linux-kernel - [PATCH v3 13/20] coresight: tmc-etr: Create per-thread buffer allocation function

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Date:   Wed,  3 Apr 2019 21:35:34 -0600
From:   Mathieu Poirier <mathieu.poirier@...aro.org>
To:     linux-arm-kernel@...ts.infradead.org
Cc:     alexander.shishkin@...ux.intel.com, peterz@...radead.org,
        suzuki.poulose@....com, mike.leach@....com, leo.yan@...aro.org,
        coresight@...ts.linaro.org, linux-kernel@...r.kernel.org
Subject: [PATCH v3 13/20] coresight: tmc-etr: Create per-thread buffer allocation function

Buffer allocation is different when dealing with per-thread and
CPU-wide sessions.  In preparation to support CPU-wide trace scenarios
simplify things by keeping allocation functions for both type separate.

Signed-off-by: Mathieu Poirier <mathieu.poirier@...aro.org>
---
 .../hwtracing/coresight/coresight-tmc-etr.c   | 29 ++++++++++++++++++-
 1 file changed, 28 insertions(+), 1 deletion(-)

diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c b/drivers/hwtracing/coresight/coresight-tmc-etr.c
index e9c77009188a..ac1efdfc0d07 100644
--- a/drivers/hwtracing/coresight/coresight-tmc-etr.c
+++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c
@@ -1206,6 +1206,33 @@ alloc_etr_buf(struct tmc_drvdata *drvdata, struct perf_event *event,
 	return etr_buf;
 }
 
+static struct etr_buf *
+get_perf_etr_buf_per_thread(struct tmc_drvdata *drvdata,
+			    struct perf_event *event, int nr_pages,
+			    void **pages, bool snapshot)
+{
+	struct etr_buf *etr_buf;
+
+	/*
+	 * In per-thread mode the etr_buf isn't shared, so just go ahead
+	 * with memory allocation.
+	 */
+	etr_buf = alloc_etr_buf(drvdata, event, nr_pages, pages, snapshot);
+
+	return etr_buf;
+}
+
+static struct etr_buf *
+get_perf_etr_buf(struct tmc_drvdata *drvdata, struct perf_event *event,
+		 int nr_pages, void **pages, bool snapshot)
+{
+	if (event->cpu == -1)
+		return get_perf_etr_buf_per_thread(drvdata, event, nr_pages,
+						   pages, snapshot);
+
+	return ERR_PTR(-ENOENT);
+}
+
 static struct etr_perf_buffer *
 tmc_etr_setup_perf_buf(struct tmc_drvdata *drvdata, struct perf_event *event,
 		       int nr_pages, void **pages, bool snapshot)
@@ -1222,7 +1249,7 @@ tmc_etr_setup_perf_buf(struct tmc_drvdata *drvdata, struct perf_event *event,
 	if (!etr_perf)
 		return ERR_PTR(-ENOMEM);
 
-	etr_buf = alloc_etr_buf(drvdata, event, nr_pages, pages, snapshot);
+	etr_buf = get_perf_etr_buf(drvdata, event, nr_pages, pages, snapshot);
 	if (!IS_ERR(etr_buf))
 		goto done;
 
-- 
2.17.1