From: Dan Williams <dan.j.williams@intel.com>
To: Keith Busch <keith.busch@intel.com>
Cc: John Hubbard <john.hubbard@gmail.com>,
Linux MM <linux-mm@kvack.org>,
Andrew Morton <akpm@linux-foundation.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
linux-rdma <linux-rdma@vger.kernel.org>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
John Hubbard <jhubbard@nvidia.com>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Dave Hansen <dave.hansen@intel.com>
Subject: Re: [PATCH v2 1/6] mm/gup: finish consolidating error handling
Date: Mon, 12 Nov 2018 08:14:46 -0800 [thread overview]
Message-ID: <CAPcyv4j7nqLOFD5dZEe_nBysHDL2pQ-tRO9Crp9oyTUP7RoDHw@mail.gmail.com> (raw)
In-Reply-To: <20181112154127.GA8247@localhost.localdomain>
On Mon, Nov 12, 2018 at 7:45 AM Keith Busch <keith.busch@intel.com> wrote:
>
> On Sat, Nov 10, 2018 at 12:50:36AM -0800, john.hubbard@gmail.com wrote:
> > From: John Hubbard <jhubbard@nvidia.com>
> >
> > An upcoming patch wants to be able to operate on each page that
> > get_user_pages has retrieved. In order to do that, it's best to
> > have a common exit point from the routine. Most of this has been
> > taken care of by commit df06b37ffe5a4 ("mm/gup: cache dev_pagemap while
> > pinning pages"), but there was one case remaining.
> >
> > Also, there was still an unnecessary shadow declaration (with a
> > different type) of the "ret" variable, which this commit removes.
> >
> > Cc: Keith Busch <keith.busch@intel.com>
> > Cc: Dan Williams <dan.j.williams@intel.com>
> > Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> > Cc: Dave Hansen <dave.hansen@intel.com>
> > Signed-off-by: John Hubbard <jhubbard@nvidia.com>
> > ---
> > mm/gup.c | 3 +--
> > 1 file changed, 1 insertion(+), 2 deletions(-)
> >
> > diff --git a/mm/gup.c b/mm/gup.c
> > index f76e77a2d34b..55a41dee0340 100644
> > --- a/mm/gup.c
> > +++ b/mm/gup.c
> > @@ -696,12 +696,11 @@ static long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
> > if (!vma || start >= vma->vm_end) {
> > vma = find_extend_vma(mm, start);
> > if (!vma && in_gate_area(mm, start)) {
> > - int ret;
> > ret = get_gate_page(mm, start & PAGE_MASK,
> > gup_flags, &vma,
> > pages ? &pages[i] : NULL);
> > if (ret)
> > - return i ? : ret;
> > + goto out;
> > ctx.page_mask = 0;
> > goto next_page;
> > }
>
> This also fixes a potentially leaked dev_pagemap reference count if a
> failure occurs when an iteration crosses a vma boundary. I don't think
> it's normal to have different vma's on a users mapped zone device memory,
> but good to fix anyway.
Does not sound abnormal to me, we should promote this as a fix for the
current cycle with an updated changelog.
next prev parent reply other threads:[~2018-11-12 16:15 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-10 8:50 [PATCH v2 0/6] RFC: gup+dma: tracking dma-pinned pages john.hubbard
2018-11-10 8:50 ` [PATCH v2 1/6] mm/gup: finish consolidating error handling john.hubbard
2018-11-12 15:41 ` Keith Busch
2018-11-12 16:14 ` Dan Williams [this message]
2018-11-15 0:45 ` John Hubbard
2018-11-10 8:50 ` [PATCH v2 2/6] mm: introduce put_user_page*(), placeholder versions john.hubbard
2018-11-11 14:10 ` Mike Rapoport
2018-11-10 8:50 ` [PATCH v2 3/6] infiniband/mm: convert put_page() to put_user_page*() john.hubbard
2018-11-10 8:50 ` [PATCH v2 4/6] mm: introduce page->dma_pinned_flags, _count john.hubbard
2018-11-10 8:50 ` [PATCH v2 5/6] mm: introduce zone_gup_lock, for dma-pinned pages john.hubbard
2018-11-10 8:50 ` [PATCH v2 6/6] mm: track gup pages with page->dma_pinned_* fields john.hubbard
2018-11-12 13:58 ` Jan Kara
2018-11-15 6:28 ` [LKP] [mm] 0e9755bfa2: kernel_BUG_at_include/linux/mm.h kernel test robot
2018-11-19 18:57 ` [PATCH v2 0/6] RFC: gup+dma: tracking dma-pinned pages Tom Talpey
2018-11-21 6:09 ` John Hubbard
2018-11-21 16:49 ` Tom Talpey
2018-11-21 22:06 ` John Hubbard
2018-11-28 1:21 ` Tom Talpey
2018-11-28 2:52 ` John Hubbard
2018-11-28 13:59 ` Tom Talpey
2018-11-30 1:39 ` John Hubbard
2018-11-30 2:18 ` Tom Talpey
2018-11-30 2:21 ` John Hubbard
2018-11-30 2:30 ` Tom Talpey
2018-11-30 3:00 ` John Hubbard
2018-11-30 3:14 ` Tom Talpey
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