1 files changed, 50 insertions, 0 deletions
diff --git a/gcip-kernel-driver/include/gcip/gcip-alloc-helper.h b/gcip-kernel-driver/include/gcip/gcip-alloc-helper.h
new file mode 100644
index 0000000..3d2c110
--- /dev/null
+++ b/gcip-kernel-driver/include/gcip/gcip-alloc-helper.h
@@ -0,0 +1,50 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * GCIP helpers for allocating memories.
+ *
+ * Copyright (C) 2022 Google LLC
+ */
+
+#ifndef __GCIP_ALLOC_HELPER_H__
+#define __GCIP_ALLOC_HELPER_H__
+
+#include <linux/device.h>
+#include <linux/scatterlist.h>
+#include <linux/types.h>
+
+/*
+ * The actual return value from the alloc_noncontiguous function.
+ * The user should only care about @sgt. @pages is used internally for freeing memory.
+ */
+struct gcip_sgt_handle {
+	struct sg_table sgt;
+	void *mem;
+};
+
+/*
+ * Allocates non-contiguous memory with size @size bytes.
+ *
+ * @dev: pointer to device structure. Is used for logging or the NUMA node for page allocation.
+ * @size: Total size in bytes. Will be page aligned.
+ * @gfp: The GFP flag for malloc internal structures.
+ *
+ * Returns the SG table represents the non-contiguous region.
+ * Returns NULL on any error.
+ */
+struct sg_table *gcip_alloc_noncontiguous(struct device *dev, size_t size, gfp_t gfp);
+/* Frees the memory allocated by gcip_alloc_noncontiguous. */
+void gcip_free_noncontiguous(struct sg_table *sgt);
+
+/*
+ * Returns the virtual memory that was used to allocate @sgt.
+ *
+ * @sgt must be the return pointer of gcip_alloc_noncontiguous.
+ */
+static inline void *gcip_noncontiguous_sgt_to_mem(struct sg_table *sgt)
+{
+	struct gcip_sgt_handle *sh = container_of(sgt, struct gcip_sgt_handle, sgt);
+
+	return sh->mem;
+}
+
+#endif /* __GCIP_ALLOC_HELPER_H__ */