[PATCH 02/46] cxl/port: Keep port->uport valid for the entire life of a port

[Dan Williams <dan.j.williams@xxxxxxxxx>]

The upcoming region provisioning implementation has a need to
dereference port->uport during the port unregister flow. Specifically,
endpoint decoders need to be able to lookup their corresponding memdev
via port->uport.

The existing ->dead flag was added for cases where the core was
committed to tearing down the port, but needed to drop locks before
calling device_unregister(). Reuse that flag to indicate to
delete_endpoint() that it has no "release action" work to do as
unregister_port() will handle it.

Fixes: 8dd2bc0f8e02 ("cxl/mem: Add the cxl_mem driver")
Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
---
 drivers/cxl/core/port.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/cxl/core/port.c b/drivers/cxl/core/port.c
index dbce99bdffab..7810d1a8369b 100644
--- a/drivers/cxl/core/port.c
+++ b/drivers/cxl/core/port.c
@@ -370,7 +370,7 @@ static void unregister_port(void *_port)
 		lock_dev = &parent->dev;
 
 	device_lock_assert(lock_dev);
-	port->uport = NULL;
+	port->dead = true;
 	device_unregister(&port->dev);
 }
 
@@ -857,7 +857,7 @@ static void delete_endpoint(void *data)
 	parent = &parent_port->dev;
 
 	device_lock(parent);
-	if (parent->driver && endpoint->uport) {
+	if (parent->driver && !endpoint->dead) {
 		devm_release_action(parent, cxl_unlink_uport, endpoint);
 		devm_release_action(parent, unregister_port, endpoint);
 	}