linux-kernel - Re: [PATCH rdma-next 01/10] RDMA: Add access flags to ib_alloc_mr() and ib_mr_pool

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20210407182811.GK7405@nvidia.com>
Date:   Wed, 7 Apr 2021 15:28:11 -0300
From:   Jason Gunthorpe <jgg@...dia.com>
To:     Christoph Hellwig <hch@....de>
Cc:     Leon Romanovsky <leon@...nel.org>,
        Bart Van Assche <bvanassche@....org>,
        Doug Ledford <dledford@...hat.com>,
        Avihai Horon <avihaih@...dia.com>,
        Adit Ranadive <aditr@...are.com>,
        Anna Schumaker <anna.schumaker@...app.com>,
        Ariel Elior <aelior@...vell.com>,
        Bernard Metzler <bmt@...ich.ibm.com>,
        Chuck Lever <chuck.lever@...cle.com>,
        "David S. Miller" <davem@...emloft.net>,
        Dennis Dalessandro <dennis.dalessandro@...nelisnetworks.com>,
        Devesh Sharma <devesh.sharma@...adcom.com>,
        Faisal Latif <faisal.latif@...el.com>,
        Jack Wang <jinpu.wang@...os.com>,
        Jakub Kicinski <kuba@...nel.org>,
        "J. Bruce Fields" <bfields@...ldses.org>,
        Jens Axboe <axboe@...com>,
        Karsten Graul <kgraul@...ux.ibm.com>,
        Keith Busch <kbusch@...nel.org>, Lijun Ou <oulijun@...wei.com>,
        linux-cifs@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-nfs@...r.kernel.org, linux-nvme@...ts.infradead.org,
        linux-rdma@...r.kernel.org, linux-s390@...r.kernel.org,
        Max Gurtovoy <maxg@...lanox.com>,
        Max Gurtovoy <mgurtovoy@...dia.com>,
        "Md. Haris Iqbal" <haris.iqbal@...os.com>,
        Michael Guralnik <michaelgur@...dia.com>,
        Michal Kalderon <mkalderon@...vell.com>,
        Mike Marciniszyn <mike.marciniszyn@...nelisnetworks.com>,
        Naresh Kumar PBS <nareshkumar.pbs@...adcom.com>,
        netdev@...r.kernel.org, Potnuri Bharat Teja <bharat@...lsio.com>,
        rds-devel@....oracle.com, Sagi Grimberg <sagi@...mberg.me>,
        samba-technical@...ts.samba.org,
        Santosh Shilimkar <santosh.shilimkar@...cle.com>,
        Selvin Xavier <selvin.xavier@...adcom.com>,
        Shiraz Saleem <shiraz.saleem@...el.com>,
        Somnath Kotur <somnath.kotur@...adcom.com>,
        Sriharsha Basavapatna <sriharsha.basavapatna@...adcom.com>,
        Steve French <sfrench@...ba.org>,
        Trond Myklebust <trond.myklebust@...merspace.com>,
        VMware PV-Drivers <pv-drivers@...are.com>,
        Weihang Li <liweihang@...wei.com>,
        Yishai Hadas <yishaih@...dia.com>,
        Zhu Yanjun <zyjzyj2000@...il.com>
Subject: Re: [PATCH rdma-next 01/10] RDMA: Add access flags to ib_alloc_mr()
 and ib_mr_pool_init()

On Tue, Apr 06, 2021 at 04:54:57PM +0200, Christoph Hellwig wrote:
> On Tue, Apr 06, 2021 at 11:40:39AM -0300, Jason Gunthorpe wrote:
> > Yes, but the complexity is how the drivers are constructed they are
> > designed to reject flags they don't know about..
> > 
> > Hum, it looks like someone has already been in here and we now have a
> > IB_ACCESS_OPTIONAL concept. 
> > 
> > Something like this would be the starting point:
> >
> > [...]
> >
> > However I see only EFA actually uses IB_ACCESS_OPTIONAL, so the lead
> > up would be to audit all the drivers to process optional access_flags
> > properly. Maybe this was done, but I don't see much evidence of it..
> >
> > Sigh. It is a big mess cleaning adventure in drivers really.
> 
> Yes.  When passing flags to drivers we need to have a good pattern
> in place for distinguishing between mandatory and optional flags.
> That is something everyone gets wrong at first (yourself included)
> and which then later needs painful untangling.  So I think we need
> to do that anyway.

It looks like we did actually do this right here, when the
RELAXED_ORDERING was originally added it was done as an optional flag
and a range of bits were set aside in the uAPI for future optional
flags.

This should be quite easy to do then

Jason