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path: root/drivers/hwtracing/coresight/coresight-syscfg.c
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Diffstat (limited to 'drivers/hwtracing/coresight/coresight-syscfg.c')
-rw-r--r--drivers/hwtracing/coresight/coresight-syscfg.c374
1 files changed, 293 insertions, 81 deletions
diff --git a/drivers/hwtracing/coresight/coresight-syscfg.c b/drivers/hwtracing/coresight/coresight-syscfg.c
index 098fc34c4829..6836b05986e8 100644
--- a/drivers/hwtracing/coresight/coresight-syscfg.c
+++ b/drivers/hwtracing/coresight/coresight-syscfg.c
@@ -89,9 +89,9 @@ static int cscfg_add_csdev_cfg(struct coresight_device *csdev,
}
/* if matched features, add config to device.*/
if (config_csdev) {
- spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags);
+ raw_spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags);
list_add(&config_csdev->node, &csdev->config_csdev_list);
- spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags);
+ raw_spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags);
}
return 0;
@@ -194,9 +194,9 @@ static int cscfg_load_feat_csdev(struct coresight_device *csdev,
/* add to internal csdev feature list & initialise using reset call */
cscfg_reset_feat(feat_csdev);
- spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags);
+ raw_spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags);
list_add(&feat_csdev->node, &csdev->feature_csdev_list);
- spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags);
+ raw_spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags);
return 0;
}
@@ -395,6 +395,8 @@ static void cscfg_remove_owned_csdev_configs(struct coresight_device *csdev, voi
if (list_empty(&csdev->config_csdev_list))
return;
+ guard(raw_spinlock_irqsave)(&csdev->cscfg_csdev_lock);
+
list_for_each_entry_safe(config_csdev, tmp, &csdev->config_csdev_list, node) {
if (config_csdev->config_desc->load_owner == load_owner)
list_del(&config_csdev->node);
@@ -415,6 +417,27 @@ static void cscfg_remove_owned_csdev_features(struct coresight_device *csdev, vo
}
/*
+ * Unregister all configuration and features from configfs owned by load_owner.
+ * Although this is called without the list mutex being held, it is in the
+ * context of an unload operation which are strictly serialised,
+ * so the lists cannot change during this call.
+ */
+static void cscfg_fs_unregister_cfgs_feats(void *load_owner)
+{
+ struct cscfg_config_desc *config_desc;
+ struct cscfg_feature_desc *feat_desc;
+
+ list_for_each_entry(config_desc, &cscfg_mgr->config_desc_list, item) {
+ if (config_desc->load_owner == load_owner)
+ cscfg_configfs_del_config(config_desc);
+ }
+ list_for_each_entry(feat_desc, &cscfg_mgr->feat_desc_list, item) {
+ if (feat_desc->load_owner == load_owner)
+ cscfg_configfs_del_feature(feat_desc);
+ }
+}
+
+/*
* removal is relatively easy - just remove from all lists, anything that
* matches the owner. Memory for the descriptors will be managed by the owner,
* memory for the csdev items is devm_ allocated with the individual csdev
@@ -426,6 +449,8 @@ static void cscfg_unload_owned_cfgs_feats(void *load_owner)
struct cscfg_feature_desc *feat_desc, *feat_tmp;
struct cscfg_registered_csdev *csdev_item;
+ lockdep_assert_held(&cscfg_mutex);
+
/* remove from each csdev instance feature and config lists */
list_for_each_entry(csdev_item, &cscfg_mgr->csdev_desc_list, item) {
/*
@@ -439,7 +464,6 @@ static void cscfg_unload_owned_cfgs_feats(void *load_owner)
/* remove from the config descriptor lists */
list_for_each_entry_safe(config_desc, cfg_tmp, &cscfg_mgr->config_desc_list, item) {
if (config_desc->load_owner == load_owner) {
- cscfg_configfs_del_config(config_desc);
etm_perf_del_symlink_cscfg(config_desc);
list_del(&config_desc->item);
}
@@ -448,12 +472,90 @@ static void cscfg_unload_owned_cfgs_feats(void *load_owner)
/* remove from the feature descriptor lists */
list_for_each_entry_safe(feat_desc, feat_tmp, &cscfg_mgr->feat_desc_list, item) {
if (feat_desc->load_owner == load_owner) {
- cscfg_configfs_del_feature(feat_desc);
list_del(&feat_desc->item);
}
}
}
+/*
+ * load the features and configs to the lists - called with list mutex held
+ */
+static int cscfg_load_owned_cfgs_feats(struct cscfg_config_desc **config_descs,
+ struct cscfg_feature_desc **feat_descs,
+ struct cscfg_load_owner_info *owner_info)
+{
+ int i, err;
+
+ lockdep_assert_held(&cscfg_mutex);
+
+ /* load features first */
+ if (feat_descs) {
+ for (i = 0; feat_descs[i]; i++) {
+ err = cscfg_load_feat(feat_descs[i]);
+ if (err) {
+ pr_err("coresight-syscfg: Failed to load feature %s\n",
+ feat_descs[i]->name);
+ return err;
+ }
+ feat_descs[i]->load_owner = owner_info;
+ }
+ }
+
+ /* next any configurations to check feature dependencies */
+ if (config_descs) {
+ for (i = 0; config_descs[i]; i++) {
+ err = cscfg_load_config(config_descs[i]);
+ if (err) {
+ pr_err("coresight-syscfg: Failed to load configuration %s\n",
+ config_descs[i]->name);
+ return err;
+ }
+ config_descs[i]->load_owner = owner_info;
+ config_descs[i]->available = false;
+ }
+ }
+ return 0;
+}
+
+/* set configurations as available to activate at the end of the load process */
+static void cscfg_set_configs_available(struct cscfg_config_desc **config_descs)
+{
+ int i;
+
+ lockdep_assert_held(&cscfg_mutex);
+
+ if (config_descs) {
+ for (i = 0; config_descs[i]; i++)
+ config_descs[i]->available = true;
+ }
+}
+
+/*
+ * Create and register each of the configurations and features with configfs.
+ * Called without mutex being held.
+ */
+static int cscfg_fs_register_cfgs_feats(struct cscfg_config_desc **config_descs,
+ struct cscfg_feature_desc **feat_descs)
+{
+ int i, err;
+
+ if (feat_descs) {
+ for (i = 0; feat_descs[i]; i++) {
+ err = cscfg_configfs_add_feature(feat_descs[i]);
+ if (err)
+ return err;
+ }
+ }
+ if (config_descs) {
+ for (i = 0; config_descs[i]; i++) {
+ err = cscfg_configfs_add_config(config_descs[i]);
+ if (err)
+ return err;
+ }
+ }
+ return 0;
+}
+
/**
* cscfg_load_config_sets - API function to load feature and config sets.
*
@@ -476,57 +578,63 @@ int cscfg_load_config_sets(struct cscfg_config_desc **config_descs,
struct cscfg_feature_desc **feat_descs,
struct cscfg_load_owner_info *owner_info)
{
- int err = 0, i = 0;
+ int err = 0;
mutex_lock(&cscfg_mutex);
-
- /* load features first */
- if (feat_descs) {
- while (feat_descs[i]) {
- err = cscfg_load_feat(feat_descs[i]);
- if (!err)
- err = cscfg_configfs_add_feature(feat_descs[i]);
- if (err) {
- pr_err("coresight-syscfg: Failed to load feature %s\n",
- feat_descs[i]->name);
- cscfg_unload_owned_cfgs_feats(owner_info);
- goto exit_unlock;
- }
- feat_descs[i]->load_owner = owner_info;
- i++;
- }
+ if (cscfg_mgr->load_state != CSCFG_NONE) {
+ mutex_unlock(&cscfg_mutex);
+ return -EBUSY;
}
+ cscfg_mgr->load_state = CSCFG_LOAD;
- /* next any configurations to check feature dependencies */
- i = 0;
- if (config_descs) {
- while (config_descs[i]) {
- err = cscfg_load_config(config_descs[i]);
- if (!err)
- err = cscfg_configfs_add_config(config_descs[i]);
- if (err) {
- pr_err("coresight-syscfg: Failed to load configuration %s\n",
- config_descs[i]->name);
- cscfg_unload_owned_cfgs_feats(owner_info);
- goto exit_unlock;
- }
- config_descs[i]->load_owner = owner_info;
- i++;
- }
- }
+ /* first load and add to the lists */
+ err = cscfg_load_owned_cfgs_feats(config_descs, feat_descs, owner_info);
+ if (err)
+ goto err_clean_load;
/* add the load owner to the load order list */
list_add_tail(&owner_info->item, &cscfg_mgr->load_order_list);
if (!list_is_singular(&cscfg_mgr->load_order_list)) {
/* lock previous item in load order list */
err = cscfg_owner_get(list_prev_entry(owner_info, item));
- if (err) {
- cscfg_unload_owned_cfgs_feats(owner_info);
- list_del(&owner_info->item);
- }
+ if (err)
+ goto err_clean_owner_list;
}
+ /*
+ * make visible to configfs - configfs manipulation must occur outside
+ * the list mutex lock to avoid circular lockdep issues with configfs
+ * built in mutexes and semaphores. This is safe as it is not possible
+ * to start a new load/unload operation till the current one is done.
+ */
+ mutex_unlock(&cscfg_mutex);
+
+ /* create the configfs elements */
+ err = cscfg_fs_register_cfgs_feats(config_descs, feat_descs);
+ mutex_lock(&cscfg_mutex);
+
+ if (err)
+ goto err_clean_cfs;
+
+ /* mark any new configs as available for activation */
+ cscfg_set_configs_available(config_descs);
+ goto exit_unlock;
+
+err_clean_cfs:
+ /* cleanup after error registering with configfs */
+ cscfg_fs_unregister_cfgs_feats(owner_info);
+
+ if (!list_is_singular(&cscfg_mgr->load_order_list))
+ cscfg_owner_put(list_prev_entry(owner_info, item));
+
+err_clean_owner_list:
+ list_del(&owner_info->item);
+
+err_clean_load:
+ cscfg_unload_owned_cfgs_feats(owner_info);
+
exit_unlock:
+ cscfg_mgr->load_state = CSCFG_NONE;
mutex_unlock(&cscfg_mutex);
return err;
}
@@ -543,6 +651,9 @@ EXPORT_SYMBOL_GPL(cscfg_load_config_sets);
* 1) no configurations are active.
* 2) the set being unloaded was the last to be loaded to maintain dependencies.
*
+ * Once the unload operation commences, we disallow any configuration being
+ * made active until it is complete.
+ *
* @owner_info: Information on owner for set being unloaded.
*/
int cscfg_unload_config_sets(struct cscfg_load_owner_info *owner_info)
@@ -551,6 +662,13 @@ int cscfg_unload_config_sets(struct cscfg_load_owner_info *owner_info)
struct cscfg_load_owner_info *load_list_item = NULL;
mutex_lock(&cscfg_mutex);
+ if (cscfg_mgr->load_state != CSCFG_NONE) {
+ mutex_unlock(&cscfg_mutex);
+ return -EBUSY;
+ }
+
+ /* unload op in progress also prevents activation of any config */
+ cscfg_mgr->load_state = CSCFG_UNLOAD;
/* cannot unload if anything is active */
if (atomic_read(&cscfg_mgr->sys_active_cnt)) {
@@ -571,7 +689,12 @@ int cscfg_unload_config_sets(struct cscfg_load_owner_info *owner_info)
goto exit_unlock;
}
- /* unload all belonging to load_owner */
+ /* remove from configfs - again outside the scope of the list mutex */
+ mutex_unlock(&cscfg_mutex);
+ cscfg_fs_unregister_cfgs_feats(owner_info);
+ mutex_lock(&cscfg_mutex);
+
+ /* unload everything from lists belonging to load_owner */
cscfg_unload_owned_cfgs_feats(owner_info);
/* remove from load order list */
@@ -582,6 +705,7 @@ int cscfg_unload_config_sets(struct cscfg_load_owner_info *owner_info)
list_del(&owner_info->item);
exit_unlock:
+ cscfg_mgr->load_state = CSCFG_NONE;
mutex_unlock(&cscfg_mutex);
return err;
}
@@ -643,7 +767,7 @@ static int cscfg_list_add_csdev(struct coresight_device *csdev,
INIT_LIST_HEAD(&csdev->feature_csdev_list);
INIT_LIST_HEAD(&csdev->config_csdev_list);
- spin_lock_init(&csdev->cscfg_csdev_lock);
+ raw_spin_lock_init(&csdev->cscfg_csdev_lock);
return 0;
}
@@ -733,7 +857,7 @@ void cscfg_csdev_reset_feats(struct coresight_device *csdev)
struct cscfg_feature_csdev *feat_csdev;
unsigned long flags;
- spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags);
+ raw_spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags);
if (list_empty(&csdev->feature_csdev_list))
goto unlock_exit;
@@ -741,10 +865,29 @@ void cscfg_csdev_reset_feats(struct coresight_device *csdev)
cscfg_reset_feat(feat_csdev);
unlock_exit:
- spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags);
+ raw_spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags);
}
EXPORT_SYMBOL_GPL(cscfg_csdev_reset_feats);
+static bool cscfg_config_desc_get(struct cscfg_config_desc *config_desc)
+{
+ if (!atomic_fetch_inc(&config_desc->active_cnt)) {
+ /* must ensure that config cannot be unloaded in use */
+ if (unlikely(cscfg_owner_get(config_desc->load_owner))) {
+ atomic_dec(&config_desc->active_cnt);
+ return false;
+ }
+ }
+
+ return true;
+}
+
+static void cscfg_config_desc_put(struct cscfg_config_desc *config_desc)
+{
+ if (!atomic_dec_return(&config_desc->active_cnt))
+ cscfg_owner_put(config_desc->load_owner);
+}
+
/*
* This activate configuration for either perf or sysfs. Perf can have multiple
* active configs, selected per event, sysfs is limited to one.
@@ -759,24 +902,26 @@ static int _cscfg_activate_config(unsigned long cfg_hash)
struct cscfg_config_desc *config_desc;
int err = -EINVAL;
+ if (cscfg_mgr->load_state == CSCFG_UNLOAD)
+ return -EBUSY;
+
list_for_each_entry(config_desc, &cscfg_mgr->config_desc_list, item) {
if ((unsigned long)config_desc->event_ea->var == cfg_hash) {
- /* must ensure that config cannot be unloaded in use */
- err = cscfg_owner_get(config_desc->load_owner);
- if (err)
+ /* if we happen upon a partly loaded config, can't use it */
+ if (config_desc->available == false)
+ return -EBUSY;
+
+ if (!cscfg_config_desc_get(config_desc)) {
+ err = -EINVAL;
break;
+ }
+
/*
* increment the global active count - control changes to
* active configurations
*/
atomic_inc(&cscfg_mgr->sys_active_cnt);
- /*
- * mark the descriptor as active so enable config on a
- * device instance will use it
- */
- atomic_inc(&config_desc->active_cnt);
-
err = 0;
dev_dbg(cscfg_device(), "Activate config %s.\n", config_desc->name);
break;
@@ -791,9 +936,8 @@ static void _cscfg_deactivate_config(unsigned long cfg_hash)
list_for_each_entry(config_desc, &cscfg_mgr->config_desc_list, item) {
if ((unsigned long)config_desc->event_ea->var == cfg_hash) {
- atomic_dec(&config_desc->active_cnt);
atomic_dec(&cscfg_mgr->sys_active_cnt);
- cscfg_owner_put(config_desc->load_owner);
+ cscfg_config_desc_put(config_desc);
dev_dbg(cscfg_device(), "Deactivate config %s.\n", config_desc->name);
break;
}
@@ -918,7 +1062,7 @@ int cscfg_csdev_enable_active_config(struct coresight_device *csdev,
unsigned long cfg_hash, int preset)
{
struct cscfg_config_csdev *config_csdev_active = NULL, *config_csdev_item;
- const struct cscfg_config_desc *config_desc;
+ struct cscfg_config_desc *config_desc;
unsigned long flags;
int err = 0;
@@ -930,17 +1074,17 @@ int cscfg_csdev_enable_active_config(struct coresight_device *csdev,
* Look for matching configuration - set the active configuration
* context if found.
*/
- spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags);
+ raw_spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags);
list_for_each_entry(config_csdev_item, &csdev->config_csdev_list, node) {
config_desc = config_csdev_item->config_desc;
- if ((atomic_read(&config_desc->active_cnt)) &&
- ((unsigned long)config_desc->event_ea->var == cfg_hash)) {
+ if (((unsigned long)config_desc->event_ea->var == cfg_hash) &&
+ cscfg_config_desc_get(config_desc)) {
config_csdev_active = config_csdev_item;
csdev->active_cscfg_ctxt = (void *)config_csdev_active;
break;
}
}
- spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags);
+ raw_spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags);
/*
* If found, attempt to enable
@@ -961,14 +1105,18 @@ int cscfg_csdev_enable_active_config(struct coresight_device *csdev,
*
* Set enabled if OK, err if not.
*/
- spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags);
+ raw_spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags);
if (csdev->active_cscfg_ctxt)
config_csdev_active->enabled = true;
else
err = -EBUSY;
- spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags);
+ raw_spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags);
}
+
+ if (err)
+ cscfg_config_desc_put(config_desc);
}
+
return err;
}
EXPORT_SYMBOL_GPL(cscfg_csdev_enable_active_config);
@@ -995,7 +1143,7 @@ void cscfg_csdev_disable_active_config(struct coresight_device *csdev)
* If it was not enabled, we have no work to do, otherwise mark as disabled.
* Clear the active config pointer.
*/
- spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags);
+ raw_spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags);
config_csdev = (struct cscfg_config_csdev *)csdev->active_cscfg_ctxt;
if (config_csdev) {
if (!config_csdev->enabled)
@@ -1004,11 +1152,13 @@ void cscfg_csdev_disable_active_config(struct coresight_device *csdev)
config_csdev->enabled = false;
}
csdev->active_cscfg_ctxt = NULL;
- spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags);
+ raw_spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags);
/* true if there was an enabled active config */
- if (config_csdev)
+ if (config_csdev) {
cscfg_csdev_disable_config(config_csdev);
+ cscfg_config_desc_put(config_csdev->config_desc);
+ }
}
EXPORT_SYMBOL_GPL(cscfg_csdev_disable_active_config);
@@ -1022,8 +1172,10 @@ struct device *cscfg_device(void)
/* Must have a release function or the kernel will complain on module unload */
static void cscfg_dev_release(struct device *dev)
{
+ mutex_lock(&cscfg_mutex);
kfree(cscfg_mgr);
cscfg_mgr = NULL;
+ mutex_unlock(&cscfg_mutex);
}
/* a device is needed to "own" some kernel elements such as sysfs entries. */
@@ -1042,6 +1194,14 @@ static int cscfg_create_device(void)
if (!cscfg_mgr)
goto create_dev_exit_unlock;
+ /* initialise the cscfg_mgr structure */
+ INIT_LIST_HEAD(&cscfg_mgr->csdev_desc_list);
+ INIT_LIST_HEAD(&cscfg_mgr->feat_desc_list);
+ INIT_LIST_HEAD(&cscfg_mgr->config_desc_list);
+ INIT_LIST_HEAD(&cscfg_mgr->load_order_list);
+ atomic_set(&cscfg_mgr->sys_active_cnt, 0);
+ cscfg_mgr->load_state = CSCFG_NONE;
+
/* setup the device */
dev = cscfg_device();
dev->release = cscfg_dev_release;
@@ -1049,24 +1209,80 @@ static int cscfg_create_device(void)
err = device_register(dev);
if (err)
- cscfg_dev_release(dev);
+ put_device(dev);
create_dev_exit_unlock:
mutex_unlock(&cscfg_mutex);
return err;
}
-static void cscfg_clear_device(void)
+/*
+ * Loading and unloading is generally on user discretion.
+ * If exiting due to coresight module unload, we need to unload any configurations that remain,
+ * before we unregister the configfs intrastructure.
+ *
+ * Do this by walking the load_owner list and taking appropriate action, depending on the load
+ * owner type.
+ */
+static void cscfg_unload_cfgs_on_exit(void)
{
- struct cscfg_config_desc *cfg_desc;
+ struct cscfg_load_owner_info *owner_info = NULL;
+ /*
+ * grab the mutex - even though we are exiting, some configfs files
+ * may still be live till we dump them, so ensure list data is
+ * protected from a race condition.
+ */
mutex_lock(&cscfg_mutex);
- list_for_each_entry(cfg_desc, &cscfg_mgr->config_desc_list, item) {
- etm_perf_del_symlink_cscfg(cfg_desc);
+ while (!list_empty(&cscfg_mgr->load_order_list)) {
+
+ /* remove in reverse order of loading */
+ owner_info = list_last_entry(&cscfg_mgr->load_order_list,
+ struct cscfg_load_owner_info, item);
+
+ /* action according to type */
+ switch (owner_info->type) {
+ case CSCFG_OWNER_PRELOAD:
+ /*
+ * preloaded descriptors are statically allocated in
+ * this module - just need to unload dynamic items from
+ * csdev lists, and remove from configfs directories.
+ */
+ pr_info("cscfg: unloading preloaded configurations\n");
+ break;
+
+ case CSCFG_OWNER_MODULE:
+ /*
+ * this is an error - the loadable module must have been unloaded prior
+ * to the coresight module unload. Therefore that module has not
+ * correctly unloaded configs in its own exit code.
+ * Nothing to do other than emit an error string as the static descriptor
+ * references we need to unload will have disappeared with the module.
+ */
+ pr_err("cscfg: ERROR: prior module failed to unload configuration\n");
+ goto list_remove;
+ }
+
+ /* remove from configfs - outside the scope of the list mutex */
+ mutex_unlock(&cscfg_mutex);
+ cscfg_fs_unregister_cfgs_feats(owner_info);
+ mutex_lock(&cscfg_mutex);
+
+ /* Next unload from csdev lists. */
+ cscfg_unload_owned_cfgs_feats(owner_info);
+
+list_remove:
+ /* remove from load order list */
+ list_del(&owner_info->item);
}
+ mutex_unlock(&cscfg_mutex);
+}
+
+static void cscfg_clear_device(void)
+{
+ cscfg_unload_cfgs_on_exit();
cscfg_configfs_release(cscfg_mgr);
device_unregister(cscfg_device());
- mutex_unlock(&cscfg_mutex);
}
/* Initialise system config management API device */
@@ -1074,20 +1290,16 @@ int __init cscfg_init(void)
{
int err = 0;
+ /* create the device and init cscfg_mgr */
err = cscfg_create_device();
if (err)
return err;
+ /* initialise configfs subsystem */
err = cscfg_configfs_init(cscfg_mgr);
if (err)
goto exit_err;
- INIT_LIST_HEAD(&cscfg_mgr->csdev_desc_list);
- INIT_LIST_HEAD(&cscfg_mgr->feat_desc_list);
- INIT_LIST_HEAD(&cscfg_mgr->config_desc_list);
- INIT_LIST_HEAD(&cscfg_mgr->load_order_list);
- atomic_set(&cscfg_mgr->sys_active_cnt, 0);
-
/* preload built-in configurations */
err = cscfg_preload(THIS_MODULE);
if (err)