mm/fail_page_alloc.c

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