Re: [PATCH v2] tracing: make ftrace_print_array_seq compute buf_len

[Dave P Martin]

On Wed, Apr 29, 2015 at 04:18:46PM +0100, Alex Bennée wrote:
> The only caller to this function (__print_array) was getting it wrong by
> passing the array length instead of buffer length. As the element size
> was already being passed for other reasons it seems reasonable to push
> the calculation of buffer length into the function.
> 
> Signed-off-by: Alex Bennée <alex.bennee@xxxxxxxxxx>

That looks better, thanks.

Reviewed-by: Dave Martin <Dave.Martin@xxxxxxx>

> 
> ---
> v2:
>   - more explicit commit message
>   - rename len -> count to reduce ambiguity
> ---
>  include/linux/ftrace_event.h | 2 +-
>  kernel/trace/trace_output.c  | 3 ++-
>  2 files changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h
> index c674ee8..33a66e6 100644
> --- a/include/linux/ftrace_event.h
> +++ b/include/linux/ftrace_event.h
> @@ -45,7 +45,7 @@ const char *ftrace_print_hex_seq(struct trace_seq *p,
>  				 const unsigned char *buf, int len);
>  
>  const char *ftrace_print_array_seq(struct trace_seq *p,
> -				   const void *buf, int buf_len,
> +				   const void *buf, int count,
>  				   size_t el_size);
>  
>  struct trace_iterator;
> diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c
> index 692bf71..25a086b 100644
> --- a/kernel/trace/trace_output.c
> +++ b/kernel/trace/trace_output.c
> @@ -178,12 +178,13 @@ ftrace_print_hex_seq(struct trace_seq *p, const unsigned char *buf, int buf_len)
>  EXPORT_SYMBOL(ftrace_print_hex_seq);
>  
>  const char *
> -ftrace_print_array_seq(struct trace_seq *p, const void *buf, int buf_len,
> +ftrace_print_array_seq(struct trace_seq *p, const void *buf, int count,
>  		       size_t el_size)
>  {
>  	const char *ret = trace_seq_buffer_ptr(p);
>  	const char *prefix = "";
>  	void *ptr = (void *)buf;
> +	size_t buf_len = count * el_size;
>  
>  	trace_seq_putc(p, '{');
>  
> -- 
> 2.3.5
> 

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