On Wed, 2007-10-17 at 07:48 -0700, Daniel Walker wrote:
> Steven,
>
> Could you include this patch, it was submitted on the list but you
> didn't get CC'd ..
Thanks, it may have been a while before I see this (/me has been nose
deep in debugging).
> > On Tue, 2007-10-16 at 10:35 +0200, Remy Bohmer wrote:
> > > Hello Daniel and Ingo,
> > >
> > > I use 2.6.23-rt1 and the patch of Daniel below which seems to be in
> > > there breaks the compilation of the RT-kernel when CONFIG_GENERIC_TIME
> > > is NOT set.
> > >
> > > It breaks in the do_gettimeofday(struct timeval *tv) code in the
> > > architecture specific code
> > > where there is a call to: seq = read_seqbegin_irqsave(&xtime_lock, flags);
> > > The PICK_FUNCTION implementation does not return anything, so the
> > > compile breaks here.
> > >
> > > I am figuring out how to solve this problem nicely, but I have not
> > > found a nice solution yet. Attached I have put my hack to make it
> > > compile on ARM again, but maybe one of you can do a better proposal to
> > > fix this.
> >
> > Here's another fix for this. I compile tested for ARM (!GENERIC_TIME) ,
> > but I didn't boot test .. Could you boot test this patch?
> >
> > ---
> >
> > Move the read_seqbegin() call up in the chain so the value
> > can be returned
> >
> > Signed-off-by: Daniel Walker <dwalker@xxxxxxxxxx>
> >
> > ---
> > include/linux/seqlock.h | 7 +++----
> > 1 file changed, 3 insertions(+), 4 deletions(-)
> >
> > Index: linux-2.6.23/include/linux/seqlock.h
> > ===================================================================
> > --- linux-2.6.23.orig/include/linux/seqlock.h
> > +++ linux-2.6.23/include/linux/seqlock.h
> > @@ -285,21 +285,20 @@ unsigned long __read_seqbegin_irqsave_ra
> > unsigned long flags;
> >
> > local_irq_save(flags);
> > - __read_seqbegin_raw(sl);
> > return flags;
> > }
> >
> > static __always_inline unsigned long __read_seqbegin_irqsave(seqlock_t *sl)
> > {
> > - __read_seqbegin(sl);
> > return 0;
> > }
The above should be renamed. They have nothing to do with seqlocks now.
> >
> > #define read_seqbegin_irqsave(lock, flags) \
> > -do { \
> > +({ \
> > flags = PICK_SEQ_OP_RET(__read_seqbegin_irqsave_raw, \
> > __read_seqbegin_irqsave, lock); \
> > -} while (0)
> > + read_seqbegin(lock); \
> > +})
Yes, definitely the raw and unraw functions should be called
local_irqsave_raw or something else that makes this obvious to what it
is doing.
-- Steve
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