-static struct rds_header *rds_ib_get_header(struct rds_connection *conn,
- struct rds_ib_recv_work *recv,
- u32 data_len)
-{
- struct rds_ib_connection *ic = conn->c_transport_data;
- void *hdr_buff = &ic->i_recv_hdrs[recv - ic->i_recvs];
- void *addr;
- u32 misplaced_hdr_bytes;
-
- /*
- * Support header at the front (RDS 3.1+) as well as header-at-end.
- *
- * Cases:
- * 1) header all in header buff (great!)
- * 2) header all in data page (copy all to header buff)
- * 3) header split across hdr buf + data page
- * (move bit in hdr buff to end before copying other bit from data page)
- */
- if (conn->c_version > RDS_PROTOCOL_3_0 || data_len == RDS_FRAG_SIZE)
- return hdr_buff;
-
- if (data_len <= (RDS_FRAG_SIZE - sizeof(struct rds_header))) {
- addr = kmap_atomic(recv->r_frag->f_page, KM_SOFTIRQ0);
- memcpy(hdr_buff,
- addr + recv->r_frag->f_offset + data_len,
- sizeof(struct rds_header));
- kunmap_atomic(addr, KM_SOFTIRQ0);
- return hdr_buff;
- }
-
- misplaced_hdr_bytes = (sizeof(struct rds_header) - (RDS_FRAG_SIZE - data_len));
-
- memmove(hdr_buff + misplaced_hdr_bytes, hdr_buff, misplaced_hdr_bytes);
-
- addr = kmap_atomic(recv->r_frag->f_page, KM_SOFTIRQ0);
- memcpy(hdr_buff, addr + recv->r_frag->f_offset + data_len,
- sizeof(struct rds_header) - misplaced_hdr_bytes);
- kunmap_atomic(addr, KM_SOFTIRQ0);
- return hdr_buff;
-}
-