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

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Date:   Wed, 13 Oct 2021 20:41:40 +0200
From:   "Javier González" <javier@...igon.com>
To:     Adam Manzanares <a.manzanares@...sung.com>
Cc:     "yi.zhang@...hat.com" <yi.zhang@...hat.com>,
        "sagi@...mberg.me" <sagi@...mberg.me>,
        Keith Busch <kbusch@...nel.org>, Jens Axboe <axboe@...com>,
        Christoph Hellwig <hch@....de>,
        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

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@...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

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

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