[PATCH 6.1.y 1/7] nfsd: prepare nfsd4_cb_sequence_done() for error handling rework

[Sasha Levin <sashal@kernel.org>]

From: Jeff Layton <jlayton@kernel.org>

[ Upstream commit 1c2d0957dc66620338eba63e0267122b6e2175cc ]

There is only one case where we want to proceed with processing the rest
of the CB_COMPOUND, and that's when the cb_seq_status is 0. Make the
default return value be false, and only set it to true in that case.

Rename the "need_restart" label to "requeue", to better indicate that
it's being requeued to the workqueue.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Stable-dep-of: 01c5d5f58a5d ("nfsd: RCU-protect cl_cb_session to fix use-after-free on session teardown")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/nfsd/nfs4callback.c | 17 ++++++++---------
 1 file changed, 8 insertions(+), 9 deletions(-)

diff --git a/fs/nfsd/nfs4callback.c b/fs/nfsd/nfs4callback.c
index 272d3facfff9d..f9c28ba1d986b 100644
--- a/fs/nfsd/nfs4callback.c
+++ b/fs/nfsd/nfs4callback.c
@@ -1157,11 +1157,12 @@ static void nfsd4_cb_prepare(struct rpc_task *task, void *calldata)
 	rpc_call_start(task);
 }
 
+/* Returns true if CB_COMPOUND processing should continue */
 static bool nfsd4_cb_sequence_done(struct rpc_task *task, struct nfsd4_callback *cb)
 {
 	struct nfs4_client *clp = cb->cb_clp;
 	struct nfsd4_session *session = clp->cl_cb_session;
-	bool ret = true;
+	bool ret = false;
 
 	if (!clp->cl_minorversion) {
 		/*
@@ -1174,13 +1175,13 @@ static bool nfsd4_cb_sequence_done(struct rpc_task *task, struct nfsd4_callback
 		 * handle that case here.
 		 */
 		if (RPC_SIGNALLED(task))
-			goto need_restart;
+			goto requeue;
 
 		return true;
 	}
 
 	if (!cb->cb_holds_slot)
-		goto need_restart;
+		goto requeue;
 
 	switch (cb->cb_seq_status) {
 	case 0:
@@ -1192,6 +1193,7 @@ static bool nfsd4_cb_sequence_done(struct rpc_task *task, struct nfsd4_callback
 		 * (sequence ID, cached reply) MUST NOT change.
 		 */
 		++session->se_cb_seq_nr;
+		ret = true;
 		break;
 	case -ESERVERFAULT:
 		++session->se_cb_seq_nr;
@@ -1199,13 +1201,11 @@ static bool nfsd4_cb_sequence_done(struct rpc_task *task, struct nfsd4_callback
 	case 1:
 	case -NFS4ERR_BADSESSION:
 		nfsd4_mark_cb_fault(cb->cb_clp, cb->cb_seq_status);
-		ret = false;
 		break;
 	case -NFS4ERR_DELAY:
 		cb->cb_seq_status = 1;
 		if (!rpc_restart_call(task))
 			goto out;
-
 		rpc_delay(task, 2 * HZ);
 		return false;
 	case -NFS4ERR_BADSLOT:
@@ -1227,14 +1227,13 @@ static bool nfsd4_cb_sequence_done(struct rpc_task *task, struct nfsd4_callback
 		clp->cl_cb_session->se_cb_seq_nr);
 
 	if (RPC_SIGNALLED(task))
-		goto need_restart;
+		goto requeue;
 out:
 	return ret;
 retry_nowait:
-	if (rpc_restart_call_prepare(task))
-		ret = false;
+	rpc_restart_call_prepare(task);
 	goto out;
-need_restart:
+requeue:
 	if (!test_bit(NFSD4_CLIENT_CB_KILL, &clp->cl_flags)) {
 		task->tk_status = 0;
 		cb->cb_need_restart = true;
-- 
2.53.0