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-rw-r--r--kernel/user.c67
1 files changed, 39 insertions, 28 deletions
diff --git a/kernel/user.c b/kernel/user.c
index 850e0ba..2c000e7 100644
--- a/kernel/user.c
+++ b/kernel/user.c
@@ -75,21 +75,6 @@ static void uid_hash_remove(struct user_struct *up)
put_user_ns(up->user_ns);
}
-static struct user_struct *uid_hash_find(uid_t uid, struct hlist_head *hashent)
-{
- struct user_struct *user;
- struct hlist_node *h;
-
- hlist_for_each_entry(user, h, hashent, uidhash_node) {
- if (user->uid == uid) {
- atomic_inc(&user->__count);
- return user;
- }
- }
-
- return NULL;
-}
-
#ifdef CONFIG_USER_SCHED
static void sched_destroy_user(struct user_struct *up)
@@ -119,6 +104,23 @@ static int sched_create_user(struct user_struct *up) { return 0; }
#if defined(CONFIG_USER_SCHED) && defined(CONFIG_SYSFS)
+static struct user_struct *uid_hash_find(uid_t uid, struct hlist_head *hashent)
+{
+ struct user_struct *user;
+ struct hlist_node *h;
+
+ hlist_for_each_entry(user, h, hashent, uidhash_node) {
+ if (user->uid == uid) {
+ /* possibly resurrect an "almost deleted" object */
+ if (atomic_inc_return(&user->__count) == 1)
+ cancel_delayed_work(&user->work);
+ return user;
+ }
+ }
+
+ return NULL;
+}
+
static struct kset *uids_kset; /* represents the /sys/kernel/uids/ directory */
static DEFINE_MUTEX(uids_mutex);
@@ -283,12 +285,12 @@ int __init uids_sysfs_init(void)
return uids_user_create(&root_user);
}
-/* work function to remove sysfs directory for a user and free up
+/* delayed work function to remove sysfs directory for a user and free up
* corresponding structures.
*/
static void cleanup_user_struct(struct work_struct *w)
{
- struct user_struct *up = container_of(w, struct user_struct, work);
+ struct user_struct *up = container_of(w, struct user_struct, work.work);
unsigned long flags;
int remove_user = 0;
@@ -297,15 +299,12 @@ static void cleanup_user_struct(struct work_struct *w)
*/
uids_mutex_lock();
- local_irq_save(flags);
-
- if (atomic_dec_and_lock(&up->__count, &uidhash_lock)) {
+ spin_lock_irqsave(&uidhash_lock, flags);
+ if (atomic_read(&up->__count) == 0) {
uid_hash_remove(up);
remove_user = 1;
- spin_unlock_irqrestore(&uidhash_lock, flags);
- } else {
- local_irq_restore(flags);
}
+ spin_unlock_irqrestore(&uidhash_lock, flags);
if (!remove_user)
goto done;
@@ -331,16 +330,28 @@ done:
*/
static void free_user(struct user_struct *up, unsigned long flags)
{
- /* restore back the count */
- atomic_inc(&up->__count);
spin_unlock_irqrestore(&uidhash_lock, flags);
-
- INIT_WORK(&up->work, cleanup_user_struct);
- schedule_work(&up->work);
+ INIT_DELAYED_WORK(&up->work, cleanup_user_struct);
+ schedule_delayed_work(&up->work, msecs_to_jiffies(1000));
}
#else /* CONFIG_USER_SCHED && CONFIG_SYSFS */
+static struct user_struct *uid_hash_find(uid_t uid, struct hlist_head *hashent)
+{
+ struct user_struct *user;
+ struct hlist_node *h;
+
+ hlist_for_each_entry(user, h, hashent, uidhash_node) {
+ if (user->uid == uid) {
+ atomic_inc(&user->__count);
+ return user;
+ }
+ }
+
+ return NULL;
+}
+
int uids_sysfs_init(void) { return 0; }
static inline int uids_user_create(struct user_struct *up) { return 0; }
static inline void uids_mutex_lock(void) { }
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