1 files changed, 65 insertions, 45 deletions

diff --git a/kernel/sys.c b/kernel/sys.c
index f2a451366953..895d2d4c9493 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -978,8 +978,7 @@ asmlinkage long sys_setpgid(pid_t pid, pid_t pgid)
                 goto out;
 
         if (task_pgrp(p) != pgrp) {
-                detach_pid(p, PIDTYPE_PGID);
-                attach_pid(p, PIDTYPE_PGID, pgrp);
+                change_pid(p, PIDTYPE_PGID, pgrp);
                 set_task_pgrp(p, pid_nr(pgrp));
         }
 
@@ -992,54 +991,67 @@ out:
 
 asmlinkage long sys_getpgid(pid_t pid)
 {
+        struct task_struct *p;
+        struct pid *grp;
+        int retval;
+
+        rcu_read_lock();
         if (!pid)
-                return task_pgrp_vnr(current);
+                grp = task_pgrp(current);
         else {
-                int retval;
-                struct task_struct *p;
-
-                read_lock(&tasklist_lock);
-                p = find_task_by_vpid(pid);
                 retval = -ESRCH;
-                if (p) {
-                        retval = security_task_getpgid(p);
-                        if (!retval)
-                                retval = task_pgrp_vnr(p);
-                }
-                read_unlock(&tasklist_lock);
-                return retval;
+                p = find_task_by_vpid(pid);
+                if (!p)
+                        goto out;
+                grp = task_pgrp(p);
+                if (!grp)
+                        goto out;
+
+                retval = security_task_getpgid(p);
+                if (retval)
+                        goto out;
         }
+        retval = pid_vnr(grp);
+out:
+        rcu_read_unlock();
+        return retval;
 }
 
 #ifdef __ARCH_WANT_SYS_GETPGRP
 
 asmlinkage long sys_getpgrp(void)
 {
-        /* SMP - assuming writes are word atomic this is fine */
-        return task_pgrp_vnr(current);
+        return sys_getpgid(0);
 }
 
 #endif
 
 asmlinkage long sys_getsid(pid_t pid)
 {
+        struct task_struct *p;
+        struct pid *sid;
+        int retval;
+
+        rcu_read_lock();
         if (!pid)
-                return task_session_vnr(current);
+                sid = task_session(current);
         else {
-                int retval;
-                struct task_struct *p;
-
-                rcu_read_lock();
-                p = find_task_by_vpid(pid);
                 retval = -ESRCH;
-                if (p) {
-                        retval = security_task_getsid(p);
-                        if (!retval)
-                                retval = task_session_vnr(p);
-                }
-                rcu_read_unlock();
-                return retval;
+                p = find_task_by_vpid(pid);
+                if (!p)
+                        goto out;
+                sid = task_session(p);
+                if (!sid)
+                        goto out;
+
+                retval = security_task_getsid(p);
+                if (retval)
+                        goto out;
         }
+        retval = pid_vnr(sid);
+out:
+        rcu_read_unlock();
+        return retval;
 }
 
 asmlinkage long sys_setsid(void)
@@ -1545,6 +1557,19 @@ out:
  *
  */
 
+static void accumulate_thread_rusage(struct task_struct *t, struct rusage *r,
+                                     cputime_t *utimep, cputime_t *stimep)
+{
+        *utimep = cputime_add(*utimep, t->utime);
+        *stimep = cputime_add(*stimep, t->stime);
+        r->ru_nvcsw += t->nvcsw;
+        r->ru_nivcsw += t->nivcsw;
+        r->ru_minflt += t->min_flt;
+        r->ru_majflt += t->maj_flt;
+        r->ru_inblock += task_io_get_inblock(t);
+        r->ru_oublock += task_io_get_oublock(t);
+}
+
 static void k_getrusage(struct task_struct *p, int who, struct rusage *r)
 {
         struct task_struct *t;
@@ -1554,12 +1579,14 @@ static void k_getrusage(struct task_struct *p, int who, struct rusage *r)
         memset((char *) r, 0, sizeof *r);
         utime = stime = cputime_zero;
 
-        rcu_read_lock();
-        if (!lock_task_sighand(p, &flags)) {
-                rcu_read_unlock();
-                return;
+        if (who == RUSAGE_THREAD) {
+                accumulate_thread_rusage(p, r, &utime, &stime);
+                goto out;
         }
 
+        if (!lock_task_sighand(p, &flags))
+                return;
+
         switch (who) {
                 case RUSAGE_BOTH:
                 case RUSAGE_CHILDREN:
@@ -1586,14 +1613,7 @@ static void k_getrusage(struct task_struct *p, int who, struct rusage *r)
                         r->ru_oublock += p->signal->oublock;
                         t = p;
                         do {
-                                utime = cputime_add(utime, t->utime);
-                                stime = cputime_add(stime, t->stime);
-                                r->ru_nvcsw += t->nvcsw;
-                                r->ru_nivcsw += t->nivcsw;
-                                r->ru_minflt += t->min_flt;
-                                r->ru_majflt += t->maj_flt;
-                                r->ru_inblock += task_io_get_inblock(t);
-                                r->ru_oublock += task_io_get_oublock(t);
+                                accumulate_thread_rusage(t, r, &utime, &stime);
                                 t = next_thread(t);
                         } while (t != p);
                         break;
@@ -1601,10 +1621,9 @@ static void k_getrusage(struct task_struct *p, int who, struct rusage *r)
                 default:
                         BUG();
         }
-
         unlock_task_sighand(p, &flags);
-        rcu_read_unlock();
 
+out:
         cputime_to_timeval(utime, &r->ru_utime);
         cputime_to_timeval(stime, &r->ru_stime);
 }
@@ -1618,7 +1637,8 @@ int getrusage(struct task_struct *p, int who, struct rusage __user *ru)
 
 asmlinkage long sys_getrusage(int who, struct rusage __user *ru)
 {
-        if (who != RUSAGE_SELF && who != RUSAGE_CHILDREN)
+        if (who != RUSAGE_SELF && who != RUSAGE_CHILDREN &&
+            who != RUSAGE_THREAD)
                 return -EINVAL;
         return getrusage(current, who, ru);
 }