From 4d4d2d4346857bf778fafaa97d6f76bb1663e3c9 Mon Sep 17 00:00:00 2001 From: Marco Pagani Date: Tue, 5 Mar 2024 20:29:26 +0100 Subject: fpga: manager: add owner module and take its refcount The current implementation of the fpga manager assumes that the low-level module registers a driver for the parent device and uses its owner pointer to take the module's refcount. This approach is problematic since it can lead to a null pointer dereference while attempting to get the manager if the parent device does not have a driver. To address this problem, add a module owner pointer to the fpga_manager struct and use it to take the module's refcount. Modify the functions for registering the manager to take an additional owner module parameter and rename them to avoid conflicts. Use the old function names for helper macros that automatically set the module that registers the manager as the owner. This ensures compatibility with existing low-level control modules and reduces the chances of registering a manager without setting the owner. Also, update the documentation to keep it consistent with the new interface for registering an fpga manager. Other changes: opportunistically move put_device() from __fpga_mgr_get() to fpga_mgr_get() and of_fpga_mgr_get() to improve code clarity since the manager device is taken in these functions. Fixes: 654ba4cc0f3e ("fpga manager: ensure lifetime with of_fpga_mgr_get") Suggested-by: Greg Kroah-Hartman Suggested-by: Xu Yilun Signed-off-by: Marco Pagani Acked-by: Xu Yilun Link: https://lore.kernel.org/r/20240305192926.84886-1-marpagan@redhat.com Signed-off-by: Xu Yilun --- include/linux/fpga/fpga-mgr.h | 26 ++++++++++++++++++++------ 1 file changed, 20 insertions(+), 6 deletions(-) (limited to 'include/linux/fpga') diff --git a/include/linux/fpga/fpga-mgr.h b/include/linux/fpga/fpga-mgr.h index 54f63459efd6..0d4fe068f3d8 100644 --- a/include/linux/fpga/fpga-mgr.h +++ b/include/linux/fpga/fpga-mgr.h @@ -201,6 +201,7 @@ struct fpga_manager_ops { * @state: state of fpga manager * @compat_id: FPGA manager id for compatibility check. * @mops: pointer to struct of fpga manager ops + * @mops_owner: module containing the mops * @priv: low level driver private date */ struct fpga_manager { @@ -210,6 +211,7 @@ struct fpga_manager { enum fpga_mgr_states state; struct fpga_compat_id *compat_id; const struct fpga_manager_ops *mops; + struct module *mops_owner; void *priv; }; @@ -230,18 +232,30 @@ struct fpga_manager *fpga_mgr_get(struct device *dev); void fpga_mgr_put(struct fpga_manager *mgr); +#define fpga_mgr_register_full(parent, info) \ + __fpga_mgr_register_full(parent, info, THIS_MODULE) struct fpga_manager * -fpga_mgr_register_full(struct device *parent, const struct fpga_manager_info *info); +__fpga_mgr_register_full(struct device *parent, const struct fpga_manager_info *info, + struct module *owner); +#define fpga_mgr_register(parent, name, mops, priv) \ + __fpga_mgr_register(parent, name, mops, priv, THIS_MODULE) struct fpga_manager * -fpga_mgr_register(struct device *parent, const char *name, - const struct fpga_manager_ops *mops, void *priv); +__fpga_mgr_register(struct device *parent, const char *name, + const struct fpga_manager_ops *mops, void *priv, struct module *owner); + void fpga_mgr_unregister(struct fpga_manager *mgr); +#define devm_fpga_mgr_register_full(parent, info) \ + __devm_fpga_mgr_register_full(parent, info, THIS_MODULE) struct fpga_manager * -devm_fpga_mgr_register_full(struct device *parent, const struct fpga_manager_info *info); +__devm_fpga_mgr_register_full(struct device *parent, const struct fpga_manager_info *info, + struct module *owner); +#define devm_fpga_mgr_register(parent, name, mops, priv) \ + __devm_fpga_mgr_register(parent, name, mops, priv, THIS_MODULE) struct fpga_manager * -devm_fpga_mgr_register(struct device *parent, const char *name, - const struct fpga_manager_ops *mops, void *priv); +__devm_fpga_mgr_register(struct device *parent, const char *name, + const struct fpga_manager_ops *mops, void *priv, + struct module *owner); #endif /*_LINUX_FPGA_MGR_H */ -- cgit v1.2.3-59-g8ed1b From 1da11f822042eb6ef4b6064dc048f157a7852529 Mon Sep 17 00:00:00 2001 From: Marco Pagani Date: Fri, 22 Mar 2024 18:18:37 +0100 Subject: fpga: bridge: add owner module and take its refcount The current implementation of the fpga bridge assumes that the low-level module registers a driver for the parent device and uses its owner pointer to take the module's refcount. This approach is problematic since it can lead to a null pointer dereference while attempting to get the bridge if the parent device does not have a driver. To address this problem, add a module owner pointer to the fpga_bridge struct and use it to take the module's refcount. Modify the function for registering a bridge to take an additional owner module parameter and rename it to avoid conflicts. Use the old function name for a helper macro that automatically sets the module that registers the bridge as the owner. This ensures compatibility with existing low-level control modules and reduces the chances of registering a bridge without setting the owner. Also, update the documentation to keep it consistent with the new interface for registering an fpga bridge. Other changes: opportunistically move put_device() from __fpga_bridge_get() to fpga_bridge_get() and of_fpga_bridge_get() to improve code clarity since the bridge device is taken in these functions. Fixes: 21aeda950c5f ("fpga: add fpga bridge framework") Suggested-by: Greg Kroah-Hartman Suggested-by: Xu Yilun Reviewed-by: Russ Weight Signed-off-by: Marco Pagani Acked-by: Xu Yilun Link: https://lore.kernel.org/r/20240322171839.233864-1-marpagan@redhat.com Signed-off-by: Xu Yilun --- Documentation/driver-api/fpga/fpga-bridge.rst | 7 +++- drivers/fpga/fpga-bridge.c | 57 +++++++++++++++------------ include/linux/fpga/fpga-bridge.h | 10 +++-- 3 files changed, 43 insertions(+), 31 deletions(-) (limited to 'include/linux/fpga') diff --git a/Documentation/driver-api/fpga/fpga-bridge.rst b/Documentation/driver-api/fpga/fpga-bridge.rst index 604208534095..833f68fb0700 100644 --- a/Documentation/driver-api/fpga/fpga-bridge.rst +++ b/Documentation/driver-api/fpga/fpga-bridge.rst @@ -6,9 +6,12 @@ API to implement a new FPGA bridge * struct fpga_bridge - The FPGA Bridge structure * struct fpga_bridge_ops - Low level Bridge driver ops -* fpga_bridge_register() - Create and register a bridge +* __fpga_bridge_register() - Create and register a bridge * fpga_bridge_unregister() - Unregister a bridge +The helper macro ``fpga_bridge_register()`` automatically sets +the module that registers the FPGA bridge as the owner. + .. kernel-doc:: include/linux/fpga/fpga-bridge.h :functions: fpga_bridge @@ -16,7 +19,7 @@ API to implement a new FPGA bridge :functions: fpga_bridge_ops .. kernel-doc:: drivers/fpga/fpga-bridge.c - :functions: fpga_bridge_register + :functions: __fpga_bridge_register .. kernel-doc:: drivers/fpga/fpga-bridge.c :functions: fpga_bridge_unregister diff --git a/drivers/fpga/fpga-bridge.c b/drivers/fpga/fpga-bridge.c index 79c473b3c7c3..8ef395b49bf8 100644 --- a/drivers/fpga/fpga-bridge.c +++ b/drivers/fpga/fpga-bridge.c @@ -55,33 +55,26 @@ int fpga_bridge_disable(struct fpga_bridge *bridge) } EXPORT_SYMBOL_GPL(fpga_bridge_disable); -static struct fpga_bridge *__fpga_bridge_get(struct device *dev, +static struct fpga_bridge *__fpga_bridge_get(struct device *bridge_dev, struct fpga_image_info *info) { struct fpga_bridge *bridge; - int ret = -ENODEV; - bridge = to_fpga_bridge(dev); + bridge = to_fpga_bridge(bridge_dev); bridge->info = info; - if (!mutex_trylock(&bridge->mutex)) { - ret = -EBUSY; - goto err_dev; - } + if (!mutex_trylock(&bridge->mutex)) + return ERR_PTR(-EBUSY); - if (!try_module_get(dev->parent->driver->owner)) - goto err_ll_mod; + if (!try_module_get(bridge->br_ops_owner)) { + mutex_unlock(&bridge->mutex); + return ERR_PTR(-ENODEV); + } dev_dbg(&bridge->dev, "get\n"); return bridge; - -err_ll_mod: - mutex_unlock(&bridge->mutex); -err_dev: - put_device(dev); - return ERR_PTR(ret); } /** @@ -98,13 +91,18 @@ err_dev: struct fpga_bridge *of_fpga_bridge_get(struct device_node *np, struct fpga_image_info *info) { - struct device *dev; + struct fpga_bridge *bridge; + struct device *bridge_dev; - dev = class_find_device_by_of_node(&fpga_bridge_class, np); - if (!dev) + bridge_dev = class_find_device_by_of_node(&fpga_bridge_class, np); + if (!bridge_dev) return ERR_PTR(-ENODEV); - return __fpga_bridge_get(dev, info); + bridge = __fpga_bridge_get(bridge_dev, info); + if (IS_ERR(bridge)) + put_device(bridge_dev); + + return bridge; } EXPORT_SYMBOL_GPL(of_fpga_bridge_get); @@ -125,6 +123,7 @@ static int fpga_bridge_dev_match(struct device *dev, const void *data) struct fpga_bridge *fpga_bridge_get(struct device *dev, struct fpga_image_info *info) { + struct fpga_bridge *bridge; struct device *bridge_dev; bridge_dev = class_find_device(&fpga_bridge_class, NULL, dev, @@ -132,7 +131,11 @@ struct fpga_bridge *fpga_bridge_get(struct device *dev, if (!bridge_dev) return ERR_PTR(-ENODEV); - return __fpga_bridge_get(bridge_dev, info); + bridge = __fpga_bridge_get(bridge_dev, info); + if (IS_ERR(bridge)) + put_device(bridge_dev); + + return bridge; } EXPORT_SYMBOL_GPL(fpga_bridge_get); @@ -146,7 +149,7 @@ void fpga_bridge_put(struct fpga_bridge *bridge) dev_dbg(&bridge->dev, "put\n"); bridge->info = NULL; - module_put(bridge->dev.parent->driver->owner); + module_put(bridge->br_ops_owner); mutex_unlock(&bridge->mutex); put_device(&bridge->dev); } @@ -316,18 +319,19 @@ static struct attribute *fpga_bridge_attrs[] = { ATTRIBUTE_GROUPS(fpga_bridge); /** - * fpga_bridge_register - create and register an FPGA Bridge device + * __fpga_bridge_register - create and register an FPGA Bridge device * @parent: FPGA bridge device from pdev * @name: FPGA bridge name * @br_ops: pointer to structure of fpga bridge ops * @priv: FPGA bridge private data + * @owner: owner module containing the br_ops * * Return: struct fpga_bridge pointer or ERR_PTR() */ struct fpga_bridge * -fpga_bridge_register(struct device *parent, const char *name, - const struct fpga_bridge_ops *br_ops, - void *priv) +__fpga_bridge_register(struct device *parent, const char *name, + const struct fpga_bridge_ops *br_ops, + void *priv, struct module *owner) { struct fpga_bridge *bridge; int id, ret; @@ -357,6 +361,7 @@ fpga_bridge_register(struct device *parent, const char *name, bridge->name = name; bridge->br_ops = br_ops; + bridge->br_ops_owner = owner; bridge->priv = priv; bridge->dev.groups = br_ops->groups; @@ -386,7 +391,7 @@ error_kfree: return ERR_PTR(ret); } -EXPORT_SYMBOL_GPL(fpga_bridge_register); +EXPORT_SYMBOL_GPL(__fpga_bridge_register); /** * fpga_bridge_unregister - unregister an FPGA bridge diff --git a/include/linux/fpga/fpga-bridge.h b/include/linux/fpga/fpga-bridge.h index 223da48a6d18..94c4edd047e5 100644 --- a/include/linux/fpga/fpga-bridge.h +++ b/include/linux/fpga/fpga-bridge.h @@ -45,6 +45,7 @@ struct fpga_bridge_info { * @dev: FPGA bridge device * @mutex: enforces exclusive reference to bridge * @br_ops: pointer to struct of FPGA bridge ops + * @br_ops_owner: module containing the br_ops * @info: fpga image specific information * @node: FPGA bridge list node * @priv: low level driver private date @@ -54,6 +55,7 @@ struct fpga_bridge { struct device dev; struct mutex mutex; /* for exclusive reference to bridge */ const struct fpga_bridge_ops *br_ops; + struct module *br_ops_owner; struct fpga_image_info *info; struct list_head node; void *priv; @@ -79,10 +81,12 @@ int of_fpga_bridge_get_to_list(struct device_node *np, struct fpga_image_info *info, struct list_head *bridge_list); +#define fpga_bridge_register(parent, name, br_ops, priv) \ + __fpga_bridge_register(parent, name, br_ops, priv, THIS_MODULE) struct fpga_bridge * -fpga_bridge_register(struct device *parent, const char *name, - const struct fpga_bridge_ops *br_ops, - void *priv); +__fpga_bridge_register(struct device *parent, const char *name, + const struct fpga_bridge_ops *br_ops, void *priv, + struct module *owner); void fpga_bridge_unregister(struct fpga_bridge *br); #endif /* _LINUX_FPGA_BRIDGE_H */ -- cgit v1.2.3-59-g8ed1b From b7c0e1ecee403a43abc89eb3e75672b01ff2ece9 Mon Sep 17 00:00:00 2001 From: Marco Pagani Date: Fri, 19 Apr 2024 10:35:59 +0200 Subject: fpga: region: add owner module and take its refcount The current implementation of the fpga region assumes that the low-level module registers a driver for the parent device and uses its owner pointer to take the module's refcount. This approach is problematic since it can lead to a null pointer dereference while attempting to get the region during programming if the parent device does not have a driver. To address this problem, add a module owner pointer to the fpga_region struct and use it to take the module's refcount. Modify the functions for registering a region to take an additional owner module parameter and rename them to avoid conflicts. Use the old function names for helper macros that automatically set the module that registers the region as the owner. This ensures compatibility with existing low-level control modules and reduces the chances of registering a region without setting the owner. Also, update the documentation to keep it consistent with the new interface for registering an fpga region. Fixes: 0fa20cdfcc1f ("fpga: fpga-region: device tree control for FPGA") Suggested-by: Greg Kroah-Hartman Suggested-by: Xu Yilun Reviewed-by: Russ Weight Signed-off-by: Marco Pagani Acked-by: Xu Yilun Link: https://lore.kernel.org/r/20240419083601.77403-1-marpagan@redhat.com Signed-off-by: Xu Yilun --- Documentation/driver-api/fpga/fpga-region.rst | 13 ++++++++----- drivers/fpga/fpga-region.c | 24 ++++++++++++++---------- include/linux/fpga/fpga-region.h | 13 ++++++++++--- 3 files changed, 32 insertions(+), 18 deletions(-) (limited to 'include/linux/fpga') diff --git a/Documentation/driver-api/fpga/fpga-region.rst b/Documentation/driver-api/fpga/fpga-region.rst index dc55d60a0b4a..2d03b5fb7657 100644 --- a/Documentation/driver-api/fpga/fpga-region.rst +++ b/Documentation/driver-api/fpga/fpga-region.rst @@ -46,13 +46,16 @@ API to add a new FPGA region ---------------------------- * struct fpga_region - The FPGA region struct -* struct fpga_region_info - Parameter structure for fpga_region_register_full() -* fpga_region_register_full() - Create and register an FPGA region using the +* struct fpga_region_info - Parameter structure for __fpga_region_register_full() +* __fpga_region_register_full() - Create and register an FPGA region using the fpga_region_info structure to provide the full flexibility of options -* fpga_region_register() - Create and register an FPGA region using standard +* __fpga_region_register() - Create and register an FPGA region using standard arguments * fpga_region_unregister() - Unregister an FPGA region +Helper macros ``fpga_region_register()`` and ``fpga_region_register_full()`` +automatically set the module that registers the FPGA region as the owner. + The FPGA region's probe function will need to get a reference to the FPGA Manager it will be using to do the programming. This usually would happen during the region's probe function. @@ -82,10 +85,10 @@ following APIs to handle building or tearing down that list. :functions: fpga_region_info .. kernel-doc:: drivers/fpga/fpga-region.c - :functions: fpga_region_register_full + :functions: __fpga_region_register_full .. kernel-doc:: drivers/fpga/fpga-region.c - :functions: fpga_region_register + :functions: __fpga_region_register .. kernel-doc:: drivers/fpga/fpga-region.c :functions: fpga_region_unregister diff --git a/drivers/fpga/fpga-region.c b/drivers/fpga/fpga-region.c index b364a929425c..753cd142503e 100644 --- a/drivers/fpga/fpga-region.c +++ b/drivers/fpga/fpga-region.c @@ -53,7 +53,7 @@ static struct fpga_region *fpga_region_get(struct fpga_region *region) } get_device(dev); - if (!try_module_get(dev->parent->driver->owner)) { + if (!try_module_get(region->ops_owner)) { put_device(dev); mutex_unlock(®ion->mutex); return ERR_PTR(-ENODEV); @@ -75,7 +75,7 @@ static void fpga_region_put(struct fpga_region *region) dev_dbg(dev, "put\n"); - module_put(dev->parent->driver->owner); + module_put(region->ops_owner); put_device(dev); mutex_unlock(®ion->mutex); } @@ -181,14 +181,16 @@ static struct attribute *fpga_region_attrs[] = { ATTRIBUTE_GROUPS(fpga_region); /** - * fpga_region_register_full - create and register an FPGA Region device + * __fpga_region_register_full - create and register an FPGA Region device * @parent: device parent * @info: parameters for FPGA Region + * @owner: module containing the get_bridges function * * Return: struct fpga_region or ERR_PTR() */ struct fpga_region * -fpga_region_register_full(struct device *parent, const struct fpga_region_info *info) +__fpga_region_register_full(struct device *parent, const struct fpga_region_info *info, + struct module *owner) { struct fpga_region *region; int id, ret = 0; @@ -213,6 +215,7 @@ fpga_region_register_full(struct device *parent, const struct fpga_region_info * region->compat_id = info->compat_id; region->priv = info->priv; region->get_bridges = info->get_bridges; + region->ops_owner = owner; mutex_init(®ion->mutex); INIT_LIST_HEAD(®ion->bridge_list); @@ -241,13 +244,14 @@ err_free: return ERR_PTR(ret); } -EXPORT_SYMBOL_GPL(fpga_region_register_full); +EXPORT_SYMBOL_GPL(__fpga_region_register_full); /** - * fpga_region_register - create and register an FPGA Region device + * __fpga_region_register - create and register an FPGA Region device * @parent: device parent * @mgr: manager that programs this region * @get_bridges: optional function to get bridges to a list + * @owner: module containing the get_bridges function * * This simple version of the register function should be sufficient for most users. * The fpga_region_register_full() function is available for users that need to @@ -256,17 +260,17 @@ EXPORT_SYMBOL_GPL(fpga_region_register_full); * Return: struct fpga_region or ERR_PTR() */ struct fpga_region * -fpga_region_register(struct device *parent, struct fpga_manager *mgr, - int (*get_bridges)(struct fpga_region *)) +__fpga_region_register(struct device *parent, struct fpga_manager *mgr, + int (*get_bridges)(struct fpga_region *), struct module *owner) { struct fpga_region_info info = { 0 }; info.mgr = mgr; info.get_bridges = get_bridges; - return fpga_region_register_full(parent, &info); + return __fpga_region_register_full(parent, &info, owner); } -EXPORT_SYMBOL_GPL(fpga_region_register); +EXPORT_SYMBOL_GPL(__fpga_region_register); /** * fpga_region_unregister - unregister an FPGA region diff --git a/include/linux/fpga/fpga-region.h b/include/linux/fpga/fpga-region.h index 9d4d32909340..5fbc05fe70a6 100644 --- a/include/linux/fpga/fpga-region.h +++ b/include/linux/fpga/fpga-region.h @@ -36,6 +36,7 @@ struct fpga_region_info { * @mgr: FPGA manager * @info: FPGA image info * @compat_id: FPGA region id for compatibility check. + * @ops_owner: module containing the get_bridges function * @priv: private data * @get_bridges: optional function to get bridges to a list */ @@ -46,6 +47,7 @@ struct fpga_region { struct fpga_manager *mgr; struct fpga_image_info *info; struct fpga_compat_id *compat_id; + struct module *ops_owner; void *priv; int (*get_bridges)(struct fpga_region *region); }; @@ -58,12 +60,17 @@ fpga_region_class_find(struct device *start, const void *data, int fpga_region_program_fpga(struct fpga_region *region); +#define fpga_region_register_full(parent, info) \ + __fpga_region_register_full(parent, info, THIS_MODULE) struct fpga_region * -fpga_region_register_full(struct device *parent, const struct fpga_region_info *info); +__fpga_region_register_full(struct device *parent, const struct fpga_region_info *info, + struct module *owner); +#define fpga_region_register(parent, mgr, get_bridges) \ + __fpga_region_register(parent, mgr, get_bridges, THIS_MODULE) struct fpga_region * -fpga_region_register(struct device *parent, struct fpga_manager *mgr, - int (*get_bridges)(struct fpga_region *)); +__fpga_region_register(struct device *parent, struct fpga_manager *mgr, + int (*get_bridges)(struct fpga_region *), struct module *owner); void fpga_region_unregister(struct fpga_region *region); #endif /* _FPGA_REGION_H */ -- cgit v1.2.3-59-g8ed1b