mm/fail_page_alloc.c

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