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Date:   Thu, 29 Oct 2020 14:54:15 +0100
From:   David Sterba <dsterba@suse.cz>
To:     Qu Wenruo <quwenruo.btrfs@gmx.com>
Cc:     Nikolay Borisov <nborisov@suse.com>, Qu Wenruo <wqu@suse.com>,
        linux-btrfs@vger.kernel.org
Subject: Re: [PATCH v2 3/3] btrfs: file-item: refactor
 btrfs_lookup_bio_sums() to handle out-of-order bvecs
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On Thu, Oct 29, 2020 at 08:43:12PM +0800, Qu Wenruo wrote:
> On 2020/10/29 下午7:50, Nikolay Borisov wrote:
> > On 29.10.20 г. 9:12 ч., Qu Wenruo wrote:
> >> +{
> >> +	struct btrfs_csum_item *item = NULL;
> >> +	struct btrfs_key key;
> >> +	u32 csum_size = btrfs_super_csum_size(fs_info->super_copy);
> >
> > nit: Why u32, btrfs_super_csum_size is defined as returning 'int',
> > however this function is really returning u16 since "struct btrfs_csums"
> > is defined as u16.
> 
> It was misguided by u32 from btrfs super block, where sectorsize,
> nodesize are all u32.
> 
> Any recommendation on this? Just u16 for csum_size or follow
> nodesize/sectorsize to use u32?

u32 is ok, this generates a bit better assembly than u16. I'm about to
send the patchset lifting it to fs_info and it uses u32.