create-ext4_kset-dynamically

   1 ext4: create ext4_kset dynamically
   2
   3 From: Riccardo Schirone <sirmy15@gmail.com>
   4
   5 ksets contain a kobject and they should always be allocated dynamically,
   6 because it is unknown to whoever creates them when ksets can be
   7 released.
   8
   9 Signed-off-by: Riccardo Schirone <sirmy15@gmail.com>
  10 Signed-off-by: Theodore Ts'o <tytso@mit.edu>
  11 ---
  12  fs/ext4/sysfs.c | 39 +++++++++++++++++++++++++--------------
  13  1 file changed, 25 insertions(+), 14 deletions(-)
  14
  15 diff --git a/fs/ext4/sysfs.c b/fs/ext4/sysfs.c
  16 index 192ade7d6fe6..1205261f130c 100644
  17 --- a/fs/ext4/sysfs.c
  18 +++ b/fs/ext4/sysfs.c
  19 @@ -330,6 +330,13 @@ static void ext4_sb_release(struct kobject *kobj)
  20         complete(&sbi->s_kobj_unregister);
  21  }
  22
  23 +static void ext4_kset_release(struct kobject *kobj)
  24 +{
  25 +       struct kset *kset = container_of(kobj, struct kset, kobj);
  26 +
  27 +       kfree(kset);
  28 +}
  29 +
  30  static const struct sysfs_ops ext4_attr_ops = {
  31         .show   = ext4_attr_show,
  32         .store  = ext4_attr_store,
  33 @@ -343,11 +350,10 @@ static struct kobj_type ext4_sb_ktype = {
  34
  35  static struct kobj_type ext4_ktype = {
  36         .sysfs_ops      = &ext4_attr_ops,
  37 +       .release        = ext4_kset_release,
  38  };
  39
  40 -static struct kset ext4_kset = {
  41 -       .kobj   = {.ktype = &ext4_ktype},
  42 -};
  43 +static struct kset *ext4_kset;
  44
  45  static struct kobj_type ext4_feat_ktype = {
  46         .default_attrs  = ext4_feat_attrs,
  47 @@ -392,7 +398,7 @@ int ext4_register_sysfs(struct super_block *sb)
  48         const struct ext4_proc_files *p;
  49         int err;
  50
  51 -       sbi->s_kobj.kset = &ext4_kset;
  52 +       sbi->s_kobj.kset = ext4_kset;
  53         init_completion(&sbi->s_kobj_unregister);
  54         err = kobject_init_and_add(&sbi->s_kobj, &ext4_sb_ktype, NULL,
  55                                    "%s", sb->s_id);
  56 @@ -430,13 +436,16 @@ int __init ext4_init_sysfs(void)
  57  {
  58         int ret;
  59
  60 -       kobject_set_name(&ext4_kset.kobj, "ext4");
  61 -       ext4_kset.kobj.parent = fs_kobj;
  62 -       ret = kset_register(&ext4_kset);
  63 -       if (ret) {
  64 -               kset_unregister(&ext4_kset);
  65 -               return ret;
  66 -       }
  67 +       ext4_kset = kzalloc(sizeof(*ext4_kset), GFP_KERNEL);
  68 +       if (!ext4_kset)
  69 +               return -ENOMEM;
  70 +
  71 +       kobject_set_name(&ext4_kset->kobj, "ext4");
  72 +       ext4_kset->kobj.parent = fs_kobj;
  73 +       ext4_kset->kobj.ktype = &ext4_ktype;
  74 +       ret = kset_register(ext4_kset);
  75 +       if (ret)
  76 +               goto kset_err;
  77
  78         ext4_feat = kzalloc(sizeof(*ext4_feat), GFP_KERNEL);
  79         if (!ext4_feat) {
  80 @@ -444,7 +453,7 @@ int __init ext4_init_sysfs(void)
  81                 goto kset_err;
  82         }
  83
  84 -       ext4_feat->kset = &ext4_kset;
  85 +       ext4_feat->kset = ext4_kset;
  86         ret = kobject_init_and_add(ext4_feat, &ext4_feat_ktype,
  87                                    NULL, "features");
  88         if (ret)
  89 @@ -456,14 +465,16 @@ int __init ext4_init_sysfs(void)
  90  feat_err:
  91         kobject_put(ext4_feat);
  92  kset_err:
  93 -       kset_unregister(&ext4_kset);
  94 +       kset_unregister(ext4_kset);
  95 +       ext4_kset = NULL;
  96         return ret;
  97  }
  98
  99  void ext4_exit_sysfs(void)
 100  {
 101         kobject_put(ext4_feat);
 102 -       kset_unregister(&ext4_kset);
 103 +       kset_unregister(ext4_kset);
 104 +       ext4_kset = NULL;
 105         remove_proc_entry(proc_dirname, NULL);
 106         ext4_proc_root = NULL;
 107  }