linux-kernel - [PATCH 2/2] cxl/region: Fix missing put_device(region

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Date: Mon, 29 Apr 2024 09:31:54 +0800
From: Li Zhijian <lizhijian@...itsu.com>
To: dave@...olabs.net,
	jonathan.cameron@...wei.com,
	dave.jiang@...el.com,
	alison.schofield@...el.com,
	vishal.l.verma@...el.com,
	ira.weiny@...el.com,
	dan.j.williams@...el.com,
	linux-cxl@...r.kernel.org
Cc: linux-kernel@...r.kernel.org,
	Li Zhijian <lizhijian@...itsu.com>
Subject: [PATCH 2/2] cxl/region: Fix missing put_device(region_dev)

>         mutex_lock(&cxlrd->range_lock);
>         region_dev = device_find_child(&cxlrd->cxlsd.cxld.dev, hpa,
>                                        match_region_by_range);
>         if (!region_dev)
>                 cxlr = construct_region(cxlrd, cxled);
>         else
>                 cxlr = to_cxl_region(region_dev);
>         mutex_unlock(&cxlrd->range_lock);
>
>         rc = PTR_ERR_OR_ZERO(cxlr);
>         if (rc)
>                 goto out;
>
>         if (!region_dev)
>                 region_dev = &cxlr->dev;

When to_cxl_region(region_dev) fails, put_device(region_dev) should be
called to decrease the reference count added by device_find_child().

Simply put_device(region_dev) if region_dev is valid in the error path.

Fixes: a32320b71f08 ("cxl/region: Add region autodiscovery")
Signed-off-by: Li Zhijian <lizhijian@...itsu.com>
---
 drivers/cxl/core/region.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
index 3c80aa263a65..75390865382f 100644
--- a/drivers/cxl/core/region.c
+++ b/drivers/cxl/core/region.c
@@ -3117,8 +3117,9 @@ int cxl_add_to_region(struct cxl_port *root, struct cxl_endpoint_decoder *cxled)
 				p->res);
 	}
 
-	put_device(region_dev);
 out:
+	if (region_dev)
+		put_device(region_dev);
 	put_device(cxlrd_dev);
 	return rc;
 }
-- 
2.29.2