NFC: Use system_nrt_wq instead of custom ones

NFC is using a number of custom ordered workqueues w/ WQ_MEM_RECLAIM.
WQ_MEM_RECLAIM is unnecessary unless NFC is gonna be used as transport
for storage device, and all use cases match one work item to one
ordered workqueue - IOW, there's no actual ordering going on at all
and using system_nrt_wq gives the same behavior.

There's nothing to be gained by using custom workqueues.  Use
system_nrt_wq instead and drop all the custom ones.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

3 files changed, 16 insertions, 55 deletions

diff --git a/net/nfc/hci/core.c b/net/nfc/hci/core.c
index 1ac7b3f..03646be 100644
--- a/net/nfc/hci/core.c
+++ b/net/nfc/hci/core.c
@@ -141,7 +141,7 @@ static void __nfc_hci_cmd_completion(struct nfc_hci_dev *hdev, int err,
 	kfree(hdev->cmd_pending_msg);
 	hdev->cmd_pending_msg = NULL;
 
-	queue_work(hdev->msg_tx_wq, &hdev->msg_tx_work);
+	queue_work(system_nrt_wq, &hdev->msg_tx_work);
 }
 
 void nfc_hci_resp_received(struct nfc_hci_dev *hdev, u8 result,
@@ -326,7 +326,7 @@ static void nfc_hci_cmd_timeout(unsigned long data)
 {
 	struct nfc_hci_dev *hdev = (struct nfc_hci_dev *)data;
 
-	queue_work(hdev->msg_tx_wq, &hdev->msg_tx_work);
+	queue_work(system_nrt_wq, &hdev->msg_tx_work);
 }
 
 static int hci_dev_connect_gates(struct nfc_hci_dev *hdev, u8 gate_count,
@@ -659,23 +659,11 @@ EXPORT_SYMBOL(nfc_hci_free_device);
 
 int nfc_hci_register_device(struct nfc_hci_dev *hdev)
 {
-	struct device *dev = &hdev->ndev->dev;
-	const char *devname = dev_name(dev);
-	char name[32];
-	int r = 0;
-
 	mutex_init(&hdev->msg_tx_mutex);
 
 	INIT_LIST_HEAD(&hdev->msg_tx_queue);
 
 	INIT_WORK(&hdev->msg_tx_work, nfc_hci_msg_tx_work);
-	snprintf(name, sizeof(name), "%s_hci_msg_tx_wq", devname);
-	hdev->msg_tx_wq = alloc_workqueue(name, WQ_NON_REENTRANT | WQ_UNBOUND |
-					  WQ_MEM_RECLAIM, 1);
-	if (hdev->msg_tx_wq == NULL) {
-		r = -ENOMEM;
-		goto exit;
-	}
 
 	init_timer(&hdev->cmd_timer);
 	hdev->cmd_timer.data = (unsigned long)hdev;
@@ -684,27 +672,10 @@ int nfc_hci_register_device(struct nfc_hci_dev *hdev)
 	skb_queue_head_init(&hdev->rx_hcp_frags);
 
 	INIT_WORK(&hdev->msg_rx_work, nfc_hci_msg_rx_work);
-	snprintf(name, sizeof(name), "%s_hci_msg_rx_wq", devname);
-	hdev->msg_rx_wq = alloc_workqueue(name, WQ_NON_REENTRANT | WQ_UNBOUND |
-					  WQ_MEM_RECLAIM, 1);
-	if (hdev->msg_rx_wq == NULL) {
-		r = -ENOMEM;
-		goto exit;
-	}
 
 	skb_queue_head_init(&hdev->msg_rx_queue);
 
-	r = nfc_register_device(hdev->ndev);
-
-exit:
-	if (r < 0) {
-		if (hdev->msg_tx_wq)
-			destroy_workqueue(hdev->msg_tx_wq);
-		if (hdev->msg_rx_wq)
-			destroy_workqueue(hdev->msg_rx_wq);
-	}
-
-	return r;
+	return nfc_register_device(hdev->ndev);
 }
 EXPORT_SYMBOL(nfc_hci_register_device);
 
@@ -725,9 +696,8 @@ void nfc_hci_unregister_device(struct nfc_hci_dev *hdev)
 
 	nfc_unregister_device(hdev->ndev);
 
-	destroy_workqueue(hdev->msg_tx_wq);
-
-	destroy_workqueue(hdev->msg_rx_wq);
+	cancel_work_sync(&hdev->msg_tx_work);
+	cancel_work_sync(&hdev->msg_rx_work);
 }
 EXPORT_SYMBOL(nfc_hci_unregister_device);
 
@@ -827,7 +797,7 @@ void nfc_hci_recv_frame(struct nfc_hci_dev *hdev, struct sk_buff *skb)
 		nfc_hci_hcp_message_rx(hdev, pipe, type, instruction, hcp_skb);
 	} else {
 		skb_queue_tail(&hdev->msg_rx_queue, hcp_skb);
-		queue_work(hdev->msg_rx_wq, &hdev->msg_rx_work);
+		queue_work(system_nrt_wq, &hdev->msg_rx_work);
 	}
 }
 EXPORT_SYMBOL(nfc_hci_recv_frame);
diff --git a/net/nfc/hci/hcp.c b/net/nfc/hci/hcp.c
index f4dad1a..2372b55 100644
--- a/net/nfc/hci/hcp.c
+++ b/net/nfc/hci/hcp.c
@@ -108,7 +108,7 @@ int nfc_hci_hcp_message_tx(struct nfc_hci_dev *hdev, u8 pipe,
 	list_add_tail(&cmd->msg_l, &hdev->msg_tx_queue);
 	mutex_unlock(&hdev->msg_tx_mutex);
 
-	queue_work(hdev->msg_tx_wq, &hdev->msg_tx_work);
+	queue_work(system_nrt_wq, &hdev->msg_tx_work);
 
 	return 0;
 
diff --git a/net/nfc/hci/shdlc.c b/net/nfc/hci/shdlc.c
index 6f840c1..39b51ea 100644
--- a/net/nfc/hci/shdlc.c
+++ b/net/nfc/hci/shdlc.c
@@ -540,7 +540,7 @@ static void nfc_shdlc_connect_timeout(unsigned long data)
 
 	pr_debug("\n");
 
-	queue_work(shdlc->sm_wq, &shdlc->sm_work);
+	queue_work(system_nrt_wq, &shdlc->sm_work);
 }
 
 static void nfc_shdlc_t1_timeout(unsigned long data)
@@ -549,7 +549,7 @@ static void nfc_shdlc_t1_timeout(unsigned long data)
 
 	pr_debug("SoftIRQ: need to send ack\n");
 
-	queue_work(shdlc->sm_wq, &shdlc->sm_work);
+	queue_work(system_nrt_wq, &shdlc->sm_work);
 }
 
 static void nfc_shdlc_t2_timeout(unsigned long data)
@@ -558,7 +558,7 @@ static void nfc_shdlc_t2_timeout(unsigned long data)
 
 	pr_debug("SoftIRQ: need to retransmit\n");
 
-	queue_work(shdlc->sm_wq, &shdlc->sm_work);
+	queue_work(system_nrt_wq, &shdlc->sm_work);
 }
 
 static void nfc_shdlc_sm_work(struct work_struct *work)
@@ -598,7 +598,7 @@ static void nfc_shdlc_sm_work(struct work_struct *work)
 	case SHDLC_NEGOCIATING:
 		if (timer_pending(&shdlc->connect_timer) == 0) {
 			shdlc->state = SHDLC_CONNECTING;
-			queue_work(shdlc->sm_wq, &shdlc->sm_work);
+			queue_work(system_nrt_wq, &shdlc->sm_work);
 		}
 
 		nfc_shdlc_handle_rcv_queue(shdlc);
@@ -662,7 +662,7 @@ static int nfc_shdlc_connect(struct nfc_shdlc *shdlc)
 
 	mutex_unlock(&shdlc->state_mutex);
 
-	queue_work(shdlc->sm_wq, &shdlc->sm_work);
+	queue_work(system_nrt_wq, &shdlc->sm_work);
 
 	wait_event(connect_wq, shdlc->connect_result != 1);
 
@@ -679,7 +679,7 @@ static void nfc_shdlc_disconnect(struct nfc_shdlc *shdlc)
 
 	mutex_unlock(&shdlc->state_mutex);
 
-	queue_work(shdlc->sm_wq, &shdlc->sm_work);
+	queue_work(system_nrt_wq, &shdlc->sm_work);
 }
 
 /*
@@ -697,7 +697,7 @@ void nfc_shdlc_recv_frame(struct nfc_shdlc *shdlc, struct sk_buff *skb)
 		skb_queue_tail(&shdlc->rcv_q, skb);
 	}
 
-	queue_work(shdlc->sm_wq, &shdlc->sm_work);
+	queue_work(system_nrt_wq, &shdlc->sm_work);
 }
 EXPORT_SYMBOL(nfc_shdlc_recv_frame);
 
@@ -754,7 +754,7 @@ static int nfc_shdlc_xmit(struct nfc_hci_dev *hdev, struct sk_buff *skb)
 
 	skb_queue_tail(&shdlc->send_q, skb);
 
-	queue_work(shdlc->sm_wq, &shdlc->sm_work);
+	queue_work(system_nrt_wq, &shdlc->sm_work);
 
 	return 0;
 }
@@ -843,7 +843,6 @@ struct nfc_shdlc *nfc_shdlc_allocate(struct nfc_shdlc_ops *ops,
 {
 	struct nfc_shdlc *shdlc;
 	int r;
-	char name[32];
 
 	if (ops->xmit == NULL)
 		return NULL;
@@ -876,11 +875,6 @@ struct nfc_shdlc *nfc_shdlc_allocate(struct nfc_shdlc_ops *ops,
 	skb_queue_head_init(&shdlc->ack_pending_q);
 
 	INIT_WORK(&shdlc->sm_work, nfc_shdlc_sm_work);
-	snprintf(name, sizeof(name), "%s_shdlc_sm_wq", devname);
-	shdlc->sm_wq = alloc_workqueue(name, WQ_NON_REENTRANT | WQ_UNBOUND |
-				       WQ_MEM_RECLAIM, 1);
-	if (shdlc->sm_wq == NULL)
-		goto err_allocwq;
 
 	shdlc->client_headroom = tx_headroom;
 	shdlc->client_tailroom = tx_tailroom;
@@ -904,9 +898,6 @@ err_regdev:
 	nfc_hci_free_device(shdlc->hdev);
 
 err_allocdev:
-	destroy_workqueue(shdlc->sm_wq);
-
-err_allocwq:
 	kfree(shdlc);
 
 	return NULL;
@@ -920,7 +911,7 @@ void nfc_shdlc_free(struct nfc_shdlc *shdlc)
 	nfc_hci_unregister_device(shdlc->hdev);
 	nfc_hci_free_device(shdlc->hdev);
 
-	destroy_workqueue(shdlc->sm_wq);
+	cancel_work_sync(&shdlc->sm_work);
 
 	skb_queue_purge(&shdlc->rcv_q);
 	skb_queue_purge(&shdlc->send_q);