diff options
Diffstat (limited to 'net/rds/ib_recv.c')
| -rw-r--r-- | net/rds/ib_recv.c | 43 |
1 files changed, 42 insertions, 1 deletions
diff --git a/net/rds/ib_recv.c b/net/rds/ib_recv.c index 5709bad28329..28bdcdcdbfe9 100644 --- a/net/rds/ib_recv.c +++ b/net/rds/ib_recv.c @@ -555,6 +555,47 @@ u64 rds_ib_piggyb_ack(struct rds_ib_connection *ic) return rds_ib_get_ack(ic); } +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; +} + /* * It's kind of lame that we're copying from the posted receive pages into * long-lived bitmaps. We could have posted the bitmaps and rdma written into @@ -667,7 +708,7 @@ static void rds_ib_process_recv(struct rds_connection *conn, } byte_len -= sizeof(struct rds_header); - ihdr = &ic->i_recv_hdrs[recv - ic->i_recvs]; + ihdr = rds_ib_get_header(conn, recv, byte_len); /* Validate the checksum. */ if (!rds_message_verify_checksum(ihdr)) { |