[PATCH v2 2/9] log: don't build the trace buffer when log is not ready

[Sean Anderson <seanga2@gmail.com>]

On 11/27/20 5:20 AM, Patrick Delaunay wrote:
> Update _log function to drop any traces when log is yet initialized:
> vsnprintf is no more executed in this case.
> 
> This patch allows to reduce the cost for the dropped early debug trace.
> 
> Reviewed-by: Simon Glass <sjg@chromium.org>
> Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>
> ---
> 
> (no changes since v1)
> 
>   common/log.c | 13 ++++++++-----
>   1 file changed, 8 insertions(+), 5 deletions(-)
> 
> diff --git a/common/log.c b/common/log.c
> index ce39918e04..212789d6b3 100644
> --- a/common/log.c
> +++ b/common/log.c
> @@ -228,6 +228,9 @@ int _log(enum log_category_t cat, enum log_level_t level, const char *file,
>   	struct log_rec rec;
>   	va_list args;
>   
> +	if (!gd)
> +		return -ENOSYS;

How early are you expecting this function to get called? AFAIK this will
only return true before board_init_f_init_reserve. Shouldn't functions
that early just not call log in the first place?

--Sean

> +
>   	/* Check for message continuation */
>   	if (cat == LOGC_CONT)
>   		cat = gd->logc_prev;
> @@ -240,15 +243,15 @@ int _log(enum log_category_t cat, enum log_level_t level, const char *file,
>   	rec.file = file;
>   	rec.line = line;
>   	rec.func = func;
> +
> +	if (!(gd->flags & GD_FLG_LOG_READY)) {
> +		gd->log_drop_count++;
> +		return -ENOSYS;
> +	}
>   	va_start(args, fmt);
>   	vsnprintf(buf, sizeof(buf), fmt, args);
>   	va_end(args);
>   	rec.msg = buf;
> -	if (!gd || !(gd->flags & GD_FLG_LOG_READY)) {
> -		if (gd)
> -			gd->log_drop_count++;
> -		return -ENOSYS;
> -	}
>   	if (!log_dispatch(&rec)) {
>   		gd->logc_prev = cat;
>   		gd->logl_prev = level;
>