RDMA: Constify the argument of the work request conversion functions

When posting a send work request, the work request that is posted is not
modified by any of the RDMA drivers. Make this explicit by constifying
most ib_send_wr pointers in RDMA transport drivers.

Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Steve Wise <swise@opengridcomputing.com>
Reviewed-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

include/rdma/ib_verbs.h

@@ -1352,7 +1352,7 @@ struct ib_rdma_wr {
 	u32			rkey;
 };
 
-static inline struct ib_rdma_wr *rdma_wr(struct ib_send_wr *wr)
+static inline const struct ib_rdma_wr *rdma_wr(const struct ib_send_wr *wr)
 {
 	return container_of(wr, struct ib_rdma_wr, wr);
 }
@@ -1367,7 +1367,7 @@ struct ib_atomic_wr {
 	u32			rkey;
 };
 
-static inline struct ib_atomic_wr *atomic_wr(struct ib_send_wr *wr)
+static inline const struct ib_atomic_wr *atomic_wr(const struct ib_send_wr *wr)
 {
 	return container_of(wr, struct ib_atomic_wr, wr);
 }
@@ -1384,7 +1384,7 @@ struct ib_ud_wr {
 	u8			port_num;   /* valid for DR SMPs on switch only */
 };
 
-static inline struct ib_ud_wr *ud_wr(struct ib_send_wr *wr)
+static inline const struct ib_ud_wr *ud_wr(const struct ib_send_wr *wr)
 {
 	return container_of(wr, struct ib_ud_wr, wr);
 }
@@ -1396,7 +1396,7 @@ struct ib_reg_wr {
 	int			access;
 };
 
-static inline struct ib_reg_wr *reg_wr(struct ib_send_wr *wr)
+static inline const struct ib_reg_wr *reg_wr(const struct ib_send_wr *wr)
 {
 	return container_of(wr, struct ib_reg_wr, wr);
 }
@@ -1409,7 +1409,8 @@ struct ib_sig_handover_wr {
 	struct ib_sge	       *prot;
 };
 
-static inline struct ib_sig_handover_wr *sig_handover_wr(struct ib_send_wr *wr)
+static inline const struct ib_sig_handover_wr *
+sig_handover_wr(const struct ib_send_wr *wr)
 {
 	return container_of(wr, struct ib_sig_handover_wr, wr);
 }