FROMLIST: android: binder: Add allocator selftest

(from https://patchwork.kernel.org/patch/9928609/)

binder_alloc_selftest tests that alloc_new_buf handles page allocation and
deallocation properly when allocate and free buffers. The test allocates 5
buffers of various sizes to cover all possible page alignment cases, and
frees the buffers using a list of exhaustive freeing order.

Test: boot the device with ANDROID_BINDER_IPC_SELFTEST config option
enabled. Allocator selftest passes.

Bug: 36007193
Change-Id: I2fe396232b7dfe4bbc50bdba99ca0de9be63cc37
Signed-off-by: Sherry Yang <sherryy@android.com>
diff --git a/drivers/android/binder_alloc.h b/drivers/android/binder_alloc.h
index 088e4ff..4f02cc0 100644
--- a/drivers/android/binder_alloc.h
+++ b/drivers/android/binder_alloc.h
@@ -102,6 +102,11 @@ struct binder_alloc {
 	int pid;
 };
 
+#ifdef CONFIG_ANDROID_BINDER_IPC_SELFTEST
+void binder_selftest_alloc(struct binder_alloc *alloc);
+#else
+static inline void binder_selftest_alloc(struct binder_alloc *alloc) {}
+#endif
 extern struct binder_buffer *binder_alloc_new_buf(struct binder_alloc *alloc,
 						  size_t data_size,
 						  size_t offsets_size,