Re: [PATCH net-next RESEND 2/2] ipv6: fix sparse warning

From: Paul E. McKenney
Date: Thu Dec 11 2014 - 12:02:41 EST


On Thu, Dec 11, 2014 at 09:56:33AM +0800, Ying Xue wrote:
> On 12/11/2014 12:04 AM, Paul E. McKenney wrote:
> > On Wed, Dec 10, 2014 at 04:46:07PM +0800, Ying Xue wrote:
> >> This fixes the following spare warning when using
> >>
> >> make C=1 CF=-D__CHECK_ENDIAN__ net/ipv6/addrconf.o
> >> net/ipv6/addrconf.c:3495:9: error: incompatible types in comparison expression (different address spaces)
> >> net/ipv6/addrconf.c:3495:9: error: incompatible types in comparison expression (different address spaces)
> >> net/ipv6/addrconf.c:3495:9: error: incompatible types in comparison expression (different address spaces)
> >> net/ipv6/addrconf.c:3495:9: error: incompatible types in comparison expression (different address spaces)
> >>
> >> To silence above spare complaint, an RCU annotation should be added
> >> to "next" pointer of hlist_node structure through hlist_next_rcu()
> >> macro when iterating over a hlist with
> >> hlist_for_each_entry_continue_rcu_bh().
> >>
> >> By the way, this commit also resolves the same error appearing in
> >> hlist_for_each_entry_continue_rcu().
> >>
> >> Signed-off-by: Ying Xue <ying.xue@xxxxxxxxxxxxx>
> >
> > If you pull the rculist.h changes from the first patch into this one,
> > I will queue it up through -rcu.
>
> Please just queue this patch into your RCU tree. Some changes of the
> first patch currently only exists in net-next tree, so it cannot be
> merged into RCU tree now. Therefore, please temporarily ignore it. In
> next 3.19 development cycle, I will resubmit it to you.

Sounds good, but could you please rebase the second patch to be
independent of the first patch? If you do that, I would be happy
to queue it.

Thanx, Paul

> Thanks,
> Ying
>
> > Thanx, Paul
> >
> >> ---
> >> include/linux/rculist.h | 16 ++++++++--------
> >> 1 file changed, 8 insertions(+), 8 deletions(-)
> >>
> >> diff --git a/include/linux/rculist.h b/include/linux/rculist.h
> >> index 866d9c9..32bd4ad 100644
> >> --- a/include/linux/rculist.h
> >> +++ b/include/linux/rculist.h
> >> @@ -524,11 +524,11 @@ static inline void hlist_add_behind_rcu(struct hlist_node *n,
> >> * @member: the name of the hlist_node within the struct.
> >> */
> >> #define hlist_for_each_entry_continue_rcu(pos, member) \
> >> - for (pos = hlist_entry_safe(rcu_dereference((pos)->member.next),\
> >> - typeof(*(pos)), member); \
> >> + for (pos = hlist_entry_safe(rcu_dereference_raw(hlist_next_rcu( \
> >> + &(pos)->member)), typeof(*(pos)), member); \
> >> pos; \
> >> - pos = hlist_entry_safe(rcu_dereference((pos)->member.next),\
> >> - typeof(*(pos)), member))
> >> + pos = hlist_entry_safe(rcu_dereference_raw(hlist_next_rcu( \
> >> + &(pos)->member)), typeof(*(pos)), member))
> >>
> >> /**
> >> * hlist_for_each_entry_continue_rcu_bh - iterate over a hlist continuing after current point
> >> @@ -536,11 +536,11 @@ static inline void hlist_add_behind_rcu(struct hlist_node *n,
> >> * @member: the name of the hlist_node within the struct.
> >> */
> >> #define hlist_for_each_entry_continue_rcu_bh(pos, member) \
> >> - for (pos = hlist_entry_safe(rcu_dereference_bh((pos)->member.next),\
> >> - typeof(*(pos)), member); \
> >> + for (pos = hlist_entry_safe(rcu_dereference_bh(hlist_next_rcu( \
> >> + &(pos)->member)), typeof(*(pos)), member); \
> >> pos; \
> >> - pos = hlist_entry_safe(rcu_dereference_bh((pos)->member.next),\
> >> - typeof(*(pos)), member))
> >> + pos = hlist_entry_safe(rcu_dereference_bh(hlist_next_rcu( \
> >> + &(pos)->member)), typeof(*(pos)), member))
> >>
> >> /**
> >> * hlist_for_each_entry_from_rcu - iterate over a hlist continuing from current point
> >> --
> >> 1.7.9.5
> >>
> >
> >
> >
>

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