cscfg_config_sysfs_get_active_cfg() will be used from idle flows, while sleeping locks are not allowed. Introduce sysfs_store_lock to replace the mutex to protect sysfs_active_config and sysfs_active_preset accesses, with IRQ-safe locking to avoid lockdep complaint.
Refactor cscfg_config_sysfs_activate() to handle errors first and use finer-grained locking only for sysfs_active_config.
Signed-off-by: Leo Yan leo.yan@arm.com --- drivers/hwtracing/coresight/coresight-syscfg.c | 35 +++++++++++++------------- drivers/hwtracing/coresight/coresight-syscfg.h | 2 ++ 2 files changed, 20 insertions(+), 17 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-syscfg.c b/drivers/hwtracing/coresight/coresight-syscfg.c index d7f5037953d6ba7fb7f83a8012a1abc5ffd0a147..2ccd7659b472e4993a16be408d0647b5993c5ec7 100644 --- a/drivers/hwtracing/coresight/coresight-syscfg.c +++ b/drivers/hwtracing/coresight/coresight-syscfg.c @@ -953,39 +953,40 @@ int cscfg_config_sysfs_activate(struct cscfg_config_desc *config_desc, bool acti unsigned long cfg_hash; int err = 0;
- mutex_lock(&cscfg_mutex); + guard(mutex)(&cscfg_mutex);
cfg_hash = (unsigned long)config_desc->event_ea->var;
if (activate) { /* cannot be a current active value to activate this */ - if (cscfg_mgr->sysfs_active_config) { - err = -EBUSY; - goto exit_unlock; - } + if (cscfg_mgr->sysfs_active_config) + return -EBUSY; + err = _cscfg_activate_config(cfg_hash); - if (!err) + if (err) + return err; + + scoped_guard(raw_spinlock_irqsave, &cscfg_mgr->sysfs_store_lock) cscfg_mgr->sysfs_active_config = cfg_hash; } else { + if (cscfg_mgr->sysfs_active_config != cfg_hash) + return -EINVAL; + /* disable if matching current value */ - if (cscfg_mgr->sysfs_active_config == cfg_hash) { - _cscfg_deactivate_config(cfg_hash); + _cscfg_deactivate_config(cfg_hash); + + scoped_guard(raw_spinlock_irqsave, &cscfg_mgr->sysfs_store_lock) cscfg_mgr->sysfs_active_config = 0; - } else - err = -EINVAL; }
-exit_unlock: - mutex_unlock(&cscfg_mutex); - return err; + return 0; }
/* set the sysfs preset value */ void cscfg_config_sysfs_set_preset(int preset) { - mutex_lock(&cscfg_mutex); + guard(raw_spinlock_irqsave)(&cscfg_mgr->sysfs_store_lock); cscfg_mgr->sysfs_active_preset = preset; - mutex_unlock(&cscfg_mutex); }
/* @@ -994,10 +995,9 @@ void cscfg_config_sysfs_set_preset(int preset) */ void cscfg_config_sysfs_get_active_cfg(unsigned long *cfg_hash, int *preset) { - mutex_lock(&cscfg_mutex); + guard(raw_spinlock_irqsave)(&cscfg_mgr->sysfs_store_lock); *preset = cscfg_mgr->sysfs_active_preset; *cfg_hash = cscfg_mgr->sysfs_active_config; - mutex_unlock(&cscfg_mutex); } EXPORT_SYMBOL_GPL(cscfg_config_sysfs_get_active_cfg);
@@ -1201,6 +1201,7 @@ static int cscfg_create_device(void) INIT_LIST_HEAD(&cscfg_mgr->load_order_list); atomic_set(&cscfg_mgr->sys_active_cnt, 0); cscfg_mgr->load_state = CSCFG_NONE; + raw_spin_lock_init(&cscfg_mgr->sysfs_store_lock);
/* setup the device */ dev = cscfg_device(); diff --git a/drivers/hwtracing/coresight/coresight-syscfg.h b/drivers/hwtracing/coresight/coresight-syscfg.h index 66e2db890d8203853a0c3c907b48aa66dd8014e6..658e93c3705f1cb3ba3523d0bc27ac704697dd70 100644 --- a/drivers/hwtracing/coresight/coresight-syscfg.h +++ b/drivers/hwtracing/coresight/coresight-syscfg.h @@ -42,6 +42,7 @@ enum cscfg_load_ops { * @sysfs_active_config:Active config hash used if CoreSight controlled from sysfs. * @sysfs_active_preset:Active preset index used if CoreSight controlled from sysfs. * @load_state: A multi-stage load/unload operation is in progress. + * @sysfs_store_lock: Exclusive access sysfs stored variables. */ struct cscfg_manager { struct device dev; @@ -54,6 +55,7 @@ struct cscfg_manager { u32 sysfs_active_config; int sysfs_active_preset; enum cscfg_load_ops load_state; + raw_spinlock_t sysfs_store_lock; };
/* get reference to dev in cscfg_manager */