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Commit 6451fe73 authored by Jens Axboe's avatar Jens Axboe
Browse files

nvme: fix irq vs io_queue calculations 



Guenter reported an boot hang issue on HPPA after we default to 0 poll
queues. We have two issues in the queue count calculations:

1) We don't separate the poll queues from the read/write queues. This is
   important, since the former doesn't need interrupts.
2) The adjust logic is broken.

Adjust the poll queue count before doing nvme_calc_io_queues(). The poll
queue count is only limited by the IO queue count we were able to get
from the controller, not failures in the IRQ allocation loop. This
leaves nvme_calc_io_queues() just adjusting the read/write queue map.

Reported-by: default avatarReported-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarSagi Grimberg <sagi@grimberg.me>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent b7934ba4

drivers/nvme/host/pci.c

+29 −35
Original line number Diff line number Diff line
@@ -2030,60 +2030,40 @@ static int nvme_setup_host_mem(struct nvme_dev *dev) 
	return ret;

}



static void nvme_calc_io_queues(struct nvme_dev *dev, unsigned int nr_io_queues)

static void nvme_calc_io_queues(struct nvme_dev *dev, unsigned int irq_queues)

{

	unsigned int this_w_queues = write_queues;

	unsigned int this_p_queues = poll_queues;



	/*

	 * Setup read/write queue split

	 */

	if (nr_io_queues == 1) {

	if (irq_queues == 1) {

		dev->io_queues[HCTX_TYPE_DEFAULT] = 1;

		dev->io_queues[HCTX_TYPE_READ] = 0;

		dev->io_queues[HCTX_TYPE_POLL] = 0;

		return;

	}



	/*

	 * Configure number of poll queues, if set

	 */

	if (this_p_queues) {

		/*

		 * We need at least one queue left. With just one queue, we'll

		 * have a single shared read/write set.

		 */

		if (this_p_queues >= nr_io_queues) {

			this_w_queues = 0;

			this_p_queues = nr_io_queues - 1;

		}



		dev->io_queues[HCTX_TYPE_POLL] = this_p_queues;

		nr_io_queues -= this_p_queues;

	} else

		dev->io_queues[HCTX_TYPE_POLL] = 0;



	/*

	 * If 'write_queues' is set, ensure it leaves room for at least

	 * one read queue

	 */

	if (this_w_queues >= nr_io_queues)

		this_w_queues = nr_io_queues - 1;

	if (this_w_queues >= irq_queues)

		this_w_queues = irq_queues - 1;



	/*

	 * If 'write_queues' is set to zero, reads and writes will share

	 * a queue set.

	 */

	if (!this_w_queues) {

		dev->io_queues[HCTX_TYPE_DEFAULT] = nr_io_queues;

		dev->io_queues[HCTX_TYPE_DEFAULT] = irq_queues;

		dev->io_queues[HCTX_TYPE_READ] = 0;

	} else {

		dev->io_queues[HCTX_TYPE_DEFAULT] = this_w_queues;

		dev->io_queues[HCTX_TYPE_READ] = nr_io_queues - this_w_queues;

		dev->io_queues[HCTX_TYPE_READ] = irq_queues - this_w_queues;

	}

}



static int nvme_setup_irqs(struct nvme_dev *dev, int nr_io_queues)

static int nvme_setup_irqs(struct nvme_dev *dev, unsigned int nr_io_queues)

{

	struct pci_dev *pdev = to_pci_dev(dev->dev);

	int irq_sets[2];
@@ -2093,6 +2073,20 @@ static int nvme_setup_irqs(struct nvme_dev *dev, int nr_io_queues) 
		.sets = irq_sets,

	};

	int result = 0;

	unsigned int irq_queues, this_p_queues;



	/*

	 * Poll queues don't need interrupts, but we need at least one IO

	 * queue left over for non-polled IO.

	 */

	this_p_queues = poll_queues;

	if (this_p_queues >= nr_io_queues) {

		this_p_queues = nr_io_queues - 1;

		irq_queues = 1;

	} else {

		irq_queues = nr_io_queues - this_p_queues;

	}

	dev->io_queues[HCTX_TYPE_POLL] = this_p_queues;



	/*

	 * For irq sets, we have to ask for minvec == maxvec. This passes
@@ -2100,7 +2094,7 @@ static int nvme_setup_irqs(struct nvme_dev *dev, int nr_io_queues) 
	 * IRQ vector needs.

	 */

	do {

		nvme_calc_io_queues(dev, nr_io_queues);

		nvme_calc_io_queues(dev, irq_queues);

		irq_sets[0] = dev->io_queues[HCTX_TYPE_DEFAULT];

		irq_sets[1] = dev->io_queues[HCTX_TYPE_READ];

		if (!irq_sets[1])
@@ -2111,11 +2105,11 @@ static int nvme_setup_irqs(struct nvme_dev *dev, int nr_io_queues) 
		 * 1 + 1 queues, just ask for a single vector. We'll share

		 * that between the single IO queue and the admin queue.

		 */

		if (!(result < 0 && nr_io_queues == 1))

			nr_io_queues = irq_sets[0] + irq_sets[1] + 1;

		if (result >= 0 && irq_queues > 1)

			irq_queues = irq_sets[0] + irq_sets[1] + 1;



		result = pci_alloc_irq_vectors_affinity(pdev, nr_io_queues,

				nr_io_queues,

		result = pci_alloc_irq_vectors_affinity(pdev, irq_queues,

				irq_queues,

				PCI_IRQ_ALL_TYPES | PCI_IRQ_AFFINITY, &affd);



		/*
@@ -2125,12 +2119,12 @@ static int nvme_setup_irqs(struct nvme_dev *dev, int nr_io_queues) 
		 * likely does not. Back down to ask for just one vector.

		 */

		if (result == -ENOSPC) {

			nr_io_queues--;

			if (!nr_io_queues)

			irq_queues--;

			if (!irq_queues)

				return result;

			continue;

		} else if (result == -EINVAL) {

			nr_io_queues = 1;

			irq_queues = 1;

			continue;

		} else if (result <= 0)

			return -EIO;