From: Heikki Krogerus <heikki.krogerus@linux.intel.com>
To: Daniel Scally <djrscally@gmail.com>
Cc: linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org,
linux-media@vger.kernel.org, devel@acpica.org, rjw@rjwysocki.net,
lenb@kernel.org, gregkh@linuxfoundation.org, mchehab@kernel.org,
sergey.senozhatsky@gmail.com, yong.zhi@intel.com,
sakari.ailus@linux.intel.com, bingbu.cao@intel.com,
tian.shu.qiu@intel.com, robert.moore@intel.com,
erik.kaneda@intel.com, pmladek@suse.com, rostedt@goodmis.org,
andriy.shevchenko@linux.intel.com, linux@rasmusvillemoes.dk,
laurent.pinchart+renesas@ideasonboard.com,
jacopo+renesas@jmondi.org,
kieran.bingham+renesas@ideasonboard.com,
hverkuil-cisco@xs4all.nl, m.felsch@pengutronix.de,
niklas.soderlund+renesas@ragnatech.se,
prabhakar.mahadev-lad.rj@bp.renesas.com, slongerbeam@gmail.com,
Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Subject: Re: [PATCH v5 05/15] software_node: Enforce parent before child ordering of nodes arrays
Date: Thu, 7 Jan 2021 16:04:18 +0200 [thread overview]
Message-ID: <20210107140418.GE940479@kuha.fi.intel.com> (raw)
In-Reply-To: <20210107132838.396641-6-djrscally@gmail.com>
On Thu, Jan 07, 2021 at 01:28:28PM +0000, Daniel Scally wrote:
> 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>
> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> Signed-off-by: Daniel Scally <djrscally@gmail.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
> ---
> Changes in v5:
>
> - None
>
> drivers/base/swnode.c | 42 ++++++++++++++++++++++++++++++------------
> 1 file changed, 30 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/base/swnode.c b/drivers/base/swnode.c
> index 4fcc1a6fb724..166c5cc73f39 100644
> --- a/drivers/base/swnode.c
> +++ b/drivers/base/swnode.c
> @@ -692,7 +692,11 @@ 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 its .parent pointer set (which can only be to another software_node),
> + * then its 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)
> {
> @@ -700,14 +704,23 @@ 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);
>
> @@ -715,18 +728,23 @@ 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
> *
> - * 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
--
heikki
next prev parent reply other threads:[~2021-01-07 14:06 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-07 13:28 [PATCH v5 00/15] Add functionality to ipu3-cio2 driver allowing software_node connections to sensors on platforms designed for Windows Daniel Scally
2021-01-07 13:28 ` [PATCH v5 01/15] software_node: Fix refcounts in software_node_get_next_child() Daniel Scally
2021-01-07 13:45 ` Heikki Krogerus
2021-01-10 15:09 ` Greg KH
2021-01-07 13:28 ` [PATCH v5 02/15] media: ipu3-cio2: Add headers that ipu3-cio2.h is direct user of Daniel Scally
2021-01-07 13:28 ` [PATCH v5 03/15] device property: Return true in fwnode_device_is_available for NULL ops Daniel Scally
2021-01-07 13:47 ` Heikki Krogerus
2021-01-10 15:09 ` Greg KH
2021-01-07 13:28 ` [PATCH v5 04/15] device property: Call fwnode_graph_get_endpoint_by_id() for fwnode->secondary Daniel Scally
2021-01-10 15:09 ` Greg KH
2021-01-07 13:28 ` [PATCH v5 05/15] software_node: Enforce parent before child ordering of nodes arrays Daniel Scally
2021-01-07 14:04 ` Heikki Krogerus [this message]
2021-01-10 15:09 ` Greg KH
2021-01-07 13:28 ` [PATCH v5 06/15] software_node: unregister software_nodes in reverse order Daniel Scally
2021-01-07 14:05 ` Heikki Krogerus
2021-01-10 15:09 ` Greg KH
2021-01-07 13:28 ` [PATCH v5 07/15] device property: Define format macros for ports and endpoints Daniel Scally
2021-01-07 14:06 ` Heikki Krogerus
2021-01-09 2:05 ` Laurent Pinchart
2021-01-12 19:30 ` Rafael J. Wysocki
2021-01-12 19:29 ` Rafael J. Wysocki
2021-01-07 13:28 ` [PATCH v5 08/15] software_node: Add support for fwnode_graph*() family of functions Daniel Scally
2021-01-10 15:08 ` Greg KH
2021-01-07 13:28 ` [PATCH v5 09/15] lib/test_printf.c: Use helper function to unwind array of software_nodes Daniel Scally
2021-01-09 2:01 ` Laurent Pinchart
[not found] ` <CAHp75VeLiMdzXL3Awhco-w6JwJhZNVao_uj7F6bmuty_aW0SNQ@mail.gmail.com>
2021-01-10 11:16 ` Laurent Pinchart
2021-01-10 15:38 ` Andy Shevchenko
2021-01-10 15:52 ` Laurent Pinchart
2021-01-13 13:23 ` Sakari Ailus
2021-01-27 9:25 ` Geert Uytterhoeven
2021-01-07 13:28 ` [PATCH v5 10/15] ipu3-cio2: Add T: entry to MAINTAINERS Daniel Scally
2021-01-07 13:28 ` [PATCH v5 11/15] ipu3-cio2: Rename ipu3-cio2.c Daniel Scally
2021-01-07 13:28 ` [PATCH v5 12/15] media: v4l2-core: v4l2-async: Check sd->fwnode->secondary in match_fwnode() Daniel Scally
2021-01-07 13:28 ` [PATCH v5 13/15] ACPI / bus: Add acpi_dev_get_next_match_dev() and helper macro Daniel Scally
2021-01-09 1:54 ` Laurent Pinchart
2021-01-12 19:26 ` Rafael J. Wysocki
2021-01-12 19:25 ` Rafael J. Wysocki
2021-01-07 13:28 ` [PATCH v5 14/15] media: v4l2-fwnode: Include v4l2_fwnode_bus_type Daniel Scally
2021-01-07 13:28 ` [PATCH v5 15/15] ipu3-cio2: Add cio2-bridge to ipu3-cio2 driver Daniel Scally
2021-01-07 14:05 ` Andy Shevchenko
2021-01-07 14:05 ` Andy Shevchenko
2021-01-07 14:07 ` Daniel Scally
2021-01-09 2:08 ` [PATCH v5 00/15] Add functionality to ipu3-cio2 driver allowing software_node connections to sensors on platforms designed for Windows Laurent Pinchart
2021-01-10 15:08 ` Greg Kroah-Hartman
2021-01-12 19:34 ` Rafael J. Wysocki
2021-01-12 23:35 ` Daniel Scally
2021-01-13 11:42 ` Sakari Ailus
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