From: Mikulas Patocka <mpatocka@redhat.com>
To: Mike Snitzer <snitzer@kernel.org>
Cc: Johannes Thumshirn <johannes.thumshirn@wdc.com>,
"axboe @ kernel . dk" <axboe@kernel.dk>,
shaggy@kernel.org, damien.lemoal@wdc.com,
cluster-devel@redhat.com, kch@nvidia.com, agruenba@redhat.com,
linux-mm@kvack.org,
Damien Le Moal <damien.lemoal@opensource.wdc.com>,
jfs-discussion@lists.sourceforge.net, willy@infradead.org,
ming.lei@redhat.com, linux-block@vger.kernel.org,
song@kernel.org, dm-devel@redhat.com, rpeterso@redhat.com,
linux-fsdevel@vger.kernel.org, linux-raid@vger.kernel.org,
hch@lst.de
Subject: Re: [PATCH v5 16/20] dm-crypt: check if adding pages to clone bio fails
Date: Tue, 30 May 2023 15:43:33 -0400 (EDT) [thread overview]
Message-ID: <alpine.LRH.2.21.2305301527410.18906@file01.intranet.prod.int.rdu2.redhat.com> (raw)
In-Reply-To: <ZHYbIYxGbcXbpvIK@redhat.com>
On Tue, 30 May 2023, Mike Snitzer wrote:
> On Tue, May 30 2023 at 11:13P -0400,
> Mikulas Patocka <mpatocka@redhat.com> wrote:
>
> > Hi
> >
> > I nack this. This just adds code that can't ever be executed.
> >
> > dm-crypt already allocates enough entries in the vector (see "unsigned int
> > nr_iovecs = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;"), so bio_add_page can't
> > fail.
> >
> > If you want to add __must_check to bio_add_page, you should change the
> > dm-crypt code to:
> > if (!bio_add_page(clone, page, len, 0)) {
> > WARN(1, "this can't happen");
> > return NULL;
> > }
> > and not write recovery code for a can't-happen case.
>
> Thanks for the review Mikulas. But the proper way forward, in the
> context of this patchset, is to simply change bio_add_page() to
> __bio_add_page()
>
> Subject becomes: "dm crypt: use __bio_add_page to add single page to clone bio"
>
> And header can explain that "crypt_alloc_buffer() already allocates
> enough entries in the clone bio's vector, so bio_add_page can't fail".
>
> Mike
Yes, __bio_add_page would look nicer. But bio_add_page can merge adjacent
pages into a single bvec entry and __bio_add_page can't (I don't know how
often the merging happens or what is the performance implication of
non-merging).
I think that for the next merge window, we can apply this patch:
https://listman.redhat.com/archives/dm-devel/2023-May/054046.html
which makes this discussion irrelevant. (you can change bio_add_page to
__bio_add_page in it)
Mikukas
WARNING: multiple messages have this Message-ID (diff)
From: Mikulas Patocka <mpatocka@redhat.com>
To: Mike Snitzer <snitzer@kernel.org>
Cc: "axboe @ kernel . dk" <axboe@kernel.dk>,
shaggy@kernel.org, damien.lemoal@wdc.com, kch@nvidia.com,
agruenba@redhat.com, song@kernel.org,
Johannes Thumshirn <johannes.thumshirn@wdc.com>,
Damien Le Moal <damien.lemoal@opensource.wdc.com>,
linux-raid@vger.kernel.org, jfs-discussion@lists.sourceforge.net,
willy@infradead.org, ming.lei@redhat.com,
cluster-devel@redhat.com, linux-mm@kvack.org,
dm-devel@redhat.com, linux-block@vger.kernel.org,
rpeterso@redhat.com, linux-fsdevel@vger.kernel.org, hch@lst.de
Subject: Re: [dm-devel] [PATCH v5 16/20] dm-crypt: check if adding pages to clone bio fails
Date: Tue, 30 May 2023 15:43:33 -0400 (EDT) [thread overview]
Message-ID: <alpine.LRH.2.21.2305301527410.18906@file01.intranet.prod.int.rdu2.redhat.com> (raw)
In-Reply-To: <ZHYbIYxGbcXbpvIK@redhat.com>
On Tue, 30 May 2023, Mike Snitzer wrote:
> On Tue, May 30 2023 at 11:13P -0400,
> Mikulas Patocka <mpatocka@redhat.com> wrote:
>
> > Hi
> >
> > I nack this. This just adds code that can't ever be executed.
> >
> > dm-crypt already allocates enough entries in the vector (see "unsigned int
> > nr_iovecs = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;"), so bio_add_page can't
> > fail.
> >
> > If you want to add __must_check to bio_add_page, you should change the
> > dm-crypt code to:
> > if (!bio_add_page(clone, page, len, 0)) {
> > WARN(1, "this can't happen");
> > return NULL;
> > }
> > and not write recovery code for a can't-happen case.
>
> Thanks for the review Mikulas. But the proper way forward, in the
> context of this patchset, is to simply change bio_add_page() to
> __bio_add_page()
>
> Subject becomes: "dm crypt: use __bio_add_page to add single page to clone bio"
>
> And header can explain that "crypt_alloc_buffer() already allocates
> enough entries in the clone bio's vector, so bio_add_page can't fail".
>
> Mike
Yes, __bio_add_page would look nicer. But bio_add_page can merge adjacent
pages into a single bvec entry and __bio_add_page can't (I don't know how
often the merging happens or what is the performance implication of
non-merging).
I think that for the next merge window, we can apply this patch:
https://listman.redhat.com/archives/dm-devel/2023-May/054046.html
which makes this discussion irrelevant. (you can change bio_add_page to
__bio_add_page in it)
Mikukas
--
dm-devel mailing list
dm-devel@redhat.com
https://listman.redhat.com/mailman/listinfo/dm-devel
WARNING: multiple messages have this Message-ID (diff)
From: Mikulas Patocka <mpatocka@redhat.com>
To: cluster-devel.redhat.com
Subject: [Cluster-devel] [PATCH v5 16/20] dm-crypt: check if adding pages to clone bio fails
Date: Tue, 30 May 2023 15:43:33 -0400 (EDT) [thread overview]
Message-ID: <alpine.LRH.2.21.2305301527410.18906@file01.intranet.prod.int.rdu2.redhat.com> (raw)
In-Reply-To: <ZHYbIYxGbcXbpvIK@redhat.com>
On Tue, 30 May 2023, Mike Snitzer wrote:
> On Tue, May 30 2023 at 11:13P -0400,
> Mikulas Patocka <mpatocka@redhat.com> wrote:
>
> > Hi
> >
> > I nack this. This just adds code that can't ever be executed.
> >
> > dm-crypt already allocates enough entries in the vector (see "unsigned int
> > nr_iovecs = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;"), so bio_add_page can't
> > fail.
> >
> > If you want to add __must_check to bio_add_page, you should change the
> > dm-crypt code to:
> > if (!bio_add_page(clone, page, len, 0)) {
> > WARN(1, "this can't happen");
> > return NULL;
> > }
> > and not write recovery code for a can't-happen case.
>
> Thanks for the review Mikulas. But the proper way forward, in the
> context of this patchset, is to simply change bio_add_page() to
> __bio_add_page()
>
> Subject becomes: "dm crypt: use __bio_add_page to add single page to clone bio"
>
> And header can explain that "crypt_alloc_buffer() already allocates
> enough entries in the clone bio's vector, so bio_add_page can't fail".
>
> Mike
Yes, __bio_add_page would look nicer. But bio_add_page can merge adjacent
pages into a single bvec entry and __bio_add_page can't (I don't know how
often the merging happens or what is the performance implication of
non-merging).
I think that for the next merge window, we can apply this patch:
https://listman.redhat.com/archives/dm-devel/2023-May/054046.html
which makes this discussion irrelevant. (you can change bio_add_page to
__bio_add_page in it)
Mikukas
next prev parent reply other threads:[~2023-05-30 19:44 UTC|newest]
Thread overview: 103+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-05-02 10:19 [PATCH v5 00/20] bio: check return values of bio_add_page Johannes Thumshirn
2023-05-02 10:19 ` [Cluster-devel] " Johannes Thumshirn
2023-05-02 10:19 ` [dm-devel] " Johannes Thumshirn
2023-05-02 10:19 ` [PATCH v5 01/20] swap: use __bio_add_page to add page to bio Johannes Thumshirn
2023-05-02 10:19 ` [Cluster-devel] " Johannes Thumshirn
2023-05-02 10:19 ` [dm-devel] " Johannes Thumshirn
2023-05-02 10:19 ` [PATCH v5 02/20] drbd: " Johannes Thumshirn
2023-05-02 10:19 ` [Cluster-devel] " Johannes Thumshirn
2023-05-02 10:19 ` [dm-devel] " Johannes Thumshirn
2023-05-02 10:19 ` [PATCH v5 03/20] dm: dm-zoned: use __bio_add_page for adding single metadata page Johannes Thumshirn
2023-05-02 10:19 ` [Cluster-devel] " Johannes Thumshirn
2023-05-02 10:19 ` [dm-devel] " Johannes Thumshirn
2023-05-02 10:19 ` [PATCH v5 04/20] fs: buffer: use __bio_add_page to add single page to bio Johannes Thumshirn
2023-05-02 10:19 ` [Cluster-devel] " Johannes Thumshirn
2023-05-02 10:19 ` [dm-devel] " Johannes Thumshirn
2023-05-30 5:41 ` gouhao
2023-05-30 6:02 ` gouhao
2023-05-30 6:02 ` [Cluster-devel] [PATCH " gouhao
2023-05-30 6:02 ` [dm-devel] " gouhao
2023-05-02 10:19 ` [dm-devel] [PATCH v5 05/20] md: use __bio_add_page to add single page Johannes Thumshirn
2023-05-02 10:19 ` [Cluster-devel] " Johannes Thumshirn
2023-05-02 10:19 ` Johannes Thumshirn
2023-05-02 10:19 ` [PATCH v5 06/20] md: raid5-log: " Johannes Thumshirn
2023-05-02 10:19 ` [Cluster-devel] " Johannes Thumshirn
2023-05-02 10:19 ` [dm-devel] " Johannes Thumshirn
2023-05-02 10:19 ` [dm-devel] [PATCH v5 07/20] md: raid5: use __bio_add_page to add single page to new bio Johannes Thumshirn
2023-05-02 10:19 ` [Cluster-devel] " Johannes Thumshirn
2023-05-02 10:19 ` Johannes Thumshirn
2023-05-02 10:19 ` [PATCH v5 08/20] jfs: logmgr: use __bio_add_page to add single page to bio Johannes Thumshirn
2023-05-02 10:19 ` [Cluster-devel] " Johannes Thumshirn
2023-05-02 10:19 ` [dm-devel] " Johannes Thumshirn
2023-05-02 10:19 ` [dm-devel] [PATCH v5 09/20] gfs2: use __bio_add_page for adding " Johannes Thumshirn
2023-05-02 10:19 ` [Cluster-devel] " Johannes Thumshirn
2023-05-02 10:19 ` Johannes Thumshirn
2023-05-02 11:51 ` Bob Peterson
2023-05-02 11:51 ` [Cluster-devel] " Bob Peterson
2023-05-02 11:51 ` [dm-devel] " Bob Peterson
2023-05-02 11:53 ` Johannes Thumshirn
2023-05-02 11:53 ` [Cluster-devel] " Johannes Thumshirn
2023-05-02 11:53 ` [dm-devel] " Johannes Thumshirn
2023-05-02 10:19 ` [dm-devel] [PATCH v5 10/20] zonefs: " Johannes Thumshirn
2023-05-02 10:19 ` [Cluster-devel] " Johannes Thumshirn
2023-05-02 10:19 ` Johannes Thumshirn
2023-05-02 10:19 ` [dm-devel] [PATCH v5 11/20] zram: " Johannes Thumshirn
2023-05-02 10:19 ` [Cluster-devel] " Johannes Thumshirn
2023-05-02 10:19 ` Johannes Thumshirn
2023-05-02 10:19 ` [dm-devel] [PATCH v5 12/20] floppy: " Johannes Thumshirn
2023-05-02 10:19 ` [Cluster-devel] " Johannes Thumshirn
2023-05-02 10:19 ` Johannes Thumshirn
2023-05-02 10:19 ` [dm-devel] [PATCH v5 13/20] md: check for failure when adding pages in alloc_behind_master_bio Johannes Thumshirn
2023-05-02 10:19 ` [Cluster-devel] " Johannes Thumshirn
2023-05-02 10:19 ` Johannes Thumshirn
2023-05-02 10:19 ` [dm-devel] [PATCH v5 14/20] md: raid1: use __bio_add_page for adding single page to bio Johannes Thumshirn
2023-05-02 10:19 ` [Cluster-devel] " Johannes Thumshirn
2023-05-02 10:19 ` Johannes Thumshirn
2023-05-02 10:19 ` [dm-devel] [PATCH v5 15/20] md: raid1: check if adding pages to resync bio fails Johannes Thumshirn
2023-05-02 10:19 ` [Cluster-devel] " Johannes Thumshirn
2023-05-02 10:19 ` Johannes Thumshirn
2023-05-02 10:19 ` [dm-devel] [PATCH v5 16/20] dm-crypt: check if adding pages to clone " Johannes Thumshirn
2023-05-02 10:19 ` [Cluster-devel] " Johannes Thumshirn
2023-05-02 10:19 ` Johannes Thumshirn
2023-05-30 15:13 ` [dm-devel] " Mikulas Patocka
2023-05-30 15:13 ` [Cluster-devel] " Mikulas Patocka
2023-05-30 15:13 ` Mikulas Patocka
2023-05-30 15:49 ` Mike Snitzer
2023-05-30 15:49 ` [Cluster-devel] " Mike Snitzer
2023-05-30 15:49 ` [dm-devel] " Mike Snitzer
2023-05-30 19:43 ` Mikulas Patocka [this message]
2023-05-30 19:43 ` [Cluster-devel] " Mikulas Patocka
2023-05-30 19:43 ` [dm-devel] " Mikulas Patocka
2023-06-01 18:46 ` Mike Snitzer
2023-06-01 18:46 ` [Cluster-devel] " Mike Snitzer
2023-06-01 18:46 ` Mike Snitzer
2023-05-02 10:19 ` [dm-devel] [PATCH v5 17/20] block: mark bio_add_page as __must_check Johannes Thumshirn
2023-05-02 10:19 ` [Cluster-devel] " Johannes Thumshirn
2023-05-02 10:19 ` Johannes Thumshirn
2023-05-02 10:19 ` [dm-devel] [PATCH v5 18/20] block: add __bio_add_folio Johannes Thumshirn
2023-05-02 10:19 ` [Cluster-devel] " Johannes Thumshirn
2023-05-02 10:19 ` Johannes Thumshirn
2023-05-02 10:19 ` [dm-devel] [PATCH v5 19/20] fs: iomap: use __bio_add_folio where possible Johannes Thumshirn
2023-05-02 10:19 ` [Cluster-devel] " Johannes Thumshirn
2023-05-02 10:19 ` Johannes Thumshirn
2023-05-02 10:19 ` [dm-devel] [PATCH v5 20/20] block: mark bio_add_folio as __must_check Johannes Thumshirn
2023-05-02 10:19 ` [Cluster-devel] " Johannes Thumshirn
2023-05-02 10:19 ` Johannes Thumshirn
2023-05-05 8:09 ` [PATCH v5 00/20] bio: check return values of bio_add_page Johannes Thumshirn
2023-05-05 8:09 ` [Cluster-devel] " Johannes Thumshirn
2023-05-05 8:09 ` [dm-devel] " Johannes Thumshirn
2023-05-05 14:11 ` Jens Axboe
2023-05-05 14:11 ` [Cluster-devel] " Jens Axboe
2023-05-05 14:11 ` [dm-devel] " Jens Axboe
2023-05-24 10:04 ` Johannes Thumshirn
2023-05-24 10:04 ` [Cluster-devel] " Johannes Thumshirn
2023-05-24 10:04 ` [dm-devel] " Johannes Thumshirn
2023-05-24 15:02 ` Jens Axboe
2023-05-24 15:02 ` [Cluster-devel] " Jens Axboe
2023-05-24 15:02 ` [dm-devel] " Jens Axboe
2023-05-26 6:37 ` Johannes Thumshirn
2023-05-26 6:37 ` [Cluster-devel] " Johannes Thumshirn
2023-05-26 6:37 ` [dm-devel] " Johannes Thumshirn
2023-05-30 15:14 ` Jens Axboe
2023-05-30 15:14 ` [Cluster-devel] " Jens Axboe
2023-05-30 15:14 ` [dm-devel] " Jens Axboe
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