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* [PATCH] nvme: Restore device naming sanity
@ 2019-09-04 17:31 Keith Busch
  2019-09-05 16:11 ` Christoph Hellwig
  2019-09-07 18:42 ` Chaitanya Kulkarni
  0 siblings, 2 replies; 3+ messages in thread
From: Keith Busch @ 2019-09-04 17:31 UTC (permalink / raw)
  To: Christoph Hellwig, linux-nvme, Sagi Grimberg
  Cc: Hannes Reinecke, Martin K . Petersen, linux-kernel, Jens Axboe,
	Keith Busch, Logan Gunthorpe

The namespace names must be unique for the lifetime of the subsystem.
This was accomplished by using their parent subsystems' instances which
was independent of the controllers connected to that subsystem.

The consequence of that naming scheme meant that name prefixes given to
namespaces may match a controller from an unrelated subsystem. This has
understandbly invited confusion when examining device nodes.

Ensure the namespace's subsystem instance never clashes with a
controller instance of another subsystem by transferring the instance
ownership to parent subsystem from the first controller discovered in
that subsystem.

Reviewed-by: Logan Gunthorpe <logang@deltatee.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>
---
 drivers/nvme/host/core.c | 21 ++++++++++-----------
 1 file changed, 10 insertions(+), 11 deletions(-)

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 14c0bfb55615..8a8279ece5ee 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -81,7 +81,6 @@ EXPORT_SYMBOL_GPL(nvme_reset_wq);
 struct workqueue_struct *nvme_delete_wq;
 EXPORT_SYMBOL_GPL(nvme_delete_wq);
 
-static DEFINE_IDA(nvme_subsystems_ida);
 static LIST_HEAD(nvme_subsystems);
 static DEFINE_MUTEX(nvme_subsystems_lock);
 
@@ -2344,7 +2343,8 @@ static void nvme_release_subsystem(struct device *dev)
 	struct nvme_subsystem *subsys =
 		container_of(dev, struct nvme_subsystem, dev);
 
-	ida_simple_remove(&nvme_subsystems_ida, subsys->instance);
+	if (subsys->instance >= 0)
+		ida_simple_remove(&nvme_instance_ida, subsys->instance);
 	kfree(subsys);
 }
 
@@ -2473,12 +2473,8 @@ static int nvme_init_subsystem(struct nvme_ctrl *ctrl, struct nvme_id_ctrl *id)
 	subsys = kzalloc(sizeof(*subsys), GFP_KERNEL);
 	if (!subsys)
 		return -ENOMEM;
-	ret = ida_simple_get(&nvme_subsystems_ida, 0, 0, GFP_KERNEL);
-	if (ret < 0) {
-		kfree(subsys);
-		return ret;
-	}
-	subsys->instance = ret;
+
+	subsys->instance = -1;
 	mutex_init(&subsys->lock);
 	kref_init(&subsys->ref);
 	INIT_LIST_HEAD(&subsys->ctrls);
@@ -2497,7 +2493,7 @@ static int nvme_init_subsystem(struct nvme_ctrl *ctrl, struct nvme_id_ctrl *id)
 	subsys->dev.class = nvme_subsys_class;
 	subsys->dev.release = nvme_release_subsystem;
 	subsys->dev.groups = nvme_subsys_attrs_groups;
-	dev_set_name(&subsys->dev, "nvme-subsys%d", subsys->instance);
+	dev_set_name(&subsys->dev, "nvme-subsys%d", ctrl->instance);
 	device_initialize(&subsys->dev);
 
 	mutex_lock(&nvme_subsystems_lock);
@@ -2528,6 +2524,8 @@ static int nvme_init_subsystem(struct nvme_ctrl *ctrl, struct nvme_id_ctrl *id)
 		goto out_put_subsystem;
 	}
 
+	if (!found)
+		subsys->instance = ctrl->instance;
 	ctrl->subsys = subsys;
 	list_add_tail(&ctrl->subsys_entry, &subsys->ctrls);
 	mutex_unlock(&nvme_subsystems_lock);
@@ -3803,7 +3801,9 @@ static void nvme_free_ctrl(struct device *dev)
 		container_of(dev, struct nvme_ctrl, ctrl_device);
 	struct nvme_subsystem *subsys = ctrl->subsys;
 
-	ida_simple_remove(&nvme_instance_ida, ctrl->instance);
+	if (subsys && ctrl->instance != subsys->instance)
+		ida_simple_remove(&nvme_instance_ida, ctrl->instance);
+
 	kfree(ctrl->effects);
 	nvme_mpath_uninit(ctrl);
 	__free_page(ctrl->discard_page);
@@ -4085,7 +4085,6 @@ static int __init nvme_core_init(void)
 
 static void __exit nvme_core_exit(void)
 {
-	ida_destroy(&nvme_subsystems_ida);
 	class_destroy(nvme_subsys_class);
 	class_destroy(nvme_class);
 	unregister_chrdev_region(nvme_chr_devt, NVME_MINORS);
-- 
2.14.5


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

^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [PATCH] nvme: Restore device naming sanity
  2019-09-04 17:31 [PATCH] nvme: Restore device naming sanity Keith Busch
@ 2019-09-05 16:11 ` Christoph Hellwig
  2019-09-07 18:42 ` Chaitanya Kulkarni
  1 sibling, 0 replies; 3+ messages in thread
From: Christoph Hellwig @ 2019-09-05 16:11 UTC (permalink / raw)
  To: Keith Busch
  Cc: Hannes Reinecke, Sagi Grimberg, Martin K . Petersen,
	linux-kernel, linux-nvme, Jens Axboe, Logan Gunthorpe,
	Christoph Hellwig

On Wed, Sep 04, 2019 at 11:31:59AM -0600, Keith Busch wrote:
> The namespace names must be unique for the lifetime of the subsystem.
> This was accomplished by using their parent subsystems' instances which
> was independent of the controllers connected to that subsystem.
> 
> The consequence of that naming scheme meant that name prefixes given to
> namespaces may match a controller from an unrelated subsystem. This has
> understandbly invited confusion when examining device nodes.
> 
> Ensure the namespace's subsystem instance never clashes with a
> controller instance of another subsystem by transferring the instance
> ownership to parent subsystem from the first controller discovered in
> that subsystem.

Sanitity sounds a little exaggerated.  The nvme naming isn't really
that different except that the block devices uses number where say
scsi uses letters.  So maybe tone down that claim a bit, but otherwise
the patch looks fine.

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

^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [PATCH] nvme: Restore device naming sanity
  2019-09-04 17:31 [PATCH] nvme: Restore device naming sanity Keith Busch
  2019-09-05 16:11 ` Christoph Hellwig
@ 2019-09-07 18:42 ` Chaitanya Kulkarni
  1 sibling, 0 replies; 3+ messages in thread
From: Chaitanya Kulkarni @ 2019-09-07 18:42 UTC (permalink / raw)
  To: Keith Busch, Christoph Hellwig, linux-nvme, Sagi Grimberg
  Cc: Jens Axboe, Hannes Reinecke, Logan Gunthorpe, linux-kernel,
	Martin K . Petersen

Apart from the some nits, this looks okay.

Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>

May be subject line should be 's/nvme/nvme-core/' ?

On 09/04/2019 10:34 AM, Keith Busch wrote:
> The namespace names must be unique for the lifetime of the subsystem.
> This was accomplished by using their parent subsystems' instances which
> was independent of the controllers connected to that subsystem.
>
> The consequence of that naming scheme meant that name prefixes given to
> namespaces may match a controller from an unrelated subsystem. This has
> understandbly invited confusion when examining device nodes.
's/understandbly/understandably/'
>
> Ensure the namespace's subsystem instance never clashes with a
> controller instance of another subsystem by transferring the instance
> ownership to parent subsystem from the first controller discovered in
> that subsystem.
>
> Reviewed-by: Logan Gunthorpe <logang@deltatee.com>
> Signed-off-by: Keith Busch <kbusch@kernel.org>
> ---
>   drivers/nvme/host/core.c | 21 ++++++++++-----------
>   1 file changed, 10 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
> index 14c0bfb55615..8a8279ece5ee 100644
> --- a/drivers/nvme/host/core.c
> +++ b/drivers/nvme/host/core.c
> @@ -81,7 +81,6 @@ EXPORT_SYMBOL_GPL(nvme_reset_wq);
>   struct workqueue_struct *nvme_delete_wq;
>   EXPORT_SYMBOL_GPL(nvme_delete_wq);
>
> -static DEFINE_IDA(nvme_subsystems_ida);
>   static LIST_HEAD(nvme_subsystems);
>   static DEFINE_MUTEX(nvme_subsystems_lock);
>
> @@ -2344,7 +2343,8 @@ static void nvme_release_subsystem(struct device *dev)
>   	struct nvme_subsystem *subsys =
>   		container_of(dev, struct nvme_subsystem, dev);
>
> -	ida_simple_remove(&nvme_subsystems_ida, subsys->instance);
> +	if (subsys->instance >= 0)
> +		ida_simple_remove(&nvme_instance_ida, subsys->instance);
>   	kfree(subsys);
>   }
>
> @@ -2473,12 +2473,8 @@ static int nvme_init_subsystem(struct nvme_ctrl *ctrl, struct nvme_id_ctrl *id)
>   	subsys = kzalloc(sizeof(*subsys), GFP_KERNEL);
>   	if (!subsys)
>   		return -ENOMEM;
> -	ret = ida_simple_get(&nvme_subsystems_ida, 0, 0, GFP_KERNEL);
> -	if (ret < 0) {
> -		kfree(subsys);
> -		return ret;
> -	}
> -	subsys->instance = ret;
> +
> +	subsys->instance = -1;
>   	mutex_init(&subsys->lock);
>   	kref_init(&subsys->ref);
>   	INIT_LIST_HEAD(&subsys->ctrls);
> @@ -2497,7 +2493,7 @@ static int nvme_init_subsystem(struct nvme_ctrl *ctrl, struct nvme_id_ctrl *id)
>   	subsys->dev.class = nvme_subsys_class;
>   	subsys->dev.release = nvme_release_subsystem;
>   	subsys->dev.groups = nvme_subsys_attrs_groups;
> -	dev_set_name(&subsys->dev, "nvme-subsys%d", subsys->instance);
> +	dev_set_name(&subsys->dev, "nvme-subsys%d", ctrl->instance);
>   	device_initialize(&subsys->dev);
>
>   	mutex_lock(&nvme_subsystems_lock);
> @@ -2528,6 +2524,8 @@ static int nvme_init_subsystem(struct nvme_ctrl *ctrl, struct nvme_id_ctrl *id)
>   		goto out_put_subsystem;
>   	}
>
> +	if (!found)
> +		subsys->instance = ctrl->instance;
>   	ctrl->subsys = subsys;
>   	list_add_tail(&ctrl->subsys_entry, &subsys->ctrls);
>   	mutex_unlock(&nvme_subsystems_lock);
> @@ -3803,7 +3801,9 @@ static void nvme_free_ctrl(struct device *dev)
>   		container_of(dev, struct nvme_ctrl, ctrl_device);
>   	struct nvme_subsystem *subsys = ctrl->subsys;
>
> -	ida_simple_remove(&nvme_instance_ida, ctrl->instance);
> +	if (subsys && ctrl->instance != subsys->instance)
> +		ida_simple_remove(&nvme_instance_ida, ctrl->instance);
> +
>   	kfree(ctrl->effects);
>   	nvme_mpath_uninit(ctrl);
>   	__free_page(ctrl->discard_page);
> @@ -4085,7 +4085,6 @@ static int __init nvme_core_init(void)
>
>   static void __exit nvme_core_exit(void)
>   {
> -	ida_destroy(&nvme_subsystems_ida);
>   	class_destroy(nvme_subsys_class);
>   	class_destroy(nvme_class);
>   	unregister_chrdev_region(nvme_chr_devt, NVME_MINORS);
>


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http://lists.infradead.org/mailman/listinfo/linux-nvme

^ permalink raw reply	[flat|nested] 3+ messages in thread

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2019-09-04 17:31 [PATCH] nvme: Restore device naming sanity Keith Busch
2019-09-05 16:11 ` Christoph Hellwig
2019-09-07 18:42 ` Chaitanya Kulkarni

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