[PATCH] erofs: avoid useless memory allocation

[Gao Xiang]

On 2023/3/3 17:45, Yue Hu wrote:
> On Fri,  3 Mar 2023 16:52:18 +0900
> Noboru Asai <asai at sijam.com> wrote:
> 
>> The variable 'vi->xattr_shared_count' could be ZERO.
>>
>> Signed-off-by: Noboru Asai <asai at sijam.com>
>> ---
>>   fs/erofs/xattr.c | 2 ++
>>   1 file changed, 2 insertions(+)
>>
>> diff --git a/fs/erofs/xattr.c b/fs/erofs/xattr.c
>> index 60729b1220b6..5164813a693b 100644
>> --- a/fs/erofs/xattr.c
>> +++ b/fs/erofs/xattr.c
>> @@ -80,6 +80,8 @@ static int init_inode_xattrs(struct inode *inode)
>>   
>>   	ih = (struct erofs_xattr_ibody_header *)(it.kaddr + it.ofs);
>>   	vi->xattr_shared_count = ih->h_shared_count;
>> +	if (!vi->xattr_shared_count)
>> +		goto out_unlock;
> 
> Questions: ret = 0? no need to erofs_put_metabuf?
> 
> I think we can keep current since kmalloc_array() will check whether the
> size(->xattr_shared_count) is zero size or not. rt?

Personally I'd like to avoid 0-sized kmalloc, but you're right,
we have to do erofs_put_metabuf() here and it needs to be fixed.

> 
>>   	vi->xattr_shared_xattrs = kmalloc_array(vi->xattr_shared_count,
>>   						sizeof(uint), GFP_KERNEL);
>>   	if (!vi->xattr_shared_xattrs) {