From mboxrd@z Thu Jan  1 00:00:00 1970
From: Stephen Hemminger <stephen@networkplumber.org>
Subject: Re: [PATCH] doc: add known issue for virtio TSO with
 clones
Date: Mon, 6 Feb 2017 15:10:47 -0800
Message-ID: <20170206151047.155aa0aa@xeon-e3>
References: <1486387013-1706-1-git-send-email-olivier.matz@6wind.com>
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Cc: dev@dpdk.org, yuanhan.liu@linux.intel.com, john.mcnamara@intel.com
To: Olivier Matz <olivier.matz@6wind.com>
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On Mon,  6 Feb 2017 14:16:53 +0100
Olivier Matz <olivier.matz@6wind.com> wrote:

> +**Implication**:
> +   In this situation, the shared data will be modified by the driver,
> +   potentially causing race conditions with the other users of the mbuf
> +   data.

This is a driver bug! The driver must check for refcount and not modify
mbuf's whose refcnt > 1. For those mbuf's it should copy the mbuf and modify
the copy. 

It is not good to force buggy refcnt handling back onto the application.
It is acceptable to document the performance impact.