Re: [PATCH 1/1] fs: Small refactoring of the code in ext4 2.6.37-rc1
From: Greg Freemyer
Date: Thu Nov 04 2010 - 18:44:53 EST
2010/11/4 André Luis Pereira dos Santos - BSRSoft <andre@xxxxxxxxxxxxxx>:
> From: Andre Luis Pereira dos Santos <andre@xxxxxxxxxxxxxx>
>
> Hi.
> Small refactoring of the code in order to make minor enhancements to critical areas.
> The notation x + 1 has been replaced by more efficient notation x + +.
>
> Signed-off-by: Andre Luis Pereira dos Santos <andre@xxxxxxxxxxxxxx>
> ---
> Signed-off-by: Andre Luis Pereira dos Santos <andre@xxxxxxxxxxxxxx>
> --- linux-2.6.37-rc1/fs/ext4/extents.c 2010-11-01 09:54:12.000000000 -0200
> +++ linux-2.6.37-rc1-patched/fs/ext4/extents.c 2010-11-04 19:54:26.000000000 -0200
> @@ -555,9 +555,9 @@ ext4_ext_binsearch(struct inode *inode,
> while (l <= r) {
> m = l + (r - l) / 2;
> if (block < le32_to_cpu(m->ee_block))
> - r = m - 1;
> + r = m--;
> else
> - l = m + 1;
> + l = m++;
> ext_debug("%p(%u):%p(%u):%p(%u) ", l, le32_to_cpu(l->ee_block),
> m, le32_to_cpu(m->ee_block),
> r, le32_to_cpu(r->ee_block));
> @@ -1557,7 +1557,7 @@ static int ext4_ext_try_to_merge(struct
> if (ext4_ext_is_uninitialized(ex))
> uninitialized = 1;
> ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
> - + ext4_ext_get_actual_len(ex + 1));
> + + ext4_ext_get_actual_len(ex++));
> if (uninitialized)
> ext4_ext_mark_uninitialized(ex);
But
r = m - 1;
is not equivalent to
r = m--;
At a minimum your code no longer passes the same value to of m to ext_debug.
NAK
Greg
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