linux-kernel - Re: [PATCH] f2fs: fix 32-bit build

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Date:   Wed, 23 Nov 2016 22:05:41 +0100
From:   Arnd Bergmann <arnd@...db.de>
To:     Jaegeuk Kim <jaegeuk@...nel.org>
Cc:     Chao Yu <yuchao0@...wei.com>, Yunlei He <heyunlei@...wei.com>,
        Damien Le Moal <damien.lemoal@....com>,
        Fan Li <fanofcode.li@...sung.com>,
        linux-f2fs-devel@...ts.sourceforge.net,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] f2fs: fix 32-bit build

On Wednesday, November 23, 2016 10:42:26 AM CET Jaegeuk Kim wrote:
> 
> Unfortunately, the sector number is usually a 64-bit number, and
> we guarantee that bdev_zone_size() returns a power-of-two number.

The sentence no longer makes sense. Maybe

Fortunately, bdev_zone_size() is guaranteed to return a power-of-two
number, so we can replace the % operator with a cheaper bit mask.

> @@ -693,7 +693,8 @@ static int __f2fs_issue_discard_zone(struct f2fs_sb_info *sbi,
>         }
>         sector = SECTOR_FROM_BLOCK(blkstart);
>  
> -       if (sector % bdev_zone_size(bdev) || nr_sects != bdev_zone_size(bdev)) {
> +       if (sector & (bdev_zone_size(bdev) - 1) ||
> 

looks good, thanks for following up!

	Arnd