[IB] uverbs: have kernel return QP capabilities

Move the computation of QP capabilities (max scatter/gather entries,
max inline data, etc) into the kernel, and have the uverbs module
return the values as part of the create QP response.  This keeps
precise knowledge of device limits in the low-level kernel driver.

This requires an ABI bump, so while we're making changes, get rid of
the max_sge parameter for the modify SRQ command -- it's not used and
shouldn't be there.

Signed-off-by: Jack Morgenstein <jackm@mellanox.co.il>
Signed-off-by: Michael S. Tsirkin <mst@mellanox.co.il>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

1 files changed, 6 insertions, 3 deletions

diff --git a/include/rdma/ib_user_verbs.h b/include/rdma/ib_user_verbs.h
index 072f3a2..5ff1490 100644
--- a/include/rdma/ib_user_verbs.h
+++ b/include/rdma/ib_user_verbs.h
@@ -43,7 +43,7 @@
  * Increment this value if any changes that break userspace ABI
  * compatibility are made.
  */
-#define IB_USER_VERBS_ABI_VERSION	3
+#define IB_USER_VERBS_ABI_VERSION	4
 
 enum {
 	IB_USER_VERBS_CMD_GET_CONTEXT,
@@ -333,6 +333,11 @@ struct ib_uverbs_create_qp {
 struct ib_uverbs_create_qp_resp {
 	__u32 qp_handle;
 	__u32 qpn;
+	__u32 max_send_wr;
+	__u32 max_recv_wr;
+	__u32 max_send_sge;
+	__u32 max_recv_sge;
+	__u32 max_inline_data;
 };
 
 /*
@@ -552,9 +557,7 @@ struct ib_uverbs_modify_srq {
 	__u32 srq_handle;
 	__u32 attr_mask;
 	__u32 max_wr;
-	__u32 max_sge;
 	__u32 srq_limit;
-	__u32 reserved;
 	__u64 driver_data[0];
 };