SUNRPC: Always manipulate rpc_rqst::rq_bc_pa_list under xprt->bc_pa_lock

commit 813b00d63f6ca1ed40a2f4f9c034d59bc424025e upstream.

Other code that accesses rq_bc_pa_list holds xprt->bc_pa_lock.
xprt_complete_bc_request() should do the same.

Fixes: 2ea24497a1b3 ("SUNRPC: RPC callbacks may be split . . .")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/sunrpc/backchannel_rqst.c b/net/sunrpc/backchannel_rqst.c
index 651f49ab601fbdd75eed30ddc0a29c9cb4369e54..9dd0ea8db463acc9daba0c51be89b1f17ec8f17d 100644 (file)
--- a/net/sunrpc/backchannel_rqst.c
+++ b/net/sunrpc/backchannel_rqst.c
@@ -309,12 +309,15 @@ void xprt_complete_bc_request(struct rpc_rqst *req, uint32_t copied)
        struct rpc_xprt *xprt = req->rq_xprt;
        struct svc_serv *bc_serv = xprt->bc_serv;
 
+       spin_lock(&xprt->bc_pa_lock);
+       list_del(&req->rq_bc_pa_list);
+       spin_unlock(&xprt->bc_pa_lock);
+
        req->rq_private_buf.len = copied;
        set_bit(RPC_BC_PA_IN_USE, &req->rq_bc_pa_state);
 
        dprintk("RPC:       add callback request to list\n");
        spin_lock(&bc_serv->sv_cb_lock);
-       list_del(&req->rq_bc_pa_list);
        list_add(&req->rq_bc_list, &bc_serv->sv_cb_list);
        wake_up(&bc_serv->sv_cb_waitq);
        spin_unlock(&bc_serv->sv_cb_lock);