Messages in this thread | | | Date | Wed, 9 Mar 2011 16:08:39 +0100 | From | Martin Schwidefsky <> | Subject | Re: [PATCH] futex: cmpxchg_futex_value_locked API change |
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On Wed, 9 Mar 2011 03:25:50 -0800 Michel Lespinasse <walken@google.com> wrote:
> On Tue, Mar 08, 2011 at 09:17:11PM +0100, Thomas Gleixner wrote: > > On Sun, 6 Mar 2011, Michel Lespinasse wrote: > > > The cmpxchg_futex_value_locked API was funny in that it returned either > > > the original, user-exposed futex value OR an error code such as -EFAULT. > > > This was confusing at best, and could be a source of livelocks in places > > > that retry the cmpxchg_futex_value_locked after trying to fix the issue > > > by running fault_in_user_writeable(). > > > > > > This change makes the cmpxchg_futex_value_locked API more similar to the > > > get_futex_value_locked one, returning an error code and updating the > > > original value through a reference argument. > > > > Ack. > > > > > static inline int > > > -futex_atomic_cmpxchg_inatomic(int __user *uaddr, int oldval, int newval) > > > +futex_atomic_cmpxchg_inatomic(int *uval, int __user *uaddr, > > > + int oldval, int newval) > > > > Can we please change the arguments to u32 while at it? The futex core > > code uses u32 all over the place so those inlines should do the same. > > All right. Attaching updated version of the diff. I also fixed the s390 > issue reported by Martin Schwidefsky.
The inline assmeblies look good now but I get this compile error on s390:
CC arch/s390/lib/uaccess_pt.o arch/s390/lib/uaccess_pt.c:373: error: conflicting types for 'futex_atomic_cmpxchg_pt' arch/s390/lib/uaccess.h:21: note: previous declaration of 'futex_atomic_cmpxchg_pt' was here arch/s390/lib/uaccess_pt.c:403: warning: initialization from incompatible pointer type make[1]: *** [arch/s390/lib/uaccess_pt.o] Error 1
The trouble is this part of the patch:
-int futex_atomic_cmpxchg_pt(int __user *uaddr, int oldval, int newval) +int futex_atomic_cmpxchg_pt(int *uval, int __user *uaddr, + int oldval, int newval)
You need to change these "int"s to "u32"s.
-- blue skies, Martin.
"Reality continues to ruin my life." - Calvin.
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