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>

2 files changed, 12 insertions, 12 deletions

diff --git a/drivers/infiniband/sw/rdmavt/qp.c b/drivers/infiniband/sw/rdmavt/qp.c
index 858c992906c1..5ce403c6cddb 100644
--- a/drivers/infiniband/sw/rdmavt/qp.c
+++ b/drivers/infiniband/sw/rdmavt/qp.c
@@ -1538,8 +1538,8 @@ int rvt_query_qp(struct ib_qp *ibqp, struct ib_qp_attr *attr,
  *
  * Return: 0 on success otherwise errno
  */
-int rvt_post_recv(struct ib_qp *ibqp, struct ib_recv_wr *wr,
-		  struct ib_recv_wr **bad_wr)
+int rvt_post_recv(struct ib_qp *ibqp, const struct ib_recv_wr *wr,
+		  const struct ib_recv_wr **bad_wr)
 {
 	struct rvt_qp *qp = ibqp_to_rvtqp(ibqp);
 	struct rvt_rwq *wq = qp->r_rq.wq;
@@ -1891,8 +1891,8 @@ bail_inval_free:
  *
  * Return: 0 on success else errno
  */
-int rvt_post_send(struct ib_qp *ibqp, struct ib_send_wr *wr,
-		  struct ib_send_wr **bad_wr)
+int rvt_post_send(struct ib_qp *ibqp, const struct ib_send_wr *wr,
+		  const struct ib_send_wr **bad_wr)
 {
 	struct rvt_qp *qp = ibqp_to_rvtqp(ibqp);
 	struct rvt_dev_info *rdi = ib_to_rvt(ibqp->device);
@@ -1948,8 +1948,8 @@ bail:
  *
  * Return: 0 on success else errno
  */
-int rvt_post_srq_recv(struct ib_srq *ibsrq, struct ib_recv_wr *wr,
-		      struct ib_recv_wr **bad_wr)
+int rvt_post_srq_recv(struct ib_srq *ibsrq, const struct ib_recv_wr *wr,
+		      const struct ib_recv_wr **bad_wr)
 {
 	struct rvt_srq *srq = ibsrq_to_rvtsrq(ibsrq);
 	struct rvt_rwq *wq;
diff --git a/drivers/infiniband/sw/rdmavt/qp.h b/drivers/infiniband/sw/rdmavt/qp.h
index 8409f80d5f25..264811fdc530 100644
--- a/drivers/infiniband/sw/rdmavt/qp.h
+++ b/drivers/infiniband/sw/rdmavt/qp.h
@@ -60,10 +60,10 @@ int rvt_modify_qp(struct ib_qp *ibqp, struct ib_qp_attr *attr,
 int rvt_destroy_qp(struct ib_qp *ibqp);
 int rvt_query_qp(struct ib_qp *ibqp, struct ib_qp_attr *attr,
 		 int attr_mask, struct ib_qp_init_attr *init_attr);
-int rvt_post_recv(struct ib_qp *ibqp, struct ib_recv_wr *wr,
-		  struct ib_recv_wr **bad_wr);
-int rvt_post_send(struct ib_qp *ibqp, struct ib_send_wr *wr,
-		  struct ib_send_wr **bad_wr);
-int rvt_post_srq_recv(struct ib_srq *ibsrq, struct ib_recv_wr *wr,
-		      struct ib_recv_wr **bad_wr);
+int rvt_post_recv(struct ib_qp *ibqp, const struct ib_recv_wr *wr,
+		  const struct ib_recv_wr **bad_wr);
+int rvt_post_send(struct ib_qp *ibqp, const struct ib_send_wr *wr,
+		  const struct ib_send_wr **bad_wr);
+int rvt_post_srq_recv(struct ib_srq *ibsrq, const struct ib_recv_wr *wr,
+		      const struct ib_recv_wr **bad_wr);
 #endif          /* DEF_RVTQP_H */