On 17 May 2017 at 16:05, Felipe Balbi <felipe.ba...@linux.intel.com> wrote:
> That way, users don't need to keep a global static pointer and can
> rely on container_of() to fetch their own structure.
>
> Signed-off-by: Felipe Balbi <felipe.ba...@linux.intel.com>
Reviewed-by: Chunyan Zhang <zhang.chun...@linaro.org>
Thanks,
Chunyan
> ---
>
> I'm working on exposing this data over a USB peripheral controller and
> I really can't have a global pointer there.
>
> drivers/hwtracing/stm/ftrace.c | 6 ++++--
> include/linux/trace.h | 2 +-
> kernel/trace/trace.c | 2 +-
> 3 files changed, 6 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/hwtracing/stm/ftrace.c b/drivers/hwtracing/stm/ftrace.c
> index bd126a7c6da2..371b8333d9ae 100644
> --- a/drivers/hwtracing/stm/ftrace.c
> +++ b/drivers/hwtracing/stm/ftrace.c
> @@ -42,9 +42,11 @@ static struct stm_ftrace {
> * @len: length of the data packet
> */
> static void notrace
> -stm_ftrace_write(const void *buf, unsigned int len)
> +stm_ftrace_write(struct trace_export *export, const void *buf, unsigned int
> len)
> {
> - stm_source_write(&stm_ftrace.data, STM_FTRACE_CHAN, buf, len);
> + struct stm_ftrace *stm = container_of(export, struct stm_ftrace,
> ftrace);
> +
> + stm_source_write(stm->data, STM_FTRACE_CHAN, buf, len);
> }
>
> static int stm_ftrace_link(struct stm_source_data *data)
> diff --git a/include/linux/trace.h b/include/linux/trace.h
> index 9330a58e2651..477aed6f0caa 100644
> --- a/include/linux/trace.h
> +++ b/include/linux/trace.h
> @@ -17,7 +17,7 @@
> */
> struct trace_export {
> struct trace_export __rcu *next;
> - void (*write)(const void *, unsigned int);
> + void (*write)(struct trace_export *, const void *, unsigned int);
> };
>
> int register_ftrace_export(struct trace_export *export);
> diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
> index c4536c449021..6a96652a3b0f 100644
> --- a/kernel/trace/trace.c
> +++ b/kernel/trace/trace.c
> @@ -2317,7 +2317,7 @@ trace_process_export(struct trace_export *export,
>
> entry = ring_buffer_event_data(event);
> size = ring_buffer_event_length(event);
> - export->write(entry, size);
> + export->write(export, entry, size);
> }
>
> static DEFINE_MUTEX(ftrace_export_lock);
> --
> 2.11.0.295.gd7dffce1ce
>
