SUNRPC: Set memalloc_nofs_save() for sync tasks

BugLink: https://bugs.launchpad.net/bugs/1919492
[ Upstream commit f0940f4b3284a00f38a5d42e6067c2aaa20e1f2e ]

We could recurse into NFS doing memory reclaim while sending a sync task,
which might result in a deadlock.  Set memalloc_nofs_save for sync task
execution.

Fixes: a1231fda7e94 ("SUNRPC: Set memalloc_nofs_save() on all rpciod/xprtiod jobs")
Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Seth Forshee <seth.forshee@canonical.com>

diff --git a/net/sunrpc/sched.c b/net/sunrpc/sched.c
index cf702a5f7fe5de023edf4814a6c326999df254e5..39ed0e0afe6d9bc25069659e853fbde29326a062 100644 (file)
--- a/net/sunrpc/sched.c
+++ b/net/sunrpc/sched.c
@@ -963,8 +963,11 @@ void rpc_execute(struct rpc_task *task)
 
        rpc_set_active(task);
        rpc_make_runnable(rpciod_workqueue, task);
-       if (!is_async)
+       if (!is_async) {
+               unsigned int pflags = memalloc_nofs_save();
                __rpc_execute(task);
+               memalloc_nofs_restore(pflags);
+       }
 }
 
 static void rpc_async_schedule(struct work_struct *work)