From: Cristian Marussi <cristian.marussi@arm.com>
To: Borislav Petkov <bp@alien8.de>
Cc: LKML <linux-kernel@vger.kernel.org>, linux-crypto@vger.kernel.org
Subject: Re: [PATCH v0 39/42] crypto: ccree - check notifier registration return value
Date: Fri, 12 Nov 2021 18:32:33 +0000 [thread overview]
Message-ID: <20211112183233.GB6655@e120937-lin> (raw)
In-Reply-To: <20211108101157.15189-40-bp@alien8.de>
On Mon, Nov 08, 2021 at 11:11:54AM +0100, Borislav Petkov wrote:
> From: Borislav Petkov <bp@suse.de>
>
> Avoid homegrown notifier registration checks.
>
> No functional changes.
>
Hi Borislav,
> Signed-off-by: Borislav Petkov <bp@suse.de>
> Cc: linux-crypto@vger.kernel.org
> ---
> drivers/crypto/ccree/cc_fips.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/crypto/ccree/cc_fips.c b/drivers/crypto/ccree/cc_fips.c
> index 702aefc21447..de842da7d51c 100644
> --- a/drivers/crypto/ccree/cc_fips.c
> +++ b/drivers/crypto/ccree/cc_fips.c
> @@ -146,7 +146,9 @@ int cc_fips_init(struct cc_drvdata *p_drvdata)
> tasklet_init(&fips_h->tasklet, fips_dsr, (unsigned long)p_drvdata);
> fips_h->drvdata = p_drvdata;
> fips_h->nb.notifier_call = cc_ree_fips_failure;
> - atomic_notifier_chain_register(&fips_fail_notif_chain, &fips_h->nb);
> +
> + if (atomic_notifier_chain_register(&fips_fail_notif_chain, &fips_h->nb))
> + pr_warn("Failure notifier already registered\n");
>
Looking at the implementation of atomic_notifier_chain_register() and
its internal helper down below, I can see that atomic_notifier_chain_register()
ALWAYS return 0 (O_o) and anyway there is a WARN() in the notifiier core already
to alert of double registrations.
What is the aim of this patch ?
It's not clear from the commit message what are you trying to achieve.
Am I missing something ?
(Is it to circumvent some static checker to avoid this false positive ?
just guessing...)
Thanks,
Cristian
-----8<----------
static int notifier_chain_register(struct notifier_block **nl,
struct notifier_block *n)
{
while ((*nl) != NULL) {
if (unlikely((*nl) == n)) {
WARN(1, "double register detected");
return 0;
}
if (n->priority > (*nl)->priority)
break;
nl = &((*nl)->next);
}
n->next = *nl;
rcu_assign_pointer(*nl, n);
return 0;
}
/**
* atomic_notifier_chain_register - Add notifier to an atomic notifier chain
* @nh: Pointer to head of the atomic notifier chain
* @n: New entry in notifier chain
*
* Adds a notifier to an atomic notifier chain.
*
* Currently always returns zero.
*/
int atomic_notifier_chain_register(struct atomic_notifier_head *nh,
struct notifier_block *n)
{
unsigned long flags;
int ret;
spin_lock_irqsave(&nh->lock, flags);
ret = notifier_chain_register(&nh->head, n);
spin_unlock_irqrestore(&nh->lock, flags);
return ret;
}
EXPORT_SYMBOL_GPL(atomic_notifier_chain_register);
------
next prev parent reply other threads:[~2021-11-12 18:32 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20211108101157.15189-1-bp@alien8.de>
2021-11-08 10:11 ` [PATCH v0 39/42] crypto: ccree - check notifier registration return value Borislav Petkov
2021-11-12 18:32 ` Cristian Marussi [this message]
2021-11-12 18:48 ` Borislav Petkov
2021-11-08 10:11 ` [PATCH v0 42/42] notifier: Return an error when callback is already registered Borislav Petkov
2021-11-08 14:07 ` Geert Uytterhoeven
2021-11-08 14:21 ` Borislav Petkov
2021-11-08 15:25 ` Geert Uytterhoeven
2021-11-08 15:58 ` Borislav Petkov
2021-11-08 16:12 ` Geert Uytterhoeven
2021-11-08 16:21 ` Borislav Petkov
2021-11-08 20:59 ` Alan Stern
2021-11-08 21:18 ` Borislav Petkov
2021-11-08 10:19 ` [PATCH v0 00/42] notifiers: " Borislav Petkov
2021-11-08 14:17 ` Alan Stern
2021-11-08 14:24 ` Borislav Petkov
2021-11-08 14:35 ` Borislav Petkov
2021-11-08 16:23 ` Steven Rostedt
2021-11-08 16:29 ` Borislav Petkov
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