From: Jens Axboe <axboe@kernel.dk>
To: Christoph Hellwig <hch@infradead.org>, Ming Lei <ming.lei@redhat.com>
Cc: linux-block@vger.kernel.org,
Kent Overstreet <kent.overstreet@gmail.com>,
Dmitry Monakhov <dmonakhov@openvz.org>,
Christoph Hellwig <hch@lst.de>, Hannes Reinecke <hare@suse.com>
Subject: Re: [PATCH] block: remove bio_rewind_iter()
Date: Sat, 15 Sep 2018 08:41:32 -0600 [thread overview]
Message-ID: <e04d57cd-2ed1-2141-41c3-099a348ed80d@kernel.dk> (raw)
In-Reply-To: <20180915070301.GB15555@infradead.org>
On 9/15/18 1:03 AM, Christoph Hellwig wrote:
> On Wed, Sep 05, 2018 at 11:33:35AM +0800, Ming Lei wrote:
>> It is pointed that bio_rewind_iter() is one very bad API[1]:
>>
>> 1) bio size may not be restored after rewinding
>>
>> 2) it causes some bogus change, such as 5151842b9d8732 (block: reset
>> bi_iter.bi_done after splitting bio)
>>
>> 3) rewinding really makes things complicated wrt. bio splitting
>>
>> 4) unnecessary updating of .bi_done in fast path
>>
>> [1] https://marc.info/?t=153549924200005&r=1&w=2
>
> Based on that this is a bug fix and should go to 4.19 instead of 4.20
> as it is queued up right now..
It's not a new issue (in fact not even close, we're about a year back),
hence not a strong reason to shove it into 4.19 vs 4.20. I'm fine
with subsequently marking it for stable.
--
Jens Axboe
prev parent reply other threads:[~2018-09-15 14:41 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-05 3:33 [PATCH] block: remove bio_rewind_iter() Ming Lei
2018-09-05 3:52 ` Kent Overstreet
2018-09-05 13:19 ` Christoph Hellwig
2018-09-05 21:46 ` Jens Axboe
2018-09-15 7:03 ` Christoph Hellwig
2018-09-15 14:41 ` Jens Axboe [this message]
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