IB/umad: Add support for large RMPP transfers

Add support for sending and receiving large RMPP transfers.  The old
code supports transfers only as large as a single contiguous kernel
memory allocation.  This patch uses linked list of memory buffers when
sending and receiving data to avoid needing contiguous pages for
larger transfers.

  Receive side: copy the arriving MADs in chunks instead of coalescing
  to one large buffer in kernel space.

  Send side: split a multipacket MAD buffer to a list of segments,
  (multipacket_list) and send these using a gather list of size 2.
  Also, save pointer to last sent segment, and retrieve requested
  segments by walking list starting at last sent segment. Finally,
  save pointer to last-acked segment.  When retrying, retrieve
  segments for resending relative to this pointer.  When updating last
  ack, start at this pointer.

Signed-off-by: Jack Morgenstein <jackm@mellanox.co.il>
Signed-off-by: Sean Hefty <sean.hefty@intel.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

1 files changed, 30 insertions, 18 deletions

diff --git a/include/rdma/ib_mad.h b/include/rdma/ib_mad.h
index 2c133506742b..51ab8eddb295 100644
--- a/include/rdma/ib_mad.h
+++ b/include/rdma/ib_mad.h
@@ -33,7 +33,7 @@
  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  * SOFTWARE.
  *
- * $Id: ib_mad.h 2775 2005-07-02 13:42:12Z halr $
+ * $Id: ib_mad.h 5596 2006-03-03 01:00:07Z sean.hefty $
  */
 
 #if !defined( IB_MAD_H )
@@ -208,15 +208,23 @@ struct ib_class_port_info
 /**
  * ib_mad_send_buf - MAD data buffer and work request for sends.
  * @next: A pointer used to chain together MADs for posting.
- * @mad: References an allocated MAD data buffer.
+ * @mad: References an allocated MAD data buffer for MADs that do not have
+ *   RMPP active.  For MADs using RMPP, references the common and management
+ *   class specific headers.
  * @mad_agent: MAD agent that allocated the buffer.
  * @ah: The address handle to use when sending the MAD.
  * @context: User-controlled context fields.
+ * @hdr_len: Indicates the size of the data header of the MAD.  This length
+ *   includes the common MAD, RMPP, and class specific headers.
+ * @data_len: Indicates the total size of user-transferred data.
+ * @seg_count: The number of RMPP segments allocated for this send.
+ * @seg_size: Size of each RMPP segment.
  * @timeout_ms: Time to wait for a response.
  * @retries: Number of times to retry a request for a response.
  *
  * Users are responsible for initializing the MAD buffer itself, with the
- * exception of specifying the payload length field in any RMPP MAD.
+ * exception of any RMPP header.  Additional segment buffer space allocated
+ * beyond data_len is padding.
  */
 struct ib_mad_send_buf {
         struct ib_mad_send_buf  *next;
@@ -224,6 +232,10 @@ struct ib_mad_send_buf {
         struct ib_mad_agent     *mad_agent;
         struct ib_ah            *ah;
         void                    *context[2];
+        int                     hdr_len;
+        int                     data_len;
+        int                     seg_count;
+        int                     seg_size;
         int                     timeout_ms;
         int                     retries;
 };
@@ -299,7 +311,7 @@ typedef void (*ib_mad_snoop_handler)(struct ib_mad_agent *mad_agent,
  * @mad_recv_wc: Received work completion information on the received MAD.
  *
  * MADs received in response to a send request operation will be handed to
- * the user after the send operation completes.  All data buffers given
+ * the user before the send operation completes.  All data buffers given
  * to registered agents through this routine are owned by the receiving
  * client, except for snooping agents.  Clients snooping MADs should not
  * modify the data referenced by @mad_recv_wc.
@@ -485,17 +497,6 @@ int ib_unregister_mad_agent(struct ib_mad_agent *mad_agent);
 int ib_post_send_mad(struct ib_mad_send_buf *send_buf,
                      struct ib_mad_send_buf **bad_send_buf);
 
-/**
- * ib_coalesce_recv_mad - Coalesces received MAD data into a single buffer.
- * @mad_recv_wc: Work completion information for a received MAD.
- * @buf: User-provided data buffer to receive the coalesced buffers.  The
- *   referenced buffer should be at least the size of the mad_len specified
- *   by @mad_recv_wc.
- *
- * This call copies a chain of received MAD segments into a single data buffer,
- * removing duplicated headers.
- */
-void ib_coalesce_recv_mad(struct ib_mad_recv_wc *mad_recv_wc, void *buf);
 
 /**
  * ib_free_recv_mad - Returns data buffers used to receive a MAD.
@@ -590,9 +591,10 @@ int ib_process_mad_wc(struct ib_mad_agent *mad_agent,
  * with an initialized work request structure.  Users may modify the returned
  * MAD data buffer before posting the send.
  *
- * The returned data buffer will be cleared.  Users are responsible for
- * initializing the common MAD and any class specific headers.  If @rmpp_active
- * is set, the RMPP header will be initialized for sending.
+ * The returned MAD header, class specific headers, and any padding will be
+ * cleared.  Users are responsible for initializing the common MAD header,
+ * any class specific header, and MAD data area.
+ * If @rmpp_active is set, the RMPP header will be initialized for sending.
  */
 struct ib_mad_send_buf * ib_create_send_mad(struct ib_mad_agent *mad_agent,
                                             u32 remote_qpn, u16 pkey_index,
@@ -601,6 +603,16 @@ struct ib_mad_send_buf * ib_create_send_mad(struct ib_mad_agent *mad_agent,
                                             gfp_t gfp_mask);
 
 /**
+ * ib_get_rmpp_segment - returns the data buffer for a given RMPP segment.
+ * @send_buf: Previously allocated send data buffer.
+ * @seg_num: number of segment to return
+ *
+ * This routine returns a pointer to the data buffer of an RMPP MAD.
+ * Users must provide synchronization to @send_buf around this call.
+ */
+void *ib_get_rmpp_segment(struct ib_mad_send_buf *send_buf, int seg_num);
+
+/**
  * ib_free_send_mad - Returns data buffers used to send a MAD.
  * @send_buf: Previously allocated send data buffer.
  */