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Subject: Re: [PATCH v2 2/7] erofs: some marcos are much more readable as a
 function
From:   Joe Perches <joe@perches.com>
To:     Gao Xiang <gaoxiang25@huawei.com>, Chao Yu <yuchao0@huawei.com>,
        Dan Carpenter <dan.carpenter@oracle.com>,
        Christoph Hellwig <hch@infradead.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        devel@driverdev.osuosl.org
Cc:     LKML <linux-kernel@vger.kernel.org>, linux-erofs@lists.ozlabs.org,
        Chao Yu <chao@kernel.org>, Miao Xie <miaoxie@huawei.com>,
        weidu.du@huawei.com, Fang Wei <fangwei1@huawei.com>
Date:   Thu, 29 Aug 2019 20:16:27 -0700
In-Reply-To: <20190830030040.10599-2-gaoxiang25@huawei.com>
References: <20190830030040.10599-1-gaoxiang25@huawei.com>
         <20190830030040.10599-2-gaoxiang25@huawei.com>
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On Fri, 2019-08-30 at 11:00 +0800, Gao Xiang wrote:
> As Christoph suggested [1], these marcos are much
> more readable as a function

s/marcos/macros/
.
[]
> diff --git a/fs/erofs/erofs_fs.h b/fs/erofs/erofs_fs.h
[]
> @@ -168,16 +168,24 @@ struct erofs_xattr_entry {
>  	char   e_name[0];       /* attribute name */
>  } __packed;
>  
> -#define ondisk_xattr_ibody_size(count)	({\
> -	u32 __count = le16_to_cpu(count); \
> -	((__count) == 0) ? 0 : \
> -	sizeof(struct erofs_xattr_ibody_header) + \
> -		sizeof(__u32) * ((__count) - 1); })
> +static inline unsigned int erofs_xattr_ibody_size(__le16 d_icount)
> +{
> +	unsigned int icount = le16_to_cpu(d_icount);
> +
> +	if (!icount)
> +		return 0;
> +
> +	return sizeof(struct erofs_xattr_ibody_header) +
> +		sizeof(__u32) * (icount - 1);

Maybe use struct_size()?

{
	struct erofs_xattr_ibody_header *ibh;
	unsigned int icount = le16_to_cpu(d_icount);

	if (!icount)
		return 0;

	return struct_size(ibh, h_shared_xattrs, icount - 1);
}