From mboxrd@z Thu Jan  1 00:00:00 1970
From: hch@lst.de (Christoph Hellwig)
Date: Wed, 31 Oct 2018 06:27:45 +0100
Subject: [PATCH] nvme: make sure ns head inherits underlying device limits
In-Reply-To: <4cd69ced-7e16-e5dd-716d-53784e2ed32f@grimberg.me>
References: <20181019222450.25397-1-sagi@grimberg.me>
 <20181022085752.GD18755@lst.de>
 <70bcef36-48da-cae7-4e23-ac9b01814a74@grimberg.me>
 <20181026075319.GC5092@lst.de>
 <4cd69ced-7e16-e5dd-716d-53784e2ed32f@grimberg.me>
Message-ID: <20181031052745.GA13521@lst.de>

On Tue, Oct 30, 2018@11:11:11AM -0700, Sagi Grimberg wrote:
> Christoph,
>
>>> Without this patch at least max_segments and max_hw_sectors of the head
>>> device node are degenerated to defaults that have nothing to do with the
>>> underlying device limits.
>>>
>>> This can result in unnecessary bio splitting for the head device
>>> node...
>>
>> But we never split bios for the multipath queue!
>
> Yes of course we don't, but we can still stack other devices on top
> of the multipath device that can split bios and in fact rely on the
> underlying queue limits.

Ok, that makes sense.  Can you resubmit it with that in a comment?