Re: [PATCH] block: allow device to have both virt_boundary_mask and max segment size

From: janpieter.sollie@edpnet.be
To: Ming Lei <ming.lei@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>, Jens Axboe <axboe@kernel.dk>,
	linux-block@vger.kernel.org, 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, 08 Apr 2024 14:48:59 +0200	[thread overview]
Message-ID: <3bd355e523a04b4a355fb84d5bc59224@edpnet.be> (raw)
In-Reply-To: <ZhOekuZdwlwNSiZV@fedora>

On 2024-04-08 09:36, 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.

I take it as a compliment, building exotic configurations is something 
I'd love to be good at.
But, as far as I understand, this warning is caused by my raid config, 
right?
How is it possible that a raid6 array has a queue/max_segment_size of 
(2^16 - 1) in sysfs while 2 others on the same system have a 
queue/max_segment_size of (2^32 - 1)?
they are all rotational devices on the same SAS controller, just this 
malfunctioning one uses SATA drives while the other 2 are SAS.
Understanding this would help me to avoid this unwanted behavior.

Kind regards,

Janpieter Sollie