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sched: Simplify sched_{set,get}affinity()

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Use guards to reduce gotos and simplify control flow.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Peter Zijlstra 2023-06-09 16:57:35 +02:00 committed by Ingo Molnar
parent febe162d4d
commit 92c2ec5bc1
1 changed files with 14 additions and 39 deletions
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53
kernel/sched/core.c
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@ -8347,39 +8347,24 @@ long sched_setaffinity(pid_t pid, const struct cpumask *in_mask)
{
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
@ -8389,8 +8374,7 @@ long sched_setaffinity(pid_t pid, const struct cpumask *in_mask)
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){
@ -8402,8 +8386,6 @@ long sched_setaffinity(pid_t pid, const struct cpumask *in_mask)
retval = __sched_setaffinity(p, &ac);
kfree(ac.user_mask);
out_put_task:
put_task_struct(p);
return retval;
}
@ -8445,28 +8427,21 @@ SYSCALL_DEFINE3(sched_setaffinity, pid_t, pid, unsigned int, len,
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;
}
/**