cxl/port: Keep port->uport valid for the entire life of a port

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.

Reviewed-by: Alison Schofield <alison.schofield@intel.com>
Reviewed-by: Adam Manzanares <a.manzanares@samsung.com>
Link: https://lore.kernel.org/r/165603871491.551046.6682199179541194356.stgit@dwillia2-xfh
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

diff --git a/drivers/cxl/core/port.c b/drivers/cxl/core/port.c
index dbce99bdffabc5e9615da5924290c5e195895229..7810d1a8369bbe55802ab9ff9930e6e6b315e51b 100644 (file)
--- 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);
        }