Re: [PATCH] libceph: simplify data length calculation

[Josh Durgin <josh.durgin@inktank.com>]

Reviewed-by: Josh Durgin <josh.durgin@inktank.com>

On 02/16/2013 09:08 AM, Alex Elder wrote:
> Simplify the way the data length recorded in a message header is
> calculated in ceph_osdc_build_request().
>
> Signed-off-by: Alex Elder <elder@inktank.com>
> ---
>   net/ceph/osd_client.c |   12 ++++--------
>   1 file changed, 4 insertions(+), 8 deletions(-)
>
> diff --git a/net/ceph/osd_client.c b/net/ceph/osd_client.c
> index bbd1575..b58748e 100644
> --- a/net/ceph/osd_client.c
> +++ b/net/ceph/osd_client.c
> @@ -335,7 +335,7 @@ void ceph_osdc_build_request(struct ceph_osd_request
> *req,
>   	void *p;
>   	size_t msg_size = sizeof(*head) + num_op*sizeof(*op);
>   	int flags = req->r_flags;
> -	u64 data_len = 0;
> +	u64 data_len;
>   	int i;
>
>   	WARN_ON((flags & (CEPH_OSD_FLAG_READ|CEPH_OSD_FLAG_WRITE)) == 0);
> @@ -363,8 +363,6 @@ void ceph_osdc_build_request(struct ceph_osd_request
> *req,
>   	while (num_op--)
>   		osd_req_encode_op(req, op++, src_op++);
>
> -	data_len += req->r_trail.length;
> -
>   	if (snapc) {
>   		head->snap_seq = cpu_to_le64(snapc->seq);
>   		head->num_snaps = cpu_to_le32(snapc->num_snaps);
> @@ -374,14 +372,12 @@ void ceph_osdc_build_request(struct
> ceph_osd_request *req,
>   		}
>   	}
>
> +	data_len = req->r_trail.length;
>   	if (flags & CEPH_OSD_FLAG_WRITE) {
>   		req->r_request->hdr.data_off = cpu_to_le16(off);
> -		req->r_request->hdr.data_len = cpu_to_le32(len + data_len);
> -	} else if (data_len) {
> -		req->r_request->hdr.data_off = 0;
> -		req->r_request->hdr.data_len = cpu_to_le32(data_len);
> +		data_len += len;
>   	}
> -
> +	req->r_request->hdr.data_len = cpu_to_le32(data_len);
>   	req->r_request->page_alignment = req->r_page_alignment;
>
>   	BUG_ON(p > msg->front.iov_base + msg->front.iov_len);
>