[PATCH 3/4] cxl/mem: Do not rely on device_add() side effects for dev_set_name() failures

From: Dan Williams <dan.j.williams@intel.com>
To: linux-cxl@vger.kernel.org
Cc: Jason Gunthorpe <jgg@nvidia.com>,
	ira.weiny@intel.com, vishal.l.verma@intel.com,
	alison.schofield@intel.com, linux-kernel@vger.kernel.org
Subject: [PATCH 3/4] cxl/mem: Do not rely on device_add() side effects for dev_set_name() failures
Date: Wed, 24 Mar 2021 14:02:01 -0700	[thread overview]
Message-ID: <161661972173.1721612.9458160848430375459.stgit@dwillia2-desk3.amr.corp.intel.com> (raw)
In-Reply-To: <161661970558.1721612.10441826898835759137.stgit@dwillia2-desk3.amr.corp.intel.com>

While device_add() will happen to catch dev_set_name() failures it is a
broken pattern to follow given that the core may try to fall back to a
different name.

Add explicit checking for dev_set_name() failures to be cleaned up by
put_device(). Skip cdev_device_add() and proceed directly to
put_device() if the name set failure.

Fixes: b39cb1052a5c ("cxl/mem: Register CXL memX devices")
Reported-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
 drivers/cxl/mem.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/cxl/mem.c b/drivers/cxl/mem.c
index e53d573ae4ab..d615f183520c 100644
--- a/drivers/cxl/mem.c
+++ b/drivers/cxl/mem.c
@@ -1204,12 +1204,14 @@ static int cxl_mem_add_memdev(struct cxl_mem *cxlm)
 	dev->bus = &cxl_bus_type;
 	dev->devt = MKDEV(cxl_mem_major, cxlmd->id);
 	dev->type = &cxl_memdev_type;
-	dev_set_name(dev, "mem%d", cxlmd->id);
 
 	cdev = &cxlmd->cdev;
 	cdev_init(cdev, &cxl_memdev_fops);
 
-	rc = cdev_device_add(cdev, dev);
+	rc = dev_set_name(dev, "mem%d", cxlmd->id);
+	if (rc == 0)
+		rc = cdev_device_add(cdev, dev);
+
 	if (rc) {
 		percpu_ref_kill(&cxlmd->ops_active);
 		put_device(dev);

