Re: [PATCH v2 -next] btrfs: Remove unnecessary casts in btrfs_read_root_item

Qu Wenruo
2019-02-20T12:37:00Z

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On 2019/2/20 下午8:32, YueHaibing wrote:
> There is a messy cast here:
> min_t(int, len, (int)sizeof(*item)));
>
> min_t() should normally cast to unsigned. It's not possible for
> "len" to be negative, but if it were then we definitely
> wouldn't want to pass negatives to read_extent_buffer(). Also there
> is an extra cast.
>
> This patch shouldn't affect runtime, it's just a clean up.
>
> Suggested-by: Dan Carpenter <dan.carpenter@oracle.com>
> Signed-off-by: YueHaibing <yuehaibing@huawei.com>

Reviewed-by: Qu Wenruo <wqu@suse.com>

The commit message is much better.

Thanks,
Qu

> ---
> v2: modify commit message as Dan suggested
> ---
> fs/btrfs/root-tree.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/fs/btrfs/root-tree.c b/fs/btrfs/root-tree.c
> index 02d1a57af78b..893d12fbfda0 100644
> --- a/fs/btrfs/root-tree.c
> +++ b/fs/btrfs/root-tree.c
> @@ -21,12 +21,12 @@ static void btrfs_read_root_item(struct extent_buffer *eb, int slot,
> struct btrfs_root_item *item)
> {
> uuid_le uuid;
> - int len;
> + u32 len;
> int need_reset = 0;
>
> len = btrfs_item_size_nr(eb, slot);
> read_extent_buffer(eb, item, btrfs_item_ptr_offset(eb, slot),
> - min_t(int, len, (int)sizeof(*item)));
> + min_t(u32, len, sizeof(*item)));
> if (len < sizeof(*item))
> need_reset = 1;
> if (!need_reset && btrfs_root_generation(item)
>
>
>

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