Merge patch series "replace old wq(s), added WQ_PERCPU to alloc_workqueue"

Marco Crivellari <marco.crivellari@suse.com> says:

Hi,

=== Current situation: problems ===

Let's consider a nohz_full system with isolated CPUs: wq_unbound_cpumask is
set to the housekeeping CPUs, for !WQ_UNBOUND the local CPU is selected.

This leads to different scenarios if a work item is scheduled on an
isolated CPU where "delay" value is 0 or greater then 0:
        schedule_delayed_work(, 0);

This will be handled by __queue_work() that will queue the work item on the
current local (isolated) CPU, while:

        schedule_delayed_work(, 1);

Will move the timer on an housekeeping CPU, and schedule the work there.

Currently if a user enqueue a work item using schedule_delayed_work() the
used wq is "system_wq" (per-cpu wq) while queue_delayed_work() use
WORK_CPU_UNBOUND (used when a cpu is not specified). The same applies to
schedule_work() that is using system_wq and queue_work(), that makes use
again of WORK_CPU_UNBOUND.

This lack of consistency cannot be addressed without refactoring the API.

=== Recent changes to the WQ API ===

The following, address the recent changes in the Workqueue API:

- commit 128ea9f6ccfb ("workqueue: Add system_percpu_wq and system_dfl_wq")
- commit 930c2ea566af ("workqueue: Add new WQ_PERCPU flag")

The old workqueues will be removed in a future release cycle.

=== Introduced Changes by this series ===

1) [P 1]  Replace uses of system_wq and system_unbound_wq

    system_unbound_wq is to be used when locality is not required.

    Because of that, system_unbound_wq has been replaced with
	system_dfl_wq, to make clear it should be used when locality
	is not required.

2) [P 2-3-4] WQ_PERCPU added to alloc_workqueue()

    This change adds a new WQ_PERCPU flag to explicitly request
    alloc_workqueue() to be per-cpu when WQ_UNBOUND has not been specified.

Thanks!

Link: https://patch.msgid.link/20251031095643.74246-1-marco.crivellari@suse.com
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

11 files changed, 25 insertions, 17 deletions

diff --git a/drivers/scsi/be2iscsi/be_main.c b/drivers/scsi/be2iscsi/be_main.c
index dc88bc46dcc0..a0e794ffc980 100644
--- a/drivers/scsi/be2iscsi/be_main.c
+++ b/drivers/scsi/be2iscsi/be_main.c
@@ -5633,7 +5633,8 @@ static int beiscsi_dev_probe(struct pci_dev *pcidev,
 
 	phba->ctrl.mcc_alloc_index = phba->ctrl.mcc_free_index = 0;
 
-	phba->wq = alloc_workqueue("beiscsi_%02x_wq", WQ_MEM_RECLAIM, 1,
+	phba->wq = alloc_workqueue("beiscsi_%02x_wq",
+				   WQ_MEM_RECLAIM | WQ_PERCPU, 1,
 				   phba->shost->host_no);
 	if (!phba->wq) {
 		beiscsi_log(phba, KERN_ERR, BEISCSI_LOG_INIT,
diff --git a/drivers/scsi/bnx2fc/bnx2fc_fcoe.c b/drivers/scsi/bnx2fc/bnx2fc_fcoe.c
index 58da993251e9..0f68739d380a 100644
--- a/drivers/scsi/bnx2fc/bnx2fc_fcoe.c
+++ b/drivers/scsi/bnx2fc/bnx2fc_fcoe.c
@@ -2695,7 +2695,7 @@ static int __init bnx2fc_mod_init(void)
 	if (rc)
 		goto detach_ft;
 
-	bnx2fc_wq = alloc_workqueue("bnx2fc", 0, 0);
+	bnx2fc_wq = alloc_workqueue("bnx2fc", WQ_PERCPU, 0);
 	if (!bnx2fc_wq) {
 		rc = -ENOMEM;
 		goto release_bt;
diff --git a/drivers/scsi/device_handler/scsi_dh_alua.c b/drivers/scsi/device_handler/scsi_dh_alua.c
index 1bf5948d1188..6fd89ae33059 100644
--- a/drivers/scsi/device_handler/scsi_dh_alua.c
+++ b/drivers/scsi/device_handler/scsi_dh_alua.c
@@ -1300,7 +1300,7 @@ static int __init alua_init(void)
 {
 	int r;
 
-	kaluad_wq = alloc_workqueue("kaluad", WQ_MEM_RECLAIM, 0);
+	kaluad_wq = alloc_workqueue("kaluad", WQ_MEM_RECLAIM | WQ_PERCPU, 0);
 	if (!kaluad_wq)
 		return -ENOMEM;
 
diff --git a/drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c b/drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c
index 5a3787f27369..f259746bc804 100644
--- a/drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c
+++ b/drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c
@@ -3533,7 +3533,8 @@ static int ibmvscsis_probe(struct vio_dev *vdev,
 	init_completion(&vscsi->wait_idle);
 	init_completion(&vscsi->unconfig);
 
-	vscsi->work_q = alloc_workqueue("ibmvscsis%s", WQ_MEM_RECLAIM, 1,
+	vscsi->work_q = alloc_workqueue("ibmvscsis%s",
+					WQ_MEM_RECLAIM | WQ_PERCPU, 1,
 					dev_name(&vdev->dev));
 	if (!vscsi->work_q) {
 		rc = -ENOMEM;
diff --git a/drivers/scsi/lpfc/lpfc_init.c b/drivers/scsi/lpfc/lpfc_init.c
index a9c6dbe3b465..2bd445703146 100644
--- a/drivers/scsi/lpfc/lpfc_init.c
+++ b/drivers/scsi/lpfc/lpfc_init.c
@@ -7944,7 +7944,7 @@ lpfc_sli4_driver_resource_setup(struct lpfc_hba *phba)
 	/* Allocate all driver workqueues here */
 
 	/* The lpfc_wq workqueue for deferred irq use */
-	phba->wq = alloc_workqueue("lpfc_wq", WQ_MEM_RECLAIM, 0);
+	phba->wq = alloc_workqueue("lpfc_wq", WQ_MEM_RECLAIM | WQ_PERCPU, 0);
 	if (!phba->wq)
 		return -ENOMEM;
 
diff --git a/drivers/scsi/pm8001/pm8001_init.c b/drivers/scsi/pm8001/pm8001_init.c
index 8ff4b89ff81e..9acca83d6958 100644
--- a/drivers/scsi/pm8001/pm8001_init.c
+++ b/drivers/scsi/pm8001/pm8001_init.c
@@ -1534,7 +1534,7 @@ static int __init pm8001_init(void)
 	if (pm8001_use_tasklet && !pm8001_use_msix)
 		pm8001_use_tasklet = false;
 
-	pm8001_wq = alloc_workqueue("pm80xx", 0, 0);
+	pm8001_wq = alloc_workqueue("pm80xx", WQ_PERCPU, 0);
 	if (!pm8001_wq)
 		goto err;
 
diff --git a/drivers/scsi/qedf/qedf_main.c b/drivers/scsi/qedf/qedf_main.c
index 6b1ebab36fa3..7792e00800ae 100644
--- a/drivers/scsi/qedf/qedf_main.c
+++ b/drivers/scsi/qedf/qedf_main.c
@@ -3374,7 +3374,8 @@ retry_probe:
 	QEDF_INFO(&(qedf->dbg_ctx), QEDF_LOG_INFO, "qedf->io_mempool=%p.\n",
 	    qedf->io_mempool);
 
-	qedf->link_update_wq = alloc_workqueue("qedf_%u_link", WQ_MEM_RECLAIM,
+	qedf->link_update_wq = alloc_workqueue("qedf_%u_link",
+					       WQ_MEM_RECLAIM | WQ_PERCPU,
 					       1, qedf->lport->host->host_no);
 	INIT_DELAYED_WORK(&qedf->link_update, qedf_handle_link_update);
 	INIT_DELAYED_WORK(&qedf->link_recovery, qedf_link_recovery);
@@ -3585,7 +3586,8 @@ retry_probe:
 	ether_addr_copy(params.ll2_mac_address, qedf->mac);
 
 	/* Start LL2 processing thread */
-	qedf->ll2_recv_wq = alloc_workqueue("qedf_%d_ll2", WQ_MEM_RECLAIM, 1,
+	qedf->ll2_recv_wq = alloc_workqueue("qedf_%d_ll2",
+					    WQ_MEM_RECLAIM | WQ_PERCPU, 1,
 					    host->host_no);
 	if (!qedf->ll2_recv_wq) {
 		QEDF_ERR(&(qedf->dbg_ctx), "Failed to LL2 workqueue.\n");
@@ -3628,7 +3630,8 @@ retry_probe:
 	}
 
 	qedf->timer_work_queue = alloc_workqueue("qedf_%u_timer",
-				WQ_MEM_RECLAIM, 1, qedf->lport->host->host_no);
+				WQ_MEM_RECLAIM | WQ_PERCPU, 1,
+				qedf->lport->host->host_no);
 	if (!qedf->timer_work_queue) {
 		QEDF_ERR(&(qedf->dbg_ctx), "Failed to start timer "
 			  "workqueue.\n");
@@ -3641,7 +3644,8 @@ retry_probe:
 		sprintf(host_buf, "qedf_%u_dpc",
 		    qedf->lport->host->host_no);
 		qedf->dpc_wq =
-			alloc_workqueue("%s", WQ_MEM_RECLAIM, 1, host_buf);
+			alloc_workqueue("%s", WQ_MEM_RECLAIM | WQ_PERCPU, 1,
+					host_buf);
 	}
 	INIT_DELAYED_WORK(&qedf->recovery_work, qedf_recovery_handler);
 
@@ -4177,7 +4181,8 @@ static int __init qedf_init(void)
 		goto err3;
 	}
 
-	qedf_io_wq = alloc_workqueue("%s", WQ_MEM_RECLAIM, 1, "qedf_io_wq");
+	qedf_io_wq = alloc_workqueue("%s", WQ_MEM_RECLAIM | WQ_PERCPU, 1,
+				     "qedf_io_wq");
 	if (!qedf_io_wq) {
 		QEDF_ERR(NULL, "Could not create qedf_io_wq.\n");
 		goto err4;
diff --git a/drivers/scsi/qedi/qedi_main.c b/drivers/scsi/qedi/qedi_main.c
index b168bb2178e9..56685ee22fdf 100644
--- a/drivers/scsi/qedi/qedi_main.c
+++ b/drivers/scsi/qedi/qedi_main.c
@@ -2768,7 +2768,7 @@ retry_probe:
 		}
 
 		qedi->offload_thread = alloc_workqueue("qedi_ofld%d",
-						       WQ_MEM_RECLAIM,
+						       WQ_MEM_RECLAIM | WQ_PERCPU,
 						       1, qedi->shost->host_no);
 		if (!qedi->offload_thread) {
 			QEDI_ERR(&qedi->dbg_ctx,
diff --git a/drivers/scsi/qla2xxx/qla_os.c b/drivers/scsi/qla2xxx/qla_os.c
index 34ee7a179a79..89ef7a2dc46c 100644
--- a/drivers/scsi/qla2xxx/qla_os.c
+++ b/drivers/scsi/qla2xxx/qla_os.c
@@ -3407,7 +3407,7 @@ qla2x00_probe_one(struct pci_dev *pdev, const struct pci_device_id *id)
 	    "req->req_q_in=%p req->req_q_out=%p rsp->rsp_q_in=%p rsp->rsp_q_out=%p.\n",
 	    req->req_q_in, req->req_q_out, rsp->rsp_q_in, rsp->rsp_q_out);
 
-	ha->wq = alloc_workqueue("qla2xxx_wq", WQ_MEM_RECLAIM, 0);
+	ha->wq = alloc_workqueue("qla2xxx_wq", WQ_MEM_RECLAIM | WQ_PERCPU, 0);
 	if (unlikely(!ha->wq)) {
 		ret = -ENOMEM;
 		goto probe_failed;
@@ -5284,7 +5284,7 @@ void qla24xx_sched_upd_fcport(fc_port_t *fcport)
 	qla2x00_set_fcport_disc_state(fcport, DSC_UPD_FCPORT);
 	spin_unlock_irqrestore(&fcport->vha->work_lock, flags);
 
-	queue_work(system_unbound_wq, &fcport->reg_work);
+	queue_work(system_dfl_wq, &fcport->reg_work);
 }
 
 static
diff --git a/drivers/scsi/scsi_transport_fc.c b/drivers/scsi/scsi_transport_fc.c
index 3a821afee9bc..987befb02408 100644
--- a/drivers/scsi/scsi_transport_fc.c
+++ b/drivers/scsi/scsi_transport_fc.c
@@ -441,7 +441,8 @@ static int fc_host_setup(struct transport_container *tc, struct device *dev,
 	fc_host->next_vport_number = 0;
 	fc_host->npiv_vports_inuse = 0;
 
-	fc_host->work_q = alloc_workqueue("fc_wq_%d", 0, 0, shost->host_no);
+	fc_host->work_q = alloc_workqueue("fc_wq_%d", WQ_PERCPU, 0,
+					  shost->host_no);
 	if (!fc_host->work_q)
 		return -ENOMEM;
 
@@ -3088,7 +3089,7 @@ fc_remote_port_create(struct Scsi_Host *shost, int channel,
 
 	spin_unlock_irqrestore(shost->host_lock, flags);
 
-	rport->devloss_work_q = alloc_workqueue("fc_dl_%d_%d", 0, 0,
+	rport->devloss_work_q = alloc_workqueue("fc_dl_%d_%d", WQ_PERCPU, 0,
 						shost->host_no, rport->number);
 	if (!rport->devloss_work_q) {
 		printk(KERN_ERR "FC Remote Port alloc_workqueue failed\n");
diff --git a/drivers/scsi/scsi_transport_iscsi.c b/drivers/scsi/scsi_transport_iscsi.c
index 743b4c792ceb..ed21c032bbc4 100644
--- a/drivers/scsi/scsi_transport_iscsi.c
+++ b/drivers/scsi/scsi_transport_iscsi.c
@@ -3961,7 +3961,7 @@ iscsi_if_recv_msg(struct sk_buff *skb, struct nlmsghdr *nlh, uint32_t *group)
 			list_del_init(&session->sess_list);
 			spin_unlock_irqrestore(&sesslock, flags);
 
-			queue_work(system_unbound_wq, &session->destroy_work);
+			queue_work(system_dfl_wq, &session->destroy_work);
 		}
 		break;
 	case ISCSI_UEVENT_UNBIND_SESSION: