From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753991AbdEQNnh (ORCPT ); Wed, 17 May 2017 09:43:37 -0400 Received: from mail.kernel.org ([198.145.29.99]:52616 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751637AbdEQNnf (ORCPT ); Wed, 17 May 2017 09:43:35 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 889EB239BA Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=goodmis.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=rostedt@goodmis.org Date: Wed, 17 May 2017 09:43:32 -0400 From: Steven Rostedt To: Felipe Balbi Cc: Alexander Shishkin , Ingo Molnar , linux-kernel@vger.kernel.org, Chunyan Zhang Subject: Re: [PATCH] kernel: trace: pass export pointer as argument to ->write() Message-ID: <20170517094332.521ea67a@gandalf.local.home> In-Reply-To: <20170517080554.1915-1-felipe.balbi@linux.intel.com> References: <20170517080554.1915-1-felipe.balbi@linux.intel.com> X-Mailer: Claws Mail 3.14.0 (GTK+ 2.24.31; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 17 May 2017 11:05:54 +0300 Felipe Balbi 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 Acked-by: Steven Rostedt (VMware) -- Steve > --- > > 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);