From e1781538cf5c870ab696e9b8f0a5c498d3900f2f Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 17 Dec 2009 13:16:30 +0100 Subject: [PATCH] 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 LKML-Reference: <20091217121830.060186433@chello.nl> Signed-off-by: Ingo Molnar --- fs/proc/array.c | 18 ++++++++++-------- include/linux/sched.h | 4 ++++ 2 files changed, 14 insertions(+), 8 deletions(-) diff --git a/fs/proc/array.c b/fs/proc/array.c index 96361e8fa3a..f560325c444 100644 --- a/fs/proc/array.c +++ b/fs/proc/array.c @@ -134,14 +134,14 @@ static inline void task_name(struct seq_file *m, struct task_struct *p) * simple bit tests. */ static const char *task_state_array[] = { - "R (running)", /* 0 */ - "S (sleeping)", /* 1 */ - "D (disk sleep)", /* 2 */ - "T (stopped)", /* 4 */ - "t (tracing stop)", /* 8 */ - "Z (zombie)", /* 16 */ - "X (dead)", /* 32 */ - "x (dead)", /* 64 */ + "R (running)", /* 0 */ + "S (sleeping)", /* 1 */ + "D (disk sleep)", /* 2 */ + "T (stopped)", /* 4 */ + "t (tracing stop)", /* 8 */ + "Z (zombie)", /* 16 */ + "X (dead)", /* 32 */ + "x (dead)", /* 64 */ "K (wakekill)", /* 128 */ "W (waking)", /* 256 */ }; @@ -151,6 +151,8 @@ static inline const char *get_task_state(struct task_struct *tsk) unsigned int state = (tsk->state & TASK_REPORT) | tsk->exit_state; const char **p = &task_state_array[0]; + BUILD_BUG_ON(1 + ilog2(TASK_STATE_MAX) != ARRAY_SIZE(task_state_array)); + while (state) { p++; state >>= 1; diff --git a/include/linux/sched.h b/include/linux/sched.h index 94858df38a8..37543876ddf 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)