dpll: fix userspace availability of pins

If parent pin was unregistered but child pin was not, the userspace
would see the "zombie" pins - the ones that were registered with
a parent pin (dpll_pin_on_pin_register(..)).
Technically those are not available - as there is no dpll device in the
system. Do not dump those pins and prevent userspace from any
interaction with them. Provide a unified function to determine if the
pin is available and use it before acting/responding for user requests.

Fixes: 9d71b54b65b1 ("dpll: netlink: Add DPLL framework base functions")
Reviewed-by: Jan Glaza <jan.glaza@intel.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: Arkadiusz Kubalewski <arkadiusz.kubalewski@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/dpll/dpll_netlink.c b/drivers/dpll/dpll_netlink.c
index 30f5be020862dd049f842badd50f2aaaa35a9b7c..314bb377546519ef25987b2e6f77827f590fe5fe 100644 (file)
--- a/drivers/dpll/dpll_netlink.c
+++ b/drivers/dpll/dpll_netlink.c
@@ -553,6 +553,24 @@ __dpll_device_change_ntf(struct dpll_device *dpll)
        return dpll_device_event_send(DPLL_CMD_DEVICE_CHANGE_NTF, dpll);
 }
 
+static bool dpll_pin_available(struct dpll_pin *pin)
+{
+       struct dpll_pin_ref *par_ref;
+       unsigned long i;
+
+       if (!xa_get_mark(&dpll_pin_xa, pin->id, DPLL_REGISTERED))
+               return false;
+       xa_for_each(&pin->parent_refs, i, par_ref)
+               if (xa_get_mark(&dpll_pin_xa, par_ref->pin->id,
+                               DPLL_REGISTERED))
+                       return true;
+       xa_for_each(&pin->dpll_refs, i, par_ref)
+               if (xa_get_mark(&dpll_device_xa, par_ref->dpll->id,
+                               DPLL_REGISTERED))
+                       return true;
+       return false;
+}
+
 /**
  * dpll_device_change_ntf - notify that the dpll device has been changed
  * @dpll: registered dpll pointer
@@ -579,7 +597,7 @@ dpll_pin_event_send(enum dpll_cmd event, struct dpll_pin *pin)
        int ret = -ENOMEM;
        void *hdr;
 
-       if (WARN_ON(!xa_get_mark(&dpll_pin_xa, pin->id, DPLL_REGISTERED)))
+       if (!dpll_pin_available(pin))
                return -ENODEV;
 
        msg = genlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
@@ -1130,6 +1148,10 @@ int dpll_nl_pin_id_get_doit(struct sk_buff *skb, struct genl_info *info)
        }
        pin = dpll_pin_find_from_nlattr(info);
        if (!IS_ERR(pin)) {
+               if (!dpll_pin_available(pin)) {
+                       nlmsg_free(msg);
+                       return -ENODEV;
+               }
                ret = dpll_msg_add_pin_handle(msg, pin);
                if (ret) {
                        nlmsg_free(msg);
@@ -1179,6 +1201,8 @@ int dpll_nl_pin_get_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
 
        xa_for_each_marked_start(&dpll_pin_xa, i, pin, DPLL_REGISTERED,
                                 ctx->idx) {
+               if (!dpll_pin_available(pin))
+                       continue;
                hdr = genlmsg_put(skb, NETLINK_CB(cb->skb).portid,
                                  cb->nlh->nlmsg_seq,
                                  &dpll_nl_family, NLM_F_MULTI,
@@ -1441,7 +1465,8 @@ int dpll_pin_pre_doit(const struct genl_split_ops *ops, struct sk_buff *skb,
        }
        info->user_ptr[0] = xa_load(&dpll_pin_xa,
                                    nla_get_u32(info->attrs[DPLL_A_PIN_ID]));
-       if (!info->user_ptr[0]) {
+       if (!info->user_ptr[0] ||
+           !dpll_pin_available(info->user_ptr[0])) {
                NL_SET_ERR_MSG(info->extack, "pin not found");
                ret = -ENODEV;
                goto unlock_dev;