[PATCH 1/2] NVMe: Namespace removal simplifications

[PATCH 1/2] NVMe: Namespace removal simplifications

[Keith Busch]

This liberates namespace removal from the device, allowing gendisk
references to be closed independent of the nvme controller reference
count.

Signed-off-by: Keith Busch <keith.busch at intel.com>
---
 drivers/block/nvme-core.c |   42 ++++++++++--------------------------------
 1 file changed, 10 insertions(+), 32 deletions(-)

diff --git a/drivers/block/nvme-core.c b/drivers/block/nvme-core.c
index b02ae3d..904b54f 100644
--- a/drivers/block/nvme-core.c
+++ b/drivers/block/nvme-core.c
@@ -1943,6 +1943,7 @@ static int nvme_compat_ioctl(struct block_device *bdev, fmode_t mode,
 #define nvme_compat_ioctl	NULL
 #endif
 
+static void nvme_free_dev(struct kref *kref);
 static void nvme_free_ns(struct kref *kref)
 {
 	struct nvme_ns *ns = container_of(kref, struct nvme_ns, kref);
@@ -1951,6 +1952,7 @@ static void nvme_free_ns(struct kref *kref)
 	ns->disk->private_data = NULL;
 	spin_unlock(&dev_list_lock);
 
+	kref_put(&ns->dev->kref, nvme_free_dev);
 	put_disk(ns->disk);
 	kfree(ns);
 }
@@ -1966,22 +1968,14 @@ static int nvme_open(struct block_device *bdev, fmode_t mode)
 		ret = -ENXIO;
 	else if (!kref_get_unless_zero(&ns->kref))
 		ret = -ENXIO;
-	else if (!kref_get_unless_zero(&ns->dev->kref)) {
-		kref_put(&ns->kref, nvme_free_ns);
-		ret = -ENXIO;
-	}
 	spin_unlock(&dev_list_lock);
 
 	return ret;
 }
 
-static void nvme_free_dev(struct kref *kref);
 static void nvme_release(struct gendisk *disk, fmode_t mode)
 {
 	struct nvme_ns *ns = disk->private_data;
-	struct nvme_dev *dev = ns->dev;
-
-	kref_put(&dev->kref, nvme_free_dev);
 	kref_put(&ns->kref, nvme_free_ns);
 }
 
@@ -2179,6 +2173,7 @@ static void nvme_alloc_ns(struct nvme_dev *dev, unsigned nsid)
 	if (nvme_revalidate_disk(ns->disk))
 		goto out_free_disk;
 
+	kref_get(&dev->kref);
 	add_disk(ns->disk);
 	if (ns->ms) {
 		struct block_device *bd = bdget_disk(ns->disk, 0);
@@ -2374,12 +2369,6 @@ static int nvme_setup_io_queues(struct nvme_dev *dev)
 	return result;
 }
 
-static void nvme_free_namespace(struct nvme_ns *ns)
-{
-	list_del(&ns->list);
-	kref_put(&ns->kref, nvme_free_ns);
-}
-
 static int ns_cmp(void *priv, struct list_head *a, struct list_head *b)
 {
 	struct nvme_ns *nsa = container_of(a, struct nvme_ns, list);
@@ -2421,7 +2410,9 @@ static void nvme_ns_remove(struct nvme_ns *ns)
 	if (kill || !blk_queue_dying(ns->queue)) {
 		blk_mq_abort_requeue_list(ns->queue);
 		blk_cleanup_queue(ns->queue);
-        }
+	}
+	list_del_init(&ns->list);
+	kref_put(&ns->kref, nvme_free_ns);
 }
 
 static void nvme_scan_namespaces(struct nvme_dev *dev, unsigned nn)
@@ -2432,18 +2423,14 @@ static void nvme_scan_namespaces(struct nvme_dev *dev, unsigned nn)
 	for (i = 1; i <= nn; i++) {
 		ns = nvme_find_ns(dev, i);
 		if (ns) {
-			if (revalidate_disk(ns->disk)) {
+			if (revalidate_disk(ns->disk))
 				nvme_ns_remove(ns);
-				nvme_free_namespace(ns);
-			}
 		} else
 			nvme_alloc_ns(dev, i);
 	}
 	list_for_each_entry_safe(ns, next, &dev->namespaces, list) {
-		if (ns->ns_id > nn) {
+		if (ns->ns_id > nn)
 			nvme_ns_remove(ns);
-			nvme_free_namespace(ns);
-		}
 	}
 	list_sort(NULL, &dev->namespaces, ns_cmp);
 }
@@ -2833,9 +2820,9 @@ static void nvme_dev_shutdown(struct nvme_dev *dev)
 
 static void nvme_dev_remove(struct nvme_dev *dev)
 {
-	struct nvme_ns *ns;
+	struct nvme_ns *ns, *next;
 
-	list_for_each_entry(ns, &dev->namespaces, list)
+	list_for_each_entry_safe(ns, next, &dev->namespaces, list)
 		nvme_ns_remove(ns);
 }
 
@@ -2891,21 +2878,12 @@ static void nvme_release_instance(struct nvme_dev *dev)
 	spin_unlock(&dev_list_lock);
 }
 
-static void nvme_free_namespaces(struct nvme_dev *dev)
-{
-	struct nvme_ns *ns, *next;
-
-	list_for_each_entry_safe(ns, next, &dev->namespaces, list)
-		nvme_free_namespace(ns);
-}
-
 static void nvme_free_dev(struct kref *kref)
 {
 	struct nvme_dev *dev = container_of(kref, struct nvme_dev, kref);
 
 	put_device(dev->dev);
 	put_device(dev->device);
-	nvme_free_namespaces(dev);
 	nvme_release_instance(dev);
 	if (dev->tagset.tags)
 		blk_mq_free_tag_set(&dev->tagset);
-- 
1.7.10.4

[PATCHv2 2/2] NVMe: Simplify device resume on io queue failure

[Keith Busch]

Releasing IO queues and disks was done in a work queue outside the
controller resume context to delete namespaces if the controller failed
after a resume from suspend. This is unnecessary since we can resume
a device asynchronously.

This patch makes resume use probe_work so it can directly remove
namespaces if the device is manageable but not IO capable. Since the
deleting disks was the only reason we had the convoluted "reset_workfn",
this patch removes that unnecessary indirection.

Signed-off-by: Keith Busch <keith.busch at intel.com>
---
v1->v2:

  Removed unrelated nvme work_queue changes.

  Merge conflict from the previous commit.

  I'll also point out the new print here should satisfy Jon's case he
  brought up here:

    http://lists.infradead.org/pipermail/linux-nvme/2015-September/002401.html

 drivers/block/nvme-core.c |   34 ++++++----------------------------
 include/linux/nvme.h      |    1 -
 2 files changed, 6 insertions(+), 29 deletions(-)

diff --git a/drivers/block/nvme-core.c b/drivers/block/nvme-core.c
index 904b54f..bf35846 100644
--- a/drivers/block/nvme-core.c
+++ b/drivers/block/nvme-core.c
@@ -1285,7 +1285,6 @@ static void nvme_abort_req(struct request *req)
 		list_del_init(&dev->node);
 		dev_warn(dev->dev, "I/O %d QID %d timeout, reset controller\n",
 							req->tag, nvmeq->qid);
-		dev->reset_workfn = nvme_reset_failed_dev;
 		queue_work(nvme_workq, &dev->reset_work);
  out:
 		spin_unlock_irqrestore(&dev_list_lock, flags);
@@ -2089,7 +2088,6 @@ static int nvme_kthread(void *data)
 				dev_warn(dev->dev,
 					"Failed status: %x, reset controller\n",
 					readl(&dev->bar->csts));
-				dev->reset_workfn = nvme_reset_failed_dev;
 				queue_work(nvme_workq, &dev->reset_work);
 				continue;
 			}
@@ -3025,14 +3023,6 @@ static int nvme_remove_dead_ctrl(void *arg)
 	return 0;
 }
 
-static void nvme_remove_disks(struct work_struct *ws)
-{
-	struct nvme_dev *dev = container_of(ws, struct nvme_dev, reset_work);
-
-	nvme_free_queues(dev, 1);
-	nvme_dev_remove(dev);
-}
-
 static int nvme_dev_resume(struct nvme_dev *dev)
 {
 	int ret;
@@ -3041,10 +3031,9 @@ static int nvme_dev_resume(struct nvme_dev *dev)
 	if (ret)
 		return ret;
 	if (dev->online_queues < 2) {
-		spin_lock(&dev_list_lock);
-		dev->reset_workfn = nvme_remove_disks;
-		queue_work(nvme_workq, &dev->reset_work);
-		spin_unlock(&dev_list_lock);
+		dev_warn(dev->dev, "IO queues not created\n");
+		nvme_free_queues(dev, 1);
+		nvme_dev_remove(dev);
 	} else {
 		nvme_unfreeze_queues(dev);
 		nvme_dev_add(dev);
@@ -3091,12 +3080,6 @@ static void nvme_reset_failed_dev(struct work_struct *ws)
 	nvme_dev_reset(dev);
 }
 
-static void nvme_reset_workfn(struct work_struct *work)
-{
-	struct nvme_dev *dev = container_of(work, struct nvme_dev, reset_work);
-	dev->reset_workfn(work);
-}
-
 static int nvme_reset(struct nvme_dev *dev)
 {
 	int ret = -EBUSY;
@@ -3106,7 +3089,6 @@ static int nvme_reset(struct nvme_dev *dev)
 
 	spin_lock(&dev_list_lock);
 	if (!work_pending(&dev->reset_work)) {
-		dev->reset_workfn = nvme_reset_failed_dev;
 		queue_work(nvme_workq, &dev->reset_work);
 		ret = 0;
 	}
@@ -3159,8 +3141,7 @@ static int nvme_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 		goto free;
 
 	INIT_LIST_HEAD(&dev->namespaces);
-	dev->reset_workfn = nvme_reset_failed_dev;
-	INIT_WORK(&dev->reset_work, nvme_reset_workfn);
+	INIT_WORK(&dev->reset_work, nvme_reset_failed_dev);
 	dev->dev = get_device(&pdev->dev);
 	pci_set_drvdata(pdev, dev);
 	result = nvme_set_instance(dev);
@@ -3223,7 +3204,7 @@ static void nvme_reset_notify(struct pci_dev *pdev, bool prepare)
 	if (prepare)
 		nvme_dev_shutdown(dev);
 	else
-		nvme_dev_resume(dev);
+		schedule_work(&dev->probe_work);
 }
 
 static void nvme_shutdown(struct pci_dev *pdev)
@@ -3277,10 +3258,7 @@ static int nvme_resume(struct device *dev)
 	struct pci_dev *pdev = to_pci_dev(dev);
 	struct nvme_dev *ndev = pci_get_drvdata(pdev);
 
-	if (nvme_dev_resume(ndev) && !work_busy(&ndev->reset_work)) {
-		ndev->reset_workfn = nvme_reset_failed_dev;
-		queue_work(nvme_workq, &ndev->reset_work);
-	}
+	schedule_work(&ndev->probe_work);
 	return 0;
 }
 #endif
diff --git a/include/linux/nvme.h b/include/linux/nvme.h
index 992b9c1..7725b4c 100644
--- a/include/linux/nvme.h
+++ b/include/linux/nvme.h
@@ -104,7 +104,6 @@ struct nvme_dev {
 	struct list_head namespaces;
 	struct kref kref;
 	struct device *device;
-	work_func_t reset_workfn;
 	struct work_struct reset_work;
 	struct work_struct probe_work;
 	struct work_struct scan_work;
-- 
1.7.10.4

[PATCH 1/2] NVMe: Namespace removal simplifications

[Christoph Hellwig]

Looks good,

Reviewed-by: Christoph Hellwig <hch at lst.de>

[PATCHv2 2/2] NVMe: Simplify device resume on io queue failure

[Christoph Hellwig]

On Fri, Oct 02, 2015@10:37:29AM -0600, Keith Busch wrote:
> Releasing IO queues and disks was done in a work queue outside the
> controller resume context to delete namespaces if the controller failed
> after a resume from suspend. This is unnecessary since we can resume
> a device asynchronously.
> 
> This patch makes resume use probe_work so it can directly remove
> namespaces if the device is manageable but not IO capable. Since the
> deleting disks was the only reason we had the convoluted "reset_workfn",
> this patch removes that unnecessary indirection.
> 
> Signed-off-by: Keith Busch <keith.busch at intel.com>

Looks good,

Reviewed-by: Christoph Hellwig <hch at lst.de>