merge task_work and rcu_head, get rid of separate allocation for keyring case

task_work and rcu_head are identical now; merge them (calling the result
struct callback_head, rcu_head #define'd to it), kill separate allocation
in security/keys since we can just use cred->rcu now.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2012-06-27 11:07:19 +04:00
parent 158e1645e0
commit 67d1214551
8 changed files with 31 additions and 52 deletions

View file

@ -1405,7 +1405,7 @@ struct task_struct {
int (*notifier)(void *priv);
void *notifier_data;
sigset_t *notifier_mask;
void *task_works;
struct callback_head *task_works;
struct audit_context *audit_context;
#ifdef CONFIG_AUDITSYSCALL

View file

@ -4,22 +4,16 @@
#include <linux/list.h>
#include <linux/sched.h>
struct task_work;
typedef void (*task_work_func_t)(struct task_work *);
struct task_work {
struct task_work *next;
task_work_func_t func;
};
typedef void (*task_work_func_t)(struct callback_head *);
static inline void
init_task_work(struct task_work *twork, task_work_func_t func)
init_task_work(struct callback_head *twork, task_work_func_t func)
{
twork->func = func;
}
int task_work_add(struct task_struct *task, struct task_work *twork, bool);
struct task_work *task_work_cancel(struct task_struct *, task_work_func_t);
int task_work_add(struct task_struct *task, struct callback_head *twork, bool);
struct callback_head *task_work_cancel(struct task_struct *, task_work_func_t);
void task_work_run(void);
static inline void exit_task_work(struct task_struct *task)

View file

@ -246,14 +246,15 @@ struct ustat {
};
/**
* struct rcu_head - callback structure for use with RCU
* struct callback_head - callback structure for use with RCU and task_work
* @next: next update requests in a list
* @func: actual update function to call after the grace period.
*/
struct rcu_head {
struct rcu_head *next;
void (*func)(struct rcu_head *head);
struct callback_head {
struct callback_head *next;
void (*func)(struct callback_head *head);
};
#define rcu_head callback_head
#endif /* __KERNEL__ */
#endif /* __ASSEMBLY__ */

View file

@ -781,7 +781,7 @@ static void wake_threads_waitq(struct irq_desc *desc)
wake_up(&desc->wait_for_threads);
}
static void irq_thread_dtor(struct task_work *unused)
static void irq_thread_dtor(struct callback_head *unused)
{
struct task_struct *tsk = current;
struct irq_desc *desc;
@ -813,7 +813,7 @@ static void irq_thread_dtor(struct task_work *unused)
*/
static int irq_thread(void *data)
{
struct task_work on_exit_work;
struct callback_head on_exit_work;
static const struct sched_param param = {
.sched_priority = MAX_USER_RT_PRIO/2,
};

View file

@ -3,7 +3,7 @@
#include <linux/tracehook.h>
int
task_work_add(struct task_struct *task, struct task_work *twork, bool notify)
task_work_add(struct task_struct *task, struct callback_head *twork, bool notify)
{
unsigned long flags;
int err = -ESRCH;
@ -19,8 +19,8 @@ task_work_add(struct task_struct *task, struct task_work *twork, bool notify)
*/
raw_spin_lock_irqsave(&task->pi_lock, flags);
if (likely(!(task->flags & PF_EXITING))) {
struct task_work *last = task->task_works;
struct task_work *first = last ? last->next : twork;
struct callback_head *last = task->task_works;
struct callback_head *first = last ? last->next : twork;
twork->next = first;
if (last)
last->next = twork;
@ -35,16 +35,16 @@ task_work_add(struct task_struct *task, struct task_work *twork, bool notify)
return err;
}
struct task_work *
struct callback_head *
task_work_cancel(struct task_struct *task, task_work_func_t func)
{
unsigned long flags;
struct task_work *last, *res = NULL;
struct callback_head *last, *res = NULL;
raw_spin_lock_irqsave(&task->pi_lock, flags);
last = task->task_works;
if (last) {
struct task_work *q = last, *p = q->next;
struct callback_head *q = last, *p = q->next;
while (1) {
if (p->func == func) {
q->next = p->next;
@ -66,7 +66,7 @@ task_work_cancel(struct task_struct *task, task_work_func_t func)
void task_work_run(void)
{
struct task_struct *task = current;
struct task_work *p, *q;
struct callback_head *p, *q;
raw_spin_lock_irq(&task->pi_lock);
p = task->task_works;

View file

@ -148,12 +148,8 @@ extern key_ref_t lookup_user_key(key_serial_t id, unsigned long flags,
#define KEY_LOOKUP_PARTIAL 0x02
#define KEY_LOOKUP_FOR_UNLINK 0x04
struct kludge { /* this will die off very soon */
struct task_work twork;
struct cred *cred;
};
extern long join_session_keyring(const char *name);
extern void key_change_session_keyring(struct task_work *twork);
extern void key_change_session_keyring(struct callback_head *twork);
extern struct work_struct key_gc_work;
extern unsigned key_gc_delay;

View file

@ -1456,8 +1456,7 @@ long keyctl_session_to_parent(void)
{
struct task_struct *me, *parent;
const struct cred *mycred, *pcred;
struct kludge *newwork;
struct task_work *oldwork;
struct callback_head *newwork, *oldwork;
key_ref_t keyring_r;
struct cred *cred;
int ret;
@ -1467,20 +1466,17 @@ long keyctl_session_to_parent(void)
return PTR_ERR(keyring_r);
ret = -ENOMEM;
newwork = kmalloc(sizeof(struct kludge), GFP_KERNEL);
if (!newwork)
goto error_keyring;
/* our parent is going to need a new cred struct, a new tgcred struct
* and new security data, so we allocate them here to prevent ENOMEM in
* our parent */
cred = cred_alloc_blank();
if (!cred)
goto error_newwork;
goto error_keyring;
newwork = &cred->rcu;
cred->tgcred->session_keyring = key_ref_to_ptr(keyring_r);
init_task_work(&newwork->twork, key_change_session_keyring);
newwork->cred = cred;
init_task_work(newwork, key_change_session_keyring);
me = current;
rcu_read_lock();
@ -1529,24 +1525,18 @@ long keyctl_session_to_parent(void)
/* the replacement session keyring is applied just prior to userspace
* restarting */
ret = task_work_add(parent, &newwork->twork, true);
ret = task_work_add(parent, newwork, true);
if (!ret)
newwork = NULL;
unlock:
write_unlock_irq(&tasklist_lock);
rcu_read_unlock();
if (oldwork) {
put_cred(container_of(oldwork, struct kludge, twork)->cred);
kfree(oldwork);
}
if (newwork) {
put_cred(newwork->cred);
kfree(newwork);
}
if (oldwork)
put_cred(container_of(oldwork, struct cred, rcu));
if (newwork)
put_cred(cred);
return ret;
error_newwork:
kfree(newwork);
error_keyring:
key_ref_put(keyring_r);
return ret;

View file

@ -834,13 +834,11 @@ error:
* Replace a process's session keyring on behalf of one of its children when
* the target process is about to resume userspace execution.
*/
void key_change_session_keyring(struct task_work *twork)
void key_change_session_keyring(struct callback_head *twork)
{
const struct cred *old = current_cred();
struct kludge *p = container_of(twork, struct kludge, twork);
struct cred *new = p->cred;
struct cred *new = container_of(twork, struct cred, rcu);
kfree(p);
if (unlikely(current->flags & PF_EXITING)) {
put_cred(new);
return;