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authorPaul E. McKenney <paulmck@linux.vnet.ibm.com>2017-04-23 09:22:05 -0700
committerIngo Molnar <mingo@kernel.org>2017-04-24 08:14:48 +0200
commit677df9d4615a2db6774cd0e8951bf7404b858b3b (patch)
tree3ddbbc31b609dda2ba8102270bf00b8649b8aa3e /init
parent58d30c36d472b75e8e9962d6a640be19d9389128 (diff)
srcu: Fix Kconfig botch when SRCU not selected
If the CONFIG_SRCU option is not selected, for example, when building arch/tile allnoconfig, the following build errors appear: kernel/rcu/tree.o: In function `srcu_online_cpu': tree.c:(.text+0x4248): multiple definition of `srcu_online_cpu' kernel/rcu/srcutree.o:srcutree.c:(.text+0x2120): first defined here kernel/rcu/tree.o: In function `srcu_offline_cpu': tree.c:(.text+0x4250): multiple definition of `srcu_offline_cpu' kernel/rcu/srcutree.o:srcutree.c:(.text+0x2160): first defined here The corresponding .config file shows CONFIG_TREE_SRCU=y, but no sign of CONFIG_SRCU, which fatally confuses SRCU's #ifdefs, resulting in the above errors. The reason this occurs is the folowing line in init/Kconfig's definition for TREE_SRCU: default y if !TINY_RCU && !CLASSIC_SRCU If CONFIG_CLASSIC_SRCU=n, as it will be in for allnoconfig, and if CONFIG_SMP=y, then we will get CONFIG_TREE_SRCU=y but no CONFIG_SRCU, as seen in the .config file, and which will result in the above errors. This error did not show up during rcutorture testing because rcutorture forces CONFIG_SRCU=y, as it must to prevent build errors in rcutorture.c. This commit therefore conditions TREE_SRCU (and TINY_SRCU, while it is at it) with SRCU, like this: default y if SRCU && !TINY_RCU && !CLASSIC_SRCU Reported-by: kbuild test robot <fengguang.wu@intel.com> Reported-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Link: http://lkml.kernel.org/r/20170423162205.GP3956@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'init')
-rw-r--r--init/Kconfig4
1 files changed, 2 insertions, 2 deletions
diff --git a/init/Kconfig b/init/Kconfig
index 4119a44e4157..fe72c12e06a5 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -545,13 +545,13 @@ config CLASSIC_SRCU
config TINY_SRCU
bool
- default y if TINY_RCU && !CLASSIC_SRCU
+ default y if SRCU && TINY_RCU && !CLASSIC_SRCU
help
This option selects the single-CPU non-preemptible version of SRCU.
config TREE_SRCU
bool
- default y if !TINY_RCU && !CLASSIC_SRCU
+ default y if SRCU && !TINY_RCU && !CLASSIC_SRCU
help
This option selects the full-fledged version of SRCU.