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

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Date:   Thu, 14 Oct 2021 09:25:03 +0800
From:   Yi Zhang <yi.zhang@...hat.com>
To:     Adam Manzanares <a.manzanares@...sung.com>
Cc:     "sagi@...mberg.me" <sagi@...mberg.me>,
        Keith Busch <kbusch@...nel.org>, Jens Axboe <axboe@...com>,
        Christoph Hellwig <hch@....de>,
        Javier González <javier.gonz@...sung.com>,
        Minwoo Im <minwoo.im.dev@...il.com>,
        "open list:NVM EXPRESS DRIVER" <linux-nvme@...ts.infradead.org>,
        open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] nvme: Cleanup per-namespace chardev deletion

Verified this patch on top of 5.15.0-rc5.

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

On Wed, Oct 13, 2021 at 11:04 PM Adam Manzanares
<a.manzanares@...sung.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@...hat.com>
> Suggested-by: Sagi Grimberg <sagi@...mberg.me>
> Signed-off-by: Adam Manzanares <a.manzanares@...sung.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