NACK: Cmt: [SRU][K:master-next][PATCH 1/1] block: handle bio_split_to_limits() NULL return
Roxana Nicolescu
roxana.nicolescu at canonical.com
Wed May 31 15:57:41 UTC 2023
On 31/05/2023 16:59, Aleksandr Mikhalitsyn wrote:
> On Wed, May 31, 2023 at 12:04 PM Roxana Nicolescu
> <roxana.nicolescu at canonical.com> wrote:
>>
>> On 30/05/2023 19:25, Alexander Mikhalitsyn wrote:
>>> From: Jens Axboe <axboe at kernel.dk>
>>>
>>> BugLink: https://bugs.launchpad.net/bugs/2020901
>>>
>>> commit 613b14884b8595e20b9fac4126bf627313827fbe upstream.
>>>
>>> This can't happen right now, but in preparation for allowing
>>> bio_split_to_limits() returning NULL if it ended the bio, check for it
>>> in all the callers.
>>>
>>> Signed-off-by: Jens Axboe <axboe at kernel.dk>
>>> Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
>>> (backported from commit 613b14884b8595e20b9fac4126bf627313827fbe)
>> This commit message is actually 7ec9a45fc4ee7fc1054c2cabf8b09a6bc708472e
> ah, yep, SOB of Greg is incorrect, but commit hash
> 613b14884b8595e20b9fac4126bf627313827fbe is the right one.
> Just take a look:
> https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=613b14884b8595e20b9fac4126bf627313827fbe
> and compare changes.
>> from the stable tree. I see it has the sob of Greg. The one in mainline
>> does not have it.
>> But the commit in the stable tree does not contain drivers/md/dm.c
>> changes, so I am not sure which commit you actually applied here.
Apologize, I think I meant pktcdvd here in my previous reply.
As discussed in private, the check in drivers/block/pktcdvd.c is added
in a separate commit,
so a separate submission that includes that patch as well will be sent.
> yes, because our kernel tree is not the same as any -stable or
> upstream. I've ported changes properly.
> drivers/md/dm.c contains a call to blk_queue_split and we have to
> check if (!bio) ... there too.
>
>> And this is not a clean cherry-pick, hence it needs some explanation on
>> how you solved it.
>>
>> Format is:
>>
>> [axboe: <Your explanation>]
>> Something like "Context adjustment due to missing commits ..."
> [amikhalitsyn: added a BIO presence checks to all blk_queue_split() callers]
>>> Signed-off-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn at canonical.com>
>>> ---
>>> block/blk-merge.c | 4 +++-
>>> block/blk-mq.c | 3 +++
>>> drivers/block/drbd/drbd_req.c | 2 ++
>>> drivers/block/pktcdvd.c | 2 ++
>>> drivers/block/ps3vram.c | 2 ++
>>> drivers/md/dm.c | 2 ++
>>> drivers/md/md.c | 2 ++
>>> drivers/nvme/host/multipath.c | 2 ++
>>> drivers/s390/block/dcssblk.c | 2 ++
>>> 9 files changed, 20 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/block/blk-merge.c b/block/blk-merge.c
>>> index 88e39b955bd6..1af8043900f4 100644
>>> --- a/block/blk-merge.c
>>> +++ b/block/blk-merge.c
>>> @@ -348,11 +348,13 @@ void __blk_queue_split(struct request_queue *q, struct bio **bio,
>>> break;
>>> default:
>>> split = blk_bio_segment_split(q, *bio, &q->bio_split, nr_segs);
>>> + if (IS_ERR(split))
>>> + *bio = split = NULL;
>>> break;
>>> }
>>>
>>> if (split) {
>>> - /* there isn't chance to merge the splitted bio */
>>> + /* there isn't chance to merge the split bio */
>>> split->bi_opf |= REQ_NOMERGE;
>>>
>>> blkcg_bio_issue_init(split);
>>> diff --git a/block/blk-mq.c b/block/blk-mq.c
>>> index 7c7e632871e7..8b22429cf94e 100644
>>> --- a/block/blk-mq.c
>>> +++ b/block/blk-mq.c
>>> @@ -2818,6 +2818,9 @@ void blk_mq_submit_bio(struct bio *bio)
>>> if (blk_may_split(q, bio))
>>> __blk_queue_split(q, &bio, &nr_segs);
>>>
>>> + if (!bio)
>>> + return;
>>> +
>>> if (!bio_integrity_prep(bio))
>>> return;
>>>
>>> diff --git a/drivers/block/drbd/drbd_req.c b/drivers/block/drbd/drbd_req.c
>>> index e60d3c6314c6..f323a4714f6a 100644
>>> --- a/drivers/block/drbd/drbd_req.c
>>> +++ b/drivers/block/drbd/drbd_req.c
>>> @@ -1609,6 +1609,8 @@ void drbd_submit_bio(struct bio *bio)
>>> struct drbd_device *device = bio->bi_bdev->bd_disk->private_data;
>>>
>>> blk_queue_split(&bio);
>>> + if (!bio)
>>> + return;
>>>
>>> /*
>>> * what we "blindly" assume:
>>> diff --git a/drivers/block/pktcdvd.c b/drivers/block/pktcdvd.c
>>> index 789093375344..1988bb05c0c7 100644
>>> --- a/drivers/block/pktcdvd.c
>>> +++ b/drivers/block/pktcdvd.c
>>> @@ -2400,6 +2400,8 @@ static void pkt_submit_bio(struct bio *bio)
>>> struct bio *split;
>>>
>>> blk_queue_split(&bio);
>>> + if (!bio)
>>> + return;
>>>
>>> pkt_dbg(2, pd, "start = %6llx stop = %6llx\n",
>>> (unsigned long long)bio->bi_iter.bi_sector,
>>> diff --git a/drivers/block/ps3vram.c b/drivers/block/ps3vram.c
>>> index 4f90819e245e..2a431178dc7e 100644
>>> --- a/drivers/block/ps3vram.c
>>> +++ b/drivers/block/ps3vram.c
>>> @@ -587,6 +587,8 @@ static void ps3vram_submit_bio(struct bio *bio)
>>> dev_dbg(&dev->core, "%s\n", __func__);
>>>
>>> blk_queue_split(&bio);
>>> + if (!bio)
>>> + return;
>>>
>>> spin_lock_irq(&priv->lock);
>>> busy = !bio_list_empty(&priv->list);
>>> diff --git a/drivers/md/dm.c b/drivers/md/dm.c
>>> index 5acee96b5a7b..bf904c153d41 100644
>>> --- a/drivers/md/dm.c
>>> +++ b/drivers/md/dm.c
>>> @@ -1674,6 +1674,8 @@ static void dm_split_and_process_bio(struct mapped_device *md,
>>> * otherwise associated queue_limits won't be imposed.
>>> */
>>> blk_queue_split(&bio);
>>> + if (!bio)
>>> + return;
>>> }
>>>
>>> init_clone_info(&ci, md, map, bio, is_abnormal);
>>> diff --git a/drivers/md/md.c b/drivers/md/md.c
>>> index 946434ced070..772a89843226 100644
>>> --- a/drivers/md/md.c
>>> +++ b/drivers/md/md.c
>>> @@ -465,6 +465,8 @@ static void md_submit_bio(struct bio *bio)
>>> }
>>>
>>> blk_queue_split(&bio);
>>> + if (!bio)
>>> + return;
>>>
>>> if (mddev->ro == 1 && unlikely(rw == WRITE)) {
>>> if (bio_sectors(bio) != 0)
>>> diff --git a/drivers/nvme/host/multipath.c b/drivers/nvme/host/multipath.c
>>> index d62c4a0f89ab..571c4791faa8 100644
>>> --- a/drivers/nvme/host/multipath.c
>>> +++ b/drivers/nvme/host/multipath.c
>>> @@ -351,6 +351,8 @@ static void nvme_ns_head_submit_bio(struct bio *bio)
>>> * pool from the original queue to allocate the bvecs from.
>>> */
>>> blk_queue_split(&bio);
>>> + if (!bio)
>>> + return;
>>>
>>> srcu_idx = srcu_read_lock(&head->srcu);
>>> ns = nvme_find_path(head);
>>> diff --git a/drivers/s390/block/dcssblk.c b/drivers/s390/block/dcssblk.c
>>> index f4401b2d30e0..18506cc222ba 100644
>>> --- a/drivers/s390/block/dcssblk.c
>>> +++ b/drivers/s390/block/dcssblk.c
>>> @@ -865,6 +865,8 @@ dcssblk_submit_bio(struct bio *bio)
>>> unsigned long bytes_done;
>>>
>>> blk_queue_split(&bio);
>>> + if (!bio)
>>> + return;
>>>
>>> bytes_done = 0;
>>> dev_info = bio->bi_bdev->bd_disk->private_data;
>> Hey,
>>
>> I have some comments inline.
> Hi Roxana,
>
> I've replied inline. Do I need to resend this or you fix a commit
> message by yourself?
>
> Kind regards,
> Alex
>
>> Thanks,
>> Roxana
>>
>> --
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