Re: [PATCH] cxl/region: Clarify pointers in unregister_region()

From: Dave Jiang
Date: Wed Aug 30 2023 - 15:24:01 EST




On 8/29/23 14:47, Ira Weiny wrote:
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@xxxxxxxxxx>
Signed-off-by: Ira Weiny <ira.weiny@xxxxxxxxx>

Great catch!
Reviewed-by: Dave Jiang <dave.jiang@xxxxxxxxx>
---
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,