kernel/signal.c | 26 ++++---------------------- 1 file changed, 4 insertions(+), 22 deletions(-)
In has_pending_signals there was a switch/case pattern that did not need
to be there, as the default for loop also covers those cases.
put i inside the for declaration so we do not risk its escape from the
scope. Moreover, i starts now from 0 and counts up, as it is a more
usual pattern.
Signed-off-by: Andrea Calabrese <andrea.calabrese@amarulasolutions.com>
---
This patch does not change the binary output of the file
kernel/signal.o. A diff between the files gives shows (old -> new):
2072c2072
< case 1: ready = signal->sig[0] &~ blocked->sig[0];
---
> ready |= signal->sig[i] & ~blocked->sig[i];
2149c2149
< case 1: ready = signal->sig[0] &~ blocked->sig[0];
---
> ready |= signal->sig[i] & ~blocked->sig[i];
2155c2155
< case 1: ready = signal->sig[0] &~ blocked->sig[0];
---
> ready |= signal->sig[i] & ~blocked->sig[i];
9799c9799
< case 1: ready = signal->sig[0] &~ blocked->sig[0];
---
> ready |= signal->sig[i] & ~blocked->sig[i];
9805c9805
< case 1: ready = signal->sig[0] &~ blocked->sig[0];
---
> ready |= signal->sig[i] & ~blocked->sig[i];
kernel/signal.c | 26 ++++----------------------
1 file changed, 4 insertions(+), 22 deletions(-)
diff --git a/kernel/signal.c b/kernel/signal.c
index 2d102e025883..799ee98cf03e 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -130,28 +130,10 @@ static bool sig_ignored(struct task_struct *t, int sig, bool force)
*/
static inline bool has_pending_signals(sigset_t *signal, sigset_t *blocked)
{
- unsigned long ready;
- long i;
-
- switch (_NSIG_WORDS) {
- default:
- for (i = _NSIG_WORDS, ready = 0; --i >= 0 ;)
- ready |= signal->sig[i] &~ blocked->sig[i];
- break;
-
- case 4: ready = signal->sig[3] &~ blocked->sig[3];
- ready |= signal->sig[2] &~ blocked->sig[2];
- ready |= signal->sig[1] &~ blocked->sig[1];
- ready |= signal->sig[0] &~ blocked->sig[0];
- break;
-
- case 2: ready = signal->sig[1] &~ blocked->sig[1];
- ready |= signal->sig[0] &~ blocked->sig[0];
- break;
-
- case 1: ready = signal->sig[0] &~ blocked->sig[0];
- }
- return ready != 0;
+ unsigned long ready = 0;
+ for (long i = 0; i < _NSIG_WORDS; i++)
+ ready |= signal->sig[i] & ~blocked->sig[i];
+ return ready != 0;
}
#define PENDING(p,b) has_pending_signals(&(p)->signal, (b))
--
2.54.0
Hi Andrea, thanks, but perhaps you can cleanup the changelog? On 05/19, Andrea Calabrese wrote: > > In has_pending_signals there was a switch/case pattern that did not need > to be there, as the default for loop also covers those cases. Yes, but this code is very, very old. I agree, this optimization makes no sense with the modern compilers, but your description doesn't look accurate. The switch/case code was added on purpose, even if the default loop covers those cases. > This patch does not change the binary output of the file > kernel/signal.o. I guess you tested x86. Good. > A diff between the files gives shows (old -> new): > 2072c2072 > < case 1: ready = signal->sig[0] &~ blocked->sig[0]; > --- > > ready |= signal->sig[i] & ~blocked->sig[i]; > 2149c2149 > < case 1: ready = signal->sig[0] &~ blocked->sig[0]; > --- > > ready |= signal->sig[i] & ~blocked->sig[i]; > 2155c2155 > < case 1: ready = signal->sig[0] &~ blocked->sig[0]; > --- > > ready |= signal->sig[i] & ~blocked->sig[i]; > 9799c9799 > < case 1: ready = signal->sig[0] &~ blocked->sig[0]; > --- > > ready |= signal->sig[i] & ~blocked->sig[i]; > 9805c9805 > < case 1: ready = signal->sig[0] &~ blocked->sig[0]; > --- > > ready |= signal->sig[i] & ~blocked->sig[i]; I don't understand this part of your changelog, but I think it should be removed anyway ;) Oleg.
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