netdev - Re: [PATCH 4/6] rhashtable: allow a walk of the hash table without missing objects.

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Message-ID: <20180327155404.GC14001@gondor.apana.org.au>
Date:   Tue, 27 Mar 2018 23:54:04 +0800
From:   Herbert Xu <herbert@...dor.apana.org.au>
To:     David Miller <davem@...emloft.net>
Cc:     neilb@...e.com, tgraf@...g.ch, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 4/6] rhashtable: allow a walk of the hash table without
 missing objects.

On Tue, Mar 27, 2018 at 11:49:41AM -0400, David Miller wrote:
>
> Merely having an elevated reference count does not explicitly prevent
> the object from being removed from the hash table.
> 
> This invariant might hold for the particular user of the rhashtable
> instance, but it is not always the case.

I think having a new interface like this should work as if the
user knows that the element has not been removed from the hash
table then it should be safe to continue from it.

Of course people may misuse it but even using the current interface
correctly may result in lost objects due to concurrent removals.

Cheers,
-- 
Email: Herbert Xu <herbert@...dor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt