Re: [dpdk-dev] Question about cd10c42eb5bc ("mem: fix ivshmem freeing")

["Mauricio Vásquez" <mauricio.vasquezbernal@studenti.polito.it>]

Sure: http://dpdk.org/ml/archives/dev/2016-April/036884.html,

On Wed, Mar 30, 2016 at 2:10 PM, Burakov, Anatoly <anatoly.burakov@intel.com
> wrote:

> Hi Mauricio,
>
>
>
> Good points. Would you be willing to prepare a patch to fix these issues?
>
>
>
> Thanks,
>
> Anatoly
>
>
>
> *From:* Mauricio Vásquez [mailto:mauricio.vasquezbernal@studenti.polito.it]
>
> *Sent:* Wednesday, March 30, 2016 10:13 AM
> *To:* Burakov, Anatoly <anatoly.burakov@intel.com>
> *Cc:* dev@dpdk.org; Gonzalez Monroy, Sergio <
> sergio.gonzalez.monroy@intel.com>; Richardson, Bruce <
> bruce.richardson@intel.com>
> *Subject:* Re: Question about cd10c42eb5bc ("mem: fix ivshmem freeing")
>
>
>
> Hi Anatoly,
>
> Thank you very much, I did not take into account that detail.
>
> I have two additional concerns about it:
>
> 1. I think it is possible to have a race condition. The memzone is marked
> as not freeable after it has been added to the ivshmem device, then it is
> possible to free the memzone just after it has been  added to the metadata
> but before it is marked as not freeable.
>
> Shouldn't the memzone be marked before adding the memzone to the ivshmem
> device?
>
>
>
> 2. Are the #ifdefs necessary?, we already are in  a file that will only
> compiled when ivshmem is enabled.
>
> Thanks,
>
> Mauricio Vasquez,
>
>
>
>
>
> On Wed, Mar 30, 2016 at 10:29 AM, Burakov, Anatoly <
> anatoly.burakov@intel.com> wrote:
>
> Hi Mauricio,
>
>
>
> You’re not missing anything. It would be done this way, if the memzone
> parameter wasn’t const. But it is const, so we have to find the memzone in
> config to edit it.
>
>
>
> Thanks,
>
> Anatoly
>
>
>
> *From:* Mauricio Vásquez [mailto:mauricio.vasquezbernal@studenti.polito.it]
>
> *Sent:* Wednesday, March 30, 2016 9:22 AM
> *To:* dev@dpdk.org
> *Cc:* Gonzalez Monroy, Sergio <sergio.gonzalez.monroy@intel.com>;
> Richardson, Bruce <bruce.richardson@intel.com>; Burakov, Anatoly <
> anatoly.burakov@intel.com>
> *Subject:* Question about cd10c42eb5bc ("mem: fix ivshmem freeing")
>
>
>
> Dear All,
>
> I was looking at that patch, I can understand its functionality but not
> its implementation..
>
> Why to calculate idx?, Just doing "mz->ioremap_addr = mz->phys_addr" would
> not be sufficient? After all, the goal is to mark the memzone as used by
> ivshmem to forbid  freeing it.
>
> Please corrected if I am missing something.
>
> Thank you,
>
> Mauricio Vasquez,
>
>
>