V4L/DVB: dib7000p: reduce large stack usage

[safe/jmp/linux-2.6] / kernel / sched.c

diff --git a/kernel/sched.c b/kernel/sched.c
index b47ceee..3c2a54f 100644 (file)
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -71,6 +71,7 @@
 #include <linux/debugfs.h>
 #include <linux/ctype.h>
 #include <linux/ftrace.h>
+#include <linux/slab.h>
 
 #include <asm/tlb.h>
 #include <asm/irq_regs.h>
@@ -322,6 +323,15 @@ static inline struct task_group *task_group(struct task_struct *p)
 /* Change a task's cfs_rq and parent entity if it moves across CPUs/groups */
 static inline void set_task_rq(struct task_struct *p, unsigned int cpu)
 {
+       /*
+        * Strictly speaking this rcu_read_lock() is not needed since the
+        * task_group is tied to the cgroup, which in turn can never go away
+        * as long as there are tasks attached to it.
+        *
+        * However since task_group() uses task_subsys_state() which is an
+        * rcu_dereference() user, this quiets CONFIG_PROVE_RCU.
+        */
+       rcu_read_lock();
 #ifdef CONFIG_FAIR_GROUP_SCHED
        p->se.cfs_rq = task_group(p)->cfs_rq[cpu];
        p->se.parent = task_group(p)->se[cpu];
@@ -331,6 +341,7 @@ static inline void set_task_rq(struct task_struct *p, unsigned int cpu)
        p->rt.rt_rq  = task_group(p)->rt_rq[cpu];
        p->rt.parent = task_group(p)->rt_se[cpu];
 #endif
+       rcu_read_unlock();
 }
 
 #else
@@ -2359,7 +2370,7 @@ static int try_to_wake_up(struct task_struct *p, unsigned int state,
 {
        int cpu, orig_cpu, this_cpu, success = 0;
        unsigned long flags;
-       struct rq *rq, *orig_rq;
+       struct rq *rq;
 
        if (!sched_feat(SYNC_WAKEUPS))
                wake_flags &= ~WF_SYNC;
@@ -2367,7 +2378,7 @@ static int try_to_wake_up(struct task_struct *p, unsigned int state,
        this_cpu = get_cpu();
 
        smp_wmb();
-       rq = orig_rq = task_rq_lock(p, &flags);
+       rq = task_rq_lock(p, &flags);
        update_rq_clock(rq);
        if (!(p->state & state))
                goto out;
@@ -2650,7 +2661,7 @@ void wake_up_new_task(struct task_struct *p, unsigned long clone_flags)
 {
        unsigned long flags;
        struct rq *rq;
-       int cpu = get_cpu();
+       int cpu __maybe_unused = get_cpu();
 
 #ifdef CONFIG_SMP
        /*
@@ -3779,7 +3790,7 @@ int mutex_spin_on_owner(struct mutex *lock, struct thread_info *owner)
         * the mutex owner just released it and exited.
         */
        if (probe_kernel_address(&owner->cpu, cpu))
-               goto out;
+               return 0;
 #else
        cpu = owner->cpu;
 #endif
@@ -3789,14 +3800,14 @@ int mutex_spin_on_owner(struct mutex *lock, struct thread_info *owner)
         * the cpu field may no longer be valid.
         */
        if (cpu >= nr_cpumask_bits)
-               goto out;
+               return 0;
 
        /*
         * We need to validate that we can do a
         * get_cpu() and that we have the percpu area.
         */
        if (!cpu_online(cpu))
-               goto out;
+               return 0;
 
        rq = cpu_rq(cpu);
 
@@ -3815,7 +3826,7 @@ int mutex_spin_on_owner(struct mutex *lock, struct thread_info *owner)
 
                cpu_relax();
        }
-out:
+
        return 1;
 }
 #endif
@@ -4902,7 +4913,9 @@ SYSCALL_DEFINE3(sched_getaffinity, pid_t, pid, unsigned int, len,
        int ret;
        cpumask_var_t mask;
 
-       if (len < cpumask_size())
+       if ((len * BITS_PER_BYTE) < nr_cpu_ids)
+               return -EINVAL;
+       if (len & (sizeof(unsigned long)-1))
                return -EINVAL;
 
        if (!alloc_cpumask_var(&mask, GFP_KERNEL))
@@ -4910,10 +4923,12 @@ SYSCALL_DEFINE3(sched_getaffinity, pid_t, pid, unsigned int, len,
 
        ret = sched_getaffinity(pid, mask);
        if (ret == 0) {
-               if (copy_to_user(user_mask_ptr, mask, cpumask_size()))
+               size_t retlen = min_t(size_t, len, cpumask_size());
+
+               if (copy_to_user(user_mask_ptr, mask, retlen))
                        ret = -EFAULT;
                else
-                       ret = cpumask_size();
+                       ret = retlen;
        }
        free_cpumask_var(mask);
 
@@ -5383,7 +5398,7 @@ int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask)
 
                get_task_struct(mt);
                task_rq_unlock(rq, &flags);
-               wake_up_process(rq->migration_thread);
+               wake_up_process(mt);
                put_task_struct(mt);
                wait_for_completion(&req.done);
                tlb_migrate_finish(p->mm);
@@ -7406,11 +7421,13 @@ static ssize_t sched_power_savings_store(const char *buf, size_t count, int smt)
 
 #ifdef CONFIG_SCHED_MC
 static ssize_t sched_mc_power_savings_show(struct sysdev_class *class,
+                                          struct sysdev_class_attribute *attr,
                                           char *page)
 {
        return sprintf(page, "%u\n", sched_mc_power_savings);
 }
 static ssize_t sched_mc_power_savings_store(struct sysdev_class *class,
+                                           struct sysdev_class_attribute *attr,
                                            const char *buf, size_t count)
 {
        return sched_power_savings_store(buf, count, 0);
@@ -7422,11 +7439,13 @@ static SYSDEV_CLASS_ATTR(sched_mc_power_savings, 0644,
 
 #ifdef CONFIG_SCHED_SMT
 static ssize_t sched_smt_power_savings_show(struct sysdev_class *dev,
+                                           struct sysdev_class_attribute *attr,
                                            char *page)
 {
        return sprintf(page, "%u\n", sched_smt_power_savings);
 }
 static ssize_t sched_smt_power_savings_store(struct sysdev_class *dev,
+                                            struct sysdev_class_attribute *attr,
                                             const char *buf, size_t count)
 {
        return sched_power_savings_store(buf, count, 1);