[PATCH] kill PF_DEAD flag

After the previous change (->flags & PF_DEAD) <=> (->state == EXIT_DEAD), we
don't need PF_DEAD any longer.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

4 files changed, 12 insertions, 15 deletions

diff --git a/include/linux/sched.h b/include/linux/sched.h
index fbc69cc3923d..9763de334f09 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1061,7 +1061,6 @@ static inline void put_task_struct(struct task_struct *t)
                                         /* Not implemented yet, only for 486*/
 #define PF_STARTING     0x00000002      /* being created */
 #define PF_EXITING      0x00000004      /* getting shut down */
-#define PF_DEAD         0x00000008      /* Dead */
 #define PF_FORKNOEXEC   0x00000040      /* forked but didn't exec */
 #define PF_SUPERPRIV    0x00000100      /* used super-user privileges */
 #define PF_DUMPCORE     0x00000200      /* dumped core */
diff --git a/kernel/exit.c b/kernel/exit.c
index 3d759c98fb11..9dd5f1336da2 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -953,10 +953,8 @@ fastcall NORET_TYPE void do_exit(long code)
         if (tsk->splice_pipe)
                 __free_pipe_info(tsk->splice_pipe);
 
-        /* PF_DEAD causes final put_task_struct after we schedule. */
         preempt_disable();
-        BUG_ON(tsk->flags & PF_DEAD);
-        tsk->flags |= PF_DEAD;
+        /* causes final put_task_struct in finish_task_switch(). */
         tsk->state = EXIT_DEAD;
 
         schedule();
@@ -972,7 +970,7 @@ NORET_TYPE void complete_and_exit(struct completion *comp, long code)
 {
         if (comp)
                 complete(comp);
-        
+
         do_exit(code);
 }
 
diff --git a/kernel/sched.c b/kernel/sched.c
index e1646b044b69..a9405d7cc6ab 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -1755,27 +1755,27 @@ static inline void finish_task_switch(struct rq *rq, struct task_struct *prev)
         __releases(rq->lock)
 {
         struct mm_struct *mm = rq->prev_mm;
-        unsigned long prev_task_flags;
+        long prev_state;
 
         rq->prev_mm = NULL;
 
         /*
          * A task struct has one reference for the use as "current".
-         * If a task dies, then it sets EXIT_ZOMBIE in tsk->exit_state and
-         * calls schedule one last time. The schedule call will never return,
-         * and the scheduled task must drop that reference.
-         * The test for EXIT_ZOMBIE must occur while the runqueue locks are
+         * If a task dies, then it sets EXIT_DEAD in tsk->state and calls
+         * schedule one last time. The schedule call will never return, and
+         * the scheduled task must drop that reference.
+         * The test for EXIT_DEAD must occur while the runqueue locks are
          * still held, otherwise prev could be scheduled on another cpu, die
          * there before we look at prev->state, and then the reference would
          * be dropped twice.
          *              Manfred Spraul <manfred@colorfullife.com>
          */
-        prev_task_flags = prev->flags;
+        prev_state = prev->state;
         finish_arch_switch(prev);
         finish_lock_switch(rq, prev);
         if (mm)
                 mmdrop(mm);
-        if (unlikely(prev_task_flags & PF_DEAD)) {
+        if (unlikely(prev_state == EXIT_DEAD)) {
                 /*
                  * Remove function-return probe instances associated with this
                  * task and put them back on the free list.
@@ -5153,7 +5153,7 @@ static void migrate_dead(unsigned int dead_cpu, struct task_struct *p)
         BUG_ON(p->exit_state != EXIT_ZOMBIE && p->exit_state != EXIT_DEAD);
 
         /* Cannot have done final schedule yet: would have vanished. */
-        BUG_ON(p->flags & PF_DEAD);
+        BUG_ON(p->state == EXIT_DEAD);
 
         get_task_struct(p);
 
diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index f3dd79c1c367..202f186a753a 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -226,8 +226,8 @@ static struct task_struct *select_bad_process(unsigned long *ppoints)
                 releasing = test_tsk_thread_flag(p, TIF_MEMDIE) ||
                                                 p->flags & PF_EXITING;
                 if (releasing) {
-                        /* PF_DEAD tasks have already released their mm */
-                        if (p->flags & PF_DEAD)
+                        /* TASK_DEAD tasks have already released their mm */
+                        if (p->state == EXIT_DEAD)
                                 continue;
                         if (p->flags & PF_EXITING && p == current) {
                                 chosen = p;