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

include/linux/futex.h

+7 −0
Original line number Diff line number Diff line
@@ -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; */

include/linux/sched.h

+3 −0
Original line number Diff line number Diff line
@@ -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;

kernel/exit.c

+8 −0
Original line number Diff line number Diff line
@@ -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:

	 */

kernel/fork.c

+3 −0
Original line number Diff line number Diff line
@@ -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

	 */

kernel/futex.c

+791 −38

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