Re: linux-next: build failure after merge of the rcu tree

Paul E. McKenney
2019-08-12T16:19:40Z

On Mon, Aug 12, 2019 at 04:12:36PM +1000, Stephen Rothwell wrote:
> Hi all,
>
> After merging the rcu tree, today's linux-next build (x86_64 allmodconfig)
> failed like this:
>
> arch/x86/xen/smp_pv.c: In function 'xen_pv_play_dead':
> arch/x86/xen/smp_pv.c:439:2: error: implicit declaration of function 'tick_nohz_idle_stop_tick_protected'; did you mean 'tick_nohz_idle_stop_tick'? [-Werror=implicit-function-declaration]
> tick_nohz_idle_stop_tick_protected();
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> tick_nohz_idle_stop_tick
>
> Caused by commit
>
> a96f9dca9820 ("idle: Prevent late-arriving interrupts from disrupting offline")

Peter, I reverted the portion of this commit that removes the
tick_nohz_idle_stop_tick_protected() function. Please let me know if
you instead convince the Xen people to stop using it.

> Also:
>
> In file included from <command-line>:
> include/linux/rcu_segcblist.h:69:2: error: unknown type name 'atomic_long_t'
> atomic_long_t len;
> ^~~~~~~~~~~~~
> include/linux/rcu_segcblist.h:74:2: error: unknown type name 'u8'
> u8 enabled;
> ^~
> include/linux/rcu_segcblist.h:75:2: error: unknown type name 'u8'
> u8 offloaded;
> ^~
>
> Caused by commits:
>
> e084617762b7 ("rcu/nocb: Use separate flag to indicate disabled ->cblist")
> 5e114ba3d7a5 ("rcu/nocb: Use separate flag to indicate offloaded ->cblist")
> 9f3ca0945104 ("rcu/nocb: Atomic ->len field in rcu_segcblist structure")
>
> We prefer our include files to be standalone now if at all possible.

Huh. "It has been building fine for me." I added

#include <uapi/asm-generic/types.h>
#include <asm-generic/atomic-long.h>

to include/linux/rcu_segcblist.h, which hopefully fixes it at your end.
I will push this after testing and rearrangement at this end.

Thanx, Paul

> I have used the rcu tree from next-20190809 for today.
>
> --
> Cheers,
> Stephen Rothwell