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authorJakub Kicinski <kuba@kernel.org>2021-10-07 15:24:06 -0700
committerJakub Kicinski <kuba@kernel.org>2021-10-07 15:24:06 -0700
commit9fe1155233c8290ca6e206053e531ef87f9026ea (patch)
treeef0d45b2562e01beb8ce4cb4cd016155b4e32a65 /drivers/base
parentc514fbb6231483b05c97eb22587188d4c453b28e (diff)
parent1da38549dd64c7f5dd22427f12dfa8db3d8a722b (diff)
Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
No conflicts. Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'drivers/base')
-rw-r--r--drivers/base/core.c90
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)