[PATCH 0/1] nvme: introduce generic per-namespace chardev

[PATCH 0/1] nvme: introduce generic per-namespace chardev

[Minwoo Im]

Hello,

This patch introduces per-namespace character device to I/O in case that
blkdev is not initialized properly.  Userspace applications are able to
I/O to the generic namespace chardev even there's no blkdev properly
initialized.

This patch is derived from Javier's patch series [1].  Changes from the
previous version are:

  - Update naming convention for the chardev exactly the same with the
    blkdev:
        /dev/nvme-generic-XcYnZ  to  /dev/nvme-generic-XnY

  - Re-consider the multipath support.  Rather than exposing all the
    path-specific namespace path with controller(e.g., nvmeXcYnZ), only
    expose head namespace instance in case of multipath.  Otherwise, it
    will expose all the blkdevs created.

[1] https://lore.kernel.org/linux-nvme/20210301192452.16770-1-javier.gonz@samsung.com/

Minwoo Im (1):
  nvme: introduce generic per-namespace chardev

 drivers/nvme/host/core.c      | 170 +++++++++++++++++++++++++++++++++-
 drivers/nvme/host/multipath.c |  17 ++++
 drivers/nvme/host/nvme.h      |  25 +++++
 3 files changed, 209 insertions(+), 3 deletions(-)

-- 
2.27.0


_______________________________________________
Linux-nvme mailing list
Linux-nvme@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-nvme

[PATCH 1/1] nvme: introduce generic per-namespace chardev

[Minwoo Im]

Userspace has not been allowed to I/O to device that's failed to
be initialized.  This patch introduces generic per-namespace character
device to allow userspace to I/O regardless the block device is there or
not.

The chardev naming convention will exactly be the same with the existing
blkdev's one.  nvme_set_generic_ns_name() introduced in this patch may
look like a duplication of nvme_set_disk_name(), but it's not allowing
controller path specific.  It just for per-namespace path specific.  So,
the naming will be:

	- /dev/nvme-generic-XnY

It also supports multipath which means it will not expose chardev for
the hidden namespace blkdevs (e.g., nvmeXcYnZ).  If
/dev/nvme-generic-XnY is created for the ns_head, then I/O request will
be routed to the controller-specified path by the iopolicy in the
subsystem.

This can be controlled by the module parameter `generic_ns` which is
turned on by default.

Signed-off-by: Minwoo Im <minwoo.im.dev@gmail.com>
Signed-off-by: Javier González <javier.gonz@samsung.com>
---
 drivers/nvme/host/core.c      | 170 +++++++++++++++++++++++++++++++++-
 drivers/nvme/host/multipath.c |  17 ++++
 drivers/nvme/host/nvme.h      |  25 +++++
 3 files changed, 209 insertions(+), 3 deletions(-)

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index c371db47de3c..7dc0e216524b 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -61,6 +61,10 @@ static bool streams;
 module_param(streams, bool, 0644);
 MODULE_PARM_DESC(streams, "turn on support for Streams write directives");
 
+static bool generic_ns = true;
+module_param(generic_ns, bool, 0644);
+MODULE_PARM_DESC(generic_ns, "support generic namespace character device");
+
 /*
  * nvme_wq - hosts nvme related works that are not reset or delete
  * nvme_reset_wq - hosts nvme reset works
@@ -85,8 +89,11 @@ static LIST_HEAD(nvme_subsystems);
 static DEFINE_MUTEX(nvme_subsystems_lock);
 
 static DEFINE_IDA(nvme_instance_ida);
+static DEFINE_IDA(nvme_generic_ns_minor_ida);
 static dev_t nvme_ctrl_base_chr_devt;
+static dev_t nvme_generic_ns_devt;
 static struct class *nvme_class;
+static struct class *nvme_generic_ns_class;
 static struct class *nvme_subsys_class;
 
 static void nvme_put_subsystem(struct nvme_subsystem *subsys);
@@ -542,6 +549,7 @@ static void nvme_free_ns_head(struct kref *ref)
 	struct nvme_ns_head *head =
 		container_of(ref, struct nvme_ns_head, ref);
 
+	cdev_device_del(&head->generic_ns->cdev, &head->generic_ns->device);
 	nvme_mpath_remove_disk(head);
 	ida_simple_remove(&head->subsys->ns_ida, head->instance);
 	cleanup_srcu_struct(&head->srcu);
@@ -3784,6 +3792,126 @@ static int __nvme_check_ids(struct nvme_subsystem *subsys,
 	return 0;
 }
 
+#ifdef CONFIG_NVME_MULTIPATH
+static int nvme_generic_ns_open(struct inode *inode, struct file *file)
+{
+	struct nvme_generic_ns *generic_ns = container_of(inode->i_cdev,
+			struct nvme_generic_ns, cdev);
+
+	if (!generic_ns->head->disk)
+		return -ENODEV;
+
+	file->private_data = generic_ns;
+	return nvme_ns_head_open(generic_ns->head->disk->part0, file->f_mode);
+}
+
+static int nvme_generic_ns_release(struct inode *inode, struct file *file)
+{
+	struct nvme_generic_ns *generic_ns = container_of(inode->i_cdev,
+			struct nvme_generic_ns, cdev);
+
+	nvme_ns_head_release(generic_ns->head->disk, file->f_mode);
+
+	return 0;
+}
+
+static long nvme_generic_ns_ioctl(struct file *file, unsigned int cmd,
+		unsigned long arg)
+{
+	struct nvme_generic_ns *generic_ns = file->private_data;
+
+	return nvme_ioctl(generic_ns->head->disk->part0, file->f_mode, cmd, arg);
+}
+#else
+static int nvme_generic_ns_open(struct inode *inode, struct file *file)
+{
+	struct nvme_generic_ns *generic_ns = container_of(inode->i_cdev,
+			struct nvme_generic_ns, cdev);
+
+	if (!generic_ns->ns)
+		return -ENODEV;
+
+	file->private_data = generic_ns;
+	return nvme_open(generic_ns->ns->disk->part0, file->f_mode);
+}
+
+static int nvme_generic_ns_release(struct inode *inode, struct file *file)
+{
+	struct nvme_generic_ns *generic_ns = container_of(inode->i_cdev,
+			struct nvme_generic_ns, cdev);
+
+	nvme_release(generic_ns->ns->disk, file->f_mode);
+
+	return 0;
+}
+
+static long nvme_generic_ns_ioctl(struct file *file, unsigned int cmd,
+		unsigned long arg)
+{
+	struct nvme_generic_ns *generic_ns = file->private_data;
+
+	return nvme_ioctl(generic_ns->ns->disk->part0, file->f_mode, cmd, arg);
+}
+#endif
+
+static const struct file_operations nvme_generic_ns_fops = {
+	.owner		= THIS_MODULE,
+	.open		= nvme_generic_ns_open,
+	.release	= nvme_generic_ns_release,
+	.unlocked_ioctl	= nvme_generic_ns_ioctl,
+	.compat_ioctl	= compat_ptr_ioctl,
+};
+
+static int nvme_alloc_generic_ns(struct nvme_ctrl *ctrl,
+		struct nvme_ns_head *head, struct nvme_ns *ns)
+{
+	struct nvme_generic_ns *generic_ns;
+	char name[DISK_NAME_LEN];
+	int minor;
+	int ret;
+
+	generic_ns = kzalloc_node(sizeof(*generic_ns), GFP_KERNEL,
+			ctrl->numa_node);
+	if (!generic_ns)
+		return -ENOMEM;
+
+	ret = ida_simple_get(&nvme_generic_ns_minor_ida, 0, 0, GFP_KERNEL);
+	if (ret < 0)
+		goto free_ns;
+	minor = ret;
+
+	device_initialize(&generic_ns->device);
+	generic_ns->device.devt = MKDEV(MAJOR(nvme_generic_ns_devt), minor);
+	generic_ns->device.class = nvme_generic_ns_class;
+	generic_ns->device.parent = ctrl->device;
+	dev_set_drvdata(&generic_ns->device, generic_ns);
+
+	nvme_set_generic_ns_name(name, head, ctrl);
+	ret = dev_set_name(&generic_ns->device, "%s", name);
+	if (ret)
+		goto put_ida;
+
+	cdev_init(&generic_ns->cdev, &nvme_generic_ns_fops);
+	generic_ns->cdev.owner = ctrl->ops->module;
+
+	ret = cdev_device_add(&generic_ns->cdev, &generic_ns->device);
+	if (ret)
+		goto free_kobj;
+
+	head->generic_ns = generic_ns;
+	generic_ns->head = head;
+	generic_ns->ns = ns;
+	return 0;
+
+free_kobj:
+	kfree_const(generic_ns->device.kobj.name);
+put_ida:
+	ida_simple_remove(&nvme_generic_ns_minor_ida, minor);
+free_ns:
+	kfree(generic_ns);
+	return ret;
+}
+
 static struct nvme_ns_head *nvme_alloc_ns_head(struct nvme_ctrl *ctrl,
 		unsigned nsid, struct nvme_ns_ids *ids)
 {
@@ -3862,6 +3990,13 @@ static int nvme_init_ns_head(struct nvme_ns *ns, unsigned nsid,
 			goto out_unlock;
 		}
 		head->shared = is_shared;
+
+		if (generic_ns && nvme_alloc_generic_ns(ctrl, head, ns)) {
+			dev_err(ctrl->device,
+				"Failed to initialize generic namespace %d\n",
+				nsid);
+			goto out_put_ns_head;
+		}
 	} else {
 		ret = -EINVAL;
 		if (!is_shared || !head->shared) {
@@ -3963,8 +4098,17 @@ static void nvme_alloc_ns(struct nvme_ctrl *ctrl, unsigned nsid,
 	memcpy(disk->disk_name, disk_name, DISK_NAME_LEN);
 	ns->disk = disk;
 
-	if (nvme_update_ns_info(ns, id))
-		goto out_put_disk;
+	/*
+	 * If the namespace update fails in a graceful manner, hide the block
+	 * device, but still allow for the generic namespae device to be
+	 * craeted.
+	 */
+	if (nvme_update_ns_info(ns, id)) {
+		if (generic_ns)
+			ns->disk->flags |= GENHD_FL_HIDDEN;
+		else
+			goto out_put_disk;
+	}
 
 	if ((ctrl->quirks & NVME_QUIRK_LIGHTNVM) && id->vs[0] == 0x1) {
 		if (nvme_nvm_register(ns, disk_name, node)) {
@@ -3983,6 +4127,7 @@ static void nvme_alloc_ns(struct nvme_ctrl *ctrl, unsigned nsid,
 
 	nvme_mpath_add_disk(ns, id);
 	nvme_fault_inject_init(&ns->fault_inject, ns->disk->disk_name);
+
 	kfree(id);
 
 	return;
@@ -4802,13 +4947,31 @@ static int __init nvme_core_init(void)
 	}
 	nvme_class->dev_uevent = nvme_class_uevent;
 
+	if (!generic_ns) return 0;
+
+	result = alloc_chrdev_region(&nvme_generic_ns_devt, 0,
+			NVME_MINORS, "nvme-generic-ns");
+	if (result < 0)
+		goto destroy_class;
+
 	nvme_subsys_class = class_create(THIS_MODULE, "nvme-subsystem");
 	if (IS_ERR(nvme_subsys_class)) {
 		result = PTR_ERR(nvme_subsys_class);
-		goto destroy_class;
+		goto unregister_generic_ns;
 	}
+
+	nvme_generic_ns_class = class_create(THIS_MODULE, "nvme-generic-ns");
+	if (IS_ERR(nvme_generic_ns_class)) {
+		result = PTR_ERR(nvme_subsys_class);
+		goto destroy_subsys_class;
+	}
+
 	return 0;
 
+destroy_subsys_class:
+	class_destroy(nvme_subsys_class);
+unregister_generic_ns:
+	unregister_chrdev_region(nvme_generic_ns_devt, NVME_MINORS);
 destroy_class:
 	class_destroy(nvme_class);
 unregister_chrdev:
@@ -4827,6 +4990,7 @@ static void __exit nvme_core_exit(void)
 {
 	class_destroy(nvme_subsys_class);
 	class_destroy(nvme_class);
+	unregister_chrdev_region(nvme_generic_ns_devt, NVME_MINORS);
 	unregister_chrdev_region(nvme_ctrl_base_chr_devt, NVME_MINORS);
 	destroy_workqueue(nvme_delete_wq);
 	destroy_workqueue(nvme_reset_wq);
diff --git a/drivers/nvme/host/multipath.c b/drivers/nvme/host/multipath.c
index a1d476e1ac02..4ec17d99de8e 100644
--- a/drivers/nvme/host/multipath.c
+++ b/drivers/nvme/host/multipath.c
@@ -65,6 +65,23 @@ void nvme_set_disk_name(char *disk_name, struct nvme_ns *ns,
 	}
 }
 
+/*
+ * It sets generic namespace chardev name based on the given namespace head.
+ * The naming convention follows the existing namespace disk name from
+ * nvme_set_disk_name(), but not allowing controller path specific.
+ */
+void nvme_set_generic_ns_name(char *dev_name, struct nvme_ns_head *head,
+			      struct nvme_ctrl *ctrl)
+{
+	if (!multipath) {
+		sprintf(dev_name, "nvme-generic-%dn%d",
+				ctrl->instance, head->instance);
+	} else {
+		sprintf(dev_name, "nvme-generic-%dn%d",
+				ctrl->subsys->instance, head->instance);
+	}
+}
+
 void nvme_failover_req(struct request *req)
 {
 	struct nvme_ns *ns = req->q->queuedata;
diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h
index 76de7ed55d90..97a4a48f78ed 100644
--- a/drivers/nvme/host/nvme.h
+++ b/drivers/nvme/host/nvme.h
@@ -410,6 +410,8 @@ struct nvme_ns_head {
 	bool			shared;
 	int			instance;
 	struct nvme_effects_log *effects;
+	struct nvme_generic_ns	*generic_ns;
+
 #ifdef CONFIG_NVME_MULTIPATH
 	struct gendisk		*disk;
 	struct bio_list		requeue_list;
@@ -461,6 +463,20 @@ struct nvme_ns {
 
 };
 
+/*
+ * Generic character device for a namespace.  This device is to support I/O to
+ * namespace even it's failed to initialize due to some reasons (e.g.,
+ * unsupported protection information, etc).
+ */
+struct nvme_generic_ns {
+	struct device		device;
+	struct cdev		cdev;
+	struct nvme_ns_head	*head;
+
+	/* targted namespace instance.  only valid in non-multipath */
+	struct nvme_ns		*ns;
+};
+
 /* NVMe ns supports metadata actions by the controller (generate/strip) */
 static inline bool nvme_ns_has_pi(struct nvme_ns *ns)
 {
@@ -663,6 +679,8 @@ void nvme_mpath_wait_freeze(struct nvme_subsystem *subsys);
 void nvme_mpath_start_freeze(struct nvme_subsystem *subsys);
 void nvme_set_disk_name(char *disk_name, struct nvme_ns *ns,
 			struct nvme_ctrl *ctrl, int *flags);
+void nvme_set_generic_ns_name(char *dev_name, struct nvme_ns_head *head,
+			      struct nvme_ctrl *ctrl);
 void nvme_failover_req(struct request *req);
 void nvme_kick_requeue_lists(struct nvme_ctrl *ctrl);
 int nvme_mpath_alloc_disk(struct nvme_ctrl *ctrl,struct nvme_ns_head *head);
@@ -711,6 +729,13 @@ static inline void nvme_set_disk_name(char *disk_name, struct nvme_ns *ns,
 	sprintf(disk_name, "nvme%dn%d", ctrl->instance, ns->head->instance);
 }
 
+static inline void nvme_set_generic_ns_name(char *dev_name,
+		struct nvme_ns_head *head, struct nvme_ctrl *ctrl)
+{
+	sprintf(dev_name, "nvme-generic-%dn%d", ctrl->instance,
+			head->instance);
+}
+
 static inline void nvme_failover_req(struct request *req)
 {
 }
-- 
2.27.0


_______________________________________________
Linux-nvme mailing list
Linux-nvme@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-nvme

Re: [PATCH 1/1] nvme: introduce generic per-namespace chardev

[Kanchan Joshi]

On Thu, Mar 25, 2021 at 6:08 PM Minwoo Im <minwoo.im.dev@gmail.com> wrote:
>
> Userspace has not been allowed to I/O to device that's failed to
> be initialized.  This patch introduces generic per-namespace character
> device to allow userspace to I/O regardless the block device is there or
> not.
>
> The chardev naming convention will exactly be the same with the existing
> blkdev's one.  nvme_set_generic_ns_name() introduced in this patch may
> look like a duplication of nvme_set_disk_name(), but it's not allowing
> controller path specific.  It just for per-namespace path specific.  So,
> the naming will be:
>
>         - /dev/nvme-generic-XnY
>
> It also supports multipath which means it will not expose chardev for
> the hidden namespace blkdevs (e.g., nvmeXcYnZ).  If
> /dev/nvme-generic-XnY is created for the ns_head, then I/O request will
> be routed to the controller-specified path by the iopolicy in the
> subsystem.
>
> This can be controlled by the module parameter `generic_ns` which is
> turned on by default.
>
> Signed-off-by: Minwoo Im <minwoo.im.dev@gmail.com>
> Signed-off-by: Javier González <javier.gonz@samsung.com>
> ---
>  drivers/nvme/host/core.c      | 170 +++++++++++++++++++++++++++++++++-
>  drivers/nvme/host/multipath.c |  17 ++++
>  drivers/nvme/host/nvme.h      |  25 +++++
>  3 files changed, 209 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
> index c371db47de3c..7dc0e216524b 100644
> --- a/drivers/nvme/host/core.c
> +++ b/drivers/nvme/host/core.c
> @@ -61,6 +61,10 @@ static bool streams;
>  module_param(streams, bool, 0644);
>  MODULE_PARM_DESC(streams, "turn on support for Streams write directives");
>
> +static bool generic_ns = true;
> +module_param(generic_ns, bool, 0644);
> +MODULE_PARM_DESC(generic_ns, "support generic namespace character device");
> +
>  /*
>   * nvme_wq - hosts nvme related works that are not reset or delete
>   * nvme_reset_wq - hosts nvme reset works
> @@ -85,8 +89,11 @@ static LIST_HEAD(nvme_subsystems);
>  static DEFINE_MUTEX(nvme_subsystems_lock);
>
>  static DEFINE_IDA(nvme_instance_ida);
> +static DEFINE_IDA(nvme_generic_ns_minor_ida);
>  static dev_t nvme_ctrl_base_chr_devt;
> +static dev_t nvme_generic_ns_devt;
>  static struct class *nvme_class;
> +static struct class *nvme_generic_ns_class;
>  static struct class *nvme_subsys_class;
>
>  static void nvme_put_subsystem(struct nvme_subsystem *subsys);
> @@ -542,6 +549,7 @@ static void nvme_free_ns_head(struct kref *ref)
>         struct nvme_ns_head *head =
>                 container_of(ref, struct nvme_ns_head, ref);
>
> +       cdev_device_del(&head->generic_ns->cdev, &head->generic_ns->device);
>         nvme_mpath_remove_disk(head);
>         ida_simple_remove(&head->subsys->ns_ida, head->instance);
>         cleanup_srcu_struct(&head->srcu);
> @@ -3784,6 +3792,126 @@ static int __nvme_check_ids(struct nvme_subsystem *subsys,
>         return 0;
>  }
>
> +#ifdef CONFIG_NVME_MULTIPATH
> +static int nvme_generic_ns_open(struct inode *inode, struct file *file)
> +{
> +       struct nvme_generic_ns *generic_ns = container_of(inode->i_cdev,
> +                       struct nvme_generic_ns, cdev);
> +
> +       if (!generic_ns->head->disk)
> +               return -ENODEV;
> +
> +       file->private_data = generic_ns;
> +       return nvme_ns_head_open(generic_ns->head->disk->part0, file->f_mode);
> +}
> +
> +static int nvme_generic_ns_release(struct inode *inode, struct file *file)
> +{
> +       struct nvme_generic_ns *generic_ns = container_of(inode->i_cdev,
> +                       struct nvme_generic_ns, cdev);
> +
> +       nvme_ns_head_release(generic_ns->head->disk, file->f_mode);
> +
> +       return 0;
> +}
> +
> +static long nvme_generic_ns_ioctl(struct file *file, unsigned int cmd,
> +               unsigned long arg)
> +{
> +       struct nvme_generic_ns *generic_ns = file->private_data;
> +
> +       return nvme_ioctl(generic_ns->head->disk->part0, file->f_mode, cmd, arg);
> +}
> +#else
> +static int nvme_generic_ns_open(struct inode *inode, struct file *file)
> +{
> +       struct nvme_generic_ns *generic_ns = container_of(inode->i_cdev,
> +                       struct nvme_generic_ns, cdev);
> +
> +       if (!generic_ns->ns)
> +               return -ENODEV;
> +
> +       file->private_data = generic_ns;
> +       return nvme_open(generic_ns->ns->disk->part0, file->f_mode);
> +}
> +
> +static int nvme_generic_ns_release(struct inode *inode, struct file *file)
> +{
> +       struct nvme_generic_ns *generic_ns = container_of(inode->i_cdev,
> +                       struct nvme_generic_ns, cdev);
> +
> +       nvme_release(generic_ns->ns->disk, file->f_mode);
> +
> +       return 0;
> +}
> +
> +static long nvme_generic_ns_ioctl(struct file *file, unsigned int cmd,
> +               unsigned long arg)
> +{
> +       struct nvme_generic_ns *generic_ns = file->private_data;
> +
> +       return nvme_ioctl(generic_ns->ns->disk->part0, file->f_mode, cmd, arg);
> +}
> +#endif
> +
> +static const struct file_operations nvme_generic_ns_fops = {
> +       .owner          = THIS_MODULE,
> +       .open           = nvme_generic_ns_open,
> +       .release        = nvme_generic_ns_release,
> +       .unlocked_ioctl = nvme_generic_ns_ioctl,
> +       .compat_ioctl   = compat_ptr_ioctl,
> +};
> +
> +static int nvme_alloc_generic_ns(struct nvme_ctrl *ctrl,
> +               struct nvme_ns_head *head, struct nvme_ns *ns)
> +{
> +       struct nvme_generic_ns *generic_ns;
> +       char name[DISK_NAME_LEN];
> +       int minor;
> +       int ret;
> +
> +       generic_ns = kzalloc_node(sizeof(*generic_ns), GFP_KERNEL,
> +                       ctrl->numa_node);
> +       if (!generic_ns)
> +               return -ENOMEM;
> +
> +       ret = ida_simple_get(&nvme_generic_ns_minor_ida, 0, 0, GFP_KERNEL);
> +       if (ret < 0)
> +               goto free_ns;
> +       minor = ret;
> +
> +       device_initialize(&generic_ns->device);
> +       generic_ns->device.devt = MKDEV(MAJOR(nvme_generic_ns_devt), minor);
> +       generic_ns->device.class = nvme_generic_ns_class;
> +       generic_ns->device.parent = ctrl->device;
> +       dev_set_drvdata(&generic_ns->device, generic_ns);
> +
> +       nvme_set_generic_ns_name(name, head, ctrl);
> +       ret = dev_set_name(&generic_ns->device, "%s", name);
> +       if (ret)
> +               goto put_ida;
> +
> +       cdev_init(&generic_ns->cdev, &nvme_generic_ns_fops);
> +       generic_ns->cdev.owner = ctrl->ops->module;
> +
> +       ret = cdev_device_add(&generic_ns->cdev, &generic_ns->device);
> +       if (ret)
> +               goto free_kobj;
> +
> +       head->generic_ns = generic_ns;
> +       generic_ns->head = head;
> +       generic_ns->ns = ns;
> +       return 0;
> +
> +free_kobj:
> +       kfree_const(generic_ns->device.kobj.name);
> +put_ida:
> +       ida_simple_remove(&nvme_generic_ns_minor_ida, minor);
> +free_ns:
> +       kfree(generic_ns);
> +       return ret;
> +}
> +
>  static struct nvme_ns_head *nvme_alloc_ns_head(struct nvme_ctrl *ctrl,
>                 unsigned nsid, struct nvme_ns_ids *ids)
>  {
> @@ -3862,6 +3990,13 @@ static int nvme_init_ns_head(struct nvme_ns *ns, unsigned nsid,
>                         goto out_unlock;
>                 }
>                 head->shared = is_shared;
> +
> +               if (generic_ns && nvme_alloc_generic_ns(ctrl, head, ns)) {
> +                       dev_err(ctrl->device,
> +                               "Failed to initialize generic namespace %d\n",
> +                               nsid);
> +                       goto out_put_ns_head;
> +               }
>         } else {
>                 ret = -EINVAL;
>                 if (!is_shared || !head->shared) {
> @@ -3963,8 +4098,17 @@ static void nvme_alloc_ns(struct nvme_ctrl *ctrl, unsigned nsid,
>         memcpy(disk->disk_name, disk_name, DISK_NAME_LEN);
>         ns->disk = disk;
>
> -       if (nvme_update_ns_info(ns, id))
> -               goto out_put_disk;
> +       /*
> +        * If the namespace update fails in a graceful manner, hide the block
> +        * device, but still allow for the generic namespae device to be
> +        * craeted.
> +        */
> +       if (nvme_update_ns_info(ns, id)) {
> +               if (generic_ns)
> +                       ns->disk->flags |= GENHD_FL_HIDDEN;
> +               else
> +                       goto out_put_disk;
> +       }
>
>         if ((ctrl->quirks & NVME_QUIRK_LIGHTNVM) && id->vs[0] == 0x1) {
>                 if (nvme_nvm_register(ns, disk_name, node)) {
> @@ -3983,6 +4127,7 @@ static void nvme_alloc_ns(struct nvme_ctrl *ctrl, unsigned nsid,
>
>         nvme_mpath_add_disk(ns, id);
>         nvme_fault_inject_init(&ns->fault_inject, ns->disk->disk_name);
> +
>         kfree(id);
>
>         return;
> @@ -4802,13 +4947,31 @@ static int __init nvme_core_init(void)
>         }
>         nvme_class->dev_uevent = nvme_class_uevent;
>
> +       if (!generic_ns) return 0;

This will suppress creation of nvme_subsys_class when generic_ns
parameter is set as 0.

> +       result = alloc_chrdev_region(&nvme_generic_ns_devt, 0,
> +                       NVME_MINORS, "nvme-generic-ns");
> +       if (result < 0)
> +               goto destroy_class;
> +
>         nvme_subsys_class = class_create(THIS_MODULE, "nvme-subsystem");
>         if (IS_ERR(nvme_subsys_class)) {
>                 result = PTR_ERR(nvme_subsys_class);
> -               goto destroy_class;
> +               goto unregister_generic_ns;
>         }
> +
> +       nvme_generic_ns_class = class_create(THIS_MODULE, "nvme-generic-ns");
> +       if (IS_ERR(nvme_generic_ns_class)) {
> +               result = PTR_ERR(nvme_subsys_class);
> +               goto destroy_subsys_class;
> +       }
> +
>         return 0;
>
> +destroy_subsys_class:
> +       class_destroy(nvme_subsys_class);
> +unregister_generic_ns:
> +       unregister_chrdev_region(nvme_generic_ns_devt, NVME_MINORS);
>  destroy_class:
>         class_destroy(nvme_class);
>  unregister_chrdev:
> @@ -4827,6 +4990,7 @@ static void __exit nvme_core_exit(void)
>  {
>         class_destroy(nvme_subsys_class);
>         class_destroy(nvme_class);
> +       unregister_chrdev_region(nvme_generic_ns_devt, NVME_MINORS);
>         unregister_chrdev_region(nvme_ctrl_base_chr_devt, NVME_MINORS);
>         destroy_workqueue(nvme_delete_wq);
>         destroy_workqueue(nvme_reset_wq);

The "nvme-generic-ns" class has not been destroyed here.

-- 
Kanchan

_______________________________________________
Linux-nvme mailing list
Linux-nvme@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-nvme

Re: [PATCH 1/1] nvme: introduce generic per-namespace chardev

[Minwoo Im]

On 21-03-29 14:01:20, Kanchan Joshi wrote:
> On Thu, Mar 25, 2021 at 6:08 PM Minwoo Im <minwoo.im.dev@gmail.com> wrote:
> >
> > Userspace has not been allowed to I/O to device that's failed to
> > be initialized.  This patch introduces generic per-namespace character
> > device to allow userspace to I/O regardless the block device is there or
> > not.
> >
> > The chardev naming convention will exactly be the same with the existing
> > blkdev's one.  nvme_set_generic_ns_name() introduced in this patch may
> > look like a duplication of nvme_set_disk_name(), but it's not allowing
> > controller path specific.  It just for per-namespace path specific.  So,
> > the naming will be:
> >
> >         - /dev/nvme-generic-XnY
> >
> > It also supports multipath which means it will not expose chardev for
> > the hidden namespace blkdevs (e.g., nvmeXcYnZ).  If
> > /dev/nvme-generic-XnY is created for the ns_head, then I/O request will
> > be routed to the controller-specified path by the iopolicy in the
> > subsystem.
> >
> > This can be controlled by the module parameter `generic_ns` which is
> > turned on by default.
> >
> > Signed-off-by: Minwoo Im <minwoo.im.dev@gmail.com>
> > Signed-off-by: Javier González <javier.gonz@samsung.com>
> > ---
> >  drivers/nvme/host/core.c      | 170 +++++++++++++++++++++++++++++++++-
> >  drivers/nvme/host/multipath.c |  17 ++++
> >  drivers/nvme/host/nvme.h      |  25 +++++
> >  3 files changed, 209 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
> > index c371db47de3c..7dc0e216524b 100644
> > --- a/drivers/nvme/host/core.c
> > +++ b/drivers/nvme/host/core.c
> > @@ -61,6 +61,10 @@ static bool streams;
> >  module_param(streams, bool, 0644);
> >  MODULE_PARM_DESC(streams, "turn on support for Streams write directives");
> >
> > +static bool generic_ns = true;
> > +module_param(generic_ns, bool, 0644);
> > +MODULE_PARM_DESC(generic_ns, "support generic namespace character device");
> > +
> >  /*
> >   * nvme_wq - hosts nvme related works that are not reset or delete
> >   * nvme_reset_wq - hosts nvme reset works
> > @@ -85,8 +89,11 @@ static LIST_HEAD(nvme_subsystems);
> >  static DEFINE_MUTEX(nvme_subsystems_lock);
> >
> >  static DEFINE_IDA(nvme_instance_ida);
> > +static DEFINE_IDA(nvme_generic_ns_minor_ida);
> >  static dev_t nvme_ctrl_base_chr_devt;
> > +static dev_t nvme_generic_ns_devt;
> >  static struct class *nvme_class;
> > +static struct class *nvme_generic_ns_class;
> >  static struct class *nvme_subsys_class;
> >
> >  static void nvme_put_subsystem(struct nvme_subsystem *subsys);
> > @@ -542,6 +549,7 @@ static void nvme_free_ns_head(struct kref *ref)
> >         struct nvme_ns_head *head =
> >                 container_of(ref, struct nvme_ns_head, ref);
> >
> > +       cdev_device_del(&head->generic_ns->cdev, &head->generic_ns->device);
> >         nvme_mpath_remove_disk(head);
> >         ida_simple_remove(&head->subsys->ns_ida, head->instance);
> >         cleanup_srcu_struct(&head->srcu);
> > @@ -3784,6 +3792,126 @@ static int __nvme_check_ids(struct nvme_subsystem *subsys,
> >         return 0;
> >  }
> >
> > +#ifdef CONFIG_NVME_MULTIPATH
> > +static int nvme_generic_ns_open(struct inode *inode, struct file *file)
> > +{
> > +       struct nvme_generic_ns *generic_ns = container_of(inode->i_cdev,
> > +                       struct nvme_generic_ns, cdev);
> > +
> > +       if (!generic_ns->head->disk)
> > +               return -ENODEV;
> > +
> > +       file->private_data = generic_ns;
> > +       return nvme_ns_head_open(generic_ns->head->disk->part0, file->f_mode);
> > +}
> > +
> > +static int nvme_generic_ns_release(struct inode *inode, struct file *file)
> > +{
> > +       struct nvme_generic_ns *generic_ns = container_of(inode->i_cdev,
> > +                       struct nvme_generic_ns, cdev);
> > +
> > +       nvme_ns_head_release(generic_ns->head->disk, file->f_mode);
> > +
> > +       return 0;
> > +}
> > +
> > +static long nvme_generic_ns_ioctl(struct file *file, unsigned int cmd,
> > +               unsigned long arg)
> > +{
> > +       struct nvme_generic_ns *generic_ns = file->private_data;
> > +
> > +       return nvme_ioctl(generic_ns->head->disk->part0, file->f_mode, cmd, arg);
> > +}
> > +#else
> > +static int nvme_generic_ns_open(struct inode *inode, struct file *file)
> > +{
> > +       struct nvme_generic_ns *generic_ns = container_of(inode->i_cdev,
> > +                       struct nvme_generic_ns, cdev);
> > +
> > +       if (!generic_ns->ns)
> > +               return -ENODEV;
> > +
> > +       file->private_data = generic_ns;
> > +       return nvme_open(generic_ns->ns->disk->part0, file->f_mode);
> > +}
> > +
> > +static int nvme_generic_ns_release(struct inode *inode, struct file *file)
> > +{
> > +       struct nvme_generic_ns *generic_ns = container_of(inode->i_cdev,
> > +                       struct nvme_generic_ns, cdev);
> > +
> > +       nvme_release(generic_ns->ns->disk, file->f_mode);
> > +
> > +       return 0;
> > +}
> > +
> > +static long nvme_generic_ns_ioctl(struct file *file, unsigned int cmd,
> > +               unsigned long arg)
> > +{
> > +       struct nvme_generic_ns *generic_ns = file->private_data;
> > +
> > +       return nvme_ioctl(generic_ns->ns->disk->part0, file->f_mode, cmd, arg);
> > +}
> > +#endif
> > +
> > +static const struct file_operations nvme_generic_ns_fops = {
> > +       .owner          = THIS_MODULE,
> > +       .open           = nvme_generic_ns_open,
> > +       .release        = nvme_generic_ns_release,
> > +       .unlocked_ioctl = nvme_generic_ns_ioctl,
> > +       .compat_ioctl   = compat_ptr_ioctl,
> > +};
> > +
> > +static int nvme_alloc_generic_ns(struct nvme_ctrl *ctrl,
> > +               struct nvme_ns_head *head, struct nvme_ns *ns)
> > +{
> > +       struct nvme_generic_ns *generic_ns;
> > +       char name[DISK_NAME_LEN];
> > +       int minor;
> > +       int ret;
> > +
> > +       generic_ns = kzalloc_node(sizeof(*generic_ns), GFP_KERNEL,
> > +                       ctrl->numa_node);
> > +       if (!generic_ns)
> > +               return -ENOMEM;
> > +
> > +       ret = ida_simple_get(&nvme_generic_ns_minor_ida, 0, 0, GFP_KERNEL);
> > +       if (ret < 0)
> > +               goto free_ns;
> > +       minor = ret;
> > +
> > +       device_initialize(&generic_ns->device);
> > +       generic_ns->device.devt = MKDEV(MAJOR(nvme_generic_ns_devt), minor);
> > +       generic_ns->device.class = nvme_generic_ns_class;
> > +       generic_ns->device.parent = ctrl->device;
> > +       dev_set_drvdata(&generic_ns->device, generic_ns);
> > +
> > +       nvme_set_generic_ns_name(name, head, ctrl);
> > +       ret = dev_set_name(&generic_ns->device, "%s", name);
> > +       if (ret)
> > +               goto put_ida;
> > +
> > +       cdev_init(&generic_ns->cdev, &nvme_generic_ns_fops);
> > +       generic_ns->cdev.owner = ctrl->ops->module;
> > +
> > +       ret = cdev_device_add(&generic_ns->cdev, &generic_ns->device);
> > +       if (ret)
> > +               goto free_kobj;
> > +
> > +       head->generic_ns = generic_ns;
> > +       generic_ns->head = head;
> > +       generic_ns->ns = ns;
> > +       return 0;
> > +
> > +free_kobj:
> > +       kfree_const(generic_ns->device.kobj.name);
> > +put_ida:
> > +       ida_simple_remove(&nvme_generic_ns_minor_ida, minor);
> > +free_ns:
> > +       kfree(generic_ns);
> > +       return ret;
> > +}
> > +
> >  static struct nvme_ns_head *nvme_alloc_ns_head(struct nvme_ctrl *ctrl,
> >                 unsigned nsid, struct nvme_ns_ids *ids)
> >  {
> > @@ -3862,6 +3990,13 @@ static int nvme_init_ns_head(struct nvme_ns *ns, unsigned nsid,
> >                         goto out_unlock;
> >                 }
> >                 head->shared = is_shared;
> > +
> > +               if (generic_ns && nvme_alloc_generic_ns(ctrl, head, ns)) {
> > +                       dev_err(ctrl->device,
> > +                               "Failed to initialize generic namespace %d\n",
> > +                               nsid);
> > +                       goto out_put_ns_head;
> > +               }
> >         } else {
> >                 ret = -EINVAL;
> >                 if (!is_shared || !head->shared) {
> > @@ -3963,8 +4098,17 @@ static void nvme_alloc_ns(struct nvme_ctrl *ctrl, unsigned nsid,
> >         memcpy(disk->disk_name, disk_name, DISK_NAME_LEN);
> >         ns->disk = disk;
> >
> > -       if (nvme_update_ns_info(ns, id))
> > -               goto out_put_disk;
> > +       /*
> > +        * If the namespace update fails in a graceful manner, hide the block
> > +        * device, but still allow for the generic namespae device to be
> > +        * craeted.
> > +        */
> > +       if (nvme_update_ns_info(ns, id)) {
> > +               if (generic_ns)
> > +                       ns->disk->flags |= GENHD_FL_HIDDEN;
> > +               else
> > +                       goto out_put_disk;
> > +       }
> >
> >         if ((ctrl->quirks & NVME_QUIRK_LIGHTNVM) && id->vs[0] == 0x1) {
> >                 if (nvme_nvm_register(ns, disk_name, node)) {
> > @@ -3983,6 +4127,7 @@ static void nvme_alloc_ns(struct nvme_ctrl *ctrl, unsigned nsid,
> >
> >         nvme_mpath_add_disk(ns, id);
> >         nvme_fault_inject_init(&ns->fault_inject, ns->disk->disk_name);
> > +
> >         kfree(id);
> >
> >         return;
> > @@ -4802,13 +4947,31 @@ static int __init nvme_core_init(void)
> >         }
> >         nvme_class->dev_uevent = nvme_class_uevent;
> >
> > +       if (!generic_ns) return 0;
> 
> This will suppress creation of nvme_subsys_class when generic_ns
> parameter is set as 0.

Ah, nice catch, Thanks!

> > +       result = alloc_chrdev_region(&nvme_generic_ns_devt, 0,
> > +                       NVME_MINORS, "nvme-generic-ns");
> > +       if (result < 0)
> > +               goto destroy_class;
> > +
> >         nvme_subsys_class = class_create(THIS_MODULE, "nvme-subsystem");
> >         if (IS_ERR(nvme_subsys_class)) {
> >                 result = PTR_ERR(nvme_subsys_class);
> > -               goto destroy_class;
> > +               goto unregister_generic_ns;
> >         }
> > +
> > +       nvme_generic_ns_class = class_create(THIS_MODULE, "nvme-generic-ns");
> > +       if (IS_ERR(nvme_generic_ns_class)) {
> > +               result = PTR_ERR(nvme_subsys_class);
> > +               goto destroy_subsys_class;
> > +       }
> > +
> >         return 0;
> >
> > +destroy_subsys_class:
> > +       class_destroy(nvme_subsys_class);
> > +unregister_generic_ns:
> > +       unregister_chrdev_region(nvme_generic_ns_devt, NVME_MINORS);
> >  destroy_class:
> >         class_destroy(nvme_class);
> >  unregister_chrdev:
> > @@ -4827,6 +4990,7 @@ static void __exit nvme_core_exit(void)
> >  {
> >         class_destroy(nvme_subsys_class);
> >         class_destroy(nvme_class);
> > +       unregister_chrdev_region(nvme_generic_ns_devt, NVME_MINORS);
> >         unregister_chrdev_region(nvme_ctrl_base_chr_devt, NVME_MINORS);
> >         destroy_workqueue(nvme_delete_wq);
> >         destroy_workqueue(nvme_reset_wq);
> 
> The "nvme-generic-ns" class has not been destroyed here.

Will take care of this in the next version. Thanks!

> 
> -- 
> Kanchan

_______________________________________________
Linux-nvme mailing list
Linux-nvme@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-nvme