RDMA, core and ULPs: Declare ib_post_send() and ib_post_recv() arguments const

Since neither ib_post_send() nor ib_post_recv() modify the data structure
their second argument points at, declare that argument const. This change
makes it necessary to declare the 'bad_wr' argument const too and also to
modify all ULPs that call ib_post_send(), ib_post_recv() or
ib_post_srq_recv(). This patch does not change any functionality but makes
it possible for the compiler to verify whether the
ib_post_(send|recv|srq_recv) really do not modify the posted work request.

To make this possible, only one cast had to be introduce that casts away
constness, namely in rpcrdma_post_recvs(). The only way I can think of to
avoid that cast is to introduce an additional loop in that function or to
change the data type of bad_wr from struct ib_recv_wr ** into int
(an index that refers to an element in the work request list). However,
both approaches would require even more extensive changes than this
patch.

Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com>
Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

1 files changed, 15 insertions, 15 deletions

diff --git a/include/rdma/ib_verbs.h b/include/rdma/ib_verbs.h
index cf38d47fa8f8..1de8f0d2797c 100644
--- a/include/rdma/ib_verbs.h
+++ b/include/rdma/ib_verbs.h
@@ -2373,8 +2373,8 @@ struct ib_device {
 						struct ib_srq_attr *srq_attr);
 	int                        (*destroy_srq)(struct ib_srq *srq);
 	int                        (*post_srq_recv)(struct ib_srq *srq,
-						    struct ib_recv_wr *recv_wr,
-						    struct ib_recv_wr **bad_recv_wr);
+						    const struct ib_recv_wr *recv_wr,
+						    const struct ib_recv_wr **bad_recv_wr);
 	struct ib_qp *             (*create_qp)(struct ib_pd *pd,
 						struct ib_qp_init_attr *qp_init_attr,
 						struct ib_udata *udata);
@@ -2388,11 +2388,11 @@ struct ib_device {
 					       struct ib_qp_init_attr *qp_init_attr);
 	int                        (*destroy_qp)(struct ib_qp *qp);
 	int                        (*post_send)(struct ib_qp *qp,
-						struct ib_send_wr *send_wr,
-						struct ib_send_wr **bad_send_wr);
+						const struct ib_send_wr *send_wr,
+						const struct ib_send_wr **bad_send_wr);
 	int                        (*post_recv)(struct ib_qp *qp,
-						struct ib_recv_wr *recv_wr,
-						struct ib_recv_wr **bad_recv_wr);
+						const struct ib_recv_wr *recv_wr,
+						const struct ib_recv_wr **bad_recv_wr);
 	struct ib_cq *             (*create_cq)(struct ib_device *device,
 						const struct ib_cq_init_attr *attr,
 						struct ib_ucontext *context,
@@ -3281,10 +3281,10 @@ int ib_destroy_srq(struct ib_srq *srq);
  *   the work request that failed to be posted on the QP.
  */
 static inline int ib_post_srq_recv(struct ib_srq *srq,
-				   struct ib_recv_wr *recv_wr,
-				   struct ib_recv_wr **bad_recv_wr)
+				   const struct ib_recv_wr *recv_wr,
+				   const struct ib_recv_wr **bad_recv_wr)
 {
-	struct ib_recv_wr *dummy;
+	const struct ib_recv_wr *dummy;
 
 	return srq->device->post_srq_recv(srq, recv_wr, bad_recv_wr ? : &dummy);
 }
@@ -3384,10 +3384,10 @@ int ib_close_qp(struct ib_qp *qp);
  * earlier work requests in the list.
  */
 static inline int ib_post_send(struct ib_qp *qp,
-			       struct ib_send_wr *send_wr,
-			       struct ib_send_wr **bad_send_wr)
+			       const struct ib_send_wr *send_wr,
+			       const struct ib_send_wr **bad_send_wr)
 {
-	struct ib_send_wr *dummy;
+	const struct ib_send_wr *dummy;
 
 	return qp->device->post_send(qp, send_wr, bad_send_wr ? : &dummy);
 }
@@ -3401,10 +3401,10 @@ static inline int ib_post_send(struct ib_qp *qp,
  *   the work request that failed to be posted on the QP.
  */
 static inline int ib_post_recv(struct ib_qp *qp,
-			       struct ib_recv_wr *recv_wr,
-			       struct ib_recv_wr **bad_recv_wr)
+			       const struct ib_recv_wr *recv_wr,
+			       const struct ib_recv_wr **bad_recv_wr)
 {
-	struct ib_recv_wr *dummy;
+	const struct ib_recv_wr *dummy;
 
 	return qp->device->post_recv(qp, recv_wr, bad_recv_wr ? : &dummy);
 }