linux-kernel - Re: [PATCH] nilfs2: Use div64_ul() instead of do

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Date: Thu, 29 Feb 2024 20:41:31 +0100
From: Thorsten Blum <thorsten.blum@...lux.com>
To: Ryusuke Konishi <konishi.ryusuke@...il.com>
Cc: linux-nilfs@...r.kernel.org,
 linux-kernel@...r.kernel.org
Subject: Re: [PATCH] nilfs2: Use div64_ul() instead of do_div()

> On Feb 29, 2024, at 19:45, Ryusuke Konishi <konishi.ryusuke@...il.com> wrote:
> 
> All of the fixes in this patch seem to be correct, but this doesn't
> cover nilfs_resize_fs(), nilfs_max_segment_count(), and
> nilfs_sb2_bad_offset(), which also have do_div() that doesn't use the
> return value.

I just tested this, and Coccinelle didn't report nilfs_resize_fs() or
nilfs_max_segment_count() because both divisors are fields of a struct. I will
refactor this and submit a v2.

For nilfs_sb2_bad_offset(), where the dividend is u64 and the divisor is u32, we
would need a dedicated function like div64_u32() that doesn't calculate the
remainder, which doesn't seem to exist. What do you think?

Thanks,
Thorsten