[PATCH 15/24] gtrace: Only copy AUX data from the path sink

[Zane Leung]

gtrace_path_copyto_auxbuf() walked the path and copied from the first
component implementing copyto_auxbuf(). For a linksink like ETF used as
a link, this picked the wrong component. Call the sink's callback
directly via gtrace_path_sink() and pass the perf handle so the sink
can set AUX flags itself.

Signed-off-by: Zane Leung <liangzhen@xxxxxxxxxxxxxxxxxx>
---
 drivers/hwtracing/gtrace/gtrace-core.c     | 39 ++++++++++------------
 drivers/hwtracing/gtrace/gtrace-perf.c     | 13 ++------
 drivers/hwtracing/gtrace/rvtrace-ramsink.c | 10 ++++--
 include/linux/gtrace.h                     | 10 +++---
 4 files changed, 34 insertions(+), 38 deletions(-)

diff --git a/drivers/hwtracing/gtrace/gtrace-core.c b/drivers/hwtracing/gtrace/gtrace-core.c
index 231d06218d8e..a42b1844da29 100644
--- a/drivers/hwtracing/gtrace/gtrace-core.c
+++ b/drivers/hwtracing/gtrace/gtrace-core.c
@@ -806,14 +806,14 @@ int gtrace_path_stop(struct gtrace_path *path)
 EXPORT_SYMBOL_GPL(gtrace_path_stop);
 
 int gtrace_path_copyto_auxbuf(struct gtrace_path *path,
+			      struct perf_output_handle *handle,
 			      struct gtrace_perf_auxbuf *buf,
-			      size_t *bytes_copied, u64 *format)
+			      size_t *bytes_copied)
 {
-	struct gtrace_comp_priv *sink = to_gtrace_comp_priv(gtrace_path_sink(path));
-	const struct gtrace_driver *gtdrv;
-	struct gtrace_component *comp;
-	struct gtrace_path_node *node;
-	int ret = -EOPNOTSUPP;
+	struct gtrace_component *sink = gtrace_path_sink(path);
+	struct gtrace_comp_priv *spriv = to_gtrace_comp_priv(sink);
+	const struct gtrace_driver *sinkdrv = to_gtrace_driver(sink->dev.driver);
+	int ret = 0;
 	unsigned long flags;
 
 	/*
@@ -823,25 +823,20 @@ int gtrace_path_copyto_auxbuf(struct gtrace_path *path,
 	 * sink's lock also stops another path from starting the sink before copy
 	 * completes.
 	 */
-	raw_spin_lock_irqsave(&sink->lock, flags);
-	if (sink->start_count) {
-		*bytes_copied = 0;
-		ret = 0;
-		goto out;
-	}
-
-	list_for_each_entry(node, &path->comp_list, head) {
-		comp = node->comp;
-		gtdrv = to_gtrace_driver(comp->dev.driver);
-		if (!gtdrv || !gtdrv->copyto_auxbuf)
-			continue;
+	raw_spin_lock_irqsave(&spriv->lock, flags);
+	if (!spriv->start_count) {
+		if (!sinkdrv) {
+			ret = -ENODEV;
+			goto out;
+		}
 
-		*bytes_copied = gtdrv->copyto_auxbuf(comp, buf, format);
-		ret = 0;
-		break;
+		if (sinkdrv->copyto_auxbuf) {
+			*bytes_copied = sinkdrv->copyto_auxbuf(sink, handle, buf);
+			ret = 0;
+		}
 	}
 out:
-	raw_spin_unlock_irqrestore(&sink->lock, flags);
+	raw_spin_unlock_irqrestore(&spriv->lock, flags);
 	return ret;
 }
 EXPORT_SYMBOL_GPL(gtrace_path_copyto_auxbuf);
diff --git a/drivers/hwtracing/gtrace/gtrace-perf.c b/drivers/hwtracing/gtrace/gtrace-perf.c
index 604b673a29d5..3c8b620df5a8 100644
--- a/drivers/hwtracing/gtrace/gtrace-perf.c
+++ b/drivers/hwtracing/gtrace/gtrace-perf.c
@@ -243,7 +243,6 @@ static void gtrace_event_stop(struct perf_event *event, int mode)
 {
 	struct gtrace_ctxt *ctxt = this_cpu_ptr(&gtrace_ctxt);
 	struct perf_output_handle *handle = &ctxt->handle;
-	u64 format = PERF_AUX_FLAG_GTRACE_FORMAT_UNKNOWN;
 	struct gtrace_event_data *event_data;
 	int ret, cpu = smp_processor_id();
 	struct gtrace_path *path;
@@ -280,17 +279,11 @@ static void gtrace_event_stop(struct perf_event *event, int mode)
 	if (handle->event && (mode & PERF_EF_UPDATE)) {
 		if (WARN_ON_ONCE(handle->event != event))
 			return;
-		ret = gtrace_path_copyto_auxbuf(path, &event_data->buf, &size, &format);
+		ret = gtrace_path_copyto_auxbuf(path, handle, &event_data->buf, &size);
 		WARN_ON_ONCE(ret);
-		if (READ_ONCE(handle->event)) {
-			/* Tag the AUX data with the source's trace format. */
-			perf_aux_output_flag(handle, format);
-			if (size > handle->size) {
-				size = handle->size;
-				perf_aux_output_flag(handle, PERF_AUX_FLAG_TRUNCATED);
-			}
+		if (READ_ONCE(handle->event))
 			perf_aux_output_end(handle, size);
-		} else
+		else
 			WARN_ON(size);
 	}
 
diff --git a/drivers/hwtracing/gtrace/rvtrace-ramsink.c b/drivers/hwtracing/gtrace/rvtrace-ramsink.c
index 9588c32c5b13..e0826d3f0d60 100644
--- a/drivers/hwtracing/gtrace/rvtrace-ramsink.c
+++ b/drivers/hwtracing/gtrace/rvtrace-ramsink.c
@@ -11,6 +11,7 @@
 #include <linux/minmax.h>
 #include <linux/types.h>
 #include <linux/sizes.h>
+#include <linux/perf_event.h>
 #include <uapi/linux/perf_event.h>
 #include "rvtrace.h"
 
@@ -147,8 +148,8 @@ static void tbuf_to_pbuf_copy(struct trace_buf *src, struct trace_buf *dst, size
 }
 
 static size_t rvtrace_ramsink_copyto_auxbuf(struct gtrace_component *comp,
-					    struct gtrace_perf_auxbuf *buf,
-					    u64 *format)
+					    struct perf_output_handle *handle,
+					    struct gtrace_perf_auxbuf *buf)
 {
 	struct rvtrace_ramsink_priv *priv = dev_get_drvdata(&comp->dev);
 	struct trace_buf src, dst;
@@ -181,6 +182,11 @@ static size_t rvtrace_ramsink_copyto_auxbuf(struct gtrace_component *comp,
 		priv->prev_wp = wp;
 	}
 
+	if (bytes > handle->size) {
+		bytes = handle->size;
+		perf_aux_output_flag(handle, PERF_AUX_FLAG_TRUNCATED);
+	}
+
 	tbuf_to_pbuf_copy(&src, &dst, bytes);
 	dev_dbg(&comp->dev, "Copied %zu bytes\n", bytes);
 	return bytes;
diff --git a/include/linux/gtrace.h b/include/linux/gtrace.h
index e9210b0a73b5..39ae13701615 100644
--- a/include/linux/gtrace.h
+++ b/include/linux/gtrace.h
@@ -13,6 +13,7 @@
 #include <linux/platform_device.h>
 #include <linux/property.h>
 #include <linux/types.h>
+#include <linux/perf_event.h>
 
 #define GTRACE_PMU_ATTR_CFG_CONTEXT_SHIFT	1
 #define GTRACE_PMU_ATTR_CFG_SYNCMODE_MASK	GENMASK(3, 2)
@@ -363,15 +364,16 @@ struct gtrace_perf_auxbuf {
 };
 
 int gtrace_path_copyto_auxbuf(struct gtrace_path *path,
+			      struct perf_output_handle *handle,
 			      struct gtrace_perf_auxbuf *buf,
-			      size_t *bytes_copied, u64 *format);
+			      size_t *bytes_copied);
 
 /**
  * struct gtrace_driver - Representation of a trace driver.
  * @id_table:      Table to match components handled by the driver.
  * @copyto_auxbuf: Callback to copy data into perf AUX buffer. The driver
  *                 reports the PMU specific trace format of the copied data
- *                 via @format (see PERF_AUX_FLAG_PMU_FORMAT_TYPE_MASK).
+ *                 via @handle (see PERF_AUX_FLAG_PMU_FORMAT_TYPE_MASK).
  * @start:         Callback to start tracing.
  * @stop:          Callback to stop tracing.
  * @start_port:    Callback to start a specific component port.
@@ -385,8 +387,8 @@ int gtrace_path_copyto_auxbuf(struct gtrace_path *path,
 struct gtrace_driver {
 	const struct gtrace_component_id *id_table;
 	size_t			(*copyto_auxbuf)(struct gtrace_component *comp,
-						 struct gtrace_perf_auxbuf *buf,
-						 u64 *format);
+						 struct perf_output_handle *handle,
+						 struct gtrace_perf_auxbuf *buf);
 	int			(*start)(struct gtrace_component *comp);
 	int			(*stop)(struct gtrace_component *comp);
 	int			(*start_port)(struct gtrace_component *comp,
-- 
2.34.1