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Wysocki (Intel)" , Saravana Kannan , Danilo Krummrich Subject: [PATCH 5.15.y] device property: Make modifications of fwnode "flags" thread safe Date: Mon, 27 Apr 2026 14:46:34 -0700 Message-ID: <20260427214635.992400-1-dianders@chromium.org> X-Mailer: git-send-email 2.54.0.545.g6539524ca2-goog In-Reply-To: <2026042717-tricycle-reaffirm-f074@gregkh> References: <2026042717-tricycle-reaffirm-f074@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 | 12 ++++++------ drivers/net/phy/mdio_bus.c | 4 ++-- drivers/of/property.c | 2 +- include/linux/fwnode.h | 40 +++++++++++++++++++++++++++++--------- 4 files changed, 40 insertions(+), 18 deletions(-) diff --git a/drivers/base/core.c b/drivers/base/core.c index 4fc62624a95e..31b47d812fa5 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -171,7 +171,7 @@ 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) @@ -1620,11 +1620,11 @@ 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) @@ -1765,7 +1765,7 @@ 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; @@ -1777,7 +1777,7 @@ 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)) { ret = -EINVAL; goto out; } @@ -1802,7 +1802,7 @@ static int fw_devlink_create_devlink(struct device *con, } /* Supplier that's already initialized without a struct device. */ - if (sup_handle->flags & FWNODE_FLAG_INITIALIZED) + if (fwnode_test_flag(sup_handle, FWNODE_FLAG_INITIALIZED)) return -EINVAL; /* diff --git a/drivers/net/phy/mdio_bus.c b/drivers/net/phy/mdio_bus.c index a8a4cd68f688..1c60581b46d1 100644 --- a/drivers/net/phy/mdio_bus.c +++ b/drivers/net/phy/mdio_bus.c @@ -534,8 +534,8 @@ 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); BUG_ON(bus->state != MDIOBUS_ALLOCATED && bus->state != MDIOBUS_UNREGISTERED); diff --git a/drivers/of/property.c b/drivers/of/property.c index 905ac6466a5b..922f70aa46f3 100644 --- a/drivers/of/property.c +++ b/drivers/of/property.c @@ -1130,7 +1130,7 @@ static int of_link_to_phandle(struct device_node *con_np, sup_dev = get_dev_from_fwnode(&sup_np->fwnode); if (!sup_dev && (of_node_check_flag(sup_np, OF_POPULATED) || - sup_np->fwnode.flags & FWNODE_FLAG_NOT_DEVICE)) { + fwnode_test_flag(&sup_np->fwnode, FWNODE_FLAG_NOT_DEVICE))) { pr_debug("Not linking %pOFP to %pOFP - No struct device\n", con_np, sup_np); of_node_put(sup_np); diff --git a/include/linux/fwnode.h b/include/linux/fwnode.h index f0833bafe6bd..022d9795269e 100644 --- a/include/linux/fwnode.h +++ b/include/linux/fwnode.h @@ -11,6 +11,7 @@ #include #include +#include #include struct fwnode_operations; @@ -27,10 +28,10 @@ struct device; * their respective drivers as soon as they are * added. */ -#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_LINKS_ADDED 0 +#define FWNODE_FLAG_NOT_DEVICE 1 +#define FWNODE_FLAG_INITIALIZED 2 +#define FWNODE_FLAG_NEEDS_CHILD_BOUND_ON_ADD 3 struct fwnode_handle { struct fwnode_handle *secondary; @@ -38,7 +39,7 @@ struct fwnode_handle { struct device *dev; struct list_head suppliers; struct list_head consumers; - u8 flags; + unsigned long flags; }; struct fwnode_link { @@ -176,16 +177,37 @@ 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); } extern u32 fw_devlink_get_flags(void); -- 2.54.0.545.g6539524ca2-goog