Date:   Mon, 5 Sep 2016 10:13:54 +0000
From:   Salil Mehta <salil.mehta@...wei.com>
To:     Doug Ledford <dledford@...hat.com>,
        David Miller <davem@...emloft.net>
CC:     "Huwei (Xavier)" <xavier.huwei@...wei.com>,
        oulijun <oulijun@...wei.com>,
        "Zhuangyuzeng (Yisen)" <yisen.zhuang@...wei.com>,
        "mehta.salil.lnk@...il.com" <mehta.salil.lnk@...il.com>,
        "linux-rdma@...r.kernel.org" <linux-rdma@...r.kernel.org>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Linuxarm <linuxarm@...wei.com>
Subject: RE: [PATCH for-next 0/2] {IB,net}/hns: Add support of ACPI to the
 Hisilicon RoCE Driver

> -----Original Message-----
> From: Doug Ledford [mailto:dledford@...hat.com]
> Sent: Thursday, August 25, 2016 4:00 PM
> To: Salil Mehta; David Miller
> Cc: Huwei (Xavier); oulijun; Zhuangyuzeng (Yisen);
> mehta.salil.lnk@...il.com; linux-rdma@...r.kernel.org;
> netdev@...r.kernel.org; linux-kernel@...r.kernel.org; Linuxarm
> Subject: Re: [PATCH for-next 0/2] {IB,net}/hns: Add support of ACPI to
> the Hisilicon RoCE Driver
> 
> On 8/25/2016 10:50 AM, Salil Mehta wrote:
> 
> >> I can take both.  I already pulled net-next to get the initial hns
> roce
> >> reset patch from Dave, so these will apply cleanly with my tree and
> >> merge cleanly with Dave's due to the common ancestral base.  The
> only
> >> problem is that if you intend to send any other patches that effect
> >> this
> >> code, then they would need to come through me until the 4.9 merge
> >> window
> >> is complete so that we don't have later merge conflicts.
> > Ok sure, I got your point. Yes, there are few patches we need to push
> in
> > but are related to RoCE CM(Connection Manager) mode and would follow
> > soon. There are no further patches we foresee which are for RoCE
> Driver but are
> > dependent upon HNS Ethernet driver.
> 
> Ok.
> 
> > But kindly note, there could be some patches in development in HNS
> Ethernet driver
> > which might sneak in through net-next. These might not be related to
> RoCE Driver but
> > might have some common files which might lead to conflict again
> further down
> > the line when you try to merge ACPI RoCE reset again. This HNS driver
> change
> > is very difficult for us to control since amount of development going
> on in HNS
> > is of much higher magnitude than the RoCE as of now. It will be
> almost impossible
> > for us to convince internally and shift that entire development being
> done right
> > now on net-next and rebase it to your internal hns-roce branch for a
> month of time
> > till 4.9. This will affect many features deadlines internally.
> 
> This is what Linus wants to avoid.  It's not necessary to shift your
> work from one tree to another, what is needed if for your RoCE team and
> your net team to plan out what you are going to submit for the next
> kernel and provide a complete list of conflicting code patches to both
> Dave and myself and allow us to pull those patches into both our trees
> so there are no conflicts.  See the recent threads on linux-rdma about
> the pull requests from Mellanox.  This is how it needs to be done.
> Neither team needs to slow down, or not do your work, you simply need
> to
> plan that work out and provide a common base for Dave and I to apply
> the
> separate patches on top of.
Hello Doug/David,
As per above discussion, we have identified certain conflicting patches
in HNS driver pipeline which are in conflict With already accepted HNS ACPI
Reset patch in your internal hns-roce repo. We would like to float them on
the lines of Mellanox git-pull request example you mentioned earlier.

HNS driver Patches *in-pipeline* are(formally, later-on, I shall provide
start and end commit IDs within our internal repo):
End-commit-ID
net: hns: fix the bug of forwarding table 
net: hns: fix port not available after testing loopback
net: hns: add promisc mode for hns
net: hns: add fuzzy match of tcam table for hns
net: hns: delete repeat read fbd num after while
net: hns: add fini_process for v2 napi process
net: hns: bug fix about setting coalsecs-usecs to 0
net:hns:fix port unavailable after hnae_reserve_buffer_map fail
start-commit-ID

All of above patches are dependent on the presence of below patch:
"IB/hns: Add support of ACPI to HNS RoCE Reset function"

This patch is already accepted and is part of your k.o/for-4.9-topics/hns-roce.
But this is not part of David Miller's "net-next" yet, so I was wondering
How should I raise the pull request of above set of patches. If I include
the already accepted patch then it will lead conflict in your repo (as it
is already part of it) else it will lead conflict in David's net-next when
he pulls above patches.

Hope the answer is not trivial and I am not missing anything here. 
Please guide. Thanks!

Best regards
Salil
> > So, if I understood you correctly, this delta (which could be large),
> when next merge
> > window open would be taken care by you. And we can expect below to be
> part of 4.9
> > 1) RoCE Base driver (*Already Accepted*)
> > 2) ACPI changes for RoCE Driver (*if accepted*)
> >    * ACPI changes for the RoCE Driver
> >    * ACPI changes for RoCE reset function part of the HNS driver
> 
> Both of these changes are already applied to my tree.  However, if you
> submit other changes to net-next and it starts generating merge
> conflicts, you and the net team are going to get yelled at.  If you are
> going to have a shared driver, then you *HAVE* to work as a larger team
> and plan your changes you submit to the linux kernel.
> 
> 
> --
> Doug Ledford <dledford@...hat.com>
>     GPG Key ID: 0E572FDD

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