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Subject[PATCH 3/4] signal: Add free_uid_to_q()
Date
Add a new free_uid_to_q() function to put the user structure on
freeing queue instead of freeing it directly. That new function is then
called from __sigqueue_free() with a free_q parameter.

Signed-off-by: Waiman Long <longman@redhat.com>
---
include/linux/sched/user.h | 3 +++
kernel/signal.c | 2 +-
kernel/user.c | 17 +++++++++++++----
3 files changed, 17 insertions(+), 5 deletions(-)

diff --git a/include/linux/sched/user.h b/include/linux/sched/user.h
index c7b5f86b91a1..77f28d5cb940 100644
--- a/include/linux/sched/user.h
+++ b/include/linux/sched/user.h
@@ -63,6 +63,9 @@ static inline struct user_struct *get_uid(struct user_struct *u)
refcount_inc(&u->__count);
return u;
}
+
+struct kmem_free_q_head;
extern void free_uid(struct user_struct *);
+extern void free_uid_to_q(struct user_struct *u, struct kmem_free_q_head *q);

#endif /* _LINUX_SCHED_USER_H */
diff --git a/kernel/signal.c b/kernel/signal.c
index 04fb202c16bd..2ecb23b540eb 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -440,7 +440,7 @@ static void __sigqueue_free(struct sigqueue *q, struct kmem_free_q_head *free_q)
if (q->flags & SIGQUEUE_PREALLOC)
return;
atomic_dec(&q->user->sigpending);
- free_uid(q->user);
+ free_uid_to_q(q->user, free_q);
if (free_q)
kmem_free_q_add(free_q, sigqueue_cachep, q);
else
diff --git a/kernel/user.c b/kernel/user.c
index 0df9b1640b2a..d92629bae546 100644
--- a/kernel/user.c
+++ b/kernel/user.c
@@ -135,14 +135,18 @@ static struct user_struct *uid_hash_find(kuid_t uid, struct hlist_head *hashent)
* IRQ state (as stored in flags) is restored and uidhash_lock released
* upon function exit.
*/
-static void free_user(struct user_struct *up, unsigned long flags)
+static void free_user(struct user_struct *up, unsigned long flags,
+ struct kmem_free_q_head *free_q)
__releases(&uidhash_lock)
{
uid_hash_remove(up);
spin_unlock_irqrestore(&uidhash_lock, flags);
key_put(up->uid_keyring);
key_put(up->session_keyring);
- kmem_cache_free(uid_cachep, up);
+ if (free_q)
+ kmem_free_q_add(free_q, uid_cachep, up);
+ else
+ kmem_cache_free(uid_cachep, up);
}

/*
@@ -162,7 +166,7 @@ struct user_struct *find_user(kuid_t uid)
return ret;
}

-void free_uid(struct user_struct *up)
+void free_uid_to_q(struct user_struct *up, struct kmem_free_q_head *free_q)
{
unsigned long flags;

@@ -170,7 +174,12 @@ void free_uid(struct user_struct *up)
return;

if (refcount_dec_and_lock_irqsave(&up->__count, &uidhash_lock, &flags))
- free_user(up, flags);
+ free_user(up, flags, free_q);
+}
+
+void free_uid(struct user_struct *up)
+{
+ free_uid_to_q(up, NULL);
}

struct user_struct *alloc_uid(kuid_t uid)
--
2.18.1
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