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Wysocki (Intel)" , Saravana Kannan , Danilo Krummrich Subject: [PATCH 6.12.y] device property: Make modifications of fwnode "flags" thread safe Date: Mon, 27 Apr 2026 11:38:54 -0700 Message-ID: <20260427183854.1889456-1-dianders@chromium.org> X-Mailer: git-send-email 2.54.0.545.g6539524ca2-goog In-Reply-To: <2026042714-catcher-manly-e588@gregkh> References: <2026042714-catcher-manly-e588@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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: c2c724c868c4 ("driver core: Add fw_devlink_parse_fwtree()") Reviewed-by: Andy Shevchenko Acked-by: Mark Brown Reviewed-by: Wolfram Sang Signed-off-by: Douglas Anderson Reviewed-by: Rafael J. Wysocki (Intel) Reviewed-by: Saravana Kannan 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: Danilo Krummrich (cherry picked from commit f72e77c33e4b5657af35125e75bab249256030f3) Signed-off-by: Douglas Anderson --- drivers/base/core.c | 24 ++++++++++----------- drivers/bus/imx-weim.c | 2 +- drivers/i2c/i2c-core-of.c | 2 +- drivers/net/phy/mdio_bus.c | 4 ++-- drivers/of/base.c | 2 +- drivers/of/dynamic.c | 2 +- drivers/of/platform.c | 2 +- drivers/spi/spi.c | 2 +- include/linux/fwnode.h | 44 ++++++++++++++++++++++++++++---------- 9 files changed, 53 insertions(+), 31 deletions(-) diff --git a/drivers/base/core.c b/drivers/base/core.c index 09139e265c9b..88895d538b7d 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -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) @@ -1013,7 +1013,7 @@ 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( @@ -1724,11 +1724,11 @@ 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) @@ -1888,7 +1888,7 @@ 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); @@ -2004,10 +2004,10 @@ 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) { @@ -2077,7 +2077,7 @@ 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); @@ -2130,7 +2130,7 @@ 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; @@ -2153,7 +2153,7 @@ 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); @@ -2165,7 +2165,7 @@ 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); diff --git a/drivers/bus/imx-weim.c b/drivers/bus/imx-weim.c index 83d623d97f5f..f735e0462c55 100644 --- a/drivers/bus/imx-weim.c +++ b/drivers/bus/imx-weim.c @@ -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", diff --git a/drivers/i2c/i2c-core-of.c b/drivers/i2c/i2c-core-of.c index a6c407d36800..50e97e2ed2cf 100644 --- a/drivers/i2c/i2c-core-of.c +++ b/drivers/i2c/i2c-core-of.c @@ -182,7 +182,7 @@ 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", diff --git a/drivers/net/phy/mdio_bus.c b/drivers/net/phy/mdio_bus.c index d80b80ba20a1..1d6216a96d7f 100644 --- a/drivers/net/phy/mdio_bus.c +++ b/drivers/net/phy/mdio_bus.c @@ -705,8 +705,8 @@ 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, diff --git a/drivers/of/base.c b/drivers/of/base.c index 576f119c2832..83f4065d009e 100644 --- a/drivers/of/base.c +++ b/drivers/of/base.c @@ -1793,7 +1793,7 @@ 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) diff --git a/drivers/of/dynamic.c b/drivers/of/dynamic.c index 492f0354a792..f5f624fc327f 100644 --- a/drivers/of/dynamic.c +++ b/drivers/of/dynamic.c @@ -225,7 +225,7 @@ static void __of_attach_node(struct device_node *np) np->sibling = np->parent->child; np->parent->child = np; of_node_clear_flag(np, OF_DETACHED); - np->fwnode.flags |= FWNODE_FLAG_NOT_DEVICE; + fwnode_set_flag(&np->fwnode, FWNODE_FLAG_NOT_DEVICE); raw_spin_unlock_irqrestore(&devtree_lock, flags); diff --git a/drivers/of/platform.c b/drivers/of/platform.c index 11124e965f65..7fe456dddce3 100644 --- a/drivers/of/platform.c +++ b/drivers/of/platform.c @@ -744,7 +744,7 @@ static int of_platform_notify(struct notifier_block *nb, * 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); /* pdev_parent may be NULL when no bus platform device */ pdev_parent = of_find_device_by_node(parent); pdev = of_platform_device_create(rd->dn, NULL, diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index 0c3200d08fe4..60ff547dcf0a 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -4811,7 +4811,7 @@ static int of_spi_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); spi = of_register_spi_device(ctlr, rd->dn); put_device(&ctlr->dev); diff --git a/include/linux/fwnode.h b/include/linux/fwnode.h index 487d4bd9b0c9..1455e24ac29e 100644 --- a/include/linux/fwnode.h +++ b/include/linux/fwnode.h @@ -10,6 +10,7 @@ #define _LINUX_FWNODE_H_ #include +#include #include #include #include @@ -37,12 +38,12 @@ struct device; * suppliers. Only enforce ordering with suppliers that have * drivers. */ -#define FWNODE_FLAG_LINKS_ADDED BIT(0) -#define FWNODE_FLAG_NOT_DEVICE BIT(1) -#define FWNODE_FLAG_INITIALIZED BIT(2) -#define FWNODE_FLAG_NEEDS_CHILD_BOUND_ON_ADD BIT(3) -#define FWNODE_FLAG_BEST_EFFORT BIT(4) -#define FWNODE_FLAG_VISITED BIT(5) +#define FWNODE_FLAG_LINKS_ADDED 0 +#define FWNODE_FLAG_NOT_DEVICE 1 +#define FWNODE_FLAG_INITIALIZED 2 +#define FWNODE_FLAG_NEEDS_CHILD_BOUND_ON_ADD 3 +#define FWNODE_FLAG_BEST_EFFORT 4 +#define FWNODE_FLAG_VISITED 5 struct fwnode_handle { struct fwnode_handle *secondary; @@ -52,7 +53,7 @@ struct fwnode_handle { struct device *dev; struct list_head suppliers; struct list_head consumers; - u8 flags; + unsigned long flags; }; /* @@ -204,16 +205,37 @@ static inline void fwnode_init(struct fwnode_handle *fwnode, INIT_LIST_HEAD(&fwnode->suppliers); } +static inline void fwnode_set_flag(struct fwnode_handle *fwnode, + unsigned int bit) +{ + set_bit(bit, &fwnode->flags); +} + +static inline void fwnode_clear_flag(struct fwnode_handle *fwnode, + unsigned int bit) +{ + clear_bit(bit, &fwnode->flags); +} + +static inline void fwnode_assign_flag(struct fwnode_handle *fwnode, + unsigned int bit, bool value) +{ + assign_bit(bit, &fwnode->flags, value); +} + +static inline bool fwnode_test_flag(struct fwnode_handle *fwnode, + unsigned int bit) +{ + return test_bit(bit, &fwnode->flags); +} + static inline void fwnode_dev_initialized(struct fwnode_handle *fwnode, bool initialized) { if (IS_ERR_OR_NULL(fwnode)) return; - if (initialized) - fwnode->flags |= FWNODE_FLAG_INITIALIZED; - else - fwnode->flags &= ~FWNODE_FLAG_INITIALIZED; + fwnode_assign_flag(fwnode, FWNODE_FLAG_INITIALIZED, initialized); } int fwnode_link_add(struct fwnode_handle *con, struct fwnode_handle *sup, -- 2.54.0.545.g6539524ca2-goog