2019-07-25 05:50:43

by Bob Liu

[permalink] [raw]
Subject: Re: [PATCH 00/12] block/bio, fs: convert put_page() to put_user_page*()

On 7/24/19 12:25 PM, [email protected] wrote:
> From: John Hubbard <[email protected]>
>
> Hi,
>
> This is mostly Jerome's work, converting the block/bio and related areas
> to call put_user_page*() instead of put_page(). Because I've changed
> Jerome's patches, in some cases significantly, I'd like to get his
> feedback before we actually leave him listed as the author (he might
> want to disown some or all of these).
>

Could you add some background to the commit log for people don't have the context..
Why this converting? What's the main differences?

Regards, -Bob

> I added a new patch, in order to make this work with Christoph Hellwig's
> recent overhaul to bio_release_pages(): "block: bio_release_pages: use
> flags arg instead of bool".
>
> I've started the series with a patch that I've posted in another
> series ("mm/gup: add make_dirty arg to put_user_pages_dirty_lock()"[1]),
> because I'm not sure which of these will go in first, and this allows each
> to stand alone.
>
> Testing: not much beyond build and boot testing has been done yet. And
> I'm not set up to even exercise all of it (especially the IB parts) at
> run time.
>
> Anyway, changes here are:
>
> * Store, in the iov_iter, a "came from gup (get_user_pages)" parameter.
> Then, use the new iov_iter_get_pages_use_gup() to retrieve it when
> it is time to release the pages. That allows choosing between put_page()
> and put_user_page*().
>
> * Pass in one more piece of information to bio_release_pages: a "from_gup"
> parameter. Similar use as above.
>
> * Change the block layer, and several file systems, to use
> put_user_page*().
>
> [1] https://urldefense.proofpoint.com/v2/url?u=https-3A__lore.kernel.org_r_20190724012606.25844-2D2-2Djhubbard-40nvidia.com&d=DwIDaQ&c=RoP1YumCXCgaWHvlZYR8PZh8Bv7qIrMUB65eapI_JnE&r=1ktT0U2YS_I8Zz2o-MS1YcCAzWZ6hFGtyTgvVMGM7gI&m=FpFhv2rjbKCAYGmO6Hy8WJAottr1Qz_mDKDLObQ40FU&s=q-_mX3daEr22WbdZMElc_ZbD8L9oGLD7U0xLeyJ661Y&e=
> And please note the correction email that I posted as a follow-up,
> if you're looking closely at that patch. :) The fixed version is
> included here.
>
> John Hubbard (3):
> mm/gup: add make_dirty arg to put_user_pages_dirty_lock()
> block: bio_release_pages: use flags arg instead of bool
> fs/ceph: fix a build warning: returning a value from void function
>
> Jérôme Glisse (9):
> iov_iter: add helper to test if an iter would use GUP v2
> block: bio_release_pages: convert put_page() to put_user_page*()
> block_dev: convert put_page() to put_user_page*()
> fs/nfs: convert put_page() to put_user_page*()
> vhost-scsi: convert put_page() to put_user_page*()
> fs/cifs: convert put_page() to put_user_page*()
> fs/fuse: convert put_page() to put_user_page*()
> fs/ceph: convert put_page() to put_user_page*()
> 9p/net: convert put_page() to put_user_page*()
>
> block/bio.c | 81 ++++++++++++---
> drivers/infiniband/core/umem.c | 5 +-
> drivers/infiniband/hw/hfi1/user_pages.c | 5 +-
> drivers/infiniband/hw/qib/qib_user_pages.c | 5 +-
> drivers/infiniband/hw/usnic/usnic_uiom.c | 5 +-
> drivers/infiniband/sw/siw/siw_mem.c | 8 +-
> drivers/vhost/scsi.c | 13 ++-
> fs/block_dev.c | 22 +++-
> fs/ceph/debugfs.c | 2 +-
> fs/ceph/file.c | 62 ++++++++---
> fs/cifs/cifsglob.h | 3 +
> fs/cifs/file.c | 22 +++-
> fs/cifs/misc.c | 19 +++-
> fs/direct-io.c | 2 +-
> fs/fuse/dev.c | 22 +++-
> fs/fuse/file.c | 53 +++++++---
> fs/nfs/direct.c | 10 +-
> include/linux/bio.h | 22 +++-
> include/linux/mm.h | 5 +-
> include/linux/uio.h | 11 ++
> mm/gup.c | 115 +++++++++------------
> net/9p/trans_common.c | 14 ++-
> net/9p/trans_common.h | 3 +-
> net/9p/trans_virtio.c | 18 +++-
> 24 files changed, 357 insertions(+), 170 deletions(-)
>


2019-07-26 01:24:59

by John Hubbard

[permalink] [raw]
Subject: Re: [PATCH 00/12] block/bio, fs: convert put_page() to put_user_page*()

On 7/24/19 5:41 PM, Bob Liu wrote:
> On 7/24/19 12:25 PM, [email protected] wrote:
>> From: John Hubbard <[email protected]>
>>
>> Hi,
>>
>> This is mostly Jerome's work, converting the block/bio and related areas
>> to call put_user_page*() instead of put_page(). Because I've changed
>> Jerome's patches, in some cases significantly, I'd like to get his
>> feedback before we actually leave him listed as the author (he might
>> want to disown some or all of these).
>>
>
> Could you add some background to the commit log for people don't have the context..
> Why this converting? What's the main differences?
>

Hi Bob,

1. Many of the patches have a blurb like this:

For pages that were retained via get_user_pages*(), release those pages
via the new put_user_page*() routines, instead of via put_page().

This is part a tree-wide conversion, as described in commit fc1d8e7cca2d
("mm: introduce put_user_page*(), placeholder versions").

...and if you look at that commit, you'll find several pages of
information in its commit description, which should address your point.

2. This whole series has to be re-worked, as per the other feedback thread.
So I'll keep your comment in mind when I post a new series.

thanks,
--
John Hubbard
NVIDIA