diff options
| -rw-r--r-- | drivers/firmware/arm_scmi/notify.c | 51 |
1 files changed, 44 insertions, 7 deletions
diff --git a/drivers/firmware/arm_scmi/notify.c b/drivers/firmware/arm_scmi/notify.c index 66196b293b6c..09015f1f9942 100644 --- a/drivers/firmware/arm_scmi/notify.c +++ b/drivers/firmware/arm_scmi/notify.c @@ -91,6 +91,7 @@ #include <linux/types.h> #include <linux/workqueue.h> +#include "common.h" #include "notify.h" #define SCMI_MAX_PROTO 256 @@ -368,7 +369,7 @@ static struct scmi_event_handler * scmi_get_active_handler(struct scmi_notify_instance *ni, u32 evt_key); static void scmi_put_active_handler(struct scmi_notify_instance *ni, struct scmi_event_handler *hndl); -static void scmi_put_handler_unlocked(struct scmi_notify_instance *ni, +static bool scmi_put_handler_unlocked(struct scmi_notify_instance *ni, struct scmi_event_handler *hndl); /** @@ -900,9 +901,21 @@ static inline int scmi_bind_event_handler(struct scmi_notify_instance *ni, if (!r_evt) return -EINVAL; - /* Remove from pending and insert into registered */ + /* + * Remove from pending and insert into registered while getting hold + * of protocol instance. + */ hash_del(&hndl->hash); + /* + * Acquire protocols only for NON pending handlers, so as NOT to trigger + * protocol initialization when a notifier is registered against a still + * not registered protocol, since it would make little sense to force init + * protocols for which still no SCMI driver user exists: they wouldn't + * emit any event anyway till some SCMI driver starts using it. + */ + scmi_protocol_acquire(ni->handle, KEY_XTRACT_PROTO_ID(hndl->key)); hndl->r_evt = r_evt; + mutex_lock(&r_evt->proto->registered_mtx); hash_add(r_evt->proto->registered_events_handlers, &hndl->hash, hndl->key); @@ -1193,41 +1206,65 @@ static int scmi_disable_events(struct scmi_event_handler *hndl) * * unregister and free the handler itself * * Context: Assumes all the proper locking has been managed by the caller. + * + * Return: True if handler was freed (users dropped to zero) */ -static void scmi_put_handler_unlocked(struct scmi_notify_instance *ni, +static bool scmi_put_handler_unlocked(struct scmi_notify_instance *ni, struct scmi_event_handler *hndl) { + bool freed = false; + if (refcount_dec_and_test(&hndl->users)) { if (!IS_HNDL_PENDING(hndl)) scmi_disable_events(hndl); scmi_free_event_handler(hndl); + freed = true; } + + return freed; } static void scmi_put_handler(struct scmi_notify_instance *ni, struct scmi_event_handler *hndl) { + bool freed; + u8 protocol_id; struct scmi_registered_event *r_evt = hndl->r_evt; mutex_lock(&ni->pending_mtx); - if (r_evt) + if (r_evt) { + protocol_id = r_evt->proto->id; mutex_lock(&r_evt->proto->registered_mtx); + } - scmi_put_handler_unlocked(ni, hndl); + freed = scmi_put_handler_unlocked(ni, hndl); - if (r_evt) + if (r_evt) { mutex_unlock(&r_evt->proto->registered_mtx); + /* + * Only registered handler acquired protocol; must be here + * released only AFTER unlocking registered_mtx, since + * releasing a protocol can trigger its de-initialization + * (ie. including r_evt and registered_mtx) + */ + if (freed) + scmi_protocol_release(ni->handle, protocol_id); + } mutex_unlock(&ni->pending_mtx); } static void scmi_put_active_handler(struct scmi_notify_instance *ni, struct scmi_event_handler *hndl) { + bool freed; struct scmi_registered_event *r_evt = hndl->r_evt; + u8 protocol_id = r_evt->proto->id; mutex_lock(&r_evt->proto->registered_mtx); - scmi_put_handler_unlocked(ni, hndl); + freed = scmi_put_handler_unlocked(ni, hndl); mutex_unlock(&r_evt->proto->registered_mtx); + if (freed) + scmi_protocol_release(ni->handle, protocol_id); } /** |