[PATCH] NVMe: Fix partition detection issue(Hot Remove followed by Hot Add)

[Shiro Itou 伊東]

----------------------------------------
> From: indraneel.m at samsung.com
> To: linux-nvme at lists.infradead.org
> CC: willy at linux.intel.com; keith.busch at intel.com; shiro.itou at outlook.com
> Subject: [PATCH] NVMe: Fix partition detection issue(Hot Remove followed by Hot Add)
> Date: Wed, 6 Aug 2014 18:24:38 +0530
>
> This patch addresses the same issue that has been discussed at
> http://lists.infradead.org/pipermail/linux-nvme/2014-August/001093.html
> recently
> and provides the best of both worlds (both static & dynamic minor allocation
> schemes similar to SCSI driver(sd)).
>
> - Partially reverts the dynamic minor allocation scheme (but retains the
> GENHD_FL_EXT_DEVT flag to allow allocating very large of minors dynamically)
>

It is same. Patch I send do not remove GENHD_FL_EXT_DEVT, which required for dynamic(same as in SCSI). It apply on latest branch.


> introduced in commit 469071a37afc8a627b6b2ddf29db0a097d864845 and
> re-introduces static minor allocation.
> - Aligns Hot-Plug behaviour to SCSI.
> - Uses one common ida allocation routine for allocating namespace & dev
> instances.
> - Introduces a new module parameter nvme_minors to manage the static minor
> allocations(default is 64).
>
> Signed-off-by: Indraneel M <indraneel.m at samsung.com>
>
> diff --git a/drivers/block/nvme-core.c b/drivers/block/nvme-core.c
> index 28aec2d..6d01164 100644
> --- a/drivers/block/nvme-core.c
> +++ b/drivers/block/nvme-core.c
> @@ -65,6 +65,10 @@ MODULE_PARM_DESC(retry_time, "time in seconds to retry
> failed I/O");
> static int nvme_major;
> module_param(nvme_major, int, 0);
>
> +static int nvme_minors = 64;
> +module_param(nvme_minors, int, 0644);
> +MODULE_PARM_DESC(nvme_minors, "Minors numbers to allocate per Namespace");
> +
> static int use_threaded_interrupts;
> module_param(use_threaded_interrupts, int, 0);
>
> @@ -1962,12 +1966,42 @@ static void nvme_config_discard(struct nvme_ns *ns)
> queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, ns->queue);
> }
>
> +static DEFINE_IDA(nvme_ns_instance_ida);
> +static DEFINE_IDA(nvme_dev_instance_ida);
> +
> +static int nvme_get_instance(struct nvme_dev *dev, struct ida *ida)
> +{
> + int instance, error;
> +
> + do {
> + if (!ida_pre_get(ida, GFP_KERNEL))
> + return -ENODEV;
> +
> + spin_lock(&dev_list_lock);
> + error = ida_get_new(ida, &instance);
> + spin_unlock(&dev_list_lock);
> + } while (error == -EAGAIN);
> +
> + if (error)
> + instance = -ENODEV;
> +
> + return instance;
> +}
> +
> +static void nvme_put_instance(struct nvme_dev *dev, struct ida *ida, int
> instance)
> +{
> + spin_lock(&dev_list_lock);
> + ida_remove(ida, instance);
> + spin_unlock(&dev_list_lock);
> +}
> +
> +
> static struct nvme_ns *nvme_alloc_ns(struct nvme_dev *dev, unsigned nsid,
> struct nvme_id_ns *id, struct nvme_lba_range_type
> *rt)
> {
> struct nvme_ns *ns;
> struct gendisk *disk;
> - int lbaf;
> + int lbaf, instance;
>
> if (rt->attributes & NVME_LBART_ATTRIB_HIDE)
> return NULL;
> @@ -1985,7 +2019,7 @@ static struct nvme_ns *nvme_alloc_ns(struct nvme_dev
> *dev, unsigned nsid,
> ns->dev = dev;
> ns->queue->queuedata = ns;
>
> - disk = alloc_disk(0);
> + disk = alloc_disk(nvme_minors);
> if (!disk)
> goto out_free_queue;
> ns->ns_id = nsid;
> @@ -2000,7 +2034,13 @@ static struct nvme_ns *nvme_alloc_ns(struct nvme_dev
> *dev, unsigned nsid,
> blk_queue_flush(ns->queue, REQ_FLUSH | REQ_FUA);
>
> disk->major = nvme_major;
> - disk->first_minor = 0;
> +
> + disk->minors = nvme_minors;
> + instance = nvme_get_instance(dev, &nvme_ns_instance_ida);
> + if (instance < 0)
> + goto out_free_disk;
> + disk->first_minor = nvme_minors * instance;
> +
> disk->fops = &nvme_fops;
> disk->private_data = ns;
> disk->queue = ns->queue;
> @@ -2014,6 +2054,8 @@ static struct nvme_ns *nvme_alloc_ns(struct nvme_dev
> *dev, unsigned nsid,
>
> return ns;
>
> + out_free_disk:
> + put_disk(ns->disk);
> out_free_queue:
> blk_cleanup_queue(ns->queue);
> out_free_ns:
> @@ -2623,42 +2665,16 @@ static void nvme_release_prp_pools(struct nvme_dev
> *dev)
> dma_pool_destroy(dev->prp_small_pool);
> }
>
> -static DEFINE_IDA(nvme_instance_ida);
> -
> -static int nvme_set_instance(struct nvme_dev *dev)
> -{
> - int instance, error;
> -
> - do {
> - if (!ida_pre_get(&nvme_instance_ida, GFP_KERNEL))
> - return -ENODEV;
> -
> - spin_lock(&dev_list_lock);
> - error = ida_get_new(&nvme_instance_ida, &instance);
> - spin_unlock(&dev_list_lock);
> - } while (error == -EAGAIN);
> -
> - if (error)
> - return -ENODEV;
> -
> - dev->instance = instance;
> - return 0;
> -}
> -
> -static void nvme_release_instance(struct nvme_dev *dev)
> -{
> - spin_lock(&dev_list_lock);
> - ida_remove(&nvme_instance_ida, dev->instance);
> - spin_unlock(&dev_list_lock);
> -}
> -
> static void nvme_free_namespaces(struct nvme_dev *dev)
> {
> struct nvme_ns *ns, *next;
> + int index;
>
> list_for_each_entry_safe(ns, next, &dev->namespaces, list) {
> + index = ns->disk->first_minor / nvme_minors;
> list_del(&ns->list);
> put_disk(ns->disk);
> + nvme_put_instance(dev, &nvme_ns_instance_ida, index);
> kfree(ns);
> }
> }
> @@ -2669,6 +2685,7 @@ static void nvme_free_dev(struct kref *kref)
>
> nvme_free_namespaces(dev);
> free_percpu(dev->io_queue);
> + nvme_put_instance(dev, &nvme_dev_instance_ida, dev->instance);
> kfree(dev->queues);
> kfree(dev->entry);
> kfree(dev);
> @@ -2844,9 +2861,10 @@ static int nvme_probe(struct pci_dev *pdev, const
> struct pci_device_id *id)
> INIT_WORK(&dev->cpu_work, nvme_cpu_workfn);
> dev->pci_dev = pdev;
> pci_set_drvdata(pdev, dev);
> - result = nvme_set_instance(dev);
> - if (result)
> + result = nvme_get_instance(dev, &nvme_dev_instance_ida);
> + if (result < 0)
> goto free;
> + dev->instance = result;
>
> result = nvme_setup_prp_pools(dev);
> if (result)
> @@ -2883,7 +2901,7 @@ static int nvme_probe(struct pci_dev *pdev, const
> struct pci_device_id *id)
> nvme_free_queues(dev, 0);
> nvme_release_prp_pools(dev);
> release:
> - nvme_release_instance(dev);
> + nvme_put_instance(dev, &nvme_dev_instance_ida, dev->instance);
> free:
> free_percpu(dev->io_queue);
> kfree(dev->queues);
> @@ -2924,7 +2942,6 @@ static void nvme_remove(struct pci_dev *pdev)
> nvme_dev_shutdown(dev);
> nvme_free_queues(dev, 0);
> rcu_barrier();
> - nvme_release_instance(dev);
> nvme_release_prp_pools(dev);
> kref_put(&dev->kref, nvme_free_dev);
> }
> --
> 1.8.3.2
>
>
>