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Subject: Re: [PATCH] rdma: siw: remove unused variable
To:     Doug Ledford <dledford@redhat.com>, Jason Gunthorpe <jgg@ziepe.ca>
CC:     Anders Roxell <anders.roxell@linaro.org>, <bmt@zurich.ibm.com>,
        <linux-rdma@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>
References: <20190726092540.22467-1-anders.roxell@linaro.org>
 <08d1942fa99465329348a1bbfd55823b590921c2.camel@redhat.com>
 <20190729190326.GG17990@ziepe.ca>
 <b5775622b2e8360e77f90dddfff9aa84af48240e.camel@redhat.com>
From:   John Hubbard <jhubbard@nvidia.com>
Message-ID: <f7500581-c3df-a0cb-8229-b832f12fcf05@nvidia.com>
Date:   Mon, 29 Jul 2019 13:14:59 -0700
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On 7/29/19 12:45 PM, Doug Ledford wrote:
> On Mon, 2019-07-29 at 16:03 -0300, Jason Gunthorpe wrote:
>> On Mon, Jul 29, 2019 at 02:19:35PM -0400, Doug Ledford wrote:
>>> On Fri, 2019-07-26 at 11:25 +0200, Anders Roxell wrote:
>>>> The variable 'p' si no longer used and the compiler rightly
>>>> complains
>>>> that it should be removed.
>>>>
>>>> ../drivers/infiniband/sw/siw/siw_mem.c: In function
>>>> =E2=80=98siw_free_plist=E2=80=99:
>>>> ../drivers/infiniband/sw/siw/siw_mem.c:66:16: warning: unused
>>>> variable
>>>>  =E2=80=98p=E2=80=99 [-Wunused-variable]
>>>>   struct page **p =3D chunk->plist;
>>>>                 ^
>>>>
>>>> Rework to remove unused variable.
>>>>
>>>> Fixes: 8288d030447f ("mm/gup: add make_dirty arg to
>>>> put_user_pages_dirty_lock()")
>>>
>>> This commit hash and the commit subject does not exist in Linus'
>>> tree as
>>> of today.  What tree is this being merged through, and is it slated
>>> to
>>> merge soon or is this a for-next item?
>>
>> This is though -mm, maybe John knows what is what
>=20
> Hmmm...if it's through -mm, doesn't that mean that we can't rely on the
> hash because the next time Andrew's tree rebases (using quilt or
> whatever it is he does) that the hash will change?  It doesn't really
> matter too much...we can't take the fix anyway, it should probably be
> squashed into the patch that it's fixing, and if you follow Bernard's
> advice, you fix the problem by eliminating this function and changing
> the sole call site to just call put_user_pages_dirty_lock() directly.
>=20

Hi,

Although I don't know which tree has 8288d030447f, I did get a report
from linux-next last night with that report about the warning, and so
I believe that the patch flowed from Andrew's -mm tree (which has=20
speculatively added my patches), to linux-next

(+CC Andrew)

I also sent out a fix for it, as a reply-to the warning report:

    https://lore.kernel.org/r/20190729074306.10368-1-jhubbard@nvidia.com

Pasting in my response (minus the trivial fix), to save you a click:

"This fixes the warning. Ideally this should be merged with the commit
that it fixes, if that's still possible.

"Andrew, would you also like a fixed version of this patch posted
as a new version of the 3-patch set that it came with?"

thanks,
--=20
John Hubbard
NVIDIA