PCI: endpoint: Fix NULL pointer dereference error when CONFIGFS is disabled

commit ef1433f717a2 ("PCI: endpoint: Create configfs entry for each
pci_epf_device_id table entry") while adding configfs entry for each
pci_epf_device_id table entry introduced a NULL pointer dereference error
when CONFIG_PCI_ENDPOINT_CONFIGFS is not enabled.

Fix it here.

Fixes: ef1433f717a2 ("PCI: endpoint: Create configfs entry for each
pci_epf_device_id table entry")
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
[lorenzo.pieralisi: updated commit log]
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

diff --git a/drivers/pci/endpoint/pci-epf-core.c b/drivers/pci/endpoint/pci-epf-core.c
index bf53fad636a5076dca0c5b564085a53621d37a9b..825fa24427a396a711b734ee03643038e1260185 100644 (file)
--- a/drivers/pci/endpoint/pci-epf-core.c
+++ b/drivers/pci/endpoint/pci-epf-core.c
@@ -137,25 +137,60 @@ void *pci_epf_alloc_space(struct pci_epf *epf, size_t size, enum pci_barno bar)
 }
 EXPORT_SYMBOL_GPL(pci_epf_alloc_space);
 
-/**
- * pci_epf_unregister_driver() - unregister the PCI EPF driver
- * @driver: the PCI EPF driver that has to be unregistered
- *
- * Invoke to unregister the PCI EPF driver.
- */
-void pci_epf_unregister_driver(struct pci_epf_driver *driver)
+static void pci_epf_remove_cfs(struct pci_epf_driver *driver)
 {
        struct config_group *group, *tmp;
 
+       if (!IS_ENABLED(CONFIG_PCI_ENDPOINT_CONFIGFS))
+               return;
+
        mutex_lock(&pci_epf_mutex);
        list_for_each_entry_safe(group, tmp, &driver->epf_group, group_entry)
                pci_ep_cfs_remove_epf_group(group);
        list_del(&driver->epf_group);
        mutex_unlock(&pci_epf_mutex);
+}
+
+/**
+ * pci_epf_unregister_driver() - unregister the PCI EPF driver
+ * @driver: the PCI EPF driver that has to be unregistered
+ *
+ * Invoke to unregister the PCI EPF driver.
+ */
+void pci_epf_unregister_driver(struct pci_epf_driver *driver)
+{
+       pci_epf_remove_cfs(driver);
        driver_unregister(&driver->driver);
 }
 EXPORT_SYMBOL_GPL(pci_epf_unregister_driver);
 
+static int pci_epf_add_cfs(struct pci_epf_driver *driver)
+{
+       struct config_group *group;
+       const struct pci_epf_device_id *id;
+
+       if (!IS_ENABLED(CONFIG_PCI_ENDPOINT_CONFIGFS))
+               return 0;
+
+       INIT_LIST_HEAD(&driver->epf_group);
+
+       id = driver->id_table;
+       while (id->name[0]) {
+               group = pci_ep_cfs_add_epf_group(id->name);
+               if (IS_ERR(group)) {
+                       pci_epf_remove_cfs(driver);
+                       return PTR_ERR(group);
+               }
+
+               mutex_lock(&pci_epf_mutex);
+               list_add_tail(&group->group_entry, &driver->epf_group);
+               mutex_unlock(&pci_epf_mutex);
+               id++;
+       }
+
+       return 0;
+}
+
 /**
  * __pci_epf_register_driver() - register a new PCI EPF driver
  * @driver: structure representing PCI EPF driver
@@ -167,8 +202,6 @@ int __pci_epf_register_driver(struct pci_epf_driver *driver,
                              struct module *owner)
 {
        int ret;
-       struct config_group *group;
-       const struct pci_epf_device_id *id;
 
        if (!driver->ops)
                return -EINVAL;
@@ -183,16 +216,7 @@ int __pci_epf_register_driver(struct pci_epf_driver *driver,
        if (ret)
                return ret;
 
-       INIT_LIST_HEAD(&driver->epf_group);
-
-       id = driver->id_table;
-       while (id->name[0]) {
-               group = pci_ep_cfs_add_epf_group(id->name);
-               mutex_lock(&pci_epf_mutex);
-               list_add_tail(&group->group_entry, &driver->epf_group);
-               mutex_unlock(&pci_epf_mutex);
-               id++;
-       }
+       pci_epf_add_cfs(driver);
 
        return 0;
 }