From: "Sverdlin, Alexander (Nokia - DE/Ulm)" <alexander.sverdlin@nokia.com>
To: "stern@rowland.harvard.edu" <stern@rowland.harvard.edu>,
"dinghao.liu@zju.edu.cn" <dinghao.liu@zju.edu.cn>,
"kjlu@umn.edu" <kjlu@umn.edu>
Cc: "mpm@selenic.com" <mpm@selenic.com>,
"gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
"herbert@gondor.apana.org.au" <herbert@gondor.apana.org.au>,
"ben.dooks@codethink.co.uk" <ben.dooks@codethink.co.uk>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"arnd@arndb.de" <arnd@arndb.de>,
"allison@lohutok.net" <allison@lohutok.net>,
"yuehaibing@huawei.com" <yuehaibing@huawei.com>,
"rfontana@redhat.com" <rfontana@redhat.com>,
"linux-crypto@vger.kernel.org" <linux-crypto@vger.kernel.org>,
"tglx@linutronix.de" <tglx@linutronix.de>
Subject: Re: [PATCH] hwrng: ks-sa - fix runtime pm imbalance on error
Date: Wed, 20 May 2020 15:42:17 +0000 [thread overview]
Message-ID: <ab400cba7523e69b15360b0928cb8fa8b9432d86.camel@nokia.com> (raw)
In-Reply-To: <20200520132957.18776-1-dinghao.liu@zju.edu.cn>
Hello Dinghao,
On Wed, 2020-05-20 at 21:29 +0800, Dinghao Liu wrote:
> pm_runtime_get_sync() increments the runtime PM usage counter even
> the call returns an error code. Thus a pairing decrement is needed
> on the error handling path to keep the counter balanced.
I believe, this is the wrong place for such kind of fix.
pm_runtime_get_sync() has obviously a broken semantics with regards to
your observation but no other driver does what you propose.
I think the proper fix belong into PM subsystem, please take a look
onto commit 15bcb91d7e60 "PM / Runtime: Implement autosuspend support".
> Signed-off-by: Dinghao Liu <dinghao.liu@zju.edu.cn>
> ---
> drivers/char/hw_random/ks-sa-rng.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/drivers/char/hw_random/ks-sa-rng.c b/drivers/char/hw_random/ks-sa-rng.c
> index e2330e757f1f..85c81da4a8af 100644
> --- a/drivers/char/hw_random/ks-sa-rng.c
> +++ b/drivers/char/hw_random/ks-sa-rng.c
> @@ -244,6 +244,7 @@ static int ks_sa_rng_probe(struct platform_device *pdev)
> ret = pm_runtime_get_sync(dev);
> if (ret < 0) {
> dev_err(dev, "Failed to enable SA power-domain\n");
> + pm_runtime_put_sync(dev);
> pm_runtime_disable(dev);
> return ret;
> }
--
Alexander Sverdlin.
next prev parent reply other threads:[~2020-05-20 15:42 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-20 13:29 [PATCH] hwrng: ks-sa - fix runtime pm imbalance on error Dinghao Liu
2020-05-20 15:42 ` Sverdlin, Alexander (Nokia - DE/Ulm) [this message]
2020-05-20 16:45 ` stern
2020-05-28 6:55 ` Herbert Xu
2020-05-28 7:13 ` dinghao.liu
2020-05-28 15:39 ` stern
2020-05-21 6:21 ` dinghao.liu
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