From: Daniel Scally <djrscally@gmail.com>
To: linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org,
linux-media@vger.kernel.org, devel@acpica.org
Cc: rjw@rjwysocki.net, lenb@kernel.org, gregkh@linuxfoundation.org,
yong.zhi@intel.com, sakari.ailus@linux.intel.com,
bingbu.cao@intel.com, tian.shu.qiu@intel.com, mchehab@kernel.org,
robert.moore@intel.com, erik.kaneda@intel.com, pmladek@suse.com,
rostedt@goodmis.org, sergey.senozhatsky@gmail.com,
andriy.shevchenko@linux.intel.com, linux@rasmusvillemoes.dk,
laurent.pinchart+renesas@ideasonboard.com,
jacopo+renesas@jmondi.org,
kieran.bingham+renesas@ideasonboard.com,
linus.walleij@linaro.org, heikki.krogerus@linux.intel.com,
kitakar@gmail.com, jorhand@linux.microsoft.com
Subject: [PATCH v2 04/12] software_node: Enforce parent before child ordering of nodes arrays
Date: Thu, 17 Dec 2020 23:43:29 +0000 [thread overview]
Message-ID: <20201217234337.1983732-5-djrscally@gmail.com> (raw)
In-Reply-To: <20201217234337.1983732-1-djrscally@gmail.com>
Registering software_nodes with the .parent member set to point to a
currently unregistered software_node has the potential for problems,
so enforce parent -> child ordering in arrays passed in to
software_node_register_nodes().
Software nodes that are children of another software node should be
unregistered before their parent. To allow easy unregistering of an array
of software_nodes ordered parent to child, reverse the order in which
software_node_unregister_nodes() unregisters software_nodes.
Suggested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Daniel Scally <djrscally@gmail.com>
---
Changes in v2:
- Squashed the patches that originally touched these separately
- Updated documentation
drivers/base/swnode.c | 43 ++++++++++++++++++++++++++++++-------------
1 file changed, 30 insertions(+), 13 deletions(-)
diff --git a/drivers/base/swnode.c b/drivers/base/swnode.c
index 615a0c93e116..cfd1faea48a7 100644
--- a/drivers/base/swnode.c
+++ b/drivers/base/swnode.c
@@ -692,7 +692,10 @@ swnode_register(const struct software_node *node, struct swnode *parent,
* software_node_register_nodes - Register an array of software nodes
* @nodes: Zero terminated array of software nodes to be registered
*
- * Register multiple software nodes at once.
+ * Register multiple software nodes at once. If any node in the array
+ * has it's .parent pointer set, then it's parent **must** have been
+ * registered before it is; either outside of this function or by
+ * ordering the array such that parent comes before child.
*/
int software_node_register_nodes(const struct software_node *nodes)
{
@@ -700,33 +703,47 @@ int software_node_register_nodes(const struct software_node *nodes)
int i;
for (i = 0; nodes[i].name; i++) {
- ret = software_node_register(&nodes[i]);
- if (ret) {
- software_node_unregister_nodes(nodes);
- return ret;
+ const struct software_node *parent = nodes[i].parent;
+
+ if (parent && !software_node_to_swnode(parent)) {
+ ret = -EINVAL;
+ goto err_unregister_nodes;
}
+
+ ret = software_node_register(&nodes[i]);
+ if (ret)
+ goto err_unregister_nodes;
}
return 0;
+
+err_unregister_nodes:
+ software_node_unregister_nodes(nodes);
+ return ret;
}
EXPORT_SYMBOL_GPL(software_node_register_nodes);
/**
* software_node_unregister_nodes - Unregister an array of software nodes
- * @nodes: Zero terminated array of software nodes to be unregistered
+ * @nodes: Zero terminated array of software nodes to be unregistered.
*
- * Unregister multiple software nodes at once.
+ * Unregister multiple software nodes at once. If parent pointers are set up
+ * in any of the software nodes then the array MUST be ordered such that
+ * parents come before their children.
*
- * NOTE: Be careful using this call if the nodes had parent pointers set up in
- * them before registering. If so, it is wiser to remove the nodes
- * individually, in the correct order (child before parent) instead of relying
- * on the sequential order of the list of nodes in the array.
+ * NOTE: If you are uncertain whether the array is ordered such that
+ * parents will be unregistered before their children, it is wiser to
+ * remove the nodes individually, in the correct order (child before
+ * parent).
*/
void software_node_unregister_nodes(const struct software_node *nodes)
{
- int i;
+ unsigned int i = 0;
+
+ while (nodes[i].name)
+ i++;
- for (i = 0; nodes[i].name; i++)
+ while (i--)
software_node_unregister(&nodes[i]);
}
EXPORT_SYMBOL_GPL(software_node_unregister_nodes);
--
2.25.1
next prev parent reply other threads:[~2020-12-17 23:44 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-17 23:43 [PATCH v2 00/12] Add functionality to ipu3-cio2 driver allowing software_node connections to sensors on platforms designed for Windows Daniel Scally
2020-12-17 23:43 ` [PATCH v2 01/12] software_node: Fix refcounts in software_node_get_next_child() Daniel Scally
2020-12-21 9:08 ` Sakari Ailus
2020-12-17 23:43 ` [PATCH v2 02/12] property: Return true in fwnode_device_is_available for NULL ops Daniel Scally
2020-12-21 9:10 ` Sakari Ailus
2020-12-17 23:43 ` [PATCH v2 03/12] property: Call fwnode_graph_get_endpoint_by_id() for fwnode->secondary Daniel Scally
2020-12-17 23:43 ` Daniel Scally [this message]
2020-12-18 16:02 ` [PATCH v2 04/12] software_node: Enforce parent before child ordering of nodes arrays Laurent Pinchart
2020-12-18 22:19 ` Daniel Scally
2020-12-18 20:29 ` Andy Shevchenko
2020-12-19 23:33 ` Daniel Scally
2020-12-17 23:43 ` [PATCH v2 05/12] software_node: unregister software_nodes in reverse order Daniel Scally
2020-12-18 20:31 ` Andy Shevchenko
2020-12-21 9:21 ` Sakari Ailus
2020-12-21 11:26 ` Andy Shevchenko
2020-12-23 22:24 ` Daniel Scally
2020-12-17 23:43 ` [PATCH v2 06/12] software_node: Add support for fwnode_graph*() family of functions Daniel Scally
2020-12-18 16:22 ` Laurent Pinchart
2020-12-18 22:13 ` Daniel Scally
2020-12-18 23:46 ` Daniel Scally
2020-12-18 20:37 ` Andy Shevchenko
2020-12-18 22:26 ` Daniel Scally
2020-12-21 9:34 ` Sakari Ailus
2020-12-21 10:01 ` Daniel Scally
2020-12-17 23:43 ` [PATCH v2 07/12] lib/test_printf.c: Use helper function to unwind array of software_nodes Daniel Scally
2020-12-17 23:43 ` [PATCH v2 08/12] ipu3-cio2: Add T: entry to MAINTAINERS Daniel Scally
2020-12-17 23:43 ` [PATCH v2 09/12] ipu3-cio2: Rename ipu3-cio2.c Daniel Scally
2020-12-17 23:43 ` [PATCH v2 10/12] media: v4l2-core: v4l2-async: Check sd->fwnode->secondary in match_fwnode() Daniel Scally
2020-12-17 23:43 ` [PATCH v2 11/12] acpi: Add acpi_dev_get_next_match_dev() and helper macro Daniel Scally
2020-12-18 20:42 ` Andy Shevchenko
2020-12-21 9:47 ` Sakari Ailus
2020-12-17 23:43 ` [PATCH v2 12/12] ipu3-cio2: Add cio2-bridge to ipu3-cio2 driver Daniel Scally
2020-12-18 16:53 ` Laurent Pinchart
2020-12-18 23:57 ` Daniel Scally
2020-12-19 0:39 ` Laurent Pinchart
2020-12-19 23:24 ` Daniel Scally
2020-12-18 21:17 ` Andy Shevchenko
2020-12-19 0:22 ` Daniel Scally
2020-12-19 18:52 ` Andy Shevchenko
2020-12-19 23:48 ` Daniel Scally
2020-12-21 10:21 ` Sakari Ailus
2020-12-21 10:52 ` Daniel Scally
2020-12-21 10:57 ` Sakari Ailus
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