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:   Thu,  8 Aug 2019 12:31:22 -0700
Message-Id: <20190808193122.76679-1-yabinc@google.com>
Mime-Version: 1.0
Subject: [PATCH] coresight: tmc-etr: Remove perf_data check.
From:   Yabin Cui <yabinc@google.com>
To:     Mathieu Poirier <mathieu.poirier@linaro.org>,
        Suzuki K Poulose <suzuki.poulose@arm.com>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc:     linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        Yabin Cui <yabinc@google.com>
Content-Type: text/plain; charset="UTF-8"
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

When tracing etm data of multiple threads on multiple cpus through
perf interface, each cpu has a unique etr_perf_buffer while sharing
the same etr device. There is no guarantee that the last cpu starts
etm tracing also stops last. So the perf_data check is no longer valid.

Signed-off-by: Yabin Cui <yabinc@google.com>
---
 drivers/hwtracing/coresight/coresight-tmc-etr.c | 9 ---------
 drivers/hwtracing/coresight/coresight-tmc.h     | 2 --
 2 files changed, 11 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c b/drivers/hwtracing/coresight/coresight-tmc-etr.c
index 17006705287a..0418440e0141 100644
--- a/drivers/hwtracing/coresight/coresight-tmc-etr.c
+++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c
@@ -1484,20 +1484,12 @@ tmc_update_etr_buffer(struct coresight_device *csdev,
 		goto out;
 	}
 
-	if (WARN_ON(drvdata->perf_data != etr_perf)) {
-		lost = true;
-		spin_unlock_irqrestore(&drvdata->spinlock, flags);
-		goto out;
-	}
-
 	CS_UNLOCK(drvdata->base);
 
 	tmc_flush_and_stop(drvdata);
 	tmc_sync_etr_buf(drvdata);
 
 	CS_LOCK(drvdata->base);
-	/* Reset perf specific data */
-	drvdata->perf_data = NULL;
 	spin_unlock_irqrestore(&drvdata->spinlock, flags);
 
 	size = etr_buf->len;
@@ -1556,7 +1548,6 @@ static int tmc_enable_etr_sink_perf(struct coresight_device *csdev, void *data)
 	}
 
 	etr_perf->head = PERF_IDX2OFF(handle->head, etr_perf);
-	drvdata->perf_data = etr_perf;
 
 	/*
 	 * No HW configuration is needed if the sink is already in
diff --git a/drivers/hwtracing/coresight/coresight-tmc.h b/drivers/hwtracing/coresight/coresight-tmc.h
index 1ed50411cc3c..3881a9ee565a 100644
--- a/drivers/hwtracing/coresight/coresight-tmc.h
+++ b/drivers/hwtracing/coresight/coresight-tmc.h
@@ -178,7 +178,6 @@ struct etr_buf {
  *		device configuration register (DEVID)
  * @idr:	Holds etr_bufs allocated for this ETR.
  * @idr_mutex:	Access serialisation for idr.
- * @perf_data:	PERF buffer for ETR.
  * @sysfs_data:	SYSFS buffer for ETR.
  */
 struct tmc_drvdata {
@@ -202,7 +201,6 @@ struct tmc_drvdata {
 	struct idr		idr;
 	struct mutex		idr_mutex;
 	struct etr_buf		*sysfs_buf;
-	void			*perf_data;
 };
 
 struct etr_buf_operations {
-- 
2.22.0.770.g0f2c4a37fd-goog