irq_poll: Fix irq_poll_sched()

The IRQ_POLL_F_SCHED bit is set as long as polling is ongoing.
This means that irq_poll_sched() must proceed if this bit has
not yet been set.

Fixes: commit ea51190c ("irq_poll: fold irq_poll_sched_prep into irq_poll_sched").
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

lib/irq_poll.c

@@ -29,7 +29,7 @@ void irq_poll_sched(struct irq_poll *iop)
 
 	if (test_bit(IRQ_POLL_F_DISABLE, &iop->state))
 		return;
-	if (!test_and_set_bit(IRQ_POLL_F_SCHED, &iop->state))
+	if (test_and_set_bit(IRQ_POLL_F_SCHED, &iop->state))
 		return;
 
 	local_irq_save(flags);