dmaengine: idxd: change MSIX allocation based on per wq activation

Change the driver where WQ interrupt is requested only when wq is being
enabled. This new scheme set things up so that request_threaded_irq() is
only called when a kernel wq type is being enabled. This also sets up for
future interrupt request where different interrupt handler such as wq
occupancy interrupt can be setup instead of the wq completion interrupt.

Not calling request_irq() until the WQ actually needs an irq also prevents
wasting of CPU irq vectors on x86 systems, which is a limited resource.

idxd_flush_pending_descs() is moved to device.c since descriptor flushing
is now part of wq disable rather than shutdown().

Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/163942149487.2412839.6691222855803875848.stgit@djiang5-desk3.ch.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

1 files changed, 14 insertions, 119 deletions

diff --git a/drivers/dma/idxd/init.c b/drivers/dma/idxd/init.c
index 03c735727f68..3505efb7ae71 100644
--- a/drivers/dma/idxd/init.c
+++ b/drivers/dma/idxd/init.c
@@ -90,7 +90,6 @@ static int idxd_setup_interrupts(struct idxd_device *idxd)
 	}
 	dev_dbg(dev, "Enabled %d msix vectors\n", msixcnt);
 
-	idxd_msix_perm_setup(idxd);
 
 	ie = idxd_get_ie(idxd, 0);
 	ie->vector = pci_irq_vector(pdev, 0);
@@ -99,65 +98,26 @@ static int idxd_setup_interrupts(struct idxd_device *idxd)
 		dev_err(dev, "Failed to allocate misc interrupt.\n");
 		goto err_misc_irq;
 	}
-
-	dev_dbg(dev, "Allocated idxd-misc handler on msix vector %d\n", ie->vector);
+	dev_dbg(dev, "Requested idxd-misc handler on msix vector %d\n", ie->vector);
 
 	for (i = 0; i < idxd->max_wqs; i++) {
 		int msix_idx = i + 1;
 
 		ie = idxd_get_ie(idxd, msix_idx);
-
-		/* MSIX vector 0 special, wq irq entry starts at 1 */
 		ie->id = msix_idx;
-		ie->vector = pci_irq_vector(pdev, msix_idx);
 		ie->int_handle = INVALID_INT_HANDLE;
-		if (device_pasid_enabled(idxd) && i > 0)
-			ie->pasid = idxd->pasid;
-		else
-			ie->pasid = INVALID_IOASID;
+		ie->pasid = INVALID_IOASID;
+
 		spin_lock_init(&ie->list_lock);
 		init_llist_head(&ie->pending_llist);
 		INIT_LIST_HEAD(&ie->work_list);
-
-		rc = request_threaded_irq(ie->vector, NULL, idxd_wq_thread, 0, "idxd-portal", ie);
-		if (rc < 0) {
-			dev_err(dev, "Failed to allocate irq %d.\n", ie->vector);
-			goto err_wq_irqs;
-		}
-
-		dev_dbg(dev, "Allocated idxd-msix %d for vector %d\n", i, ie->vector);
-		if (idxd->request_int_handles) {
-			rc = idxd_device_request_int_handle(idxd, i, &ie->int_handle,
-							    IDXD_IRQ_MSIX);
-			if (rc < 0) {
-				free_irq(ie->vector, ie);
-				goto err_wq_irqs;
-			}
-			dev_dbg(dev, "int handle requested: %u\n", ie->int_handle);
-		} else {
-			ie->int_handle = msix_idx;
-		}
-
 	}
 
 	idxd_unmask_error_interrupts(idxd);
 	return 0;
 
- err_wq_irqs:
-	while (--i >= 0) {
-		ie = &idxd->wqs[i]->ie;
-		free_irq(ie->vector, ie);
-		if (ie->int_handle != INVALID_INT_HANDLE) {
-			idxd_device_release_int_handle(idxd, ie->int_handle, IDXD_IRQ_MSIX);
-			ie->int_handle = INVALID_INT_HANDLE;
-			ie->pasid = INVALID_IOASID;
-		}
-		ie->vector = -1;
-	}
  err_misc_irq:
-	/* Disable error interrupt generation */
 	idxd_mask_error_interrupts(idxd);
-	idxd_msix_perm_clear(idxd);
 	pci_free_irq_vectors(pdev);
 	dev_err(dev, "No usable interrupts\n");
 	return rc;
@@ -167,20 +127,15 @@ static void idxd_cleanup_interrupts(struct idxd_device *idxd)
 {
 	struct pci_dev *pdev = idxd->pdev;
 	struct idxd_irq_entry *ie;
-	int i;
+	int msixcnt;
 
-	for (i = 0; i < idxd->irq_cnt; i++) {
-		ie = idxd_get_ie(idxd, i);
-		if (ie->int_handle != INVALID_INT_HANDLE) {
-			idxd_device_release_int_handle(idxd, ie->int_handle, IDXD_IRQ_MSIX);
-			ie->int_handle = INVALID_INT_HANDLE;
-			ie->pasid = INVALID_IOASID;
-		}
-		free_irq(ie->vector, ie);
-		ie->vector = -1;
-	}
+	msixcnt = pci_msix_vec_count(pdev);
+	if (msixcnt <= 0)
+		return;
 
+	ie = idxd_get_ie(idxd, 0);
 	idxd_mask_error_interrupts(idxd);
+	free_irq(ie->vector, ie);
 	pci_free_irq_vectors(pdev);
 }
 
@@ -592,8 +547,6 @@ static int idxd_probe(struct idxd_device *idxd)
 	if (rc)
 		goto err_config;
 
-	dev_dbg(dev, "IDXD interrupt setup complete.\n");
-
 	idxd->major = idxd_cdev_get_major(idxd);
 
 	rc = perfmon_pmu_init(idxd);
@@ -689,31 +642,6 @@ static int idxd_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 	return rc;
 }
 
-static void idxd_flush_pending_descs(struct idxd_irq_entry *ie)
-{
-	struct idxd_desc *desc, *itr;
-	struct llist_node *head;
-	LIST_HEAD(flist);
-	enum idxd_complete_type ctype;
-
-	spin_lock(&ie->list_lock);
-	head = llist_del_all(&ie->pending_llist);
-	if (head) {
-		llist_for_each_entry_safe(desc, itr, head, llnode)
-			list_add_tail(&desc->list, &ie->work_list);
-	}
-
-	list_for_each_entry_safe(desc, itr, &ie->work_list, list)
-		list_move_tail(&desc->list, &flist);
-	spin_unlock(&ie->list_lock);
-
-	list_for_each_entry_safe(desc, itr, &flist, list) {
-		list_del(&desc->list);
-		ctype = desc->completion->status ? IDXD_COMPLETE_NORMAL : IDXD_COMPLETE_ABORT;
-		idxd_dma_complete_txd(desc, ctype, true);
-	}
-}
-
 void idxd_wqs_quiesce(struct idxd_device *idxd)
 {
 	struct idxd_wq *wq;
@@ -726,46 +654,19 @@ void idxd_wqs_quiesce(struct idxd_device *idxd)
 	}
 }
 
-static void idxd_release_int_handles(struct idxd_device *idxd)
-{
-	struct device *dev = &idxd->pdev->dev;
-	int i, rc;
-
-	for (i = 1; i < idxd->irq_cnt; i++) {
-		struct idxd_irq_entry *ie = idxd_get_ie(idxd, i);
-
-		if (ie->int_handle != INVALID_INT_HANDLE) {
-			rc = idxd_device_release_int_handle(idxd, ie->int_handle, IDXD_IRQ_MSIX);
-			if (rc < 0)
-				dev_warn(dev, "irq handle %d release failed\n", ie->int_handle);
-			else
-				dev_dbg(dev, "int handle released: %u\n", ie->int_handle);
-		}
-	}
-}
-
 static void idxd_shutdown(struct pci_dev *pdev)
 {
 	struct idxd_device *idxd = pci_get_drvdata(pdev);
-	int rc, i;
 	struct idxd_irq_entry *irq_entry;
-	int msixcnt = pci_msix_vec_count(pdev);
+	int rc;
 
 	rc = idxd_device_disable(idxd);
 	if (rc)
 		dev_err(&pdev->dev, "Disabling device failed\n");
 
-	dev_dbg(&pdev->dev, "%s called\n", __func__);
-	idxd_mask_msix_vectors(idxd);
+	irq_entry = &idxd->ie;
+	synchronize_irq(irq_entry->vector);
 	idxd_mask_error_interrupts(idxd);
-
-	for (i = 0; i < msixcnt; i++) {
-		irq_entry = idxd_get_ie(idxd, i);
-		synchronize_irq(irq_entry->vector);
-		if (i == 0)
-			continue;
-		idxd_flush_pending_descs(irq_entry);
-	}
 	flush_workqueue(idxd->wq);
 }
 
@@ -773,8 +674,6 @@ static void idxd_remove(struct pci_dev *pdev)
 {
 	struct idxd_device *idxd = pci_get_drvdata(pdev);
 	struct idxd_irq_entry *irq_entry;
-	int msixcnt = pci_msix_vec_count(pdev);
-	int i;
 
 	idxd_unregister_devices(idxd);
 	/*
@@ -790,12 +689,8 @@ static void idxd_remove(struct pci_dev *pdev)
 	if (device_pasid_enabled(idxd))
 		idxd_disable_system_pasid(idxd);
 
-	for (i = 0; i < msixcnt; i++) {
-		irq_entry = idxd_get_ie(idxd, i);
-		free_irq(irq_entry->vector, irq_entry);
-	}
-	idxd_msix_perm_clear(idxd);
-	idxd_release_int_handles(idxd);
+	irq_entry = idxd_get_ie(idxd, 0);
+	free_irq(irq_entry->vector, irq_entry);
 	pci_free_irq_vectors(pdev);
 	pci_iounmap(pdev, idxd->reg_base);
 	iommu_dev_disable_feature(&pdev->dev, IOMMU_DEV_FEAT_SVA);