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From: Christoph Hellwig <hch@lst.de>
To: Ming Lei <ming.lei@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>, Jens Axboe <axboe@kernel.dk>,
	linux-block@vger.kernel.org, janpieter.sollie@edpnet.be,
	Mike Snitzer <snitzer@kernel.org>,
	dm-devel@lists.linux.dev, Song Liu <song@kernel.org>,
	linux-raid@vger.kernel.org
Subject: Re: [PATCH] block: allow device to have both virt_boundary_mask and max segment size
Date: Mon, 8 Apr 2024 10:47:39 +0200	[thread overview]
Message-ID: <20240408084739.GA26968@lst.de> (raw)
In-Reply-To: <ZhOekuZdwlwNSiZV@fedora>

On Mon, Apr 08, 2024 at 03:36:50PM +0800, Ming Lei wrote:
> It isn't now we put the limit, and this way has been done for stacking device
> since beginning, it is actually added by commit d690cb8ae14b in v6.9-rc1.
> 
> If max segment size isn't aligned with virt_boundary_mask, bio_split_rw()
> will split the bio with max segment size, this way still works, just not
> efficiently. And in reality, the two are often aligned.

We've had real bugs due to this, which is why we have the check.  We also
had a warning before the commit, it's just it got skipped for
stacking.  So even if we want to return to the broken pre-6.9-rc behavior
it should only be for stacking.  I don't think that is a good outcome,
though.


  reply	other threads:[~2024-04-08  8:47 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-04-07 13:19 [PATCH] block: allow device to have both virt_boundary_mask and max segment size Ming Lei
2024-04-07 14:57 ` Mike Snitzer
2024-04-07 21:50 ` [PATCH] " Jens Axboe
2024-04-08  5:55 ` Christoph Hellwig
2024-04-08  7:36   ` Ming Lei
2024-04-08  8:47     ` Christoph Hellwig [this message]
2024-04-08  9:48       ` Ming Lei
2024-04-09 13:57         ` Christoph Hellwig
2024-04-09 15:56           ` Ming Lei
2024-04-08 12:48     ` janpieter.sollie
2024-04-24 10:26 ` Geert Uytterhoeven
2024-04-24 12:41   ` Ming Lei
2024-04-24 13:09     ` Geert Uytterhoeven

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