Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Date:   Tue, 3 Jul 2018 15:40:26 +0200
From:   Jiri Olsa <jolsa@redhat.com>
To:     Mathieu Poirier <mathieu.poirier@linaro.org>
Cc:     peterz@infradead.org, acme@kernel.org, mingo@redhat.com,
        tglx@linutronix.de, alexander.shishkin@linux.intel.com,
        schwidefsky@de.ibm.com, heiko.carstens@de.ibm.com,
        will.deacon@arm.com, mark.rutland@arm.com, namhyung@kernel.org,
        adrian.hunter@intel.com, ast@kernel.org,
        gregkh@linuxfoundation.org, hpa@zytor.com,
        linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 5/6] perf/core: Use ioctl to communicate driver
 configuration to kernel
Message-ID: <20180703134026.GA3728@krava>
References: <1530570810-28929-1-git-send-email-mathieu.poirier@linaro.org>
 <1530570810-28929-6-git-send-email-mathieu.poirier@linaro.org>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <1530570810-28929-6-git-send-email-mathieu.poirier@linaro.org>
User-Agent: Mutt/1.10.0 (2018-05-17)
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Mon, Jul 02, 2018 at 04:33:29PM -0600, Mathieu Poirier wrote:

SNIP

> +static int
> +perf_event_process_drv_config(struct perf_event *event, char *config_str)
> +{
> +	int ret = -EINVAL;
> +	void *drv_data;
> +
> +	/* Make sure ctx.mutex it held */
> +	lockdep_assert_held(&event->ctx->mutex);
> +
> +	/* Children take their configuration from their parent */
> +	if (WARN_ON_ONCE(event->parent))
> +		goto out;
> +
> +	drv_data = event->pmu->drv_config_validate(event, config_str);
> +	if (!drv_data)
> +		goto out;

what's this check for? doc does not mention that,
also the coresight callback does not return NULL

jirka