netdev - Re: [PATCH net v2] ibmvnic: Ensure that CRQ entry read are correctly ordered

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: <20210127173133.1fb08b8a@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com>
Date:   Wed, 27 Jan 2021 17:31:33 -0800
From:   Jakub Kicinski <kuba@...nel.org>
To:     Lijun Pan <lijunp213@...il.com>
Cc:     Lijun Pan <ljp@...ux.ibm.com>, netdev@...r.kernel.org
Subject: Re: [PATCH net v2] ibmvnic: Ensure that CRQ entry read are
 correctly ordered

On Wed, 27 Jan 2021 19:22:25 -0600 Lijun Pan wrote:
> On Wed, Jan 27, 2021 at 7:06 PM Jakub Kicinski <kuba@...nel.org> wrote:
> >
> > On Mon, 25 Jan 2021 17:20:23 -0600 Lijun Pan wrote:  
> > > Ensure that received Command-Response Queue (CRQ) entries are
> > > properly read in order by the driver. dma_rmb barrier has
> > > been added before accessing the CRQ descriptor to ensure
> > > the entire descriptor is read before processing.
> > >
> > > Fixes: 032c5e82847a ("Driver for IBM System i/p VNIC protocol")
> > > Signed-off-by: Lijun Pan <ljp@...ux.ibm.com>
> > > ---
> > > v2: drop dma_wmb according to Jakub's opinion
> > >
> > >  drivers/net/ethernet/ibm/ibmvnic.c | 8 ++++++++
> > >  1 file changed, 8 insertions(+)
> > >
> > > diff --git a/drivers/net/ethernet/ibm/ibmvnic.c b/drivers/net/ethernet/ibm/ibmvnic.c
> > > index 9778c83150f1..d84369bd5fc9 100644
> > > --- a/drivers/net/ethernet/ibm/ibmvnic.c
> > > +++ b/drivers/net/ethernet/ibm/ibmvnic.c
> > > @@ -5084,6 +5084,14 @@ static void ibmvnic_tasklet(struct tasklet_struct *t)
> > >       while (!done) {
> > >               /* Pull all the valid messages off the CRQ */
> > >               while ((crq = ibmvnic_next_crq(adapter)) != NULL) {
> > > +                     /* Ensure that the entire CRQ descriptor queue->msgs
> > > +                      * has been loaded before reading its contents.  
> >
> > I still find this sentence confusing, maybe you mean to say stored
> > instead of loaded?  
> 
> The above 2 lines are the general description. The below 4 lines are
> detailed explanations. If it is still confusing, we can delete the above
> 2 lines of comments.

Yes, I'd find the comment clearer without them, thanks.