[PATCH v2 11/16] coresight: tmc-etr: Refactor function tmc_etr_setup_perf_buf()

From: Mathieu Poirier <mathieu.poirier@linaro.org>
To: linux-arm-kernel@lists.infradead.org
Cc: suzuki.poulose@arm.com, alexander.shishkin@linux.intel.com,
	coresight@lists.linaro.org, peterz@infradead.org,
	mike.leach@arm.com, leo.yan@linaro.org
Subject: [PATCH v2 11/16] coresight: tmc-etr: Refactor function tmc_etr_setup_perf_buf()
Date: Mon, 25 Mar 2019 15:56:27 -0600	[thread overview]
Message-ID: <20190325215632.17013-12-mathieu.poirier@linaro.org> (raw)
In-Reply-To: <20190325215632.17013-1-mathieu.poirier@linaro.org>

Refactoring function tmc_etr_setup_perf_buf() so that it only deals
with the high level etr_perf_buffer, and leaving the allocation of the
backend buffer (i.e etr_buf) to another function.

That way the backend buffer allocation function can decide if it wants
to reuse an existing buffer (CPU-wide trace scenarios) or simply create
a new one.

Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
---
 .../hwtracing/coresight/coresight-tmc-etr.c   | 46 +++++++++++++------
 1 file changed, 31 insertions(+), 15 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c b/drivers/hwtracing/coresight/coresight-tmc-etr.c
index 6e2c2aa130d5..79fee9341446 100644
--- a/drivers/hwtracing/coresight/coresight-tmc-etr.c
+++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c
@@ -1159,25 +1159,13 @@ static int tmc_enable_etr_sink_sysfs(struct coresight_device *csdev)
 	return ret;
 }
 
-/*
- * tmc_etr_setup_perf_buf: Allocate ETR buffer for use by perf.
- * The size of the hardware buffer is dependent on the size configured
- * via sysfs and the perf ring buffer size. We prefer to allocate the
- * largest possible size, scaling down the size by half until it
- * reaches a minimum limit (1M), beyond which we give up.
- */
-static struct etr_perf_buffer *
-tmc_etr_setup_perf_buf(struct tmc_drvdata *drvdata, int node, int nr_pages,
-		       void **pages, bool snapshot)
+static struct etr_buf *
+tmc_etr_get_etr_buf(struct tmc_drvdata *drvdata, int node,
+		    int nr_pages, void **pages)
 {
 	struct etr_buf *etr_buf;
-	struct etr_perf_buffer *etr_perf;
 	unsigned long size;
 
-	etr_perf = kzalloc_node(sizeof(*etr_perf), GFP_KERNEL, node);
-	if (!etr_perf)
-		return ERR_PTR(-ENOMEM);
-
 	/*
 	 * Try to match the perf ring buffer size if it is larger
 	 * than the size requested via sysfs.
@@ -1201,6 +1189,34 @@ tmc_etr_setup_perf_buf(struct tmc_drvdata *drvdata, int node, int nr_pages,
 		size /= 2;
 	} while (size >= TMC_ETR_PERF_MIN_BUF_SIZE);
 
+	return ERR_PTR(-ENOMEM);
+
+done:
+	return etr_buf;
+}
+
+/*
+ * tmc_etr_setup_perf_buf: Allocate ETR buffer for use by perf.
+ * The size of the hardware buffer is dependent on the size configured
+ * via sysfs and the perf ring buffer size. We prefer to allocate the
+ * largest possible size, scaling down the size by half until it
+ * reaches a minimum limit (1M), beyond which we give up.
+ */
+static struct etr_perf_buffer *
+tmc_etr_setup_perf_buf(struct tmc_drvdata *drvdata, int node,
+		       int nr_pages, void **pages, bool snapshot)
+{
+	struct etr_buf *etr_buf;
+	struct etr_perf_buffer *etr_perf;
+
+	etr_perf = kzalloc_node(sizeof(*etr_perf), GFP_KERNEL, node);
+	if (!etr_perf)
+		return ERR_PTR(-ENOMEM);
+
+	etr_buf = tmc_etr_get_etr_buf(drvdata, node, nr_pages, pages);
+	if (!IS_ERR(etr_buf))
+		goto done;
+
 	kfree(etr_perf);
 	return ERR_PTR(-ENOMEM);
 
-- 
2.17.1


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