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Diffstat (limited to 'net/rds/ib_recv.c')
-rw-r--r--net/rds/ib_recv.c43
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)) {