2019-09-05 20:03:07

by Keith Busch

[permalink] [raw]
Subject: [PATCHv2] nvme: Assign subsy instance from first ctrl

The namespace disk names must be unique for the lifetime of the
subsystem. This was accomplished by using their parent subsystems'
instances which were allocated independently from the controllers
connected to that subsystem. This allowed name prefixes assigned to
namespaces to match a controller from an unrelated subsystem, and has
created confusion among users examining device nodes.

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

Reviewed-by: Logan Gunthorpe <[email protected]>
Signed-off-by: Keith Busch <[email protected]>
---
v1 -> v2:

Changelog: reduce sensationalism, fix spelling

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


2019-09-05 21:16:30

by Christoph Hellwig

[permalink] [raw]
Subject: Re: [PATCHv2] nvme: Assign subsy instance from first ctrl

Looks good:

Reviewed-by: Christoph Hellwig <[email protected]>

2019-09-05 23:20:06

by Sagi Grimberg

[permalink] [raw]
Subject: Re: [PATCHv2] nvme: Assign subsy instance from first ctrl

Looks good,

Reviewed-by: Sagi Grimberg <[email protected]>

Applied to nvme-5.4

2019-09-08 15:03:58

by Minwoo Im

[permalink] [raw]
Subject: Re: [PATCHv2] nvme: Assign subsy instance from first ctrl

> Subject: [PATCHv2] nvme: Assign subsy instance from first ctrl

I'm not sure but, I have not seen 'subsy' thing before. Maybe
s/sybsy/subsys/ ?

>
> The namespace disk names must be unique for the lifetime of the
> subsystem. This was accomplished by using their parent subsystems'
> instances which were allocated independently from the controllers
> connected to that subsystem. This allowed name prefixes assigned to
> namespaces to match a controller from an unrelated subsystem, and has
> created confusion among users examining device nodes.
>
> Ensure a namespace's subsystem instance never clashes with a controller
> instance of another subsystem by transferring the instance ownership
> to the parent subsystem from the first controller discovered in that
> subsystem.
>
> Reviewed-by: Logan Gunthorpe <[email protected]>
> Signed-off-by: Keith Busch <[email protected]>

Keith, Thanks for this patch. I really like this concept which can
avoid from instance mistakes.

Otherwise looks good to me.

Reviewed-by: Minwoo Im <[email protected]>

2019-09-10 04:38:03

by Hannes Reinecke

[permalink] [raw]
Subject: Re: [PATCHv2] nvme: Assign subsy instance from first ctrl

On 9/5/19 6:33 PM, Keith Busch wrote:
> The namespace disk names must be unique for the lifetime of the
> subsystem. This was accomplished by using their parent subsystems'
> instances which were allocated independently from the controllers
> connected to that subsystem. This allowed name prefixes assigned to
> namespaces to match a controller from an unrelated subsystem, and has
> created confusion among users examining device nodes.
>
> Ensure a namespace's subsystem instance never clashes with a controller
> instance of another subsystem by transferring the instance ownership
> to the parent subsystem from the first controller discovered in that
> subsystem.
>
> Reviewed-by: Logan Gunthorpe <[email protected]>
> Signed-off-by: Keith Busch <[email protected]>
> ---
> v1 -> v2:
>
> Changelog: reduce sensationalism, fix spelling
>
> drivers/nvme/host/core.c | 21 ++++++++++-----------
> 1 file changed, 10 insertions(+), 11 deletions(-)
>
Reviewed-by: Hannes Reinecke <[email protected]>

Cheers,

Hannes
--
Dr. Hannes Reinecke Teamlead Storage & Networking
[email protected] +49 911 74053 688
SUSE Software Solutions Germany GmbH, Maxfeldstr. 5, 90409 Nürnberg
HRB 247165 (AG München), GF: Felix Imendörffer