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, 6 insertions, 3 deletions

diff --git a/drivers/infiniband/core/uverbs_cmd.c b/drivers/infiniband/core/uverbs_cmd.c
index 38d7de3f9b2f..d4c3bc042343 100644
--- a/drivers/infiniband/core/uverbs_cmd.c
+++ b/drivers/infiniband/core/uverbs_cmd.c
@@ -2155,7 +2155,8 @@ ssize_t ib_uverbs_post_send(struct ib_uverbs_file *file,
 	struct ib_uverbs_post_send      cmd;
 	struct ib_uverbs_post_send_resp resp;
 	struct ib_uverbs_send_wr       *user_wr;
-	struct ib_send_wr              *wr = NULL, *last, *next, *bad_wr;
+	struct ib_send_wr              *wr = NULL, *last, *next;
+	const struct ib_send_wr	       *bad_wr;
 	struct ib_qp                   *qp;
 	int                             i, sg_ind;
 	int				is_ud;
@@ -2434,7 +2435,8 @@ ssize_t ib_uverbs_post_recv(struct ib_uverbs_file *file,
 {
 	struct ib_uverbs_post_recv      cmd;
 	struct ib_uverbs_post_recv_resp resp;
-	struct ib_recv_wr              *wr, *next, *bad_wr;
+	struct ib_recv_wr              *wr, *next;
+	const struct ib_recv_wr	       *bad_wr;
 	struct ib_qp                   *qp;
 	ssize_t                         ret = -EINVAL;
 
@@ -2483,7 +2485,8 @@ ssize_t ib_uverbs_post_srq_recv(struct ib_uverbs_file *file,
 {
 	struct ib_uverbs_post_srq_recv      cmd;
 	struct ib_uverbs_post_srq_recv_resp resp;
-	struct ib_recv_wr                  *wr, *next, *bad_wr;
+	struct ib_recv_wr                  *wr, *next;
+	const struct ib_recv_wr		   *bad_wr;
 	struct ib_srq                      *srq;
 	ssize_t                             ret = -EINVAL;