[PATCH 3.19 102/177] SUNRPC: Always manipulate rpc_rqst::rq_bc_pa_list under xprt->bc_pa_lock

Greg Kroah-Hartman
2015-03-16T15:43:29Z

From: Chuck Lever <chuck.lever@oracle.com>

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>

---
net/sunrpc/backchannel_rqst.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

--- a/net/sunrpc/backchannel_rqst.c
+++ b/net/sunrpc/backchannel_rqst.c
@@ -309,12 +309,15 @@ void xprt_complete_bc_request(struct rpc
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);