From: Roland Dreier <rdreier-FYB4Gu1CFyUAvxtiuMwx3w@public.gmane.org>
To: Yevgeny Petrilin <yevgenyp-VPRAkNaXOzVS1MOuV/RT9w@public.gmane.org>
Cc: linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
liranl-VPRAkNaXOzVS1MOuV/RT9w@public.gmane.org,
tziporet-VPRAkNaXOzVS1MOuV/RT9w@public.gmane.org
Subject: Re: [PATCH 19/25] mlx4: Randomizing mac addresses for slaves
Date: Wed, 04 Nov 2009 12:04:21 -0800 [thread overview]
Message-ID: <adar5seys3e.fsf@cisco.com> (raw)
In-Reply-To: <4AF19E69.8070605-VPRAkNaXOzVS1MOuV/RT9w@public.gmane.org> (Yevgeny Petrilin's message of "Wed, 04 Nov 2009 17:31:53 +0200")
> +#define MLX4_MAC_HEAD 0x2c9000000ULL
> + random_ether_addr(rand_mac);
> + caps->def_mac[i] = MLX4_MAC_HEAD | rand_mac[0] |
> + ((u64)(rand_mac[1]) << 8) | ((u64)(rand_mac[2]) << 16);
Is this a good idea? You're basically choosing 24 random bits within
your OUI... seems the chance of collision with another MAC used on the
same network is high enough that it could easily happen in practice on a
moderately big network. Can you pick a reserved range or something?
Also I'm not sure if there's much point in using random_ether_addr if
you're going to override the high order part anyway, since
random_ether_addr just makes sure it doesn't pick a multicast address.
- R.
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next prev parent reply other threads:[~2009-11-04 20:04 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-11-04 15:31 [PATCH 19/25] mlx4: Randomizing mac addresses for slaves Yevgeny Petrilin
[not found] ` <4AF19E69.8070605-VPRAkNaXOzVS1MOuV/RT9w@public.gmane.org>
2009-11-04 20:04 ` Roland Dreier [this message]
2009-11-04 21:33 ` Or Gerlitz
[not found] ` <15ddcffd0911041333l165ee274mfae3508a3db755e7-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2009-11-05 13:38 ` Liran Liss
[not found] ` <2ED289D4E09FBD4D92D911E869B97FDD0166CA59-ia22CT07NJfiMCgWhms8HQC/G2K4zDHf@public.gmane.org>
2009-11-05 15:58 ` Roland Dreier
2009-11-06 4:06 ` Simon Horman
[not found] ` <20091106040624.GA6629-/R6kz+dDXgpPR4JQBCEnsQ@public.gmane.org>
2009-11-06 6:08 ` Roland Dreier
[not found] ` <adaeiocyykl.fsf-BjVyx320WGW9gfZ95n9DRSW4+XlvGpQz@public.gmane.org>
2009-11-06 7:07 ` Simon Horman
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