[PATCH 8/8] cxl/region: Unregister the pmem region bridge on setup failure

[Guixin Liu <kanie@linux.alibaba.com>]

When the nvdimm bridge has no driver bound, devm_cxl_add_pmem_region()
bails out with -ENXIO through the err_bridge label. That label only drops
the reference on @cxl_nvb, so the cxl_pmem_region device that device_add()
just published stays in sysfs forever: there is no device_del() and no
put_device(), and no devm action was registered to do either later.

Beyond the leak, cxlr->cxlr_pmem is left pointing at the stale device, so
a later probe of the same region allocates a second one and fails in
device_add() with -EEXIST on the duplicate "pmem_region%d" name.

Call cxlr_pmem_unregister() explicitly in that branch. It runs under the
bridge's device lock held by the scoped_guard(), which is what its
device_lock_assert() expects, and it performs the same teardown the devm
action would have done, including clearing cxlr->cxlr_pmem, so err_bridge
only has the @cxl_nvb reference left to drop.

Fixes: f17b558d6663 ("cxl/pmem: Refactor nvdimm device registration, delete the workqueue")
Signed-off-by: Guixin Liu <kanie@linux.alibaba.com>
---
 drivers/cxl/core/region_pmem.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/cxl/core/region_pmem.c b/drivers/cxl/core/region_pmem.c
index 23d97e3d78b6..7ab1373a95e0 100644
--- a/drivers/cxl/core/region_pmem.c
+++ b/drivers/cxl/core/region_pmem.c
@@ -168,12 +168,14 @@ int devm_cxl_add_pmem_region(struct cxl_region *cxlr)
 		dev_name(dev));
 
 	scoped_guard(device, &cxl_nvb->dev) {
-		if (cxl_nvb->dev.driver)
+		if (cxl_nvb->dev.driver) {
 			rc = devm_add_action_or_reset(&cxl_nvb->dev,
 						      cxlr_pmem_unregister,
 						      cxlr_pmem);
-		else
+		} else {
 			rc = -ENXIO;
+			cxlr_pmem_unregister(cxlr_pmem);
+		}
 	}
 
 	if (rc)
-- 
2.43.7