iwlwifi: pcie: fix rb_allocator workqueue allocation

BugLink: https://bugs.launchpad.net/bugs/1868628

commit 8188a18e upstream

We don't handle failures in the rb_allocator workqueue allocation
correctly. To fix that, move the code earlier so the cleanup is
easier and we don't have to undo all the interrupt allocations in
this case.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
[Ajay: Rewrote this patch for v4.4.y, as 4.4.y codebase is different from mainline]
Signed-off-by: Ajay Kaher <akaher@vmware.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>
Signed-off-by: Kelsey Skunberg <kelsey.skunberg@canonical.com>

drivers/net/wireless/iwlwifi/pcie/rx.c

@@ -708,9 +708,13 @@ int iwl_pcie_rx_init(struct iwl_trans *trans)
 		if (err)
 			return err;
 	}
-	if (!rba->alloc_wq)
+	if (!rba->alloc_wq) {
 		rba->alloc_wq = alloc_workqueue("rb_allocator",
 						WQ_HIGHPRI | WQ_UNBOUND, 1);
+		if (!rba->alloc_wq)
+			return -ENOMEM;
+	}
+
 	INIT_WORK(&rba->rx_alloc, iwl_pcie_rx_allocator_work);
 
 	cancel_work_sync(&rba->rx_alloc);