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

[Paul E. McKenney]

On Tue, Mar 14, 2023 at 12:29:22PM +1100, Stephen Rothwell wrote:
> Hi all,
> 
> After merging the rcu tree, today's linux-next build (x86_64 allmodconfig)
> failed like this:
> 
> net/mac802154/scan.c: In function 'mac802154_scan_cleanup_locked':
> net/mac802154/scan.c:55:26: error: macro "kfree_rcu" requires 2 arguments, but only 1 given
>    55 |         kfree_rcu(request);
>       |                          ^
> In file included from include/linux/rbtree.h:24,
>                  from include/linux/mm_types.h:11,
>                  from include/linux/buildid.h:5,
>                  from include/linux/module.h:14,
>                  from net/mac802154/scan.c:11:
> include/linux/rcupdate.h:984: note: macro "kfree_rcu" defined here
>   984 | #define kfree_rcu(ptr, rhf) kvfree_rcu_arg_2(ptr, rhf)
>       | 
> net/mac802154/scan.c:55:9: error: 'kfree_rcu' undeclared (first use in this function); did you mean 'kfree_skb'?
>    55 |         kfree_rcu(request);
>       |         ^~~~~~~~~
>       |         kfree_skb
> net/mac802154/scan.c:55:9: note: each undeclared identifier is reported only once for each function it appears in
> net/mac802154/scan.c: In function 'mac802154_stop_beacons_locked':
> net/mac802154/scan.c:406:26: error: macro "kfree_rcu" requires 2 arguments, but only 1 given
>   406 |         kfree_rcu(request);
>       |                          ^
> include/linux/rcupdate.h:984: note: macro "kfree_rcu" defined here
>   984 | #define kfree_rcu(ptr, rhf) kvfree_rcu_arg_2(ptr, rhf)
>       | 
> net/mac802154/scan.c:406:9: error: 'kfree_rcu' undeclared (first use in this function); did you mean 'kfree_skb'?
>   406 |         kfree_rcu(request);
>       |         ^~~~~~~~~
>       |         kfree_skb
> drivers/infiniband/sw/rxe/rxe_mr.c: In function 'rxe_dereg_mr':
> drivers/infiniband/sw/rxe/rxe_mr.c:734:21: error: macro "kfree_rcu" requires 2 arguments, but only 1 given
>   734 |         kfree_rcu(mr);
>       |                     ^
> In file included from include/linux/rculist.h:11,
>                  from include/linux/dcache.h:8,
>                  from include/linux/fs.h:8,
>                  from include/linux/highmem.h:5,
>                  from include/linux/bvec.h:10,
>                  from include/linux/blk_types.h:10,
>                  from include/linux/bio.h:10,
>                  from include/linux/libnvdimm.h:14,
>                  from drivers/infiniband/sw/rxe/rxe_mr.c:7:
> include/linux/rcupdate.h:984: note: macro "kfree_rcu" defined here
>   984 | #define kfree_rcu(ptr, rhf) kvfree_rcu_arg_2(ptr, rhf)
>       | 
> drivers/infiniband/sw/rxe/rxe_mr.c:734:9: error: 'kfree_rcu' undeclared (first use in this function); did you mean 'kfree_skb'?
>   734 |         kfree_rcu(mr);
>       |         ^~~~~~~~~
>       |         kfree_skb
> drivers/infiniband/sw/rxe/rxe_mr.c:734:9: note: each undeclared identifier is reported only once for each function it appears in
> 
> Caused by commit
> 
>   62a2ac23b35f ("rcu/kvfree: Eliminate k[v]free_rcu() single argument macro")
> 
> I have used the rcu tree from next-20230310 for today.

Please accept my apologies -- I left out that revert.  I have pushed
out an rcu/next including it.

But I guess we now know for sure that this revert is still needed.  :-/

							Thanx, Paul