[net-next,3/9] devlink: Add support for creating region snapshots

diff --git a/include/net/devlink.h b/include/net/devlink.h
index 5697c55..83e569f 100644
--- a/include/net/devlink.h
+++ b/include/net/devlink.h
@@ -429,6 +429,8 @@  struct devlink_region *devlink_region_create(struct devlink *devlink,
 					     u64 region_size);
 void devlink_region_destroy(struct devlink_region *region);
 u32 devlink_region_shapshot_id_get(struct devlink *devlink);
+int devlink_region_snapshot_create(struct devlink_region *region, u64 data_len,
+				   u8 *data, u32 snapshot_id);
 
 #else
 
@@ -619,6 +621,13 @@  static inline bool devlink_dpipe_table_counter_enabled(struct devlink *devlink,
 	return 0;
 }
 
+static inline int
+devlink_region_snapshot_create(struct devlink_region *region, u64 data_len,
+			       u8 *data, u32 snapshot_id)
+{
+	return 0;
+}
+
 #endif
 
 #endif /* _NET_DEVLINK_H_ */
diff --git a/net/core/devlink.c b/net/core/devlink.c
index 4822a08..785e87d 100644
--- a/net/core/devlink.c
+++ b/net/core/devlink.c
@@ -336,6 +336,14 @@  struct devlink_region {
 	u64 size;
 };
 
+struct devlink_snapshot {
+	struct list_head list;
+	struct devlink_region *region;
+	u64 data_len;
+	u8 *data;
+	u32 id;
+};
+
 static struct devlink_region *
 devlink_region_get_by_name(struct devlink *devlink, const char *region_name)
 {
@@ -348,6 +356,26 @@  struct devlink_region {
 	return NULL;
 }
 
+static struct devlink_snapshot *
+devlink_region_snapshot_get_by_id(struct devlink_region *region, u32 id)
+{
+	struct devlink_snapshot *snapshot;
+
+	list_for_each_entry(snapshot, &region->snapshot_list, list)
+		if (snapshot->id == id)
+			return snapshot;
+
+	return NULL;
+}
+
+static void devlink_region_snapshot_del(struct devlink_snapshot *snapshot)
+{
+	snapshot->region->cur_snapshots--;
+	list_del(&snapshot->list);
+	kfree(snapshot->data);
+	kfree(snapshot);
+}
+
 #define DEVLINK_NL_FLAG_NEED_DEVLINK	BIT(0)
 #define DEVLINK_NL_FLAG_NEED_PORT	BIT(1)
 #define DEVLINK_NL_FLAG_NEED_SB		BIT(2)
@@ -3391,8 +3419,14 @@  struct devlink_region *devlink_region_create(struct devlink *devlink,
 void devlink_region_destroy(struct devlink_region *region)
 {
 	struct devlink *devlink = region->devlink;
+	struct devlink_snapshot *snapshot, *ts;
 
 	mutex_lock(&devlink->lock);
+
+	/* Free all snapshots of region */
+	list_for_each_entry_safe(snapshot, ts, &region->snapshot_list, list)
+		devlink_region_snapshot_del(snapshot);
+
 	list_del(&region->list);
 	mutex_unlock(&devlink->lock);
 	kfree(region);
@@ -3420,6 +3454,71 @@  u32 devlink_region_shapshot_id_get(struct devlink *devlink)
 }
 EXPORT_SYMBOL_GPL(devlink_region_shapshot_id_get);
 
+/**
+ *	devlink_region_snapshot_create - create a new snapshot
+ *	This will add a new snapshot of a region. The snapshot
+ *	will be stored on the region struct and can be accessed
+ *	from devlink. This is useful for future	analyses of snapshots.
+ *	Multiple snapshots can be created on a region.
+ *	The @snapshot_id should be obtained using the getter function.
+ *
+ *	@devlink_region: devlink region of the snapshot
+ *	@data_len: size of snapshot data
+ *	@data: snapshot data
+ *	@snapshot_id: snapshot id to be created
+ */
+int devlink_region_snapshot_create(struct devlink_region *region, u64 data_len,
+				   u8 *data, u32 snapshot_id)
+{
+	struct devlink *devlink = region->devlink;
+	struct devlink_snapshot *snapshot;
+	int err;
+
+	mutex_lock(&devlink->lock);
+
+	/* check if region can hold one more snapshot */
+	if (region->cur_snapshots == region->max_snapshots) {
+		err = -ENOMEM;
+		goto unlock;
+	}
+
+	if (devlink_region_snapshot_get_by_id(region, snapshot_id)) {
+		err = -EEXIST;
+		goto unlock;
+	}
+
+	snapshot = kzalloc(sizeof(*snapshot), GFP_KERNEL);
+	if (!snapshot) {
+		err = -ENOMEM;
+		goto unlock;
+	}
+
+	snapshot->data = kzalloc(data_len, GFP_KERNEL);
+	if (!snapshot->data) {
+		err = -ENOMEM;
+		goto free_snapshot;
+	}
+
+	snapshot->id = snapshot_id;
+	snapshot->region = region;
+	snapshot->data_len = data_len;
+	memcpy(snapshot->data, data, data_len);
+
+	list_add_tail(&snapshot->list, &region->snapshot_list);
+
+	region->cur_snapshots++;
+
+	mutex_unlock(&devlink->lock);
+	return 0;
+
+free_snapshot:
+	kfree(snapshot);
+unlock:
+	mutex_unlock(&devlink->lock);
+	return err;
+}
+EXPORT_SYMBOL_GPL(devlink_region_snapshot_create);
+
 static int __init devlink_module_init(void)
 {
 	return genl_register_family(&devlink_nl_family);