xprtrdma: Improve locking around rpcrdma_rep creation

Defensive clean up: Protect the rb_all_reps list during rep
creation.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

diff --git a/net/sunrpc/xprtrdma/verbs.c b/net/sunrpc/xprtrdma/verbs.c
index baf4b8c..95ce932 100644 (file)
--- a/net/sunrpc/xprtrdma/verbs.c
+++ b/net/sunrpc/xprtrdma/verbs.c
@@ -963,13 +963,11 @@ static void rpcrdma_reqs_reset(struct rpcrdma_xprt *r_xprt)
                rpcrdma_req_reset(req);
 }
 
-/* No locking needed here. This function is called only by the
- * Receive completion handler.
- */
 static noinline
 struct rpcrdma_rep *rpcrdma_rep_create(struct rpcrdma_xprt *r_xprt,
                                       bool temp)
 {
+       struct rpcrdma_buffer *buf = &r_xprt->rx_buf;
        struct rpcrdma_rep *rep;
 
        rep = kzalloc(sizeof(*rep), GFP_KERNEL);
@@ -996,7 +994,10 @@ struct rpcrdma_rep *rpcrdma_rep_create(struct rpcrdma_xprt *r_xprt,
        rep->rr_recv_wr.sg_list = &rep->rr_rdmabuf->rg_iov;
        rep->rr_recv_wr.num_sge = 1;
        rep->rr_temp = temp;
-       list_add(&rep->rr_all, &r_xprt->rx_buf.rb_all_reps);
+
+       spin_lock(&buf->rb_lock);
+       list_add(&rep->rr_all, &buf->rb_all_reps);
+       spin_unlock(&buf->rb_lock);
        return rep;
 
 out_free_regbuf: