[IB] Fix MAD layer DMA mappings to avoid touching data buffer once mapped

The MAD layer was violating the DMA API by touching data buffers used
for sends after the DMA mapping was done.  This causes problems on
non-cache-coherent architectures, because the device doing DMA won't
see updates to the payload buffers that exist only in the CPU cache.

Fix this by having all MAD consumers use ib_create_send_mad() to
allocate their send buffers, and moving the DMA mapping into the MAD
layer so it can be done just before calling send (and after any
modifications of the send buffer by the MAD layer).

Tested on a non-cache-coherent PowerPC 440SPe system.

Signed-off-by: Sean Hefty <sean.hefty@intel.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/drivers/infiniband/core/mad_rmpp.h b/drivers/infiniband/core/mad_rmpp.h
index c4924df..f0616fd 100644
--- a/drivers/infiniband/core/mad_rmpp.h
+++ b/drivers/infiniband/core/mad_rmpp.h
@@ -51,6 +51,8 @@ ib_process_rmpp_recv_wc(struct ib_mad_agent_private *agent,
 int ib_process_rmpp_send_wc(struct ib_mad_send_wr_private *mad_send_wr,
 			    struct ib_mad_send_wc *mad_send_wc);
 
+void ib_rmpp_send_handler(struct ib_mad_send_wc *mad_send_wc);
+
 void ib_cancel_rmpp_recvs(struct ib_mad_agent_private *agent);
 
 int ib_retry_rmpp(struct ib_mad_send_wr_private *mad_send_wr);