Re: [PATCH 1/5] ipc/sem: do not call wake_sem_queue_do() prematurely

From	Davidlohr Bueso <dave@stgolabs.net>
Newsgroups	linux.kernel
Subject	Re: [PATCH 1/5] ipc/sem: do not call wake_sem_queue_do() prematurely
Date	2016-09-13 10:20 +0200
Message-ID	<sgR6G-7I4-29@gated-at.bofh.it> (permalink)
References	<sgy41-2Jz-5@gated-at.bofh.it> <sgy41-2Jz-7@gated-at.bofh.it> <sgNmq-4WR-3@gated-at.bofh.it>
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On Tue, 13 Sep 2016, Manfred Spraul wrote:

>>-	if (ipcperms(ns, &sma->sem_perm, alter ? S_IWUGO : S_IRUGO))
>>-		goto out_rcu_wakeup;
>>+	if (ipcperms(ns, &sma->sem_perm, alter ? S_IWUGO : S_IRUGO)) {
>>+		rcu_read_unlock();
>>+		goto out_free;
>>+	}
>Is this really better/simpler?
>You replace "if (error) goto cleanup" with "if (error) {cleanup_1(); 
>goto cleanup_2()}".

I believe it is better as it clearly separates blocking from non-blocking
exit paths. Overhead of course is irrelevant in both in-house wake_up_sem_queue_do
and wake_up_q.

Thanks,
Davidlohr

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[PATCH 1/5] ipc/sem: do not call wake_sem_queue_do() prematurely Davidlohr Bueso <dave@stgolabs.net> - 2016-09-12 14:00 +0200
  Re: [PATCH 1/5] ipc/sem: do not call wake_sem_queue_do() prematurely Manfred Spraul <manfred@colorfullife.com> - 2016-09-13 06:20 +0200
    Re: [PATCH 1/5] ipc/sem: do not call wake_sem_queue_do() prematurely Davidlohr Bueso <dave@stgolabs.net> - 2016-09-13 10:20 +0200

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