diff options
author | Dan Williams <dan.j.williams@intel.com> | 2022-01-31 22:50:09 +0300 |
---|---|---|
committer | Dan Williams <dan.j.williams@intel.com> | 2022-02-09 09:57:29 +0300 |
commit | 3c5b903955251ea464fca383a42d981e33004df6 (patch) | |
tree | c4ff8665db9ad785d73be3a5ec462964e2148b86 /drivers/cxl/cxl.h | |
parent | 53fa1bff3426344d466d91e81f076eab677d0ece (diff) |
cxl: Prove CXL locking
When CONFIG_PROVE_LOCKING is enabled the 'struct device' definition gets
an additional mutex that is not clobbered by
lockdep_set_novalidate_class() like the typical device_lock(). This
allows for local annotation of subsystem locks with mutex_lock_nested()
per the subsystem's object/lock hierarchy. For CXL, this primarily needs
the ability to lock ports by depth and child objects of ports by their
parent parent-port lock.
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Ben Widawsky <ben.widawsky@intel.com>
Link: https://lore.kernel.org/r/164365853422.99383.1052399160445197427.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Diffstat (limited to 'drivers/cxl/cxl.h')
-rw-r--r-- | drivers/cxl/cxl.h | 81 |
1 files changed, 81 insertions, 0 deletions
diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h index 7ade555076bc..6a38d2e1f3dd 100644 --- a/drivers/cxl/cxl.h +++ b/drivers/cxl/cxl.h @@ -291,6 +291,7 @@ static inline bool is_cxl_root(struct cxl_port *port) return port->uport == port->dev.parent; } +bool is_cxl_port(struct device *dev); struct cxl_port *to_cxl_port(struct device *dev); struct cxl_port *devm_cxl_add_port(struct device *host, struct device *uport, resource_size_t component_reg_phys, @@ -301,6 +302,7 @@ int cxl_add_dport(struct cxl_port *port, struct device *dport, int port_id, struct cxl_decoder *to_cxl_decoder(struct device *dev); bool is_root_decoder(struct device *dev); +bool is_cxl_decoder(struct device *dev); struct cxl_decoder *cxl_root_decoder_alloc(struct cxl_port *port, unsigned int nr_targets); struct cxl_decoder *cxl_switch_decoder_alloc(struct cxl_port *port, @@ -353,4 +355,83 @@ struct cxl_nvdimm_bridge *cxl_find_nvdimm_bridge(struct cxl_nvdimm *cxl_nvd); #ifndef __mock #define __mock static #endif + +#ifdef CONFIG_PROVE_CXL_LOCKING +enum cxl_lock_class { + CXL_ANON_LOCK, + CXL_NVDIMM_LOCK, + CXL_NVDIMM_BRIDGE_LOCK, + CXL_PORT_LOCK, + /* + * Be careful to add new lock classes here, CXL_PORT_LOCK is + * extended by the port depth, so a maximum CXL port topology + * depth would need to be defined first. + */ +}; + +static inline void cxl_nested_lock(struct device *dev) +{ + if (is_cxl_port(dev)) { + struct cxl_port *port = to_cxl_port(dev); + + mutex_lock_nested(&dev->lockdep_mutex, + CXL_PORT_LOCK + port->depth); + } else if (is_cxl_decoder(dev)) { + struct cxl_port *port = to_cxl_port(dev->parent); + + /* + * A decoder is the immediate child of a port, so set + * its lock class equal to other child device siblings. + */ + mutex_lock_nested(&dev->lockdep_mutex, + CXL_PORT_LOCK + port->depth + 1); + } else if (is_cxl_nvdimm_bridge(dev)) + mutex_lock_nested(&dev->lockdep_mutex, CXL_NVDIMM_BRIDGE_LOCK); + else if (is_cxl_nvdimm(dev)) + mutex_lock_nested(&dev->lockdep_mutex, CXL_NVDIMM_LOCK); + else + mutex_lock_nested(&dev->lockdep_mutex, CXL_ANON_LOCK); +} + +static inline void cxl_nested_unlock(struct device *dev) +{ + mutex_unlock(&dev->lockdep_mutex); +} + +static inline void cxl_device_lock(struct device *dev) +{ + /* + * For double lock errors the lockup will happen before lockdep + * warns at cxl_nested_lock(), so assert explicitly. + */ + lockdep_assert_not_held(&dev->lockdep_mutex); + + device_lock(dev); + cxl_nested_lock(dev); +} + +static inline void cxl_device_unlock(struct device *dev) +{ + cxl_nested_unlock(dev); + device_unlock(dev); +} +#else +static inline void cxl_nested_lock(struct device *dev) +{ +} + +static inline void cxl_nested_unlock(struct device *dev) +{ +} + +static inline void cxl_device_lock(struct device *dev) +{ + device_lock(dev); +} + +static inline void cxl_device_unlock(struct device *dev) +{ + device_unlock(dev); +} +#endif #endif /* __CXL_H__ */ |