linux-kernel - [PATCH] cxl/region: Clarify pointers in unregister

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Message-Id: <20230829-cxl-clarify-ptrs-v1-1-40e0705c6188@intel.com>
Date:   Tue, 29 Aug 2023 14:47:46 -0700
From:   Ira Weiny <ira.weiny@...el.com>
To:     Davidlohr Bueso <dave@...olabs.net>,
        Jonathan Cameron <jonathan.cameron@...wei.com>,
        Dave Jiang <dave.jiang@...el.com>,
        Alison Schofield <alison.schofield@...el.com>,
        Vishal Verma <vishal.l.verma@...el.com>,
        Dan Williams <dan.j.williams@...el.com>
Cc:     linux-cxl@...r.kernel.org, linux-kernel@...r.kernel.org,
        Ben Widawsky <bwidawsk@...nel.org>,
        Ira Weiny <ira.weiny@...el.com>
Subject: [PATCH] cxl/region: Clarify pointers in unregister_region()

devm_add_action_or_reset() passes a void * data parameter to the
callback.  In the case of CXL regions, unregister_region() is passed a
struct cxl_region *.

unregister_region() incorrectly interprets this as a struct device
pointer.  Fortunately the device structure was the first member of
cxl_region.  Therefore the code still works.  However, should struct
cxl_region change the bug could be subtle.

Use the proper types in unregister_region() and extract the device
pointer correctly.

Fixes: 779dd20cfb56 ("cxl/region: Add region creation support")
Cc: Ben Widawsky <bwidawsk@...nel.org>
Signed-off-by: Ira Weiny <ira.weiny@...el.com>
---
 drivers/cxl/core/region.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
index e115ba382e04..471d305ef675 100644
--- a/drivers/cxl/core/region.c
+++ b/drivers/cxl/core/region.c
@@ -2018,10 +2018,11 @@ static struct cxl_region *to_cxl_region(struct device *dev)
 	return container_of(dev, struct cxl_region, dev);
 }
 
-static void unregister_region(void *dev)
+static void unregister_region(void *_cxlr)
 {
-	struct cxl_region *cxlr = to_cxl_region(dev);
+	struct cxl_region *cxlr = _cxlr;
 	struct cxl_region_params *p = &cxlr->params;
+	struct device *dev = &cxlr->dev;
 	int i;
 
 	device_del(dev);

---
base-commit: 1c59d383390f970b891b503b7f79b63a02db2ec5
change-id: 20230829-cxl-clarify-ptrs-f38255b7e52b

Best regards,
-- 
Ira Weiny <ira.weiny@...el.com>