linux-kernel - [PATCH v3 12/12] mtd: mtdpart: Don't create platform device that'll never probe

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Message-Id: <20230207014207.1678715-13-saravanak@google.com>
Date:   Mon,  6 Feb 2023 17:42:04 -0800
From:   Saravana Kannan <saravanak@...gle.com>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        "Rafael J. Wysocki" <rafael@...nel.org>,
        Sudeep Holla <sudeep.holla@....com>,
        Cristian Marussi <cristian.marussi@....com>,
        Linus Walleij <linus.walleij@...aro.org>,
        Bartosz Golaszewski <brgl@...ev.pl>,
        Thomas Gleixner <tglx@...utronix.de>,
        Marc Zyngier <maz@...nel.org>, Shawn Guo <shawnguo@...nel.org>,
        Sascha Hauer <s.hauer@...gutronix.de>,
        Pengutronix Kernel Team <kernel@...gutronix.de>,
        Fabio Estevam <festevam@...il.com>,
        NXP Linux Team <linux-imx@....com>,
        Miquel Raynal <miquel.raynal@...tlin.com>,
        Richard Weinberger <richard@....at>,
        Vignesh Raghavendra <vigneshr@...com>,
        Rob Herring <robh+dt@...nel.org>,
        Frank Rowand <frowand.list@...il.com>,
        Geert Uytterhoeven <geert+renesas@...der.be>,
        Magnus Damm <magnus.damm@...il.com>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Daniel Scally <djrscally@...il.com>,
        Heikki Krogerus <heikki.krogerus@...ux.intel.com>,
        Sakari Ailus <sakari.ailus@...ux.intel.com>,
        Len Brown <lenb@...nel.org>,
        Saravana Kannan <saravanak@...gle.com>,
        "Rafał Miłecki" <rafal@...ecki.pl>
Cc:     Abel Vesa <abel.vesa@...aro.org>,
        Alexander Stein <alexander.stein@...tq-group.com>,
        Tony Lindgren <tony@...mide.com>,
        Geert Uytterhoeven <geert@...ux-m68k.org>,
        John Stultz <jstultz@...gle.com>,
        Doug Anderson <dianders@...omium.org>,
        Guenter Roeck <linux@...ck-us.net>,
        Dmitry Baryshkov <dmitry.baryshkov@...aro.org>,
        Maxim Kiselev <bigunclemax@...il.com>,
        Maxim Kochetkov <fido_max@...ox.ru>,
        Luca Weiss <luca.weiss@...rphone.com>,
        Colin Foster <colin.foster@...advantage.com>,
        Martin Kepplinger <martin.kepplinger@...i.sm>,
        Jean-Philippe Brucker <jpb@...nel.org>,
        Vladimir Oltean <vladimir.oltean@....com>,
        kernel-team@...roid.com, linux-kernel@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-gpio@...r.kernel.org,
        linux-mtd@...ts.infradead.org, devicetree@...r.kernel.org,
        linux-renesas-soc@...r.kernel.org, linux-acpi@...r.kernel.org
Subject: [PATCH v3 12/12] mtd: mtdpart: Don't create platform device that'll
 never probe

These "nvmem-cells" platform devices never get probed because there's no
platform driver for it and it's never used anywhere else. So it's a
waste of memory. These devices also cause fw_devlink to block nvmem
consumers of "nvmem-cells" partition from probing because the supplier
device never probes.

So stop creating platform devices for nvmem-cells partitions to avoid
wasting memory and to avoid blocking probing of consumers.

Reported-by: Maxim Kiselev <bigunclemax@...il.com>
Fixes: bcdf0315a61a ("mtd: call of_platform_populate() for MTD partitions")
Signed-off-by: Saravana Kannan <saravanak@...gle.com>
---
 drivers/mtd/mtdpart.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/mtd/mtdpart.c b/drivers/mtd/mtdpart.c
index d442fa94c872..85f5ee6f06fc 100644
--- a/drivers/mtd/mtdpart.c
+++ b/drivers/mtd/mtdpart.c
@@ -577,6 +577,7 @@ static int mtd_part_of_parse(struct mtd_info *master,
 {
 	struct mtd_part_parser *parser;
 	struct device_node *np;
+	struct device_node *child;
 	struct property *prop;
 	struct device *dev;
 	const char *compat;
@@ -594,6 +595,15 @@ static int mtd_part_of_parse(struct mtd_info *master,
 	else
 		np = of_get_child_by_name(np, "partitions");
 
+	/*
+	 * Don't create devices that are added to a bus but will never get
+	 * probed. That'll cause fw_devlink to block probing of consumers of
+	 * this partition until the partition device is probed.
+	 */
+	for_each_child_of_node(np, child)
+		if (of_device_is_compatible(child, "nvmem-cells"))
+			of_node_set_flag(child, OF_POPULATED);
+
 	of_property_for_each_string(np, "compatible", prop, compat) {
 		parser = mtd_part_get_compatible_parser(compat);
 		if (!parser)
-- 
2.39.1.519.gcb327c4b5f-goog