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Message-ID: <43716438-2fb9-4377-a4a0-6f803d7b8aec@kernel.dk>
Date: Sat, 2 Aug 2025 09:37:32 -0600
From: Jens Axboe <axboe@...nel.dk>
To: Keith Busch <kbusch@...a.com>, linux-block@...r.kernel.org,
linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org
Cc: snitzer@...nel.org, dw@...idwei.uk, brauner@...nel.org,
Keith Busch <kbusch@...nel.org>
Subject: Re: [PATCH 0/7] direct-io: even more flexible io vectors
On 8/1/25 5:47 PM, Keith Busch wrote:
> From: Keith Busch <kbusch@...nel.org>
>
> In furthering direct IO use from user space buffers without bouncing to
> align to unnecessary kernel software constraints, this series removes
> the requirement that io vector lengths align to the logical block size.
> The downside (if want to call it that) is that mis-aligned io vectors
> are caught further down the block stack rather than closer to the
> syscall.
That's not a downside imho, it's much nicer to have the correct/expected
case be fast, and catch the unexpected error case down the line when we
have to iterate the vecs anyway.
IOW, I love this patchset. I'll spend some time going over the details.
Did you write some test cases for this?
> This change also removes one walking of the io vector, so that's nice
> too.
>
> Keith Busch (7):
> block: check for valid bio while splitting
> block: align the bio after building it
> block: simplify direct io validity check
> iomap: simplify direct io validity check
> block: remove bdev_iter_is_aligned
> blk-integrity: use simpler alignment check
> iov_iter: remove iov_iter_is_aligned
>
> block/bio-integrity.c | 4 +-
> block/bio.c | 58 +++++++++++++++++---------
> block/blk-merge.c | 5 +++
> block/fops.c | 4 +-
> fs/iomap/direct-io.c | 3 +-
> include/linux/blkdev.h | 7 ----
> include/linux/uio.h | 2 -
> lib/iov_iter.c | 95 ------------------------------------------
> 8 files changed, 49 insertions(+), 129 deletions(-)
Now that's a beautiful diffstat.
--
Jens Axboe
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