Messages in this thread | | | Subject | Re: [net-next PATCH 1/2] net: Busy polling should ignore sender CPUs | From | Eric Dumazet <> | Date | Mon, 20 Mar 2017 15:16:11 -0700 |
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On Mon, 2017-03-20 at 14:48 -0700, Alexander Duyck wrote: > From: Alexander Duyck <alexander.h.duyck@intel.com> > > This patch is a cleanup/fix for NAPI IDs following the changes that made it > so that sender_cpu and napi_id were doing a better job of sharing the same > location in the sk_buff. > > One issue I found is that we weren't validating the napi_id as being valid > before we started trying to setup the busy polling. This change corrects > that by using the MIN_NAPI_ID value that is now used in both allocating the > NAPI IDs, as well as validating them. > > Fixes: 52bd2d62ce675 ("net: better skb->sender_cpu and skb->napi_id cohabitation") > Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com> > ---
This Fixes: tag seems not really needed here.
If really busy polling is attempted to a socket with a <wrong> napi id, nothing bad happens. This fits the advisory model of busy polling...
Otherwise, your patch would be a candidate for net tree.
Also note that as soon as sk_can_busy_loop(sk) returns some status, another cpu might already have changed sk->sk_napi_id to something else, possibly with a <wrong> napi id again.
If your upcoming code depends on sk->sk_napi_id being verified, then you need to read it once.
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