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	Sun, 07 Apr 2024 05:11:19 +0000
Date: Sun, 7 Apr 2024 06:11:19 +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
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Sender: Al Viro <viro@ftp.linux.org.uk>

On Sun, Apr 07, 2024 at 05:57:58AM +0100, Al Viro wrote:

> PS: in grow_dev_folio() we probably want
> 	struct address_space *mapping = bdev->bd_inode->i_mapping;
> instead of
> 	struct inode *inode = bdev->bd_inode;
> as one of the preliminary chunks.
> FWIW, it really looks like address_space (== page cache of block device,
> not an unreasonably candidate for primitive) and block size (well,
> logarithm thereof) cover the majority of what remains, with device
> size possibly being (remote) third...

Incidentally, how painful would it be to switch __bread_gfp() and __bread()
to passing *logarithm* of block size instead of block size?  And possibly
supply the same to clean_bdev_aliases()...

That would reduce fs/buffer.c uses to just "give me the address_space of
that block device"...