nfsd: Fix slot wake up race in the nfsv4.1 callback code

[platform/adaptation/renesas_rcar/renesas_kernel.git] / fs / nfsd / nfs4callback.c

diff --git a/fs/nfsd/nfs4callback.c b/fs/nfsd/nfs4callback.c
index cc8c5b3..f42bbe5 100644 (file)
--- a/fs/nfsd/nfs4callback.c
+++ b/fs/nfsd/nfs4callback.c
@@ -784,8 +784,12 @@ static bool nfsd41_cb_get_slot(struct nfs4_client *clp, struct rpc_task *task)
 {
        if (test_and_set_bit(0, &clp->cl_cb_slot_busy) != 0) {
                rpc_sleep_on(&clp->cl_cb_waitq, task, NULL);
-               dprintk("%s slot is busy\n", __func__);
-               return false;
+               /* Race breaker */
+               if (test_and_set_bit(0, &clp->cl_cb_slot_busy) != 0) {
+                       dprintk("%s slot is busy\n", __func__);
+                       return false;
+               }
+               rpc_wake_up_queued_task(&clp->cl_cb_waitq, task);
        }
        return true;
 }