linux-kernel - Re: [PATCH v0 00/42] notifiers: Return an error when callback is already registered

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Message-ID: <YYkzJ3+faVga2Tl3@zn.tnic>
Date:   Mon, 8 Nov 2021 15:24:39 +0100
From:   Borislav Petkov <bp@...en8.de>
To:     Alan Stern <stern@...land.harvard.edu>
Cc:     LKML <linux-kernel@...r.kernel.org>, Arnd Bergmann <arnd@...db.de>,
        Ayush Sawal <ayush.sawal@...lsio.com>,
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Subject: Re: [PATCH v0 00/42] notifiers: Return an error when callback is
 already registered

On Mon, Nov 08, 2021 at 09:17:03AM -0500, Alan Stern wrote:
> What reason is there for moving the check into the callers?  It seems 
> like pointless churn.  Why not add the error return code, change the 
> WARN to pr_warn, and leave the callers as they are?  Wouldn't that end 
> up having exactly the same effect?
> 
> For that matter, what sort of remedial action can a caller take if the 
> return code is -EEXIST?  Is there any point in forcing callers to check 
> the return code if they can't do anything about it?

See my reply to Geert from just now:

https://lore.kernel.org/r/YYkyUEqcsOwQMb1S@zn.tnic

I guess I can add another indirection to notifier_chain_register() and
avoid touching all the call sites.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette