linux-kernel - Re: [PATCH] [v2] test_rhashtable: remove semaphore usage

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Message-Id: <20181218.153614.1607918853242585355.davem@davemloft.net>
Date:   Tue, 18 Dec 2018 15:36:14 -0800 (PST)
From:   David Miller <davem@...emloft.net>
To:     arnd@...db.de
Cc:     netdev@...r.kernel.org, phil@....cc, tgraf@...g.ch,
        herbert@...dor.apana.org.au, neilb@...e.com,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] [v2] test_rhashtable: remove semaphore usage

From: Arnd Bergmann <arnd@...db.de>
Date: Sun, 16 Dec 2018 20:48:21 +0100

> This is one of only two files that initialize a semaphore to a negative
> value. We don't really need the two semaphores here at all, but can do
> the same thing in more conventional and more effient way, by using a
> single waitqueue and an atomic thread counter.
> 
> This gets us a little bit closer to eliminating classic semaphores from
> the kernel. It also fixes a corner case where we fail to continue after
> one of the threads fails to start up.
> 
> An alternative would be to use a split kthread_create()+wake_up_process()
> and completely eliminate the separate synchronization.
> 
> Acked-by: Phil Sutter <phil@....cc>
> Signed-off-by: Arnd Bergmann <arnd@...db.de>
> ---
> Changes from v1:
>  - rebase to mainline,
>  - fix pr_err() output
>  - bail out if interrupted

Applied, thanks Arnd.