Hi! > From: Richard Maina <quic_rmaina@xxxxxxxxxxx> > > [ Upstream commit 7c327d56597d8de1680cf24e956b704270d3d84a ] > > When a remoteproc crashes or goes down unexpectedly this can result in > a state where locks held by the remoteproc will remain locked possibly > resulting in deadlock. This new API hwspin_lock_bust() allows > hwspinlock implementers to define a bust operation for freeing previously > acquired hwspinlocks after verifying ownership of the acquired lock. This adds unused infrastructure to -stable. Please drop. Best regards, Pavel > +++ b/Documentation/locking/hwspinlock.rst > @@ -85,6 +85,17 @@ is already free). > > Should be called from a process context (might sleep). > > +:: > + > + int hwspin_lock_bust(struct hwspinlock *hwlock, unsigned int id); > + > +After verifying the owner of the hwspinlock, release a previously acquired > +hwspinlock; returns 0 on success, or an appropriate error code on failure > +(e.g. -EOPNOTSUPP if the bust operation is not defined for the specific > +hwspinlock). > + > +Should be called from a process context (might sleep). > + > :: > > int hwspin_lock_timeout(struct hwspinlock *hwlock, unsigned int timeout); > diff --git a/drivers/hwspinlock/hwspinlock_core.c b/drivers/hwspinlock/hwspinlock_core.c > index fd5f5c5a5244d..425597151dd3e 100644 > --- a/drivers/hwspinlock/hwspinlock_core.c > +++ b/drivers/hwspinlock/hwspinlock_core.c > @@ -302,6 +302,34 @@ void __hwspin_unlock(struct hwspinlock *hwlock, int mode, unsigned long *flags) > } > EXPORT_SYMBOL_GPL(__hwspin_unlock); > > +/** > + * hwspin_lock_bust() - bust a specific hwspinlock > + * @hwlock: a previously-acquired hwspinlock which we want to bust > + * @id: identifier of the remote lock holder, if applicable > + * > + * This function will bust a hwspinlock that was previously acquired as > + * long as the current owner of the lock matches the id given by the caller. > + * > + * Context: Process context. > + * > + * Returns: 0 on success, or -EINVAL if the hwspinlock does not exist, or > + * the bust operation fails, and -EOPNOTSUPP if the bust operation is not > + * defined for the hwspinlock. > + */ > +int hwspin_lock_bust(struct hwspinlock *hwlock, unsigned int id) > +{ > + if (WARN_ON(!hwlock)) > + return -EINVAL; > + > + if (!hwlock->bank->ops->bust) { > + pr_err("bust operation not defined\n"); > + return -EOPNOTSUPP; > + } > + > + return hwlock->bank->ops->bust(hwlock, id); > +} > +EXPORT_SYMBOL_GPL(hwspin_lock_bust); > + > /** > * of_hwspin_lock_simple_xlate - translate hwlock_spec to return a lock id > * @bank: the hwspinlock device bank > diff --git a/drivers/hwspinlock/hwspinlock_internal.h b/drivers/hwspinlock/hwspinlock_internal.h > index 29892767bb7a0..f298fc0ee5adb 100644 > --- a/drivers/hwspinlock/hwspinlock_internal.h > +++ b/drivers/hwspinlock/hwspinlock_internal.h > @@ -21,6 +21,8 @@ struct hwspinlock_device; > * @trylock: make a single attempt to take the lock. returns 0 on > * failure and true on success. may _not_ sleep. > * @unlock: release the lock. always succeed. may _not_ sleep. > + * @bust: optional, platform-specific bust handler, called by hwspinlock > + * core to bust a specific lock. > * @relax: optional, platform-specific relax handler, called by hwspinlock > * core while spinning on a lock, between two successive > * invocations of @trylock. may _not_ sleep. > @@ -28,6 +30,7 @@ struct hwspinlock_device; > struct hwspinlock_ops { > int (*trylock)(struct hwspinlock *lock); > void (*unlock)(struct hwspinlock *lock); > + int (*bust)(struct hwspinlock *lock, unsigned int id); > void (*relax)(struct hwspinlock *lock); > }; > > diff --git a/include/linux/hwspinlock.h b/include/linux/hwspinlock.h > index bfe7c1f1ac6d1..f0231dbc47771 100644 > --- a/include/linux/hwspinlock.h > +++ b/include/linux/hwspinlock.h > @@ -68,6 +68,7 @@ int __hwspin_lock_timeout(struct hwspinlock *, unsigned int, int, > int __hwspin_trylock(struct hwspinlock *, int, unsigned long *); > void __hwspin_unlock(struct hwspinlock *, int, unsigned long *); > int of_hwspin_lock_get_id_byname(struct device_node *np, const char *name); > +int hwspin_lock_bust(struct hwspinlock *hwlock, unsigned int id); > int devm_hwspin_lock_free(struct device *dev, struct hwspinlock *hwlock); > struct hwspinlock *devm_hwspin_lock_request(struct device *dev); > struct hwspinlock *devm_hwspin_lock_request_specific(struct device *dev, > @@ -127,6 +128,11 @@ void __hwspin_unlock(struct hwspinlock *hwlock, int mode, unsigned long *flags) > { > } > > +static inline int hwspin_lock_bust(struct hwspinlock *hwlock, unsigned int id) > +{ > + return 0; > +} > + > static inline int of_hwspin_lock_get_id(struct device_node *np, int index) > { > return 0; -- DENX Software Engineering GmbH, Managing Director: Erika Unter HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
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