From: Christoph Hellwig <hch@lst.de>
To: Keith Busch <kbusch@meta.com>
Cc: dm-devel@lists.linux.dev, linux-block@vger.kernel.org,
snitzer@kernel.org, hch@lst.de, axboe@kernel.dk,
ebiggers@kernel.org, Keith Busch <kbusch@kernel.org>
Subject: Re: [PATCHv2 1/3] block: remove stacking default dma_alignment
Date: Mon, 24 Nov 2025 18:12:30 +0100 [thread overview]
Message-ID: <20251124171230.GA29490@lst.de> (raw)
In-Reply-To: <20251124170903.3931792-2-kbusch@meta.com>
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.
next prev parent reply other threads:[~2025-11-24 17:12 UTC|newest]
Thread overview: 10+ 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 [this message]
2025-11-25 2:49 ` Keith Busch
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
-- strict thread matches above, loose matches on Subject: below --
2025-11-28 3:22 kernel test robot
2025-11-28 6:15 ` Dan Carpenter
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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