PCI: endpoint: Fix configfs group removal on driver teardown

commit 910bdb8 upstream.

An endpoint driver configfs attributes group is added to the
epf_group list of struct pci_epf_driver by pci_epf_add_cfs() but an
added group is not removed from this list when the attribute group is
unregistered with pci_ep_cfs_remove_epf_group().

Add the missing list_del() call in pci_ep_cfs_remove_epf_group()
to correctly remove the attribute group from the driver list.

With this change, once the loop over all attribute groups in
pci_epf_remove_cfs() completes, the driver epf_group list should be
empty. Add a WARN_ON() to make sure of that.

Fixes: ef1433f ("PCI: endpoint: Create configfs entry for each pci_epf_device_id table entry")
Signed-off-by: Damien Le Moal <[email protected]>
Signed-off-by: Manivannan Sadhasivam <[email protected]>
Reviewed-by: Niklas Cassel <[email protected]>
Cc: [email protected]
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

Author: damien-lemoal

drivers/pci/endpoint/pci-ep-cfs.c

@@ -658,6 +658,7 @@ void pci_ep_cfs_remove_epf_group(struct config_group *group)
 	if (IS_ERR_OR_NULL(group))
 		return;
 
+	list_del(&group->group_entry);
 	configfs_unregister_default_group(group);
 }
 EXPORT_SYMBOL(pci_ep_cfs_remove_epf_group);

drivers/pci/endpoint/pci-epf-core.c

@@ -343,6 +343,7 @@ static void pci_epf_remove_cfs(struct pci_epf_driver *driver)
 	mutex_lock(&pci_epf_mutex);
 	list_for_each_entry_safe(group, tmp, &driver->epf_group, group_entry)
 		pci_ep_cfs_remove_epf_group(group);
+	WARN_ON(!list_empty(&driver->epf_group));
 	mutex_unlock(&pci_epf_mutex);
 }