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	Sun, 07 Apr 2024 01:51:49 +0000
Date: Sun, 7 Apr 2024 02:51:49 +0100
From: Al Viro <viro@zeniv.linux.org.uk>
To: Yu Kuai <yukuai1@huaweicloud.com>
Cc: jack@suse.cz, hch@lst.de, brauner@kernel.org, axboe@kernel.dk,
	linux-fsdevel@vger.kernel.org, linux-block@vger.kernel.org,
	yi.zhang@huawei.com, yangerkun@huawei.com,
	"yukuai (C)" <yukuai3@huawei.com>
Subject: Re: [PATCH vfs.all 22/26] block: stash a bdev_file to read/write raw
 blcok_device
Message-ID: <20240407015149.GG538574@ZenIV>
References: <20240406090930.2252838-1-yukuai1@huaweicloud.com>
 <20240406090930.2252838-23-yukuai1@huaweicloud.com>
 <20240406194206.GC538574@ZenIV>
 <20240406202947.GD538574@ZenIV>
 <3567de30-a7ce-b639-fa1f-805a8e043e18@huaweicloud.com>
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Sender: Al Viro <viro@ftp.linux.org.uk>

On Sun, Apr 07, 2024 at 09:18:20AM +0800, Yu Kuai wrote:

> Yes, patch 23-26 already do the work to remove the field block_device
> and convert to use bdev_file for iomap and buffer_head.

What for?  I mean, what makes that dummy struct file * any better than
struct block_device *?  What's the point?

I agree that keeping an opened struct file for a block device is
a good idea - certainly better than weird crap used to carry the
"how had it been opened" along with bdev.  But that does *not*
mean not keeping ->s_bdev around; we might or might not find that
convenient, but it's not "struct block_device is Evil(tm), let's
exorcise".

Why do we care to do anything to struct buffer_head?  Or to
struct bio, for that matter...

I'm not saying that parts of the patchset do not make sense on
their own, but I don't understand what the last part is all
about.

Al, still going through that series...