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Commit fa08a396 authored by Ramachandra Rao Gajula's avatar Ramachandra Rao Gajula Committed by Matthew Wilcox
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NVMe: Add MSI support 



Some devices only have support for MSI, not MSI-X.  While MSI is more
limited, it still provides better performance than line-based interrupts.

Signed-off-by: default avatarRamachandra Gajula <rama@fastorsystems.com>
Signed-off-by: default avatarMatthew Wilcox <matthew.r.wilcox@intel.com>
parent cf9f123b

drivers/block/nvme-core.c

+32 −8
Original line number Diff line number Diff line
@@ -1637,7 +1637,8 @@ static int set_queue_count(struct nvme_dev *dev, int count) 


static int nvme_setup_io_queues(struct nvme_dev *dev)

{

	int result, cpu, i, nr_io_queues, db_bar_size, q_depth;

	struct pci_dev *pdev = dev->pci_dev;

	int result, cpu, i, nr_io_queues, db_bar_size, q_depth, q_count;



	nr_io_queues = num_online_cpus();

	result = set_queue_count(dev, nr_io_queues);
@@ -1646,14 +1647,14 @@ static int nvme_setup_io_queues(struct nvme_dev *dev) 
	if (result < nr_io_queues)

		nr_io_queues = result;



	q_count = nr_io_queues;

	/* Deregister the admin queue's interrupt */

	free_irq(dev->entry[0].vector, dev->queues[0]);



	db_bar_size = 4096 + ((nr_io_queues + 1) << (dev->db_stride + 3));

	if (db_bar_size > 8192) {

		iounmap(dev->bar);

		dev->bar = ioremap(pci_resource_start(dev->pci_dev, 0),

								db_bar_size);

		dev->bar = ioremap(pci_resource_start(pdev, 0), db_bar_size);

		dev->dbs = ((void __iomem *)dev->bar) + 4096;

		dev->queues[0]->q_db = dev->dbs;

	}
@@ -1661,18 +1662,35 @@ static int nvme_setup_io_queues(struct nvme_dev *dev) 
	for (i = 0; i < nr_io_queues; i++)

		dev->entry[i].entry = i;

	for (;;) {

		result = pci_enable_msix(dev->pci_dev, dev->entry,

								nr_io_queues);

		result = pci_enable_msix(pdev, dev->entry, nr_io_queues);

		if (result == 0) {

			break;

		} else if (result > 0) {

			nr_io_queues = result;

			continue;

		} else {

			nr_io_queues = 0;

			break;

		}

	}



	if (nr_io_queues == 0) {

		nr_io_queues = q_count;

		for (;;) {

			result = pci_enable_msi_block(pdev, nr_io_queues);

			if (result == 0) {

				for (i = 0; i < nr_io_queues; i++)

					dev->entry[i].vector = i + pdev->irq;

				break;

			} else if (result > 0) {

				nr_io_queues = result;

				continue;

			} else {

				nr_io_queues = 1;

				break;

			}

		}

	}



	result = queue_request_irq(dev, dev->queues[0], "nvme admin");

	/* XXX: handle failure here */
@@ -1854,6 +1872,9 @@ static void nvme_free_dev(struct kref *kref) 
{

	struct nvme_dev *dev = container_of(kref, struct nvme_dev, kref);

	nvme_dev_remove(dev);

	if (dev->pci_dev->msi_enabled)

		pci_disable_msi(dev->pci_dev);

	else if (dev->pci_dev->msix_enabled)

		pci_disable_msix(dev->pci_dev);

	iounmap(dev->bar);

	nvme_release_instance(dev);
@@ -1987,7 +2008,10 @@ static int nvme_probe(struct pci_dev *pdev, const struct pci_device_id *id) 
 unmap:

	iounmap(dev->bar);

 disable_msix:

	pci_disable_msix(pdev);

	if (dev->pci_dev->msi_enabled)

		pci_disable_msi(dev->pci_dev);

	else if (dev->pci_dev->msix_enabled)

		pci_disable_msix(dev->pci_dev);

	nvme_release_instance(dev);

	nvme_release_prp_pools(dev);

 disable: