[PATCH] nvme: Cleanup per-namespace chardev deletion

[PATCH] nvme: Cleanup per-namespace chardev deletion

[Adam Manzanares]

Decrease reference count of chardevice during char device deletion in order to
fix a kmemleak. Add relese function for the device associated chardev and moved
ida_simple_remove into the release function.

Fixes: 2637bae (nvme: introduce generic per-namespace chardev)
Reported-by: Yi Zhang <yi.zhang@redhat.com>
Suggested-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Adam Manzanares <a.manzanares@samsung.com>
---
 drivers/nvme/host/core.c      | 21 ++++++++++++---------
 drivers/nvme/host/multipath.c |  2 --
 2 files changed, 12 insertions(+), 11 deletions(-)

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index f9a25c61fb8b..3bc4bb620ab7 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -3583,10 +3583,15 @@ static int __nvme_check_ids(struct nvme_subsystem *subsys,
 	return 0;
 }
 
+static void nvme_cdev_rel(struct device *dev)
+{
+	ida_simple_remove(&nvme_ns_chr_minor_ida, MINOR(dev->devt));
+}
+
 void nvme_cdev_del(struct cdev *cdev, struct device *cdev_device)
 {
 	cdev_device_del(cdev, cdev_device);
-	ida_simple_remove(&nvme_ns_chr_minor_ida, MINOR(cdev_device->devt));
+	put_device(cdev_device);
 }
 
 int nvme_cdev_add(struct cdev *cdev, struct device *cdev_device,
@@ -3599,14 +3604,14 @@ int nvme_cdev_add(struct cdev *cdev, struct device *cdev_device,
 		return minor;
 	cdev_device->devt = MKDEV(MAJOR(nvme_ns_chr_devt), minor);
 	cdev_device->class = nvme_ns_chr_class;
+	cdev_device->release = nvme_cdev_rel;
 	device_initialize(cdev_device);
 	cdev_init(cdev, fops);
 	cdev->owner = owner;
 	ret = cdev_device_add(cdev, cdev_device);
-	if (ret) {
+	if (ret)
 		put_device(cdev_device);
-		ida_simple_remove(&nvme_ns_chr_minor_ida, minor);
-	}
+
 	return ret;
 }
 
@@ -3638,11 +3643,9 @@ static int nvme_add_ns_cdev(struct nvme_ns *ns)
 			   ns->ctrl->instance, ns->head->instance);
 	if (ret)
 		return ret;
-	ret = nvme_cdev_add(&ns->cdev, &ns->cdev_device, &nvme_ns_chr_fops,
-			    ns->ctrl->ops->module);
-	if (ret)
-		kfree_const(ns->cdev_device.kobj.name);
-	return ret;
+
+	return nvme_cdev_add(&ns->cdev, &ns->cdev_device, &nvme_ns_chr_fops,
+			     ns->ctrl->ops->module);
 }
 
 static struct nvme_ns_head *nvme_alloc_ns_head(struct nvme_ctrl *ctrl,
diff --git a/drivers/nvme/host/multipath.c b/drivers/nvme/host/multipath.c
index fb96e900dd3a..bd490a7c4808 100644
--- a/drivers/nvme/host/multipath.c
+++ b/drivers/nvme/host/multipath.c
@@ -434,8 +434,6 @@ static int nvme_add_ns_head_cdev(struct nvme_ns_head *head)
 		return ret;
 	ret = nvme_cdev_add(&head->cdev, &head->cdev_device,
 			    &nvme_ns_head_chr_fops, THIS_MODULE);
-	if (ret)
-		kfree_const(head->cdev_device.kobj.name);
 	return ret;
 }
 
-- 
2.25.1

Re: [PATCH] nvme: Cleanup per-namespace chardev deletion

[Javier González]

On 13.10.2021 15:04, Adam Manzanares wrote:
>Decrease reference count of chardevice during char device deletion in order to
>fix a kmemleak. Add relese function for the device associated chardev and moved
>ida_simple_remove into the release function.
>
>Fixes: 2637bae (nvme: introduce generic per-namespace chardev)
>Reported-by: Yi Zhang <yi.zhang@redhat.com>
>Suggested-by: Sagi Grimberg <sagi@grimberg.me>
>Signed-off-by: Adam Manzanares <a.manzanares@samsung.com>
>---
> drivers/nvme/host/core.c      | 21 ++++++++++++---------
> drivers/nvme/host/multipath.c |  2 --
> 2 files changed, 12 insertions(+), 11 deletions(-)
>
>diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
>index f9a25c61fb8b..3bc4bb620ab7 100644
>--- a/drivers/nvme/host/core.c
>+++ b/drivers/nvme/host/core.c
>@@ -3583,10 +3583,15 @@ static int __nvme_check_ids(struct nvme_subsystem *subsys,
> 	return 0;
> }
>
>+static void nvme_cdev_rel(struct device *dev)
>+{
>+	ida_simple_remove(&nvme_ns_chr_minor_ida, MINOR(dev->devt));
>+}
>+
> void nvme_cdev_del(struct cdev *cdev, struct device *cdev_device)
> {
> 	cdev_device_del(cdev, cdev_device);
>-	ida_simple_remove(&nvme_ns_chr_minor_ida, MINOR(cdev_device->devt));
>+	put_device(cdev_device);
> }
>
> int nvme_cdev_add(struct cdev *cdev, struct device *cdev_device,
>@@ -3599,14 +3604,14 @@ int nvme_cdev_add(struct cdev *cdev, struct device *cdev_device,
> 		return minor;
> 	cdev_device->devt = MKDEV(MAJOR(nvme_ns_chr_devt), minor);
> 	cdev_device->class = nvme_ns_chr_class;
>+	cdev_device->release = nvme_cdev_rel;
> 	device_initialize(cdev_device);
> 	cdev_init(cdev, fops);
> 	cdev->owner = owner;
> 	ret = cdev_device_add(cdev, cdev_device);
>-	if (ret) {
>+	if (ret)
> 		put_device(cdev_device);
>-		ida_simple_remove(&nvme_ns_chr_minor_ida, minor);
>-	}
>+
> 	return ret;
> }
>
>@@ -3638,11 +3643,9 @@ static int nvme_add_ns_cdev(struct nvme_ns *ns)
> 			   ns->ctrl->instance, ns->head->instance);
> 	if (ret)
> 		return ret;
>-	ret = nvme_cdev_add(&ns->cdev, &ns->cdev_device, &nvme_ns_chr_fops,
>-			    ns->ctrl->ops->module);
>-	if (ret)
>-		kfree_const(ns->cdev_device.kobj.name);
>-	return ret;
>+
>+	return nvme_cdev_add(&ns->cdev, &ns->cdev_device, &nvme_ns_chr_fops,
>+			     ns->ctrl->ops->module);
> }
>
> static struct nvme_ns_head *nvme_alloc_ns_head(struct nvme_ctrl *ctrl,
>diff --git a/drivers/nvme/host/multipath.c b/drivers/nvme/host/multipath.c
>index fb96e900dd3a..bd490a7c4808 100644
>--- a/drivers/nvme/host/multipath.c
>+++ b/drivers/nvme/host/multipath.c
>@@ -434,8 +434,6 @@ static int nvme_add_ns_head_cdev(struct nvme_ns_head *head)
> 		return ret;
> 	ret = nvme_cdev_add(&head->cdev, &head->cdev_device,
> 			    &nvme_ns_head_chr_fops, THIS_MODULE);
>-	if (ret)
>-		kfree_const(head->cdev_device.kobj.name);
> 	return ret;
> }
>
>-- 
>2.25.1

Thanks for taking a look at this Adam. Looks good to me.

Reviewed-by: Javier González <javier@javigon.com>

Re: [PATCH] nvme: Cleanup per-namespace chardev deletion

[Yi Zhang]

Verified this patch on top of 5.15.0-rc5.

Tested-by: Yi Zhang <yi.zhang@redhat.com>

On Wed, Oct 13, 2021 at 11:04 PM Adam Manzanares
<a.manzanares@samsung.com> wrote:
>
> Decrease reference count of chardevice during char device deletion in order to
> fix a kmemleak. Add relese function for the device associated chardev and moved
> ida_simple_remove into the release function.
>
> Fixes: 2637bae (nvme: introduce generic per-namespace chardev)
> Reported-by: Yi Zhang <yi.zhang@redhat.com>
> Suggested-by: Sagi Grimberg <sagi@grimberg.me>
> Signed-off-by: Adam Manzanares <a.manzanares@samsung.com>
> ---
>  drivers/nvme/host/core.c      | 21 ++++++++++++---------
>  drivers/nvme/host/multipath.c |  2 --
>  2 files changed, 12 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
> index f9a25c61fb8b..3bc4bb620ab7 100644
> --- a/drivers/nvme/host/core.c
> +++ b/drivers/nvme/host/core.c
> @@ -3583,10 +3583,15 @@ static int __nvme_check_ids(struct nvme_subsystem *subsys,
>         return 0;
>  }
>
> +static void nvme_cdev_rel(struct device *dev)
> +{
> +       ida_simple_remove(&nvme_ns_chr_minor_ida, MINOR(dev->devt));
> +}
> +
>  void nvme_cdev_del(struct cdev *cdev, struct device *cdev_device)
>  {
>         cdev_device_del(cdev, cdev_device);
> -       ida_simple_remove(&nvme_ns_chr_minor_ida, MINOR(cdev_device->devt));
> +       put_device(cdev_device);
>  }
>
>  int nvme_cdev_add(struct cdev *cdev, struct device *cdev_device,
> @@ -3599,14 +3604,14 @@ int nvme_cdev_add(struct cdev *cdev, struct device *cdev_device,
>                 return minor;
>         cdev_device->devt = MKDEV(MAJOR(nvme_ns_chr_devt), minor);
>         cdev_device->class = nvme_ns_chr_class;
> +       cdev_device->release = nvme_cdev_rel;
>         device_initialize(cdev_device);
>         cdev_init(cdev, fops);
>         cdev->owner = owner;
>         ret = cdev_device_add(cdev, cdev_device);
> -       if (ret) {
> +       if (ret)
>                 put_device(cdev_device);
> -               ida_simple_remove(&nvme_ns_chr_minor_ida, minor);
> -       }
> +
>         return ret;
>  }
>
> @@ -3638,11 +3643,9 @@ static int nvme_add_ns_cdev(struct nvme_ns *ns)
>                            ns->ctrl->instance, ns->head->instance);
>         if (ret)
>                 return ret;
> -       ret = nvme_cdev_add(&ns->cdev, &ns->cdev_device, &nvme_ns_chr_fops,
> -                           ns->ctrl->ops->module);
> -       if (ret)
> -               kfree_const(ns->cdev_device.kobj.name);
> -       return ret;
> +
> +       return nvme_cdev_add(&ns->cdev, &ns->cdev_device, &nvme_ns_chr_fops,
> +                            ns->ctrl->ops->module);
>  }
>
>  static struct nvme_ns_head *nvme_alloc_ns_head(struct nvme_ctrl *ctrl,
> diff --git a/drivers/nvme/host/multipath.c b/drivers/nvme/host/multipath.c
> index fb96e900dd3a..bd490a7c4808 100644
> --- a/drivers/nvme/host/multipath.c
> +++ b/drivers/nvme/host/multipath.c
> @@ -434,8 +434,6 @@ static int nvme_add_ns_head_cdev(struct nvme_ns_head *head)
>                 return ret;
>         ret = nvme_cdev_add(&head->cdev, &head->cdev_device,
>                             &nvme_ns_head_chr_fops, THIS_MODULE);
> -       if (ret)
> -               kfree_const(head->cdev_device.kobj.name);
>         return ret;
>  }
>
> --
> 2.25.1
>


-- 
Best Regards,
  Yi Zhang

Re: [PATCH] nvme: Cleanup per-namespace chardev deletion

[Christoph Hellwig]

On Wed, Oct 13, 2021 at 03:04:19PM +0000, Adam Manzanares wrote:
> Decrease reference count of chardevice during char device deletion in order to
> fix a kmemleak. Add relese function for the device associated chardev and moved
> ida_simple_remove into the release function.
> 
> Fixes: 2637bae (nvme: introduce generic per-namespace chardev)
> Reported-by: Yi Zhang <yi.zhang@redhat.com>
> Suggested-by: Sagi Grimberg <sagi@grimberg.me>
> Signed-off-by: Adam Manzanares <a.manzanares@samsung.com>

This looks good, but the subject seems wrong.  This isn't a cleanup
but a fix.  I can fix up the subject when applying it.