[PATCH] simplify k_getrusage()

Factor out common code for different RUSAGE_xxx cases.

Don't take ->sighand->siglock in RUSAGE_SELF case, suggested by Ravikiran G
Thirumalai <kiran@scalex86.org>.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 11 insertions, 18 deletions

diff --git a/kernel/sys.c b/kernel/sys.c
index 218937e837dc..b6941e06d5d5 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -1692,7 +1692,10 @@ static void k_getrusage(struct task_struct *p, int who, struct rusage *r)
         if (unlikely(!p->signal))
                 return;
 
+        utime = stime = cputime_zero;
+
         switch (who) {
+                case RUSAGE_BOTH:
                 case RUSAGE_CHILDREN:
                         spin_lock_irqsave(&p->sighand->siglock, flags);
                         utime = p->signal->cutime;
@@ -1702,22 +1705,11 @@ static void k_getrusage(struct task_struct *p, int who, struct rusage *r)
                         r->ru_minflt = p->signal->cmin_flt;
                         r->ru_majflt = p->signal->cmaj_flt;
                         spin_unlock_irqrestore(&p->sighand->siglock, flags);
-                        cputime_to_timeval(utime, &r->ru_utime);
-                        cputime_to_timeval(stime, &r->ru_stime);
-                        break;
+
+                        if (who == RUSAGE_CHILDREN)
+                                break;
+
                 case RUSAGE_SELF:
-                        spin_lock_irqsave(&p->sighand->siglock, flags);
-                        utime = stime = cputime_zero;
-                        goto sum_group;
-                case RUSAGE_BOTH:
-                        spin_lock_irqsave(&p->sighand->siglock, flags);
-                        utime = p->signal->cutime;
-                        stime = p->signal->cstime;
-                        r->ru_nvcsw = p->signal->cnvcsw;
-                        r->ru_nivcsw = p->signal->cnivcsw;
-                        r->ru_minflt = p->signal->cmin_flt;
-                        r->ru_majflt = p->signal->cmaj_flt;
-                sum_group:
                         utime = cputime_add(utime, p->signal->utime);
                         stime = cputime_add(stime, p->signal->stime);
                         r->ru_nvcsw += p->signal->nvcsw;
@@ -1734,13 +1726,14 @@ static void k_getrusage(struct task_struct *p, int who, struct rusage *r)
                                 r->ru_majflt += t->maj_flt;
                                 t = next_thread(t);
                         } while (t != p);
-                        spin_unlock_irqrestore(&p->sighand->siglock, flags);
-                        cputime_to_timeval(utime, &r->ru_utime);
-                        cputime_to_timeval(stime, &r->ru_stime);
                         break;
+
                 default:
                         BUG();
         }
+
+        cputime_to_timeval(utime, &r->ru_utime);
+        cputime_to_timeval(stime, &r->ru_stime);
 }
 
 int getrusage(struct task_struct *p, int who, struct rusage __user *ru)