From: Keith Busch <kbusch@kernel.org>
To: Christoph Hellwig <hch@lst.de>
Cc: Keith Busch <kbusch@meta.com>,
dm-devel@lists.linux.dev, linux-block@vger.kernel.org,
snitzer@kernel.org, axboe@kernel.dk, ebiggers@kernel.org
Subject: Re: [PATCHv2 1/3] block: remove stacking default dma_alignment
Date: Mon, 24 Nov 2025 19:49:35 -0700 [thread overview]
Message-ID: <aSUZP6yP8mvi-q7v@kbusch-mbp> (raw)
In-Reply-To: <20251124171230.GA29490@lst.de>
On Mon, Nov 24, 2025 at 06:12:30PM +0100, Christoph Hellwig wrote:
> On Mon, Nov 24, 2025 at 09:09:01AM -0800, Keith Busch wrote:
> > From: Keith Busch <kbusch@kernel.org>
> >
> > The dma_alignment becomes 511 anyway if the caller doesn't explicitly
> > set it. But setting this default prevents the stacked device from
> > requesting a lower value even if it can handle lower alignments.
>
> Given how much trouble we had with drivers doing software processing
> and unaligned buffers I'd feel more comfortable keeping this default
> limitation. Drivers that want to relax it can still trivially do
> that right after calling blk_set_stacking_limits.
That should have the same result, but it's totally fine with me if you
prefer the caller overwrite the default instead.
next prev parent reply other threads:[~2025-11-25 2:49 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-11-24 17:09 [PATCHv2 0/2] dm-crypt: support relaxed memory alignment Keith Busch
2025-11-24 17:09 ` [PATCHv2 1/3] block: remove stacking default dma_alignment Keith Busch
2025-11-24 17:12 ` Christoph Hellwig
2025-11-25 2:49 ` Keith Busch [this message]
2025-11-25 6:35 ` Christoph Hellwig
2025-11-24 17:09 ` [PATCHv2 2/3] dm-crypt: allow unaligned bio_vecs for direct io Keith Busch
2025-11-24 17:09 ` [PATCHv2 3/3] dm-crypt: dynamic scatterlist for many segments Keith Busch
2025-11-28 6:15 ` Dan Carpenter
-- strict thread matches above, loose matches on Subject: below --
2026-01-14 15:41 [PATCHv2 0/2] dm-crypt: support relaxed memory alignment Keith Busch
2026-01-14 15:41 ` [PATCHv2 1/3] block: remove stacking default dma_alignment Keith Busch
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