sched: Assert task state bits at build time

Since everybody is lazy and prone to forgetting things, make the
compiler help us a bit.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <20091217121830.060186433@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 4 insertions, 0 deletions

diff --git a/include/linux/sched.h b/include/linux/sched.h
index 94858df38a87..37543876ddf5 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -192,9 +192,13 @@ print_cfs_rq(struct seq_file *m, int cpu, struct cfs_rq *cfs_rq)
 #define TASK_DEAD               64
 #define TASK_WAKEKILL           128
 #define TASK_WAKING             256
+#define TASK_STATE_MAX          512
 
 #define TASK_STATE_TO_CHAR_STR "RSDTtZXxKW"
 
+extern char ___assert_task_state[1 - 2*!!(
+                sizeof(TASK_STATE_TO_CHAR_STR)-1 != ilog2(TASK_STATE_MAX)+1)];
+
 /* Convenience macros for the sake of set_task_state */
 #define TASK_KILLABLE           (TASK_WAKEKILL | TASK_UNINTERRUPTIBLE)
 #define TASK_STOPPED            (TASK_WAKEKILL | __TASK_STOPPED)