linux-ext4 - Re: [PATCH] ext4: convert to DIV_ROUND_UP() in mpage_process_page

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Message-ID: <ZAulevdpZg/W/JbL@sol.localdomain>
Date:   Fri, 10 Mar 2023 13:47:38 -0800
From:   Eric Biggers <ebiggers@...nel.org>
To:     Al Viro <viro@...iv.linux.org.uk>
Cc:     Yangtao Li <frank.li@...o.com>, tytso@....edu,
        adilger.kernel@...ger.ca, linux-ext4@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] ext4: convert to DIV_ROUND_UP() in
 mpage_process_page_bufs()

On Fri, Mar 10, 2023 at 07:12:31AM +0000, Al Viro wrote:
> 
> Out of curiosity (and that's already too brittle for practical use) -
> does DIV_ROUND_UP_ULL() do any better on full example?

'DIV_ROUND_UP_ULL(i_size_read(inode), i_blocksize(inode))' works properly with
clang but not gcc.   If i_blocksize() is changed to do '1U << inode->i_blkbits'
instead of '1 << inode->i_blkbits', it works with gcc too.

- Eric