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From: David Sterba <dsterba@suse.cz>
To: Nikolay Borisov <nborisov@suse.com>
Cc: linux-btrfs@vger.kernel.org
Subject: Re: [PATCH] btrfs: Use DIV_ROUND_UP rathen than opencoding it
Date: Wed, 4 Oct 2017 16:49:27 +0200	[thread overview]
Message-ID: <20171004144927.GD3521@twin.jikos.cz> (raw)
In-Reply-To: <1506606499-15127-1-git-send-email-nborisov@suse.com>

On Thu, Sep 28, 2017 at 04:48:19PM +0300, Nikolay Borisov wrote:
> Signed-off-by: Nikolay Borisov <nborisov@suse.com>
> ---
>  fs/btrfs/extent-tree.c | 5 ++---
>  1 file changed, 2 insertions(+), 3 deletions(-)
> 
> diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
> index e2d7e86b51d1..9e67616892cd 100644
> --- a/fs/btrfs/extent-tree.c
> +++ b/fs/btrfs/extent-tree.c
> @@ -2896,9 +2896,8 @@ u64 btrfs_csum_bytes_to_leaves(struct btrfs_fs_info *fs_info, u64 csum_bytes)
>  	num_csums_per_leaf = div64_u64(csum_size,
>  			(u64)btrfs_super_csum_size(fs_info->super_copy));
>  	num_csums = div64_u64(csum_bytes, fs_info->sectorsize);
> -	num_csums += num_csums_per_leaf - 1;
> -	num_csums = div64_u64(num_csums, num_csums_per_leaf);
> -	return num_csums;
> +
> +	return DIV_ROUND_UP(num_csums, num_csums_per_leaf);

DIV_ROUND_UP ends up as plain division (/) so this will not work on
32bit. We need to keep it opencoded, or convert all the relevant
variabless to 32bit first.

#define DIV_ROUND_UP __KERNEL_DIV_ROUND_UP
#define __KERNEL_DIV_ROUND_UP(n, d) (((n) + (d) - 1) / (d))

      reply	other threads:[~2017-10-04 14:51 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-09-28 13:48 [PATCH] btrfs: Use DIV_ROUND_UP rathen than opencoding it Nikolay Borisov
2017-10-04 14:49 ` David Sterba [this message]

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