Commit f72e77c3 authored by Douglas Anderson's avatar Douglas Anderson Committed by Danilo Krummrich
Browse files

device property: Make modifications of fwnode "flags" thread safe 



In various places in the kernel, we modify the fwnode "flags" member
by doing either:
  fwnode->flags |= SOME_FLAG;
  fwnode->flags &= ~SOME_FLAG;

This type of modification is not thread-safe. If two threads are both
mucking with the flags at the same time then one can clobber the
other.

While flags are often modified while under the "fwnode_link_lock",
this is not universally true.

Create some accessor functions for setting, clearing, and testing the
FWNODE flags and move all users to these accessor functions. New
accessor functions use set_bit() and clear_bit(), which are
thread-safe.

Cc: stable@vger.kernel.org
Fixes: c2c724c8 ("driver core: Add fw_devlink_parse_fwtree()")
Reviewed-by: default avatarAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: default avatarMark Brown <broonie@kernel.org>
Reviewed-by: default avatarWolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: default avatarDouglas Anderson <dianders@chromium.org>
Reviewed-by: default avatarRafael J. Wysocki (Intel) <rafael@kernel.org>
Reviewed-by: default avatarSaravana Kannan <saravanak@kernel.org>
Link: https://patch.msgid.link/20260317090112.v2.1.I0a4d03104ecd5103df3d76f66c8d21b1d15a2e38@changeid


[ Fix fwnode_clear_flag() argument alignment, restore dropped blank
  line in fwnode_dev_initialized(), and remove unnecessary parentheses
  around fwnode_test_flag() calls. - Danilo ]
Signed-off-by: default avatarDanilo Krummrich <dakr@kernel.org>
parent 14cf406e

drivers/base/core.c

+12 −12
Original line number Diff line number Diff line
@@ -182,7 +182,7 @@ void fw_devlink_purge_absent_suppliers(struct fwnode_handle *fwnode) 
	if (fwnode->dev)

		return;



	fwnode->flags |= FWNODE_FLAG_NOT_DEVICE;

	fwnode_set_flag(fwnode, FWNODE_FLAG_NOT_DEVICE);

	fwnode_links_purge_consumers(fwnode);



	fwnode_for_each_available_child_node(fwnode, child)
@@ -228,7 +228,7 @@ static void __fw_devlink_pickup_dangling_consumers(struct fwnode_handle *fwnode, 
	if (fwnode->dev && fwnode->dev->bus)

		return;



	fwnode->flags |= FWNODE_FLAG_NOT_DEVICE;

	fwnode_set_flag(fwnode, FWNODE_FLAG_NOT_DEVICE);

	__fwnode_links_move_consumers(fwnode, new_sup);



	fwnode_for_each_available_child_node(fwnode, child)
@@ -1012,7 +1012,7 @@ static void device_links_missing_supplier(struct device *dev) 
static bool dev_is_best_effort(struct device *dev)

{

	return (fw_devlink_best_effort && dev->can_match) ||

		(dev->fwnode && (dev->fwnode->flags & FWNODE_FLAG_BEST_EFFORT));

		(dev->fwnode && fwnode_test_flag(dev->fwnode, FWNODE_FLAG_BEST_EFFORT));

}



static struct fwnode_handle *fwnode_links_check_suppliers(
@@ -1723,11 +1723,11 @@ bool fw_devlink_is_strict(void) 


static void fw_devlink_parse_fwnode(struct fwnode_handle *fwnode)

{

	if (fwnode->flags & FWNODE_FLAG_LINKS_ADDED)

	if (fwnode_test_flag(fwnode, FWNODE_FLAG_LINKS_ADDED))

		return;



	fwnode_call_int_op(fwnode, add_links);

	fwnode->flags |= FWNODE_FLAG_LINKS_ADDED;

	fwnode_set_flag(fwnode, FWNODE_FLAG_LINKS_ADDED);

}



static void fw_devlink_parse_fwtree(struct fwnode_handle *fwnode)
@@ -1885,7 +1885,7 @@ static bool fwnode_init_without_drv(struct fwnode_handle *fwnode) 
	struct device *dev;

	bool ret;



	if (!(fwnode->flags & FWNODE_FLAG_INITIALIZED))

	if (!fwnode_test_flag(fwnode, FWNODE_FLAG_INITIALIZED))

		return false;



	dev = get_dev_from_fwnode(fwnode);
@@ -2001,10 +2001,10 @@ static bool __fw_devlink_relax_cycles(struct fwnode_handle *con_handle, 
	 * We aren't trying to find all cycles. Just a cycle between con and

	 * sup_handle.

	 */

	if (sup_handle->flags & FWNODE_FLAG_VISITED)

	if (fwnode_test_flag(sup_handle, FWNODE_FLAG_VISITED))

		return false;



	sup_handle->flags |= FWNODE_FLAG_VISITED;

	fwnode_set_flag(sup_handle, FWNODE_FLAG_VISITED);



	/* Termination condition. */

	if (sup_handle == con_handle) {
@@ -2074,7 +2074,7 @@ static bool __fw_devlink_relax_cycles(struct fwnode_handle *con_handle, 
	}



out:

	sup_handle->flags &= ~FWNODE_FLAG_VISITED;

	fwnode_clear_flag(sup_handle, FWNODE_FLAG_VISITED);

	put_device(sup_dev);

	put_device(con_dev);

	put_device(par_dev);
@@ -2127,7 +2127,7 @@ static int fw_devlink_create_devlink(struct device *con, 
	 * 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 &&

	if (fwnode_test_flag(sup_handle, FWNODE_FLAG_NEEDS_CHILD_BOUND_ON_ADD) &&

	    fwnode_is_ancestor_of(sup_handle, con->fwnode))

		return -EINVAL;
@@ -2150,7 +2150,7 @@ static int fw_devlink_create_devlink(struct device *con, 
	else

		flags = FW_DEVLINK_FLAGS_PERMISSIVE;



	if (sup_handle->flags & FWNODE_FLAG_NOT_DEVICE)

	if (fwnode_test_flag(sup_handle, FWNODE_FLAG_NOT_DEVICE))

		sup_dev = fwnode_get_next_parent_dev(sup_handle);

	else

		sup_dev = get_dev_from_fwnode(sup_handle);
@@ -2162,7 +2162,7 @@ static int fw_devlink_create_devlink(struct device *con, 
		 * supplier device indefinitely.

		 */

		if (sup_dev->links.status == DL_DEV_NO_DRIVER &&

		    sup_handle->flags & FWNODE_FLAG_INITIALIZED) {

		    fwnode_test_flag(sup_handle, FWNODE_FLAG_INITIALIZED)) {

			dev_dbg(con,

				"Not linking %pfwf - dev might never probe\n",

				sup_handle);

drivers/bus/imx-weim.c

+1 −1
Original line number Diff line number Diff line
@@ -332,7 +332,7 @@ static int of_weim_notify(struct notifier_block *nb, unsigned long action, 
			 * fw_devlink doesn't skip adding consumers to this

			 * device.

			 */

			rd->dn->fwnode.flags &= ~FWNODE_FLAG_NOT_DEVICE;

			fwnode_clear_flag(&rd->dn->fwnode, FWNODE_FLAG_NOT_DEVICE);

			if (!of_platform_device_create(rd->dn, NULL, &pdev->dev)) {

				dev_err(&pdev->dev,

					"Failed to create child device '%pOF'\n",

drivers/i2c/i2c-core-of.c

+1 −1
Original line number Diff line number Diff line
@@ -180,7 +180,7 @@ static int of_i2c_notify(struct notifier_block *nb, unsigned long action, 
		 * Clear the flag before adding the device so that fw_devlink

		 * doesn't skip adding consumers to this device.

		 */

		rd->dn->fwnode.flags &= ~FWNODE_FLAG_NOT_DEVICE;

		fwnode_clear_flag(&rd->dn->fwnode, FWNODE_FLAG_NOT_DEVICE);

		client = of_i2c_register_device(adap, rd->dn);

		if (IS_ERR(client)) {

			dev_err(&adap->dev, "failed to create client for '%pOF'\n",

drivers/net/phy/mdio_bus_provider.c

+2 −2
Original line number Diff line number Diff line
@@ -294,8 +294,8 @@ int __mdiobus_register(struct mii_bus *bus, struct module *owner) 
		return -EINVAL;



	if (bus->parent && bus->parent->of_node)

		bus->parent->of_node->fwnode.flags |=

					FWNODE_FLAG_NEEDS_CHILD_BOUND_ON_ADD;

		fwnode_set_flag(&bus->parent->of_node->fwnode,

				FWNODE_FLAG_NEEDS_CHILD_BOUND_ON_ADD);



	WARN(bus->state != MDIOBUS_ALLOCATED &&

	     bus->state != MDIOBUS_UNREGISTERED,

drivers/of/base.c

+1 −1
Original line number Diff line number Diff line
@@ -1943,7 +1943,7 @@ void of_alias_scan(void * (*dt_alloc)(u64 size, u64 align)) 
		if (name)

			of_stdout = of_find_node_opts_by_path(name, &of_stdout_options);

		if (of_stdout)

			of_stdout->fwnode.flags |= FWNODE_FLAG_BEST_EFFORT;

			fwnode_set_flag(&of_stdout->fwnode, FWNODE_FLAG_BEST_EFFORT);

	}



	if (!of_aliases)