From: Daniel Vetter <daniel.vetter@ffwll.ch>
To: DRI Development <dri-devel@lists.freedesktop.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
"Daniel Vetter" <daniel.vetter@ffwll.ch>,
"Daniel Vetter" <daniel.vetter@intel.com>,
"Andrew Morton" <akpm@linux-foundation.org>,
"John Hubbard" <jhubbard@nvidia.com>,
"Jérôme Glisse" <jglisse@redhat.com>, "Jan Kara" <jack@suse.cz>,
"Dan Williams" <dan.j.williams@intel.com>,
linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org,
linux-samsung-soc@vger.kernel.org, linux-media@vger.kernel.org
Subject: [PATCH 2/2] mm/frame-vec: use FOLL_LONGTERM
Date: Fri, 2 Oct 2020 19:53:03 +0200 [thread overview]
Message-ID: <20201002175303.390363-2-daniel.vetter@ffwll.ch> (raw)
In-Reply-To: <20201002175303.390363-1-daniel.vetter@ffwll.ch>
For $reasons I've stumbled over this code and I'm not sure the change
to the new gup functions in 55a650c35fea ("mm/gup: frame_vector:
convert get_user_pages() --> pin_user_pages()") was entirely correct.
This here is used for long term buffers (not just quick I/O) like
RDMA, and John notes this in his patch. But I thought the rule for
these is that they need to add FOLL_LONGTERM, which John's patch
didn't do.
There is already a dax specific check (added in b7f0554a56f2 ("mm:
fail get_vaddr_frames() for filesystem-dax mappings")), so this seems
like the prudent thing to do.
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: linux-mm@kvack.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-samsung-soc@vger.kernel.org
Cc: linux-media@vger.kernel.org
---
Hi all,
I stumbled over this and figured typing this patch can't hurt. Really
just to maybe learn a few things about how gup/pup is supposed to be
used (we have a bit of that in drivers/gpu), this here isn't really
ralated to anything I'm doing.
I'm also wondering whether the explicit dax check should be removed,
since FOLL_LONGTERM should take care of that already.
-Daniel
---
mm/frame_vector.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/mm/frame_vector.c b/mm/frame_vector.c
index 5d34c9047e9c..3507e09cb3ff 100644
--- a/mm/frame_vector.c
+++ b/mm/frame_vector.c
@@ -35,7 +35,7 @@ int get_vaddr_frames(unsigned long start, unsigned int nr_frames,
{
struct mm_struct *mm = current->mm;
struct vm_area_struct *vma;
- unsigned int gup_flags = FOLL_WRITE | FOLL_FORCE;
+ unsigned int gup_flags = FOLL_WRITE | FOLL_FORCE | FOLL_LONGTERM;
int ret = 0;
int err;
int locked;
--
2.28.0
next prev parent reply other threads:[~2020-10-02 17:53 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-02 17:53 [PATCH 1/2] mm/frame-vec: Drop gup_flags from get_vaddr_frames() Daniel Vetter
2020-10-02 17:53 ` Daniel Vetter [this message]
2020-10-02 18:06 ` [PATCH 2/2] mm/frame-vec: use FOLL_LONGTERM Jason Gunthorpe
2020-10-02 18:16 ` Daniel Vetter
2020-10-02 23:31 ` Jason Gunthorpe
2020-10-03 8:34 ` Oded Gabbay
2020-10-03 9:40 ` Daniel Vetter
2020-10-04 12:50 ` Jason Gunthorpe
2020-10-04 16:09 ` Daniel Vetter
2020-10-05 17:28 ` Jason Gunthorpe
2020-10-05 18:16 ` Daniel Vetter
2020-10-05 18:37 ` Jason Gunthorpe
2020-10-05 18:54 ` Daniel Vetter
2020-10-05 22:43 ` Daniel Vetter
2020-10-05 23:41 ` Jason Gunthorpe
2020-10-06 6:23 ` Daniel Vetter
2020-10-06 12:26 ` Jason Gunthorpe
2020-10-06 13:08 ` Daniel Vetter
2020-10-07 10:47 ` Marek Szyprowski
2020-10-07 12:01 ` Daniel Vetter
2020-10-07 12:33 ` Marek Szyprowski
2020-10-07 12:44 ` Jason Gunthorpe
2020-10-07 12:47 ` Tomasz Figa
2020-10-07 12:58 ` Daniel Vetter
2020-10-07 13:06 ` Jason Gunthorpe
2020-10-07 13:34 ` Tomasz Figa
2020-10-07 13:42 ` Jason Gunthorpe
2020-10-07 14:08 ` Daniel Vetter
2020-10-07 14:11 ` Tomasz Figa
2020-10-07 14:22 ` Daniel Vetter
2020-10-07 15:05 ` Tomasz Figa
2020-10-07 14:58 ` Jason Gunthorpe
2020-10-07 13:06 ` Tomasz Figa
2020-10-07 13:14 ` Jason Gunthorpe
2020-10-05 15:03 ` Jan Kara
2020-10-02 22:39 ` John Hubbard
2020-10-03 9:45 ` Daniel Vetter
2020-10-03 22:52 ` John Hubbard
2020-10-03 23:24 ` Jason Gunthorpe
2020-10-04 11:20 ` Daniel Vetter
2020-10-05 17:35 ` Jason Gunthorpe
2020-10-02 18:22 ` [PATCH 1/2] mm/frame-vec: Drop gup_flags from get_vaddr_frames() Tomasz Figa
2020-10-02 19:21 ` Oded Gabbay
2020-10-05 17:38 [PATCH 2/2] mm/frame-vec: use FOLL_LONGTERM Jason Gunthorpe
2020-10-05 17:47 ` Jason Gunthorpe
2020-10-06 3:36 ` Andrew Morton
2020-10-06 11:57 ` Jason Gunthorpe
2020-10-05 17:53 ` Jan Kara
2020-10-05 17:57 ` Jason Gunthorpe
2020-10-05 18:16 ` Daniel Vetter
2020-10-06 11:56 ` Daniel Vetter
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