[PATCH -next] erofs: fix return value check in erofs_read_superblock()

[Chao Yu]

On 2019/9/18 16:30, Wei Yongjun wrote:
> In case of error, the function read_mapping_page() returns
> ERR_PTR() not NULL. The NULL test in the return value check
> should be replaced with IS_ERR().
> 
> Fixes: fe7c2423570d ("erofs: use read_mapping_page instead of sb_bread")
> Signed-off-by: Wei Yongjun <weiyongjun1 at huawei.com>

Reviewed-by: Chao Yu <yuchao0 at huawei.com>

Thanks,