[PATCH] lightweight robust futexes updates
- fix: initialize the robust list(s) to NULL in copy_process.
- doc update
- cleanup: rename _inuser to _inatomic
- __user cleanups and other small cleanups
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Arjan van de Ven <arjan@infradead.org>
Cc: Ulrich Drepper <drepper@redhat.com>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/kernel/fork.c b/kernel/fork.c
index e0a2b44..c49bd19 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1061,7 +1061,10 @@
* Clear TID on mm_release()?
*/
p->clear_child_tid = (clone_flags & CLONE_CHILD_CLEARTID) ? child_tidptr: NULL;
-
+ p->robust_list = NULL;
+#ifdef CONFIG_COMPAT
+ p->compat_robust_list = NULL;
+#endif
/*
* sigaltstack should be cleared when sharing the same VM
*/
diff --git a/kernel/futex.c b/kernel/futex.c
index feb724b..9c9b2b6 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -913,15 +913,15 @@
* Process a futex-list entry, check whether it's owned by the
* dying task, and do notification if so:
*/
-int handle_futex_death(unsigned int *uaddr, struct task_struct *curr)
+int handle_futex_death(u32 __user *uaddr, struct task_struct *curr)
{
- unsigned int futex_val;
+ u32 uval;
-repeat:
- if (get_user(futex_val, uaddr))
+retry:
+ if (get_user(uval, uaddr))
return -1;
- if ((futex_val & FUTEX_TID_MASK) == curr->pid) {
+ if ((uval & FUTEX_TID_MASK) == curr->pid) {
/*
* Ok, this dying thread is truly holding a futex
* of interest. Set the OWNER_DIED bit atomically
@@ -932,12 +932,11 @@
* thread-death.) The rest of the cleanup is done in
* userspace.
*/
- if (futex_atomic_cmpxchg_inuser(uaddr, futex_val,
- futex_val | FUTEX_OWNER_DIED) !=
- futex_val)
- goto repeat;
+ if (futex_atomic_cmpxchg_inatomic(uaddr, uval,
+ uval | FUTEX_OWNER_DIED) != uval)
+ goto retry;
- if (futex_val & FUTEX_WAITERS)
+ if (uval & FUTEX_WAITERS)
futex_wake((unsigned long)uaddr, 1);
}
return 0;
@@ -985,7 +984,6 @@
if (handle_futex_death((void *)entry + futex_offset,
curr))
return;
-
/*
* Fetch the next entry in the list:
*/
diff --git a/kernel/futex_compat.c b/kernel/futex_compat.c
index c153559..9c077cf 100644
--- a/kernel/futex_compat.c
+++ b/kernel/futex_compat.c
@@ -121,9 +121,9 @@
return ret;
}
-asmlinkage long compat_sys_futex(u32 __user *uaddr, int op, int val,
+asmlinkage long compat_sys_futex(u32 __user *uaddr, int op, u32 val,
struct compat_timespec __user *utime, u32 __user *uaddr2,
- int val3)
+ u32 val3)
{
struct timespec t;
unsigned long timeout = MAX_SCHEDULE_TIMEOUT;
@@ -137,6 +137,5 @@
if (op >= FUTEX_REQUEUE)
val2 = (int) (unsigned long) utime;
- return do_futex((unsigned long)uaddr, op, val, timeout,
- (unsigned long)uaddr2, val2, val3);
+ return do_futex(uaddr, op, val, timeout, uaddr2, val2, val3);
}