Coresight: Introduce a new struct coresight_path

Introduce a new strcuture, 'struct coresight_path', to store the data that
utilized by the devices in the path. The coresight_path will be built/released
by coresight_build_path/coresight_release_path functions.

Signed-off-by: Jie Gan <[email protected]>
Signed-off-by: Suzuki K Poulose <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

Author: Jie Gan

drivers/hwtracing/coresight/coresight-core.c

@@ -670,7 +670,7 @@ static void coresight_drop_device(struct coresight_device *csdev)
 static int _coresight_build_path(struct coresight_device *csdev,
 				 struct coresight_device *source,
 				 struct coresight_device *sink,
-				 struct list_head *path)
+				 struct coresight_path *path)
 {
 	int i, ret;
 	bool found = false;
@@ -723,25 +723,25 @@ static int _coresight_build_path(struct coresight_device *csdev,
 		return -ENOMEM;
 
 	node->csdev = csdev;
-	list_add(&node->link, path);
+	list_add(&node->link, &path->path_list);
 
 	return 0;
 }
 
-struct list_head *coresight_build_path(struct coresight_device *source,
+struct coresight_path *coresight_build_path(struct coresight_device *source,
 				       struct coresight_device *sink)
 {
-	struct list_head *path;
+	struct coresight_path *path;
 	int rc;
 
 	if (!sink)
 		return ERR_PTR(-EINVAL);
 
-	path = kzalloc(sizeof(struct list_head), GFP_KERNEL);
+	path = kzalloc(sizeof(struct coresight_path), GFP_KERNEL);
 	if (!path)
 		return ERR_PTR(-ENOMEM);
 
-	INIT_LIST_HEAD(path);
+	INIT_LIST_HEAD(&path->path_list);
 
 	rc = _coresight_build_path(source, source, sink, path);
 	if (rc) {
@@ -759,12 +759,12 @@ struct list_head *coresight_build_path(struct coresight_device *source,
  * Go through all the elements of a path and 1) removed it from the list and
  * 2) free the memory allocated for each node.
  */
-void coresight_release_path(struct list_head *path)
+void coresight_release_path(struct coresight_path *path)
 {
 	struct coresight_device *csdev;
 	struct coresight_node *nd, *next;
 
-	list_for_each_entry_safe(nd, next, path, link) {
+	list_for_each_entry_safe(nd, next, &path->path_list, link) {
 		csdev = nd->csdev;
 
 		coresight_drop_device(csdev);

drivers/hwtracing/coresight/coresight-etm-perf.c

@@ -136,13 +136,13 @@ static const struct attribute_group *etm_pmu_attr_groups[] = {
 	NULL,
 };
 
-static inline struct list_head **
+static inline struct coresight_path **
 etm_event_cpu_path_ptr(struct etm_event_data *data, int cpu)
 {
 	return per_cpu_ptr(data->path, cpu);
 }
 
-static inline struct list_head *
+static inline struct coresight_path *
 etm_event_cpu_path(struct etm_event_data *data, int cpu)
 {
 	return *etm_event_cpu_path_ptr(data, cpu);
@@ -197,6 +197,7 @@ static void free_sink_buffer(struct etm_event_data *event_data)
 	int cpu;
 	cpumask_t *mask = &event_data->mask;
 	struct coresight_device *sink;
+	struct coresight_path *path;
 
 	if (!event_data->snk_config)
 		return;
@@ -205,7 +206,8 @@ static void free_sink_buffer(struct etm_event_data *event_data)
 		return;
 
 	cpu = cpumask_first(mask);
-	sink = coresight_get_sink(etm_event_cpu_path(event_data, cpu));
+	path = etm_event_cpu_path(event_data, cpu);
+	sink = coresight_get_sink(&path->path_list);
 	sink_ops(sink)->free_buffer(event_data->snk_config);
 }
 
@@ -226,11 +228,11 @@ static void free_event_data(struct work_struct *work)
 		cscfg_deactivate_config(event_data->cfg_hash);
 
 	for_each_cpu(cpu, mask) {
-		struct list_head **ppath;
+		struct coresight_path **ppath;
 
 		ppath = etm_event_cpu_path_ptr(event_data, cpu);
 		if (!(IS_ERR_OR_NULL(*ppath))) {
-			struct coresight_device *sink = coresight_get_sink(*ppath);
+			struct coresight_device *sink = coresight_get_sink(&((*ppath)->path_list));
 
 			/*
 			 * Mark perf event as done for trace id allocator, but don't call
@@ -276,7 +278,7 @@ static void *alloc_event_data(int cpu)
 	 * unused memory when dealing with single CPU trace scenarios is small
 	 * compared to the cost of searching through an optimized array.
 	 */
-	event_data->path = alloc_percpu(struct list_head *);
+	event_data->path = alloc_percpu(struct coresight_path *);
 
 	if (!event_data->path) {
 		kfree(event_data);
@@ -352,7 +354,7 @@ static void *etm_setup_aux(struct perf_event *event, void **pages,
 	 * CPUs, we can handle it and fail the session.
 	 */
 	for_each_cpu(cpu, mask) {
-		struct list_head *path;
+		struct coresight_path *path;
 		struct coresight_device *csdev;
 
 		csdev = per_cpu(csdev_src, cpu);
@@ -458,7 +460,7 @@ static void etm_event_start(struct perf_event *event, int flags)
 	struct etm_ctxt *ctxt = this_cpu_ptr(&etm_ctxt);
 	struct perf_output_handle *handle = &ctxt->handle;
 	struct coresight_device *sink, *csdev = per_cpu(csdev_src, cpu);
-	struct list_head *path;
+	struct coresight_path *path;
 	u64 hw_id;
 	u8 trace_id;
 
@@ -494,12 +496,12 @@ static void etm_event_start(struct perf_event *event, int flags)
 
 	path = etm_event_cpu_path(event_data, cpu);
 	/* We need a sink, no need to continue without one */
-	sink = coresight_get_sink(path);
+	sink = coresight_get_sink(&path->path_list);
 	if (WARN_ON_ONCE(!sink))
 		goto fail_end_stop;
 
 	/* Nothing will happen without a path */
-	if (coresight_enable_path(path, CS_MODE_PERF, handle))
+	if (coresight_enable_path(&path->path_list, CS_MODE_PERF, handle))
 		goto fail_end_stop;
 
 	/* Finally enable the tracer */
@@ -534,7 +536,7 @@ static void etm_event_start(struct perf_event *event, int flags)
 	return;
 
 fail_disable_path:
-	coresight_disable_path(path);
+	coresight_disable_path(&path->path_list);
 fail_end_stop:
 	/*
 	 * Check if the handle is still associated with the event,
@@ -558,7 +560,7 @@ static void etm_event_stop(struct perf_event *event, int mode)
 	struct etm_ctxt *ctxt = this_cpu_ptr(&etm_ctxt);
 	struct perf_output_handle *handle = &ctxt->handle;
 	struct etm_event_data *event_data;
-	struct list_head *path;
+	struct coresight_path *path;
 
 	/*
 	 * If we still have access to the event_data via handle,
@@ -599,7 +601,7 @@ static void etm_event_stop(struct perf_event *event, int mode)
 	if (!path)
 		return;
 
-	sink = coresight_get_sink(path);
+	sink = coresight_get_sink(&path->path_list);
 	if (!sink)
 		return;
 
@@ -643,7 +645,7 @@ static void etm_event_stop(struct perf_event *event, int mode)
 	}
 
 	/* Disabling the path make its elements available to other sessions */
-	coresight_disable_path(path);
+	coresight_disable_path(&path->path_list);
 }
 
 static int etm_event_add(struct perf_event *event, int mode)

drivers/hwtracing/coresight/coresight-etm-perf.h

@@ -59,7 +59,7 @@ struct etm_event_data {
 	cpumask_t aux_hwid_done;
 	void *snk_config;
 	u32 cfg_hash;
-	struct list_head * __percpu *path;
+	struct coresight_path * __percpu *path;
 };
 
 int etm_perf_symlink(struct coresight_device *csdev, bool link);

drivers/hwtracing/coresight/coresight-priv.h

@@ -139,9 +139,9 @@ struct coresight_device *coresight_get_sink(struct list_head *path);
 struct coresight_device *coresight_get_sink_by_id(u32 id);
 struct coresight_device *
 coresight_find_default_sink(struct coresight_device *csdev);
-struct list_head *coresight_build_path(struct coresight_device *csdev,
-				       struct coresight_device *sink);
-void coresight_release_path(struct list_head *path);
+struct coresight_path *coresight_build_path(struct coresight_device *csdev,
+					    struct coresight_device *sink);
+void coresight_release_path(struct coresight_path *path);
 int coresight_add_sysfs_link(struct coresight_sysfs_link *info);
 void coresight_remove_sysfs_link(struct coresight_sysfs_link *info);
 int coresight_create_conns_sysfs_group(struct coresight_device *csdev);

drivers/hwtracing/coresight/coresight-sysfs.c

@@ -22,7 +22,7 @@ static DEFINE_IDR(path_idr);
  * When operating Coresight drivers from the sysFS interface, only a single
  * path can exist from a tracer (associated to a CPU) to a sink.
  */
-static DEFINE_PER_CPU(struct list_head *, tracer_path);
+static DEFINE_PER_CPU(struct coresight_path *, tracer_path);
 
 ssize_t coresight_simple_show_pair(struct device *_dev,
 			      struct device_attribute *attr, char *buf)
@@ -167,7 +167,7 @@ int coresight_enable_sysfs(struct coresight_device *csdev)
 {
 	int cpu, ret = 0;
 	struct coresight_device *sink;
-	struct list_head *path;
+	struct coresight_path *path;
 	enum coresight_dev_subtype_source subtype;
 	u32 hash;
 
@@ -209,7 +209,7 @@ int coresight_enable_sysfs(struct coresight_device *csdev)
 		goto out;
 	}
 
-	ret = coresight_enable_path(path, CS_MODE_SYSFS, NULL);
+	ret = coresight_enable_path(&path->path_list, CS_MODE_SYSFS, NULL);
 	if (ret)
 		goto err_path;
 
@@ -251,7 +251,7 @@ int coresight_enable_sysfs(struct coresight_device *csdev)
 	return ret;
 
 err_source:
-	coresight_disable_path(path);
+	coresight_disable_path(&path->path_list);
 
 err_path:
 	coresight_release_path(path);
@@ -262,7 +262,7 @@ EXPORT_SYMBOL_GPL(coresight_enable_sysfs);
 void coresight_disable_sysfs(struct coresight_device *csdev)
 {
 	int cpu, ret;
-	struct list_head *path = NULL;
+	struct coresight_path *path = NULL;
 	u32 hash;
 
 	mutex_lock(&coresight_mutex);
@@ -297,7 +297,7 @@ void coresight_disable_sysfs(struct coresight_device *csdev)
 		break;
 	}
 
-	coresight_disable_path(path);
+	coresight_disable_path(&path->path_list);
 	coresight_release_path(path);
 
 out:

include/linux/coresight.h

@@ -329,6 +329,16 @@ static struct coresight_dev_list (var) = {				\
 
 #define to_coresight_device(d) container_of(d, struct coresight_device, dev)
 
+/**
+ * struct coresight_path - data needed by enable/disable path
+ * @path_list:              path from source to sink.
+ * @trace_id:          trace_id of the whole path.
+ */
+struct coresight_path {
+	struct list_head	path_list;
+	u8			trace_id;
+};
+
 enum cs_mode {
 	CS_MODE_DISABLED,
 	CS_MODE_SYSFS,