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

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Date:   Wed, 13 Oct 2021 15:04:19 +0000
From:   Adam Manzanares <a.manzanares@...sung.com>
To:     "yi.zhang@...hat.com" <yi.zhang@...hat.com>,
        "sagi@...mberg.me" <sagi@...mberg.me>
CC:     Adam Manzanares <a.manzanares@...sung.com>,
        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: [PATCH] nvme: Cleanup per-namespace chardev deletion

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