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-rw-r--r--drivers/s390/block/dasd_alias.c235
1 files changed, 152 insertions, 83 deletions
diff --git a/drivers/s390/block/dasd_alias.c b/drivers/s390/block/dasd_alias.c
index 286782c60da4..cbbdd3e7fea1 100644
--- a/drivers/s390/block/dasd_alias.c
+++ b/drivers/s390/block/dasd_alias.c
@@ -319,22 +319,14 @@ static int _add_device_to_lcu(struct alias_lcu *lcu,
struct dasd_eckd_private *private;
struct alias_pav_group *group;
struct dasd_uid uid;
- unsigned long flags;
private = (struct dasd_eckd_private *) device->private;
- /* only lock if not already locked */
- if (device != pos)
- spin_lock_irqsave_nested(get_ccwdev_lock(device->cdev), flags,
- CDEV_NESTED_SECOND);
private->uid.type = lcu->uac->unit[private->uid.real_unit_addr].ua_type;
private->uid.base_unit_addr =
lcu->uac->unit[private->uid.real_unit_addr].base_ua;
uid = private->uid;
- if (device != pos)
- spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
-
/* if we have no PAV anyway, we don't need to bother with PAV groups */
if (lcu->pav == NO_PAV) {
list_move(&device->alias_list, &lcu->active_devices);
@@ -411,6 +403,130 @@ suborder_not_supported(struct dasd_ccw_req *cqr)
return 0;
}
+/*
+ * This function tries to lock all devices on an lcu via trylock
+ * return NULL on success otherwise return first failed device
+ */
+static struct dasd_device *_trylock_all_devices_on_lcu(struct alias_lcu *lcu,
+ struct dasd_device *pos)
+
+{
+ struct alias_pav_group *pavgroup;
+ struct dasd_device *device;
+
+ list_for_each_entry(device, &lcu->active_devices, alias_list) {
+ if (device == pos)
+ continue;
+ if (!spin_trylock(get_ccwdev_lock(device->cdev)))
+ return device;
+ }
+ list_for_each_entry(device, &lcu->inactive_devices, alias_list) {
+ if (device == pos)
+ continue;
+ if (!spin_trylock(get_ccwdev_lock(device->cdev)))
+ return device;
+ }
+ list_for_each_entry(pavgroup, &lcu->grouplist, group) {
+ list_for_each_entry(device, &pavgroup->baselist, alias_list) {
+ if (device == pos)
+ continue;
+ if (!spin_trylock(get_ccwdev_lock(device->cdev)))
+ return device;
+ }
+ list_for_each_entry(device, &pavgroup->aliaslist, alias_list) {
+ if (device == pos)
+ continue;
+ if (!spin_trylock(get_ccwdev_lock(device->cdev)))
+ return device;
+ }
+ }
+ return NULL;
+}
+
+/*
+ * unlock all devices except the one that is specified as pos
+ * stop if enddev is specified and reached
+ */
+static void _unlock_all_devices_on_lcu(struct alias_lcu *lcu,
+ struct dasd_device *pos,
+ struct dasd_device *enddev)
+
+{
+ struct alias_pav_group *pavgroup;
+ struct dasd_device *device;
+
+ list_for_each_entry(device, &lcu->active_devices, alias_list) {
+ if (device == pos)
+ continue;
+ if (device == enddev)
+ return;
+ spin_unlock(get_ccwdev_lock(device->cdev));
+ }
+ list_for_each_entry(device, &lcu->inactive_devices, alias_list) {
+ if (device == pos)
+ continue;
+ if (device == enddev)
+ return;
+ spin_unlock(get_ccwdev_lock(device->cdev));
+ }
+ list_for_each_entry(pavgroup, &lcu->grouplist, group) {
+ list_for_each_entry(device, &pavgroup->baselist, alias_list) {
+ if (device == pos)
+ continue;
+ if (device == enddev)
+ return;
+ spin_unlock(get_ccwdev_lock(device->cdev));
+ }
+ list_for_each_entry(device, &pavgroup->aliaslist, alias_list) {
+ if (device == pos)
+ continue;
+ if (device == enddev)
+ return;
+ spin_unlock(get_ccwdev_lock(device->cdev));
+ }
+ }
+}
+
+/*
+ * this function is needed because the locking order
+ * device lock -> lcu lock
+ * needs to be assured when iterating over devices in an LCU
+ *
+ * if a device is specified in pos then the device lock is already hold
+ */
+static void _trylock_and_lock_lcu_irqsave(struct alias_lcu *lcu,
+ struct dasd_device *pos,
+ unsigned long *flags)
+{
+ struct dasd_device *failed;
+
+ do {
+ spin_lock_irqsave(&lcu->lock, *flags);
+ failed = _trylock_all_devices_on_lcu(lcu, pos);
+ if (failed) {
+ _unlock_all_devices_on_lcu(lcu, pos, failed);
+ spin_unlock_irqrestore(&lcu->lock, *flags);
+ cpu_relax();
+ }
+ } while (failed);
+}
+
+static void _trylock_and_lock_lcu(struct alias_lcu *lcu,
+ struct dasd_device *pos)
+{
+ struct dasd_device *failed;
+
+ do {
+ spin_lock(&lcu->lock);
+ failed = _trylock_all_devices_on_lcu(lcu, pos);
+ if (failed) {
+ _unlock_all_devices_on_lcu(lcu, pos, failed);
+ spin_unlock(&lcu->lock);
+ cpu_relax();
+ }
+ } while (failed);
+}
+
static int read_unit_address_configuration(struct dasd_device *device,
struct alias_lcu *lcu)
{
@@ -505,10 +621,7 @@ static int _lcu_update(struct dasd_device *refdev, struct alias_lcu *lcu)
if (rc)
return rc;
- /* need to take cdev lock before lcu lock */
- spin_lock_irqsave_nested(get_ccwdev_lock(refdev->cdev), flags,
- CDEV_NESTED_FIRST);
- spin_lock(&lcu->lock);
+ _trylock_and_lock_lcu_irqsave(lcu, NULL, &flags);
lcu->pav = NO_PAV;
for (i = 0; i < MAX_DEVICES_PER_LCU; ++i) {
switch (lcu->uac->unit[i].ua_type) {
@@ -527,8 +640,8 @@ static int _lcu_update(struct dasd_device *refdev, struct alias_lcu *lcu)
alias_list) {
_add_device_to_lcu(lcu, device, refdev);
}
- spin_unlock(&lcu->lock);
- spin_unlock_irqrestore(get_ccwdev_lock(refdev->cdev), flags);
+ _unlock_all_devices_on_lcu(lcu, NULL, NULL);
+ spin_unlock_irqrestore(&lcu->lock, flags);
return 0;
}
@@ -616,8 +729,6 @@ int dasd_alias_add_device(struct dasd_device *device)
private = (struct dasd_eckd_private *) device->private;
lcu = private->lcu;
rc = 0;
-
- /* need to take cdev lock before lcu lock */
spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
spin_lock(&lcu->lock);
if (!(lcu->flags & UPDATE_PENDING)) {
@@ -754,30 +865,19 @@ static void _restart_all_base_devices_on_lcu(struct alias_lcu *lcu)
struct alias_pav_group *pavgroup;
struct dasd_device *device;
struct dasd_eckd_private *private;
- unsigned long flags;
/* active and inactive list can contain alias as well as base devices */
list_for_each_entry(device, &lcu->active_devices, alias_list) {
private = (struct dasd_eckd_private *) device->private;
- spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
- if (private->uid.type != UA_BASE_DEVICE) {
- spin_unlock_irqrestore(get_ccwdev_lock(device->cdev),
- flags);
+ if (private->uid.type != UA_BASE_DEVICE)
continue;
- }
- spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
dasd_schedule_block_bh(device->block);
dasd_schedule_device_bh(device);
}
list_for_each_entry(device, &lcu->inactive_devices, alias_list) {
private = (struct dasd_eckd_private *) device->private;
- spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
- if (private->uid.type != UA_BASE_DEVICE) {
- spin_unlock_irqrestore(get_ccwdev_lock(device->cdev),
- flags);
+ if (private->uid.type != UA_BASE_DEVICE)
continue;
- }
- spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
dasd_schedule_block_bh(device->block);
dasd_schedule_device_bh(device);
}
@@ -841,38 +941,20 @@ static void flush_all_alias_devices_on_lcu(struct alias_lcu *lcu)
spin_unlock_irqrestore(&lcu->lock, flags);
}
-static void __stop_device_on_lcu(struct dasd_device *device,
- struct dasd_device *pos)
-{
- /* If pos == device then device is already locked! */
- if (pos == device) {
- dasd_device_set_stop_bits(pos, DASD_STOPPED_SU);
- return;
- }
- spin_lock(get_ccwdev_lock(pos->cdev));
- dasd_device_set_stop_bits(pos, DASD_STOPPED_SU);
- spin_unlock(get_ccwdev_lock(pos->cdev));
-}
-
-/*
- * This function is called in interrupt context, so the
- * cdev lock for device is already locked!
- */
-static void _stop_all_devices_on_lcu(struct alias_lcu *lcu,
- struct dasd_device *device)
+static void _stop_all_devices_on_lcu(struct alias_lcu *lcu)
{
struct alias_pav_group *pavgroup;
- struct dasd_device *pos;
+ struct dasd_device *device;
- list_for_each_entry(pos, &lcu->active_devices, alias_list)
- __stop_device_on_lcu(device, pos);
- list_for_each_entry(pos, &lcu->inactive_devices, alias_list)
- __stop_device_on_lcu(device, pos);
+ list_for_each_entry(device, &lcu->active_devices, alias_list)
+ dasd_device_set_stop_bits(device, DASD_STOPPED_SU);
+ list_for_each_entry(device, &lcu->inactive_devices, alias_list)
+ dasd_device_set_stop_bits(device, DASD_STOPPED_SU);
list_for_each_entry(pavgroup, &lcu->grouplist, group) {
- list_for_each_entry(pos, &pavgroup->baselist, alias_list)
- __stop_device_on_lcu(device, pos);
- list_for_each_entry(pos, &pavgroup->aliaslist, alias_list)
- __stop_device_on_lcu(device, pos);
+ list_for_each_entry(device, &pavgroup->baselist, alias_list)
+ dasd_device_set_stop_bits(device, DASD_STOPPED_SU);
+ list_for_each_entry(device, &pavgroup->aliaslist, alias_list)
+ dasd_device_set_stop_bits(device, DASD_STOPPED_SU);
}
}
@@ -880,33 +962,16 @@ static void _unstop_all_devices_on_lcu(struct alias_lcu *lcu)
{
struct alias_pav_group *pavgroup;
struct dasd_device *device;
- unsigned long flags;
- list_for_each_entry(device, &lcu->active_devices, alias_list) {
- spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
+ list_for_each_entry(device, &lcu->active_devices, alias_list)
dasd_device_remove_stop_bits(device, DASD_STOPPED_SU);
- spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
- }
-
- list_for_each_entry(device, &lcu->inactive_devices, alias_list) {
- spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
+ list_for_each_entry(device, &lcu->inactive_devices, alias_list)
dasd_device_remove_stop_bits(device, DASD_STOPPED_SU);
- spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
- }
-
list_for_each_entry(pavgroup, &lcu->grouplist, group) {
- list_for_each_entry(device, &pavgroup->baselist, alias_list) {
- spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
+ list_for_each_entry(device, &pavgroup->baselist, alias_list)
dasd_device_remove_stop_bits(device, DASD_STOPPED_SU);
- spin_unlock_irqrestore(get_ccwdev_lock(device->cdev),
- flags);
- }
- list_for_each_entry(device, &pavgroup->aliaslist, alias_list) {
- spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
+ list_for_each_entry(device, &pavgroup->aliaslist, alias_list)
dasd_device_remove_stop_bits(device, DASD_STOPPED_SU);
- spin_unlock_irqrestore(get_ccwdev_lock(device->cdev),
- flags);
- }
}
}
@@ -932,13 +997,14 @@ static void summary_unit_check_handling_work(struct work_struct *work)
spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
reset_summary_unit_check(lcu, device, suc_data->reason);
- spin_lock_irqsave(&lcu->lock, flags);
+ _trylock_and_lock_lcu_irqsave(lcu, NULL, &flags);
_unstop_all_devices_on_lcu(lcu);
_restart_all_base_devices_on_lcu(lcu);
/* 3. read new alias configuration */
_schedule_lcu_update(lcu, device);
lcu->suc_data.device = NULL;
dasd_put_device(device);
+ _unlock_all_devices_on_lcu(lcu, NULL, NULL);
spin_unlock_irqrestore(&lcu->lock, flags);
}
@@ -974,10 +1040,7 @@ void dasd_alias_handle_summary_unit_check(struct dasd_device *device,
" unit check (no lcu structure)");
return;
}
- spin_lock(&lcu->lock);
- _stop_all_devices_on_lcu(lcu, device);
- /* prepare for lcu_update */
- private->lcu->flags |= NEED_UAC_UPDATE | UPDATE_PENDING;
+ _trylock_and_lock_lcu(lcu, device);
/* If this device is about to be removed just return and wait for
* the next interrupt on a different device
*/
@@ -985,6 +1048,7 @@ void dasd_alias_handle_summary_unit_check(struct dasd_device *device,
DBF_DEV_EVENT(DBF_WARNING, device, "%s",
"device is in offline processing,"
" don't do summary unit check handling");
+ _unlock_all_devices_on_lcu(lcu, device, NULL);
spin_unlock(&lcu->lock);
return;
}
@@ -993,12 +1057,17 @@ void dasd_alias_handle_summary_unit_check(struct dasd_device *device,
DBF_DEV_EVENT(DBF_WARNING, device, "%s",
"previous instance of summary unit check worker"
" still pending");
+ _unlock_all_devices_on_lcu(lcu, device, NULL);
spin_unlock(&lcu->lock);
return ;
}
+ _stop_all_devices_on_lcu(lcu);
+ /* prepare for lcu_update */
+ private->lcu->flags |= NEED_UAC_UPDATE | UPDATE_PENDING;
lcu->suc_data.reason = reason;
lcu->suc_data.device = device;
dasd_get_device(device);
+ _unlock_all_devices_on_lcu(lcu, device, NULL);
spin_unlock(&lcu->lock);
if (!schedule_work(&lcu->suc_data.worker))
dasd_put_device(device);
generated by cgit v1.2.3 (git 2.0.4) at 2024-10-05 09:26:21 +0000