RDMA/rxe: Create AH index and return to user space

Make changes to rdma_user_rxe.h to allow indexing AH objects, passing the
index in UD send WRs to the driver and returning the index to the rxe
provider.

Modify rxe_create_ah() to add an index to AH when created and if called
from a new user provider return it to user space. If called from an old
provider mark the AH as not having a useful index.  Modify rxe_destroy_ah
to drop the index before deleting the object.

Link: https://lore.kernel.org/r/20211007204051.10086-4-rpearsonhpe@gmail.com
Signed-off-by: Bob Pearson <rpearsonhpe@gmail.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

diff --git a/drivers/infiniband/sw/rxe/rxe_verbs.c b/drivers/infiniband/sw/rxe/rxe_verbs.c
index 4233fd9..e20f2dd 100644 (file)
--- a/drivers/infiniband/sw/rxe/rxe_verbs.c
+++ b/drivers/infiniband/sw/rxe/rxe_verbs.c
@@ -158,9 +158,19 @@ static int rxe_create_ah(struct ib_ah *ibah,
                         struct ib_udata *udata)
 
 {
-       int err;
        struct rxe_dev *rxe = to_rdev(ibah->device);
        struct rxe_ah *ah = to_rah(ibah);
+       struct rxe_create_ah_resp __user *uresp = NULL;
+       int err;
+
+       if (udata) {
+               /* test if new user provider */
+               if (udata->outlen >= sizeof(*uresp))
+                       uresp = udata->outbuf;
+               ah->is_user = true;
+       } else {
+               ah->is_user = false;
+       }
 
        err = rxe_av_chk_attr(rxe, init_attr->ah_attr);
        if (err)
@@ -170,6 +180,24 @@ static int rxe_create_ah(struct ib_ah *ibah,
        if (err)
                return err;
 
+       /* create index > 0 */
+       rxe_add_index(ah);
+       ah->ah_num = ah->pelem.index;
+
+       if (uresp) {
+               /* only if new user provider */
+               err = copy_to_user(&uresp->ah_num, &ah->ah_num,
+                                        sizeof(uresp->ah_num));
+               if (err) {
+                       rxe_drop_index(ah);
+                       rxe_drop_ref(ah);
+                       return -EFAULT;
+               }
+       } else if (ah->is_user) {
+               /* only if old user provider */
+               ah->ah_num = 0;
+       }
+
        rxe_init_av(init_attr->ah_attr, &ah->av);
        return 0;
 }
@@ -202,6 +230,7 @@ static int rxe_destroy_ah(struct ib_ah *ibah, u32 flags)
 {
        struct rxe_ah *ah = to_rah(ibah);
 
+       rxe_drop_index(ah);
        rxe_drop_ref(ah);
        return 0;
 }

diff --git a/drivers/infiniband/sw/rxe/rxe_verbs.h b/drivers/infiniband/sw/rxe/rxe_verbs.h
index 098fde6..c56fae2 100644 (file)
--- a/drivers/infiniband/sw/rxe/rxe_verbs.h
+++ b/drivers/infiniband/sw/rxe/rxe_verbs.h
@@ -48,6 +48,8 @@ struct rxe_ah {
        struct rxe_pool_entry   pelem;
        struct rxe_pd           *pd;
        struct rxe_av           av;
+       bool                    is_user;
+       int                     ah_num;
 };
 
 struct rxe_cqe {

diff --git a/include/uapi/rdma/rdma_user_rxe.h b/include/uapi/rdma/rdma_user_rxe.h
index 2f1ebbe..dc9f7a5 100644 (file)
--- a/include/uapi/rdma/rdma_user_rxe.h
+++ b/include/uapi/rdma/rdma_user_rxe.h
@@ -99,7 +99,8 @@ struct rxe_send_wr {
                        __u32   remote_qkey;
                        __u16   pkey_index;
                        __u16   reserved;
-                       __u32   pad[5];
+                       __u32   ah_num;
+                       __u32   pad[4];
                        struct rxe_av av;
                } ud;
                struct {
@@ -170,6 +171,11 @@ struct rxe_recv_wqe {
        struct rxe_dma_info     dma;
 };
 
+struct rxe_create_ah_resp {
+       __u32 ah_num;
+       __u32 reserved;
+};
+
 struct rxe_create_cq_resp {
        struct mminfo mi;
 };