[PATCHv5 5/6] NVMe: Add pci suspend/resume driver callbacks

[Keith Busch]

Used for going in and out of low power states. Resuming reuses the IO
queues from the previous initialization, freeing any allocated queues
that are no longer usable.

Signed-off-by: Keith Busch <keith.busch at intel.com>
---
 drivers/block/nvme-core.c |   73 +++++++++++++++++++++++++++++++++++---------
 1 files changed, 58 insertions(+), 15 deletions(-)

diff --git a/drivers/block/nvme-core.c b/drivers/block/nvme-core.c
index bf002a8..9649844 100644
--- a/drivers/block/nvme-core.c
+++ b/drivers/block/nvme-core.c
@@ -792,6 +792,12 @@ static void nvme_make_request(struct request_queue *q, struct bio *bio)
 	struct nvme_queue *nvmeq = get_nvmeq(ns->dev);
 	int result = -EBUSY;
 
+	if (!nvmeq) {
+		put_nvmeq(NULL);
+		bio_endio(bio, -EIO);
+		return;
+	}
+
 	spin_lock_irq(&nvmeq->q_lock);
 	if (!nvmeq->q_suspended && bio_list_empty(&nvmeq->sq_cong))
 		result = nvme_submit_bio_queue(nvmeq, ns, bio);
@@ -1259,9 +1265,13 @@ static int nvme_configure_admin_queue(struct nvme_dev *dev)
 	if (result < 0)
 		return result;
 
-	nvmeq = nvme_alloc_queue(dev, 0, 64, 0);
-	if (!nvmeq)
-		return -ENOMEM;
+	nvmeq = dev->queues[0];
+	if (!nvmeq) {
+		nvmeq = nvme_alloc_queue(dev, 0, 64, 0);
+		if (!nvmeq)
+			return -ENOMEM;
+		dev->queues[0] = nvmeq;
+	}
 
 	aqa = nvmeq->q_depth - 1;
 	aqa |= aqa << 16;
@@ -1278,21 +1288,16 @@ static int nvme_configure_admin_queue(struct nvme_dev *dev)
 
 	result = nvme_enable_ctrl(dev, cap);
 	if (result)
-		goto free_q;
+		return result;
 
 	result = queue_request_irq(dev, nvmeq, "nvme admin");
 	if (result)
-		goto free_q;
+		return result;
 
-	dev->queues[0] = nvmeq;
 	spin_lock(&nvmeq->q_lock);
 	nvme_init_queue(nvmeq, 0);
 	spin_unlock(&nvmeq->q_lock);
 	return result;
-
- free_q:
-	nvme_free_queue(nvmeq);
-	return result;
 }
 
 struct nvme_iod *nvme_map_user_pages(struct nvme_dev *dev, int write,
@@ -1799,6 +1804,21 @@ static int nvme_setup_io_queues(struct nvme_dev *dev)
 	if (result)
 		goto free_queues;
 
+	/* Free previously allocated queues that are no longer usable */
+	spin_lock(&dev_list_lock);
+	for (i = dev->queue_count - 1; i > nr_io_queues; i--) {
+		struct nvme_queue *nvmeq = dev->queues[i];
+
+		spin_lock(&nvmeq->q_lock);
+		nvme_cancel_ios(nvmeq, false);
+		spin_unlock(&nvmeq->q_lock);
+
+		nvme_free_queue(nvmeq);
+		dev->queue_count--;
+		dev->queues[i] = NULL;
+	}
+	spin_unlock(&dev_list_lock);
+
 	cpu = cpumask_first(cpu_online_mask);
 	for (i = 0; i < nr_io_queues; i++) {
 		irq_set_affinity_hint(dev->entry[i].vector, get_cpu_mask(cpu));
@@ -1807,7 +1827,7 @@ static int nvme_setup_io_queues(struct nvme_dev *dev)
 
 	q_depth = min_t(int, NVME_CAP_MQES(readq(&dev->bar->cap)) + 1,
 								NVME_Q_DEPTH);
-	for (i = 0; i < nr_io_queues; i++) {
+	for (i = dev->queue_count - 1; i < nr_io_queues; i++) {
 		dev->queues[i + 1] = nvme_alloc_queue(dev, i + 1, q_depth, i);
 		if (!dev->queues[i + 1]) {
 			result = -ENOMEM;
@@ -2193,8 +2213,30 @@ static void nvme_remove(struct pci_dev *pdev)
 #define nvme_link_reset NULL
 #define nvme_slot_reset NULL
 #define nvme_error_resume NULL
-#define nvme_suspend NULL
-#define nvme_resume NULL
+
+static int nvme_suspend(struct device *dev)
+{
+	struct pci_dev *pdev = to_pci_dev(dev);
+	struct nvme_dev *ndev = pci_get_drvdata(pdev);
+
+	nvme_dev_shutdown(ndev);
+	return 0;
+}
+
+static int nvme_resume(struct device *dev)
+{
+	struct pci_dev *pdev = to_pci_dev(dev);
+	struct nvme_dev *ndev = pci_get_drvdata(pdev);
+	int ret;
+
+	ret = nvme_dev_start(ndev);
+	/* XXX: should remove gendisks if resume fails */
+	if (ret)
+		nvme_free_queues(ndev);
+	return ret;
+}
+
+SIMPLE_DEV_PM_OPS(nvme_dev_pm_ops, nvme_suspend, nvme_resume);
 
 static const struct pci_error_handlers nvme_err_handler = {
 	.error_detected	= nvme_error_detected,
@@ -2218,8 +2260,9 @@ static struct pci_driver nvme_driver = {
 	.id_table	= nvme_id_table,
 	.probe		= nvme_probe,
 	.remove		= nvme_remove,
-	.suspend	= nvme_suspend,
-	.resume		= nvme_resume,
+	.driver		= {
+		.pm	= &nvme_dev_pm_ops,
+	},
 	.err_handler	= &nvme_err_handler,
 };
 
-- 
1.7.0.4