rcu: Disable TASKS_RCU for usermode Linux

Usermode Linux currently does not implement arch_irqs_disabled_flags(),
which results in a build failure in TASKS_RCU.  Therefore, this commit
disables the TASKS_RCU Kconfig option in usermode Linux builds.  The
usermode Linux maintainers expect to merge arch_irqs_disabled_flags()
into 4.8, at which point this commit may be reverted.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Jeff Dike <jdike@addtoit.com>
Acked-by: Richard Weinberger <richard@nod.at>

diff --git a/init/Kconfig b/init/Kconfig
index f755a60..a068265 100644 (file)
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -517,6 +517,7 @@ config SRCU
 config TASKS_RCU
        bool
        default n
+       depends on !UML
        select SRCU
        help
          This option enables a task-based RCU implementation that uses