From: Pavel Begunkov <[email protected]>
To: Christoph Hellwig <[email protected]>
Cc: Ming Lei <[email protected]>,
[email protected], Jens Axboe <[email protected]>,
Matthew Wilcox <[email protected]>,
Johannes Weiner <[email protected]>,
Alexander Viro <[email protected]>,
"Darrick J . Wong" <[email protected]>,
"Martin K . Petersen" <[email protected]>,
Jonathan Corbet <[email protected]>,
[email protected], [email protected],
[email protected], [email protected],
[email protected], [email protected],
[email protected]
Subject: Re: [PATCH v1 0/6] no-copy bvec
Date: Wed, 23 Dec 2020 12:52:59 +0000 [thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>
On 22/12/2020 14:11, Christoph Hellwig wrote:
> On Tue, Dec 15, 2020 at 02:05:35PM +0000, Pavel Begunkov wrote:
>>> You may find clue from the following link:
>>>
>>> https://www.mail-archive.com/[email protected]/msg2262077.html
>>
>> Thanks for the link!
>>
>> Al, you mentioned "Zero-length segments are not disallowed", do you have
>> a strong opinion on that? Apart from already diverged behaviour from the
>> block layer and getting in the way of this series, without it we'd also be
>> able to remove some extra ifs, e.g. in iterate_bvec()
>
> I'd prefer not to support zero-length ITER_BVEC and catching them
> early, as the block layer can't deal with them either. From a quick
> look at iter_file_splice_write it should be pretty trivial to fix there,
> although we'll need to audit other callers as well (even if I don't
> expect them to submit this degenerate case).
Can scatterlist have 0-len entries? Those are directly translated into
bvecs, e.g. in nvme/target/io-cmd-file.c and target/target_core_file.c.
I've audited most of others by this moment, they're fine.
Thanks for other nits, they will go into next version.
--
Pavel Begunkov
next prev parent reply other threads:[~2020-12-23 12:57 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-15 0:20 [PATCH v1 0/6] no-copy bvec Pavel Begunkov
2020-12-15 0:20 ` [PATCH v1 1/6] target/file: allocate the bvec array as part of struct target_core_file_cmd Pavel Begunkov
2020-12-15 0:20 ` [PATCH v1 2/6] iov_iter: optimise bvec iov_iter_advance() Pavel Begunkov
2020-12-15 9:37 ` David Laight
2020-12-15 11:23 ` Pavel Begunkov
2020-12-15 13:54 ` David Laight
2020-12-15 13:56 ` Pavel Begunkov
2020-12-22 14:03 ` Christoph Hellwig
2020-12-15 0:20 ` [PATCH v1 3/6] bio: deduplicate adding a page into bio Pavel Begunkov
2020-12-22 14:04 ` Christoph Hellwig
2020-12-15 0:20 ` [PATCH v1 4/6] block/psi: remove PSI annotations from direct IO Pavel Begunkov
2020-12-15 0:56 ` Dave Chinner
2020-12-15 1:03 ` Pavel Begunkov
2020-12-15 1:33 ` Dave Chinner
2020-12-15 11:41 ` Pavel Begunkov
2020-12-22 14:07 ` Christoph Hellwig
2020-12-15 0:20 ` [PATCH v1 5/6] bio: add a helper calculating nr segments to alloc Pavel Begunkov
2020-12-15 1:00 ` Dave Chinner
2020-12-15 1:07 ` Pavel Begunkov
2020-12-15 1:09 ` Dave Chinner
2020-12-22 14:07 ` Christoph Hellwig
2020-12-15 0:20 ` [PATCH v1 6/6] block/iomap: don't copy bvec for direct IO Pavel Begunkov
2020-12-15 1:09 ` Dave Chinner
2020-12-15 1:15 ` Pavel Begunkov
2020-12-22 14:15 ` Christoph Hellwig
2020-12-15 1:41 ` [PATCH v1 0/6] no-copy bvec Ming Lei
2020-12-15 11:14 ` Pavel Begunkov
2020-12-15 12:03 ` Ming Lei
2020-12-15 14:05 ` Pavel Begunkov
2020-12-22 14:11 ` Christoph Hellwig
2020-12-23 12:52 ` Pavel Begunkov [this message]
2020-12-23 15:51 ` Christoph Hellwig
2020-12-23 16:04 ` James Bottomley
2020-12-23 20:23 ` Douglas Gilbert
2020-12-23 20:32 ` Pavel Begunkov
2020-12-24 6:41 ` Christoph Hellwig
2020-12-24 16:45 ` Douglas Gilbert
2020-12-24 17:30 ` James Bottomley
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