Commit 8f17d3a5 authored by Ingo Molnar's avatar Ingo Molnar Committed by Linus Torvalds

[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: default avatarIngo 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: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 8fdd6c6d
......@@ -142,8 +142,6 @@ On insertion:
of the 'lock word', to the linked list starting at 'head', and
4) clear the 'list_op_pending' word.
XXX I am particularly unsure of the following -pj XXX
On removal:
1) set the 'list_op_pending' word to the address of the 'lock word'
to be removed,
......
......@@ -213,6 +213,6 @@ robust-mutex testcases.
All other architectures should build just fine too - but they wont have
the new syscalls yet.
Architectures need to implement the new futex_atomic_cmpxchg_inuser()
Architectures need to implement the new futex_atomic_cmpxchg_inatomic()
inline function before writing up the syscalls (that function returns
-ENOSYS right now).
......@@ -10,7 +10,7 @@
extern int futex_atomic_op_inuser(int encoded_op, int __user *uaddr);
static inline int
futex_atomic_cmpxchg_inuser(int __user *uaddr, int oldval, int newval)
futex_atomic_cmpxchg_inatomic(int __user *uaddr, int oldval, int newval)
{
return -ENOSYS;
}
......
......@@ -50,7 +50,7 @@ futex_atomic_op_inuser (int encoded_op, int __user *uaddr)
}
static inline int
futex_atomic_cmpxchg_inuser(int __user *uaddr, int oldval, int newval)
futex_atomic_cmpxchg_inatomic(int __user *uaddr, int oldval, int newval)
{
return -ENOSYS;
}
......
......@@ -105,7 +105,7 @@ futex_atomic_op_inuser (int encoded_op, int __user *uaddr)
}
static inline int
futex_atomic_cmpxchg_inuser(int __user *uaddr, int oldval, int newval)
futex_atomic_cmpxchg_inatomic(int __user *uaddr, int oldval, int newval)
{
if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int)))
return -EFAULT;
......
......@@ -100,7 +100,7 @@ futex_atomic_op_inuser (int encoded_op, int __user *uaddr)
}
static inline int
futex_atomic_cmpxchg_inuser(int __user *uaddr, int oldval, int newval)
futex_atomic_cmpxchg_inatomic(int __user *uaddr, int oldval, int newval)
{
return -ENOSYS;
}
......
......@@ -82,7 +82,7 @@ static inline int futex_atomic_op_inuser (int encoded_op, int __user *uaddr)
}
static inline int
futex_atomic_cmpxchg_inuser(int __user *uaddr, int oldval, int newval)
futex_atomic_cmpxchg_inatomic(int __user *uaddr, int oldval, int newval)
{
return -ENOSYS;
}
......
......@@ -95,7 +95,7 @@ futex_atomic_op_inuser (int encoded_op, int __user *uaddr)
}
static inline int
futex_atomic_cmpxchg_inuser(int __user *uaddr, int oldval, int newval)
futex_atomic_cmpxchg_inatomic(int __user *uaddr, int oldval, int newval)
{
if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int)))
return -EFAULT;
......
......@@ -100,7 +100,7 @@ long do_futex(unsigned long uaddr, int op, int val,
unsigned long timeout, unsigned long uaddr2, int val2,
int val3);
extern int handle_futex_death(unsigned int *uaddr, struct task_struct *curr);
extern int handle_futex_death(u32 __user *uaddr, struct task_struct *curr);
#ifdef CONFIG_FUTEX
extern void exit_robust_list(struct task_struct *curr);
......
......@@ -1061,7 +1061,10 @@ static task_t *copy_process(unsigned long clone_flags,
* 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
*/
......
......@@ -913,15 +913,15 @@ sys_get_robust_list(int pid, struct robust_list_head __user **head_ptr,
* 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 @@ int handle_futex_death(unsigned int *uaddr, struct task_struct *curr)
* 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 @@ void exit_robust_list(struct task_struct *curr)
if (handle_futex_death((void *)entry + futex_offset,
curr))
return;
/*
* Fetch the next entry in the list:
*/
......
......@@ -121,9 +121,9 @@ compat_sys_get_robust_list(int pid, compat_uptr_t *head_ptr,
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 @@ asmlinkage long compat_sys_futex(u32 __user *uaddr, int op, int val,
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);
}
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