// SPDX-License-Identifier: GPL-2.0+
  /*
   * test_free_pages.c: Check that free_pages() doesn't leak memory
   * Copyright (c) 2020 Oracle
   * Author: Matthew Wilcox <willy@infradead.org>
   */
  
  #include <linux/gfp.h>
  #include <linux/mm.h>
  #include <linux/module.h>
  
  static void test_free_pages(gfp_t gfp)
  {
  	unsigned int i;
  
  	for (i = 0; i < 1000 * 1000; i++) {
  		unsigned long addr = __get_free_pages(gfp, 3);
  		struct page *page = virt_to_page(addr);
  
  		/* Simulate page cache getting a speculative reference */
  		get_page(page);
  		free_pages(addr, 3);
  		put_page(page);
  	}
  }
  
  static int m_in(void)
  {
  	test_free_pages(GFP_KERNEL);
  	test_free_pages(GFP_KERNEL | __GFP_COMP);
  
  	return 0;
  }
  
  static void m_ex(void)
  {
  }
  
  module_init(m_in);
  module_exit(m_ex);
  MODULE_AUTHOR("Matthew Wilcox <willy@infradead.org>");
  MODULE_LICENSE("GPL");