Re: [PATCH] Btrfs: remove unnecessary code of chunk_root assignment in btrfs_read_chunk_tree.

[Qu Wenruo <quwenruo@cn.fujitsu.com>]

At 09/05/2016 09:19 AM, Zhao Lei wrote:
> Hi, Sean Fu
>
>> From: Sean Fu [mailto:fxinrong@gmail.com]
>> Sent: Sunday, September 04, 2016 7:54 PM
>> To: dsterba@suse.com
>> Cc: clm@fb.com; anand.jain@oracle.com; fdmanana@suse.com;
>> zhaolei@cn.fujitsu.com; linux-btrfs@vger.kernel.org;
>> linux-kernel@vger.kernel.org; Sean Fu <fxinrong@gmail.com>
>> Subject: [PATCH] Btrfs: remove unnecessary code of chunk_root assignment in
>> btrfs_read_chunk_tree.
>>
>> The input argument root is already set with "fs_info->chunk_root".
>> "chunk_root = fs_info->chunk_root = btrfs_alloc_root(fs_info)" in caller
>> "open_ctree".
>> “root->fs_info = fs_info” in "btrfs_alloc_root".
>>
> The root argument of this function means "any root".
> And the function is designed getting chunk root from
> "any root" in head.
>
> Since there is only one caller of this function,
> and the caller always send chunk_root as root argument in
> current code, we can remove above conversion,
> and I suggest renaming root to chunk_root to make it clear,
> something like:
>
> - btrfs_read_chunk_tree(struct btrfs_root *root)
> + btrfs_read_chunk_tree(struct btrfs_root *chunk_root)

Since root is only used to get fs_info->chunk_root, why not use fs_info 
directly?

Thanks,
Qu

>
> Thanks
> Zhaolei
>
>> Signed-off-by: Sean Fu <fxinrong@gmail.com>
>> ---
>>  fs/btrfs/volumes.c | 2 --
>>  1 file changed, 2 deletions(-)
>>
>> diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
>> index 366b335..384a6d2 100644
>> --- a/fs/btrfs/volumes.c
>> +++ b/fs/btrfs/volumes.c
>> @@ -6600,8 +6600,6 @@ int btrfs_read_chunk_tree(struct btrfs_root *root)
>>  	int ret;
>>  	int slot;
>>
>> -	root = root->fs_info->chunk_root;
>> -
>>  	path = btrfs_alloc_path();
>>  	if (!path)
>>  		return -ENOMEM;
>> --
>> 2.6.2
>>
>
>
>
>
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