On Mon, Apr 24, 2017 at 03:00:38AM +0800, kbuild test robot wrote: > tree: https://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git > rcu/urgent > head: 746ec1f689abc74dca72fdce4134decdbfaec295 > commit: 746ec1f689abc74dca72fdce4134decdbfaec295 [11/11] srcu: Fix Kconfig > botch when SRCU not selected > config: sparc64-allnoconfig (attached as .config) > compiler: sparc64-linux-gnu-gcc (Debian 6.1.1-9) 6.1.1 20160705 > reproduce: > wget > https://raw.githubusercontent.com/01org/lkp-tests/master/sbin/make.cross -O > ~/bin/make.cross > chmod +x ~/bin/make.cross > git checkout 746ec1f689abc74dca72fdce4134decdbfaec295 > # save the attached .config to linux build tree > make.cross ARCH=sparc64 > > All errors (new ones prefixed by >>): > > In file included from include/linux/notifier.h:15:0, > from include/linux/pm_qos.h:8, > from kernel/power/qos.c:32: > >> include/linux/srcu.h:66:2: error: #error "Unknown SRCU implementation > >> specified to kernel configuration" > #error "Unknown SRCU implementation specified to kernel configuration" > ^~~~~ > In file included from include/linux/pm_qos.h:8:0, > from kernel/power/qos.c:32: > >> include/linux/notifier.h:77:21: error: field 'srcu' has incomplete type > struct srcu_struct srcu; > ^~~~
And it appears that there is much code that includes srcu.h without having "select SRCU", which underlines the point that SRCU is no longer optional. Patch below, pushing to -rcu as well. ------------------------------------------------------------------------ commit b0d5280678ad03d0b8dbdbe827c9e31c43923e02 Author: Paul E. McKenney <[email protected]> Date: Sun Apr 23 12:50:59 2017 -0700 srcu: Make SRCU be built by default SRCU is optional, and included only if there is a "select SRCU" in effect. However, we now have Tiny SRCU, so this commit defaults CONFIG_SRCU=y. Reported-by: kbuild test robot <[email protected]> Signed-off-by: Paul E. McKenney <[email protected]> diff --git a/init/Kconfig b/init/Kconfig index fe72c12e06a5..42a346b0df43 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -521,6 +521,7 @@ config RCU_EXPERT config SRCU bool + default y help This option selects the sleepable version of RCU. This version permits arbitrary sleeping or blocking within RCU read-side critical
