Re: [PATCH 2/2] kernel/{exit.c, signal.c, power/process.c}: replace !likely(x) by likely(!x)

[Roel Kluin]

H. Peter Anvin wrote:
> Roel Kluin wrote:
>> H. Peter Anvin wrote:
>>> Roel Kluin wrote:
>>>> Not entirely sure who to send this to
>>>> ---
>>>> Replace !likely(x) by likely(!x)
>>> Whoa...
>>>
>>> Are you sure this is correct?
>>>
>>> !likely(x) is equivalent to unlikely(!x), not the opposite, so this is a
>>> functional change...
>>>
>> You are right, sorry, Need more caffeine. I will send the right patch
>> later.
> 
> Note I didn't say it was wrong, I just wanted a bit more explanation
> about why it's right, if it is.

No, I just wanted to move the '!' within the parentheses, I didn't want
to change semantics. below is how I guess the patch should have been. 
Thanks for your response.
---
Replace !likely(x) by unlikely(!x)

Signed-off-by: Roel Kluin <[EMAIL PROTECTED]>
---
diff --git a/kernel/signal.c b/kernel/signal.c
index 84917fe..cf5d45a 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -1308,7 +1308,7 @@ int send_sigqueue(int sig, struct sigqueue *q, struct 
task_struct *p)
         */
        rcu_read_lock();
 
-       if (!likely(lock_task_sighand(p, &flags))) {
+       if (unlikely(!lock_task_sighand(p, &flags))) {
                ret = -1;
                goto out_err;
        }
@@ -1548,7 +1548,7 @@ static void do_notify_parent_cldstop(struct task_struct 
*tsk, int why)
 
 static inline int may_ptrace_stop(void)
 {
-       if (!likely(current->ptrace & PT_PTRACED))
+       if (unlikely(!(current->ptrace & PT_PTRACED)))
                return 0;
        /*
         * Are we in the middle of do_coredump?
@@ -1574,7 +1574,7 @@ static int sigkill_pending(struct task_struct *tsk)
 {
        return ((sigismember(&tsk->pending.signal, SIGKILL) ||
                 sigismember(&tsk->signal->shared_pending.signal, SIGKILL)) &&
-               !unlikely(sigismember(&tsk->blocked, SIGKILL)));
+                likely(!sigismember(&tsk->blocked, SIGKILL)));
 }
 
 /*
@@ -1625,7 +1625,7 @@ static void ptrace_stop(int exit_code, int clear_code, 
siginfo_t *info)
        spin_unlock_irq(&current->sighand->siglock);
        try_to_freeze();
        read_lock(&tasklist_lock);
-       if (!unlikely(killed) && may_ptrace_stop()) {
+       if (likely(!killed) && may_ptrace_stop()) {
                do_notify_parent_cldstop(current, CLD_TRAPPED);
                read_unlock(&tasklist_lock);
                schedule();
@@ -1717,8 +1717,8 @@ static int do_signal_stop(int signr)
        } else {
                struct task_struct *t;
 
-               if (!likely(sig->flags & SIGNAL_STOP_DEQUEUED) ||
-                   unlikely(sig->group_exit_task))
+               if (unlikely(!(sig->flags & SIGNAL_STOP_DEQUEUED) ||
+                   sig->group_exit_task))
                        return 0;
                /*
                 * There is no group stop already in progress.

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [EMAIL PROTECTED]
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/