cpuset: modify cpuset_set_cpus_allowed to use cpumask pointer

  * Modify cpuset_cpus_allowed to return the currently allowed cpuset
    via a pointer argument instead of as the function return value.

  * Use new set_cpus_allowed_ptr function.

  * Cleanup CPU_MASK_ALL and NODE_MASK_ALL uses.

Depends on:
	[sched-devel]: sched: add new set_cpus_allowed_ptr function

Signed-off-by: Mike Travis <travis@sgi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

4 files changed, 26 insertions, 30 deletions

diff --git a/include/linux/cpuset.h b/include/linux/cpuset.h
index 0a26be353cb3..726761e24003 100644
--- a/include/linux/cpuset.h
+++ b/include/linux/cpuset.h
@@ -20,8 +20,8 @@ extern int number_of_cpusets;	/* How many cpusets are defined in system? */
 extern int cpuset_init_early(void);
 extern int cpuset_init(void);
 extern void cpuset_init_smp(void);
-extern cpumask_t cpuset_cpus_allowed(struct task_struct *p);
-extern cpumask_t cpuset_cpus_allowed_locked(struct task_struct *p);
+extern void cpuset_cpus_allowed(struct task_struct *p, cpumask_t *mask);
+extern void cpuset_cpus_allowed_locked(struct task_struct *p, cpumask_t *mask);
 extern nodemask_t cpuset_mems_allowed(struct task_struct *p);
 #define cpuset_current_mems_allowed (current->mems_allowed)
 void cpuset_init_current_mems_allowed(void);
@@ -84,13 +84,14 @@ static inline int cpuset_init_early(void) { return 0; }
 static inline int cpuset_init(void) { return 0; }
 static inline void cpuset_init_smp(void) {}
 
-static inline cpumask_t cpuset_cpus_allowed(struct task_struct *p)
+static inline void cpuset_cpus_allowed(struct task_struct *p, cpumask_t *mask)
 {
-        return cpu_possible_map;
+        *mask = cpu_possible_map;
 }
-static inline cpumask_t cpuset_cpus_allowed_locked(struct task_struct *p)
+static inline void cpuset_cpus_allowed_locked(struct task_struct *p,
+                                                                cpumask_t *mask)
 {
-        return cpu_possible_map;
+        *mask = cpu_possible_map;
 }
 
 static inline nodemask_t cpuset_mems_allowed(struct task_struct *p)
diff --git a/kernel/cpuset.c b/kernel/cpuset.c
index a1b61f414228..6b9ac296a05c 100644
--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -729,7 +729,7 @@ int cpuset_test_cpumask(struct task_struct *tsk, struct cgroup_scanner *scan)
  */
 void cpuset_change_cpumask(struct task_struct *tsk, struct cgroup_scanner *scan)
 {
-        set_cpus_allowed(tsk, (cgroup_cs(scan->cg))->cpus_allowed);
+        set_cpus_allowed_ptr(tsk, &((cgroup_cs(scan->cg))->cpus_allowed));
 }
 
 /**
@@ -1178,7 +1178,7 @@ static void cpuset_attach(struct cgroup_subsys *ss,
 
         mutex_lock(&callback_mutex);
         guarantee_online_cpus(cs, &cpus);
-        set_cpus_allowed(tsk, cpus);
+        set_cpus_allowed_ptr(tsk, &cpus);
         mutex_unlock(&callback_mutex);
 
         from = oldcs->mems_allowed;
@@ -1555,8 +1555,8 @@ static struct cgroup_subsys_state *cpuset_create(
         if (is_spread_slab(parent))
                 set_bit(CS_SPREAD_SLAB, &cs->flags);
         set_bit(CS_SCHED_LOAD_BALANCE, &cs->flags);
-        cs->cpus_allowed = CPU_MASK_NONE;
-        cs->mems_allowed = NODE_MASK_NONE;
+        cpus_clear(cs->cpus_allowed);
+        nodes_clear(cs->mems_allowed);
         cs->mems_generation = cpuset_mems_generation++;
         fmeter_init(&cs->fmeter);
 
@@ -1625,8 +1625,8 @@ int __init cpuset_init(void)
 {
         int err = 0;
 
-        top_cpuset.cpus_allowed = CPU_MASK_ALL;
-        top_cpuset.mems_allowed = NODE_MASK_ALL;
+        cpus_setall(top_cpuset.cpus_allowed);
+        nodes_setall(top_cpuset.mems_allowed);
 
         fmeter_init(&top_cpuset.fmeter);
         top_cpuset.mems_generation = cpuset_mems_generation++;
@@ -1844,6 +1844,7 @@ void __init cpuset_init_smp(void)
 
  * cpuset_cpus_allowed - return cpus_allowed mask from a tasks cpuset.
  * @tsk: pointer to task_struct from which to obtain cpuset->cpus_allowed.
+ * @pmask: pointer to cpumask_t variable to receive cpus_allowed set.
  *
  * Description: Returns the cpumask_t cpus_allowed of the cpuset
  * attached to the specified @tsk.  Guaranteed to return some non-empty
@@ -1851,35 +1852,27 @@ void __init cpuset_init_smp(void)
  * tasks cpuset.
  **/
 
-cpumask_t cpuset_cpus_allowed(struct task_struct *tsk)
+void cpuset_cpus_allowed(struct task_struct *tsk, cpumask_t *pmask)
 {
-        cpumask_t mask;
-
         mutex_lock(&callback_mutex);
-        mask = cpuset_cpus_allowed_locked(tsk);
+        cpuset_cpus_allowed_locked(tsk, pmask);
         mutex_unlock(&callback_mutex);
-
-        return mask;
 }
 
 /**
  * cpuset_cpus_allowed_locked - return cpus_allowed mask from a tasks cpuset.
  * Must be called with callback_mutex held.
  **/
-cpumask_t cpuset_cpus_allowed_locked(struct task_struct *tsk)
+void cpuset_cpus_allowed_locked(struct task_struct *tsk, cpumask_t *pmask)
 {
-        cpumask_t mask;
-
         task_lock(tsk);
-        guarantee_online_cpus(task_cs(tsk), &mask);
+        guarantee_online_cpus(task_cs(tsk), pmask);
         task_unlock(tsk);
-
-        return mask;
 }
 
 void cpuset_init_current_mems_allowed(void)
 {
-        current->mems_allowed = NODE_MASK_ALL;
+        nodes_setall(current->mems_allowed);
 }
 
 /**
diff --git a/kernel/sched.c b/kernel/sched.c
index ef3f28b334ea..ccc23a9cd264 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -4941,13 +4941,13 @@ long sched_setaffinity(pid_t pid, cpumask_t new_mask)
         if (retval)
                 goto out_unlock;
 
-        cpus_allowed = cpuset_cpus_allowed(p);
+        cpuset_cpus_allowed(p, &cpus_allowed);
         cpus_and(new_mask, new_mask, cpus_allowed);
  again:
         retval = set_cpus_allowed(p, new_mask);
 
         if (!retval) {
-                cpus_allowed = cpuset_cpus_allowed(p);
+                cpuset_cpus_allowed(p, &cpus_allowed);
                 if (!cpus_subset(new_mask, cpus_allowed)) {
                         /*
                          * We must have raced with a concurrent cpuset
@@ -5661,7 +5661,9 @@ static void move_task_off_dead_cpu(int dead_cpu, struct task_struct *p)
 
                 /* No more Mr. Nice Guy. */
                 if (dest_cpu >= nr_cpu_ids) {
-                        cpumask_t cpus_allowed = cpuset_cpus_allowed_locked(p);
+                        cpumask_t cpus_allowed;
+
+                        cpuset_cpus_allowed_locked(p, &cpus_allowed);
                         /*
                          * Try to stay on the same cpuset, where the
                          * current cpuset may be a subset of all cpus.
diff --git a/mm/pdflush.c b/mm/pdflush.c
index 8f6ee073c0e3..0ceacff56457 100644
--- a/mm/pdflush.c
+++ b/mm/pdflush.c
@@ -187,8 +187,8 @@ static int pdflush(void *dummy)
          * This is needed as pdflush's are dynamically created and destroyed.
          * The boottime pdflush's are easily placed w/o these 2 lines.
          */
-        cpus_allowed = cpuset_cpus_allowed(current);
-        set_cpus_allowed(current, cpus_allowed);
+        cpuset_cpus_allowed(current, &cpus_allowed);
+        set_cpus_allowed_ptr(current, &cpus_allowed);
 
         return __pdflush(&my_work);
 }