RDMA/rxe: Check rxe_get() return value

In the tasklets (completer, responder, and requester) check the return
value from rxe_get() to detect failures to get a reference.  This only
occurs if the qp has had its reference count drop to zero which indicates
that it no longer should be used.

The ref is never 0 today because the tasklets are flushed before the ref
is dropped. The next patch changes this so that the ref is dropped then
the tasklets are flushed.

Link: https://lore.kernel.org/r/20220421014042.26985-4-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_comp.c b/drivers/infiniband/sw/rxe/rxe_comp.c
index 138b3e7..da3a398 100644 (file)
--- a/drivers/infiniband/sw/rxe/rxe_comp.c
+++ b/drivers/infiniband/sw/rxe/rxe_comp.c
@@ -562,7 +562,8 @@ int rxe_completer(void *arg)
        enum comp_state state;
        int ret = 0;
 
-       rxe_get(qp);
+       if (!rxe_get(qp))
+               return -EAGAIN;
 
        if (!qp->valid || qp->req.state == QP_STATE_ERROR ||
            qp->req.state == QP_STATE_RESET) {

diff --git a/drivers/infiniband/sw/rxe/rxe_req.c b/drivers/infiniband/sw/rxe/rxe_req.c
index e85a529..9d98237 100644 (file)
--- a/drivers/infiniband/sw/rxe/rxe_req.c
+++ b/drivers/infiniband/sw/rxe/rxe_req.c
@@ -606,7 +606,8 @@ int rxe_requester(void *arg)
        struct rxe_ah *ah;
        struct rxe_av *av;
 
-       rxe_get(qp);
+       if (!rxe_get(qp))
+               return -EAGAIN;
 
 next_wqe:
        if (unlikely(!qp->valid || qp->req.state == QP_STATE_ERROR))

diff --git a/drivers/infiniband/sw/rxe/rxe_resp.c b/drivers/infiniband/sw/rxe/rxe_resp.c
index e2653a8..d995ddb 100644 (file)
--- a/drivers/infiniband/sw/rxe/rxe_resp.c
+++ b/drivers/infiniband/sw/rxe/rxe_resp.c
@@ -1247,7 +1247,8 @@ int rxe_responder(void *arg)
        struct rxe_pkt_info *pkt = NULL;
        int ret = 0;
 
-       rxe_get(qp);
+       if (!rxe_get(qp))
+               return -EAGAIN;
 
        qp->resp.aeth_syndrome = AETH_ACK_UNLIMITED;