mm/fail_page_alloc.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <linux/fault-inject.h>
   3 #include <linux/error-injection.h>
   4 #include <linux/mm.h>
   5
   6 static struct {
   7         struct fault_attr attr;
   8
   9         bool ignore_gfp_highmem;
  10         bool ignore_gfp_reclaim;
  11         u32 min_order;
  12 } fail_page_alloc = {
  13         .attr = FAULT_ATTR_INITIALIZER,
  14         .ignore_gfp_reclaim = true,
  15         .ignore_gfp_highmem = true,
  16         .min_order = 1,
  17 };
  18
  19 static int __init setup_fail_page_alloc(char *str)
  20 {
  21         return setup_fault_attr(&fail_page_alloc.attr, str);
  22 }
  23 __setup("fail_page_alloc=", setup_fail_page_alloc);
  24
  25 bool should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
  26 {
  27         int flags = 0;
  28
  29         if (order < fail_page_alloc.min_order)
  30                 return false;
  31         if (gfp_mask & __GFP_NOFAIL)
  32                 return false;
  33         if (fail_page_alloc.ignore_gfp_highmem && (gfp_mask & __GFP_HIGHMEM))
  34                 return false;
  35         if (fail_page_alloc.ignore_gfp_reclaim &&
  36                         (gfp_mask & __GFP_DIRECT_RECLAIM))
  37                 return false;
  38
  39         /* See comment in __should_failslab() */
  40         if (gfp_mask & __GFP_NOWARN)
  41                 flags |= FAULT_NOWARN;
  42
  43         return should_fail_ex(&fail_page_alloc.attr, 1 << order, flags);
  44 }
  45 ALLOW_ERROR_INJECTION(should_fail_alloc_page, TRUE);
  46
  47 #ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
  48
  49 static int __init fail_page_alloc_debugfs(void)
  50 {
  51         umode_t mode = S_IFREG | 0600;
  52         struct dentry *dir;
  53
  54         dir = fault_create_debugfs_attr("fail_page_alloc", NULL,
  55                                         &fail_page_alloc.attr);
  56
  57         debugfs_create_bool("ignore-gfp-wait", mode, dir,
  58                             &fail_page_alloc.ignore_gfp_reclaim);
  59         debugfs_create_bool("ignore-gfp-highmem", mode, dir,
  60                             &fail_page_alloc.ignore_gfp_highmem);
  61         debugfs_create_u32("min-order", mode, dir, &fail_page_alloc.min_order);
  62
  63         return 0;
  64 }
  65
  66 late_initcall(fail_page_alloc_debugfs);
  67
  68 #endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */