rcu: Select IRQ_WORK from TREE_PREEMPT_RCU

TREE_RCU and TREE_PREEMPT_RCU both cause kernel/rcutree.c to be built,
but only TREE_RCU selects IRQ_WORK, which can result in an undefined
reference to irq_work_queue for some (random) configs:

kernel/built-in.o In function `rcu_start_gp_advanced':
kernel/rcutree.c:1564: undefined reference to `irq_work_queue'

Select IRQ_WORK from TREE_PREEMPT_RCU too to fix this.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Dipankar Sarma <dipankar@in.ibm.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>

1 files changed, 1 insertions, 0 deletions

diff --git a/init/Kconfig b/init/Kconfig
index 247084be0590..c08a5495dbb7 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -470,6 +470,7 @@ config TREE_RCU
 config TREE_PREEMPT_RCU
         bool "Preemptible tree-based hierarchical RCU"
         depends on PREEMPT
+        select IRQ_WORK
         help
           This option selects the RCU implementation that is
           designed for very large SMP systems with hundreds or