xfs_mount.c
> index c5513e5a226a..bb91f04266b9 100644
> --- a/fs/xfs/xfs_mount.c
> +++ b/fs/xfs/xfs_mount.c
> @@ -1300,10 +1300,9 @@ xfs_mod_fdblocks(
>  		spin_unlock(&mp->m_sb_lock);
>  		return 0;
>  	}
> -	printk_once(KERN_WARNING
> -		"Filesystem \"%s\": reserve blocks depleted! "
> -		"Consider increasing reserve pool size.",
> -		mp->m_super->s_id);
> +	xfs_warn_once(mp,
> +"Reserve blocks depleted! Consider increasing reserve pool size.");
> +
>  fdblocks_enospc:
>  	spin_unlock(&mp->m_sb_lock);
>  	return -ENOSPC;
> diff --git a/fs/xfs/xfs_pnfs.c b/fs/xfs/xfs_pnfs.c
> index bb3008d390aa..b101feb2aab4 100644
> --- a/fs/xfs/xfs_pnfs.c
> +++ b/fs/xfs/xfs_pnfs.c
> @@ -58,9 +58,8 @@ xfs_fs_get_uuid(
>  {
>  	struct xfs_mount	*mp = XFS_M(sb);
>  
> -	printk_once(KERN_NOTICE
> -"XFS (%s): using experimental pNFS feature, use at your own risk!\n",
> -		mp->m_super->s_id);
> +	xfs_notice_once(mp,
> +"Using experimental pNFS feature, use at your own risk!");
>  
>  	if (*len < sizeof(uuid_t))
>  		return -EINVAL;
>