@@ -8258,39 +8258,24 @@ long sched_setaffinity(pid_t pid, const
{
struct affinity_context ac;
struct cpumask *user_mask;
- struct task_struct *p;
int retval;
- rcu_read_lock();
-
- p = find_process_by_pid(pid);
- if (!p) {
- rcu_read_unlock();
+ CLASS(find_get_task, p)(pid);
+ if (!p)
return -ESRCH;
- }
- /* Prevent p going away */
- get_task_struct(p);
- rcu_read_unlock();
-
- if (p->flags & PF_NO_SETAFFINITY) {
- retval = -EINVAL;
- goto out_put_task;
- }
+ if (p->flags & PF_NO_SETAFFINITY)
+ return -EINVAL;
if (!check_same_owner(p)) {
- rcu_read_lock();
- if (!ns_capable(__task_cred(p)->user_ns, CAP_SYS_NICE)) {
- rcu_read_unlock();
- retval = -EPERM;
- goto out_put_task;
- }
- rcu_read_unlock();
+ guard(rcu)();
+ if (!ns_capable(__task_cred(p)->user_ns, CAP_SYS_NICE))
+ return -EPERM;
}
retval = security_task_setscheduler(p);
if (retval)
- goto out_put_task;
+ return retval;
/*
* With non-SMP configs, user_cpus_ptr/user_mask isn't used and
@@ -8300,8 +8285,7 @@ long sched_setaffinity(pid_t pid, const
if (user_mask) {
cpumask_copy(user_mask, in_mask);
} else if (IS_ENABLED(CONFIG_SMP)) {
- retval = -ENOMEM;
- goto out_put_task;
+ return -ENOMEM;
}
ac = (struct affinity_context){
@@ -8313,8 +8297,6 @@ long sched_setaffinity(pid_t pid, const
retval = __sched_setaffinity(p, &ac);
kfree(ac.user_mask);
-out_put_task:
- put_task_struct(p);
return retval;
}
@@ -8356,28 +8338,21 @@ SYSCALL_DEFINE3(sched_setaffinity, pid_t
long sched_getaffinity(pid_t pid, struct cpumask *mask)
{
struct task_struct *p;
- unsigned long flags;
int retval;
- rcu_read_lock();
-
- retval = -ESRCH;
+ guard(rcu)();
p = find_process_by_pid(pid);
if (!p)
- goto out_unlock;
+ return -ESRCH;
retval = security_task_getscheduler(p);
if (retval)
- goto out_unlock;
+ return retval;
- raw_spin_lock_irqsave(&p->pi_lock, flags);
+ guard(raw_spinlock_irqsave)(&p->pi_lock);
cpumask_and(mask, &p->cpus_mask, cpu_active_mask);
- raw_spin_unlock_irqrestore(&p->pi_lock, flags);
-out_unlock:
- rcu_read_unlock();
-
- return retval;
+ return 0;
}
/**
Use guards to reduce gotos and simplify control flow. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> --- kernel/sched/core.c | 53 +++++++++++++--------------------------------------- 1 file changed, 14 insertions(+), 39 deletions(-)