Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

No conflicts.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>

1 files changed, 63 insertions, 27 deletions

diff --git a/drivers/base/core.c b/drivers/base/core.c
index e65dd803a453..15986cc2fe5e 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -95,6 +95,8 @@ int fwnode_link_add(struct fwnode_handle *con, struct fwnode_handle *sup)
 
 	list_add(&link->s_hook, &sup->consumers);
 	list_add(&link->c_hook, &con->suppliers);
+	pr_debug("%pfwP Linked as a fwnode consumer to %pfwP\n",
+		 con, sup);
 out:
 	mutex_unlock(&fwnode_link_lock);
 
@@ -102,6 +104,21 @@ out:
 }
 
 /**
+ * __fwnode_link_del - Delete a link between two fwnode_handles.
+ * @link: the fwnode_link to be deleted
+ *
+ * The fwnode_link_lock needs to be held when this function is called.
+ */
+static void __fwnode_link_del(struct fwnode_link *link)
+{
+	pr_debug("%pfwP Dropping the fwnode link to %pfwP\n",
+		 link->consumer, link->supplier);
+	list_del(&link->s_hook);
+	list_del(&link->c_hook);
+	kfree(link);
+}
+
+/**
  * fwnode_links_purge_suppliers - Delete all supplier links of fwnode_handle.
  * @fwnode: fwnode whose supplier links need to be deleted
  *
@@ -112,11 +129,8 @@ static void fwnode_links_purge_suppliers(struct fwnode_handle *fwnode)
 	struct fwnode_link *link, *tmp;
 
 	mutex_lock(&fwnode_link_lock);
-	list_for_each_entry_safe(link, tmp, &fwnode->suppliers, c_hook) {
-		list_del(&link->s_hook);
-		list_del(&link->c_hook);
-		kfree(link);
-	}
+	list_for_each_entry_safe(link, tmp, &fwnode->suppliers, c_hook)
+		__fwnode_link_del(link);
 	mutex_unlock(&fwnode_link_lock);
 }
 
@@ -131,11 +145,8 @@ static void fwnode_links_purge_consumers(struct fwnode_handle *fwnode)
 	struct fwnode_link *link, *tmp;
 
 	mutex_lock(&fwnode_link_lock);
-	list_for_each_entry_safe(link, tmp, &fwnode->consumers, s_hook) {
-		list_del(&link->s_hook);
-		list_del(&link->c_hook);
-		kfree(link);
-	}
+	list_for_each_entry_safe(link, tmp, &fwnode->consumers, s_hook)
+		__fwnode_link_del(link);
 	mutex_unlock(&fwnode_link_lock);
 }
 
@@ -975,6 +986,7 @@ int device_links_check_suppliers(struct device *dev)
 {
 	struct device_link *link;
 	int ret = 0;
+	struct fwnode_handle *sup_fw;
 
 	/*
 	 * Device waiting for supplier to become available is not allowed to
@@ -983,10 +995,11 @@ int device_links_check_suppliers(struct device *dev)
 	mutex_lock(&fwnode_link_lock);
 	if (dev->fwnode && !list_empty(&dev->fwnode->suppliers) &&
 	    !fw_devlink_is_permissive()) {
-		dev_dbg(dev, "probe deferral - wait for supplier %pfwP\n",
-			list_first_entry(&dev->fwnode->suppliers,
-			struct fwnode_link,
-			c_hook)->supplier);
+		sup_fw = list_first_entry(&dev->fwnode->suppliers,
+					  struct fwnode_link,
+					  c_hook)->supplier;
+		dev_err_probe(dev, -EPROBE_DEFER, "wait for supplier %pfwP\n",
+			      sup_fw);
 		mutex_unlock(&fwnode_link_lock);
 		return -EPROBE_DEFER;
 	}
@@ -1001,8 +1014,9 @@ int device_links_check_suppliers(struct device *dev)
 		if (link->status != DL_STATE_AVAILABLE &&
 		    !(link->flags & DL_FLAG_SYNC_STATE_ONLY)) {
 			device_links_missing_supplier(dev);
-			dev_dbg(dev, "probe deferral - supplier %s not ready\n",
-				dev_name(link->supplier));
+			dev_err_probe(dev, -EPROBE_DEFER,
+				      "supplier %s not ready\n",
+				      dev_name(link->supplier));
 			ret = -EPROBE_DEFER;
 			break;
 		}
@@ -1722,6 +1736,25 @@ static int fw_devlink_create_devlink(struct device *con,
 	struct device *sup_dev;
 	int ret = 0;
 
+	/*
+	 * In some cases, a device P might also be a supplier to its child node
+	 * C. However, this would defer the probe of C until the probe of P
+	 * completes successfully. This is perfectly fine in the device driver
+	 * model. device_add() doesn't guarantee probe completion of the device
+	 * by the time it returns.
+	 *
+	 * However, there are a few drivers that assume C will finish probing
+	 * as soon as it's added and before P finishes probing. So, we provide
+	 * a flag to let fw_devlink know not to delay the probe of C until the
+	 * probe of P completes successfully.
+	 *
+	 * When such a flag is set, we can't create device links where P is the
+	 * supplier of C as that would delay the probe of C.
+	 */
+	if (sup_handle->flags & FWNODE_FLAG_NEEDS_CHILD_BOUND_ON_ADD &&
+	    fwnode_is_ancestor_of(sup_handle, con->fwnode))
+		return -EINVAL;
+
 	sup_dev = get_dev_from_fwnode(sup_handle);
 	if (sup_dev) {
 		/*
@@ -1772,14 +1805,21 @@ static int fw_devlink_create_devlink(struct device *con,
 	 * be broken by applying logic. Check for these types of cycles and
 	 * break them so that devices in the cycle probe properly.
 	 *
-	 * If the supplier's parent is dependent on the consumer, then
-	 * the consumer-supplier dependency is a false dependency. So,
-	 * treat it as an invalid link.
+	 * If the supplier's parent is dependent on the consumer, then the
+	 * consumer and supplier have a cyclic dependency. Since fw_devlink
+	 * can't tell which of the inferred dependencies are incorrect, don't
+	 * enforce probe ordering between any of the devices in this cyclic
+	 * dependency. Do this by relaxing all the fw_devlink device links in
+	 * this cycle and by treating the fwnode link between the consumer and
+	 * the supplier as an invalid dependency.
 	 */
 	sup_dev = fwnode_get_next_parent_dev(sup_handle);
 	if (sup_dev && device_is_dependent(con, sup_dev)) {
-		dev_dbg(con, "Not linking to %pfwP - False link\n",
-			sup_handle);
+		dev_info(con, "Fixing up cyclic dependency with %pfwP (%s)\n",
+			 sup_handle, dev_name(sup_dev));
+		device_links_write_lock();
+		fw_devlink_relax_cycle(con, sup_dev);
+		device_links_write_unlock();
 		ret = -EINVAL;
 	} else {
 		/*
@@ -1858,9 +1898,7 @@ static void __fw_devlink_link_to_consumers(struct device *dev)
 		if (!own_link || ret == -EAGAIN)
 			continue;
 
-		list_del(&link->s_hook);
-		list_del(&link->c_hook);
-		kfree(link);
+		__fwnode_link_del(link);
 	}
 }
 
@@ -1912,9 +1950,7 @@ static void __fw_devlink_link_to_suppliers(struct device *dev,
 		if (!own_link || ret == -EAGAIN)
 			continue;
 
-		list_del(&link->s_hook);
-		list_del(&link->c_hook);
-		kfree(link);
+		__fwnode_link_del(link);
 
 		/* If no device link was created, nothing more to do. */
 		if (ret)