[PATCH] pi-futex: futex_lock_pi/futex_unlock_pi support

This adds the actual pi-futex implementation, based on rt-mutexes. [[email protected]: fix an oops-causing race] Signed-off-by: Ingo Molnar <[email protected]> Signed-off-by: Thomas Gleixner <[email protected]> Signed-off-by: Arjan van de Ven <[email protected]> Signed-off-by: Dinakar Guniguntala <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
josf · Jun 28, 2006 · c87e283 · c87e283
1 parent 0cdbee9
commit c87e283
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Showing 7 changed files with 828 additions and 41 deletions.
diff --git a/include/linux/futex.h b/include/linux/futex.h
@@ -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; */

diff --git a/include/linux/sched.h b/include/linux/sched.h
@@ -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;

diff --git a/kernel/exit.c b/kernel/exit.c
@@ -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:
 	 */

diff --git a/kernel/fork.c b/kernel/fork.c
@@ -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
 	 */