dpll: fix dpll_pin_on_pin_register() for multiple parent pins

In scenario where pin is registered with multiple parent pins via
dpll_pin_on_pin_register(..), all belonging to the same dpll device.
A second call to dpll_pin_on_pin_unregister(..) would cause a call trace,
as it tries to use already released registration resources (due to fix
introduced in b446631f355e). In this scenario pin was registered twice,
so resources are not yet expected to be release until each registered
pin/pin pair is unregistered.

Currently, the following crash/call trace is produced when ice driver is
removed on the system with installed E810T NIC which includes dpll device:

WARNING: CPU: 51 PID: 9155 at drivers/dpll/dpll_core.c:809 dpll_pin_ops+0x20/0x30
RIP: 0010:dpll_pin_ops+0x20/0x30
Call Trace:
? __warn+0x7f/0x130
? dpll_pin_ops+0x20/0x30
dpll_msg_add_pin_freq+0x37/0x1d0
dpll_cmd_pin_get_one+0x1c0/0x400
? __nlmsg_put+0x63/0x80
dpll_pin_event_send+0x93/0x140
dpll_pin_on_pin_unregister+0x3f/0x100
ice_dpll_deinit_pins+0xa1/0x230 [ice]
ice_remove+0xf1/0x210 [ice]

Fix by adding a parent pointer as a cookie when creating a registration,
also when searching for it. For the regular pins pass NULL, this allows to
create separated registration for each parent the pin is registered with.

Fixes: b446631f355e ("dpll: fix dpll_xa_ref_*_del() for multiple registrations")
Signed-off-by: Arkadiusz Kubalewski <[e-mail]>
Reviewed-by: Jiri Pirko <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Jakub Kicinski <[e-mail]>

drivers/dpll/dpll_core.c

···
 	struct list_head list;
 	const struct dpll_pin_ops *ops;
 	void *priv;
+	void *cookie;
 };
 
 struct dpll_device *dpll_device_get_by_id(int id)
···
 
 static struct dpll_pin_registration *
 dpll_pin_registration_find(struct dpll_pin_ref *ref,
-			   const struct dpll_pin_ops *ops, void *priv)
+			   const struct dpll_pin_ops *ops, void *priv,
+			   void *cookie)
 {
 	struct dpll_pin_registration *reg;
 
 	list_for_each_entry(reg, &ref->registration_list, list) {
-		if (reg->ops == ops && reg->priv == priv)
+		if (reg->ops == ops && reg->priv == priv &&
+		    reg->cookie == cookie)
 			return reg;
 	}
 	return NULL;
···
 
 static int
 dpll_xa_ref_pin_add(struct xarray *xa_pins, struct dpll_pin *pin,
-		    const struct dpll_pin_ops *ops, void *priv)
+		    const struct dpll_pin_ops *ops, void *priv,
+		    void *cookie)
 {
 	struct dpll_pin_registration *reg;
 	struct dpll_pin_ref *ref;
···
 	xa_for_each(xa_pins, i, ref) {
 		if (ref->pin != pin)
 			continue;
-		reg = dpll_pin_registration_find(ref, ops, priv);
+		reg = dpll_pin_registration_find(ref, ops, priv, cookie);
 		if (reg) {
 			refcount_inc(&ref->refcount);
 			return 0;
···
 	}
 	reg->ops = ops;
 	reg->priv = priv;
+	reg->cookie = cookie;
 	if (ref_exists)
 		refcount_inc(&ref->refcount);
 	list_add_tail(&reg->list, &ref->registration_list);
···
 }
 
 static int dpll_xa_ref_pin_del(struct xarray *xa_pins, struct dpll_pin *pin,
-			       const struct dpll_pin_ops *ops, void *priv)
+			       const struct dpll_pin_ops *ops, void *priv,
+			       void *cookie)
 {
 	struct dpll_pin_registration *reg;
 	struct dpll_pin_ref *ref;
···
 	xa_for_each(xa_pins, i, ref) {
 		if (ref->pin != pin)
 			continue;
-		reg = dpll_pin_registration_find(ref, ops, priv);
+		reg = dpll_pin_registration_find(ref, ops, priv, cookie);
 		if (WARN_ON(!reg))
 			return -EINVAL;
 		list_del(&reg->list);
···
 
 static int
 dpll_xa_ref_dpll_add(struct xarray *xa_dplls, struct dpll_device *dpll,
-		     const struct dpll_pin_ops *ops, void *priv)
+		     const struct dpll_pin_ops *ops, void *priv, void *cookie)
 {
 	struct dpll_pin_registration *reg;
 	struct dpll_pin_ref *ref;
···
 	xa_for_each(xa_dplls, i, ref) {
 		if (ref->dpll != dpll)
 			continue;
-		reg = dpll_pin_registration_find(ref, ops, priv);
+		reg = dpll_pin_registration_find(ref, ops, priv, cookie);
 		if (reg) {
 			refcount_inc(&ref->refcount);
 			return 0;
···
 	}
 	reg->ops = ops;
 	reg->priv = priv;
+	reg->cookie = cookie;
 	if (ref_exists)
 		refcount_inc(&ref->refcount);
 	list_add_tail(&reg->list, &ref->registration_list);
···
 
 static void
 dpll_xa_ref_dpll_del(struct xarray *xa_dplls, struct dpll_device *dpll,
-		     const struct dpll_pin_ops *ops, void *priv)
+		     const struct dpll_pin_ops *ops, void *priv, void *cookie)
 {
 	struct dpll_pin_registration *reg;
 	struct dpll_pin_ref *ref;
···
 	xa_for_each(xa_dplls, i, ref) {
 		if (ref->dpll != dpll)
 			continue;
-		reg = dpll_pin_registration_find(ref, ops, priv);
+		reg = dpll_pin_registration_find(ref, ops, priv, cookie);
 		if (WARN_ON(!reg))
 			return;
 		list_del(&reg->list);
···
 
 static int
 __dpll_pin_register(struct dpll_device *dpll, struct dpll_pin *pin,
-		    const struct dpll_pin_ops *ops, void *priv)
+		    const struct dpll_pin_ops *ops, void *priv, void *cookie)
 {
 	int ret;
 
-	ret = dpll_xa_ref_pin_add(&dpll->pin_refs, pin, ops, priv);
+	ret = dpll_xa_ref_pin_add(&dpll->pin_refs, pin, ops, priv, cookie);
 	if (ret)
 		return ret;
-	ret = dpll_xa_ref_dpll_add(&pin->dpll_refs, dpll, ops, priv);
+	ret = dpll_xa_ref_dpll_add(&pin->dpll_refs, dpll, ops, priv, cookie);
 	if (ret)
 		goto ref_pin_del;
 	xa_set_mark(&dpll_pin_xa, pin->id, DPLL_REGISTERED);
···
 	return ret;
 
 ref_pin_del:
-	dpll_xa_ref_pin_del(&dpll->pin_refs, pin, ops, priv);
+	dpll_xa_ref_pin_del(&dpll->pin_refs, pin, ops, priv, cookie);
 	return ret;
 }
 
···
 		      dpll->clock_id == pin->clock_id)))
 		ret = -EINVAL;
 	else
-		ret = __dpll_pin_register(dpll, pin, ops, priv);
+		ret = __dpll_pin_register(dpll, pin, ops, priv, NULL);
 	mutex_unlock(&dpll_lock);
 
 	return ret;
···
 
 static void
 __dpll_pin_unregister(struct dpll_device *dpll, struct dpll_pin *pin,
-		      const struct dpll_pin_ops *ops, void *priv)
+		      const struct dpll_pin_ops *ops, void *priv, void *cookie)
 {
 	ASSERT_DPLL_PIN_REGISTERED(pin);
-	dpll_xa_ref_pin_del(&dpll->pin_refs, pin, ops, priv);
-	dpll_xa_ref_dpll_del(&pin->dpll_refs, dpll, ops, priv);
+	dpll_xa_ref_pin_del(&dpll->pin_refs, pin, ops, priv, cookie);
+	dpll_xa_ref_dpll_del(&pin->dpll_refs, dpll, ops, priv, cookie);
 	if (xa_empty(&pin->dpll_refs))
 		xa_clear_mark(&dpll_pin_xa, pin->id, DPLL_REGISTERED);
 }
···
 
 	mutex_lock(&dpll_lock);
 	dpll_pin_delete_ntf(pin);
-	__dpll_pin_unregister(dpll, pin, ops, priv);
+	__dpll_pin_unregister(dpll, pin, ops, priv, NULL);
 	mutex_unlock(&dpll_lock);
 }
 EXPORT_SYMBOL_GPL(dpll_pin_unregister);
···
 		return -EINVAL;
 
 	mutex_lock(&dpll_lock);
-	ret = dpll_xa_ref_pin_add(&pin->parent_refs, parent, ops, priv);
+	ret = dpll_xa_ref_pin_add(&pin->parent_refs, parent, ops, priv, pin);
 	if (ret)
 		goto unlock;
 	refcount_inc(&pin->refcount);
 	xa_for_each(&parent->dpll_refs, i, ref) {
-		ret = __dpll_pin_register(ref->dpll, pin, ops, priv);
+		ret = __dpll_pin_register(ref->dpll, pin, ops, priv, parent);
 		if (ret) {
 			stop = i;
 			goto dpll_unregister;
···
 dpll_unregister:
 	xa_for_each(&parent->dpll_refs, i, ref)
 		if (i < stop) {
-			__dpll_pin_unregister(ref->dpll, pin, ops, priv);
+			__dpll_pin_unregister(ref->dpll, pin, ops, priv,
+					      parent);
 			dpll_pin_delete_ntf(pin);
 		}
 	refcount_dec(&pin->refcount);
-	dpll_xa_ref_pin_del(&pin->parent_refs, parent, ops, priv);
+	dpll_xa_ref_pin_del(&pin->parent_refs, parent, ops, priv, pin);
 unlock:
 	mutex_unlock(&dpll_lock);
 	return ret;
···
 
 	mutex_lock(&dpll_lock);
 	dpll_pin_delete_ntf(pin);
-	dpll_xa_ref_pin_del(&pin->parent_refs, parent, ops, priv);
+	dpll_xa_ref_pin_del(&pin->parent_refs, parent, ops, priv, pin);
 	refcount_dec(&pin->refcount);
 	xa_for_each(&pin->dpll_refs, i, ref)
-		__dpll_pin_unregister(ref->dpll, pin, ops, priv);
+		__dpll_pin_unregister(ref->dpll, pin, ops, priv, parent);
 	mutex_unlock(&dpll_lock);
 }
 EXPORT_SYMBOL_GPL(dpll_pin_on_pin_unregister);