Commit c87e2837 authored by Ingo Molnar's avatar Ingo Molnar Committed by Linus Torvalds
Browse files

[PATCH] pi-futex: futex_lock_pi/futex_unlock_pi support



This adds the actual pi-futex implementation, based on rt-mutexes.

[dino@in.ibm.com: fix an oops-causing race]
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarArjan van de Ven <arjan@linux.intel.com>
Signed-off-by: default avatarDinakar Guniguntala <dino@in.ibm.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 0cdbee99
......@@ -12,6 +12,9 @@
#define FUTEX_REQUEUE 3
#define FUTEX_CMP_REQUEUE 4
#define FUTEX_WAKE_OP 5
#define FUTEX_LOCK_PI 6
#define FUTEX_UNLOCK_PI 7
#define FUTEX_TRYLOCK_PI 8
/*
* Support for robust futexes: the kernel cleans up held futexes at
......@@ -97,10 +100,14 @@ extern int handle_futex_death(u32 __user *uaddr, struct task_struct *curr);
#ifdef CONFIG_FUTEX
extern void exit_robust_list(struct task_struct *curr);
extern void exit_pi_state_list(struct task_struct *curr);
#else
static inline void exit_robust_list(struct task_struct *curr)
{
}
static inline void exit_pi_state_list(struct task_struct *curr)
{
}
#endif
#define FUTEX_OP_SET 0 /* *(int *)UADDR2 = OPARG; */
......
......@@ -84,6 +84,7 @@ struct sched_param {
#include <asm/processor.h>
struct exec_domain;
struct futex_pi_state;
/*
* List of flags we want to share for kernel threads,
......@@ -915,6 +916,8 @@ struct task_struct {
#ifdef CONFIG_COMPAT
struct compat_robust_list_head __user *compat_robust_list;
#endif
struct list_head pi_state_list;
struct futex_pi_state *pi_state_cache;
atomic_t fs_excl; /* holding fs exclusive resources */
struct rcu_head rcu;
......
......@@ -925,6 +925,14 @@ fastcall NORET_TYPE void do_exit(long code)
mpol_free(tsk->mempolicy);
tsk->mempolicy = NULL;
#endif
/*
* This must happen late, after the PID is not
* hashed anymore:
*/
if (unlikely(!list_empty(&tsk->pi_state_list)))
exit_pi_state_list(tsk);
if (unlikely(current->pi_state_cache))
kfree(current->pi_state_cache);
/*
* If DEBUG_MUTEXES is on, make sure we are holding no locks:
*/
......
......@@ -1092,6 +1092,9 @@ static task_t *copy_process(unsigned long clone_flags,
#ifdef CONFIG_COMPAT
p->compat_robust_list = NULL;
#endif
INIT_LIST_HEAD(&p->pi_state_list);
p->pi_state_cache = NULL;
/*
* sigaltstack should be cleared when sharing the same VM
*/
......
This diff is collapsed.
......@@ -129,14 +129,19 @@ asmlinkage long compat_sys_futex(u32 __user *uaddr, int op, u32 val,
unsigned long timeout = MAX_SCHEDULE_TIMEOUT;
int val2 = 0;
if (utime && (op == FUTEX_WAIT)) {
if (utime && (op == FUTEX_WAIT || op == FUTEX_LOCK_PI)) {
if (get_compat_timespec(&t, utime))
return -EFAULT;
if (!timespec_valid(&t))
return -EINVAL;
timeout = timespec_to_jiffies(&t) + 1;
if (op == FUTEX_WAIT)
timeout = timespec_to_jiffies(&t) + 1;
else {
timeout = t.tv_sec;
val2 = t.tv_nsec;
}
}
if (op >= FUTEX_REQUEUE)
if (op == FUTEX_REQUEUE || op == FUTEX_CMP_REQUEUE)
val2 = (int) (unsigned long) utime;
return do_futex(uaddr, op, val, timeout, uaddr2, val2, val3);
......
......@@ -112,4 +112,12 @@ static inline unsigned long rt_mutex_owner_pending(struct rt_mutex *lock)
return (unsigned long)lock->owner & RT_MUTEX_OWNER_PENDING;
}
/*
* PI-futex support (proxy locking functions, etc.):
*/
extern struct task_struct *rt_mutex_next_owner(struct rt_mutex *lock);
extern void rt_mutex_init_proxy_locked(struct rt_mutex *lock,
struct task_struct *proxy_owner);
extern void rt_mutex_proxy_unlock(struct rt_mutex *lock,
struct task_struct *proxy_owner);
#endif
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