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From:   Benjamin Coddington <bcodding@redhat.com>
To:     Trond Myklebust <trondmy@hammerspace.com>,
        Anna Schumaker <anna.schumaker@netapp.com>
Cc:     linux-nfs@vger.kernel.org
Subject: [PATCH] SUNRPC: Set memalloc_nofs_save() for sync tasks
Date:   Wed,  3 Mar 2021 08:47:16 -0500
Message-Id: <cfe95384d2a48eac40191969531e4e89bbdf6328.1614779136.git.bcodding@redhat.com>
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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>
---
 net/sunrpc/sched.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/net/sunrpc/sched.c b/net/sunrpc/sched.c
index cf702a5f7fe5..39ed0e0afe6d 100644
--- 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)
-- 
2.29.2