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b1124cd3ec
When an lldd invokes ->notify_port_event() it can trigger a chain of libsas events to: 1/ form the port and find the direct attached device 2/ if the attached device is an expander perform domain discovery A call to flush_workqueue() will only flush the initial port formation work. Currently libsas users need to call scsi_flush_work() up to the max depth of chain (which will grow from 2 to 3 when ata discovery is moved to its own discovery event). Instead of open coding multiple calls switch to use drain_workqueue() to flush sas work. drain_workqueue() does not handle new work submitted during the drain so libsas needs a bit of infrastructure to hold off unchained work submissions while a drain is in flight. A lldd ->notify() event is considered 'unchained' while a sas_discover_event() is 'chained'. As Tejun notes: "For now, I think it would be best to add private wrapper in libsas to support deferring unchained work items while draining." Signed-off-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
131 lines
3.4 KiB
C
131 lines
3.4 KiB
C
/*
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* Serial Attached SCSI (SAS) Event processing
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*
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* Copyright (C) 2005 Adaptec, Inc. All rights reserved.
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* Copyright (C) 2005 Luben Tuikov <luben_tuikov@adaptec.com>
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*
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* This file is licensed under GPLv2.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of the
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* License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*
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*/
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#include <linux/export.h>
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#include <scsi/scsi_host.h>
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#include "sas_internal.h"
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#include "sas_dump.h"
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static void sas_queue_work(struct sas_ha_struct *ha, struct work_struct *work)
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{
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if (!test_bit(SAS_HA_REGISTERED, &ha->state))
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return;
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if (test_bit(SAS_HA_DRAINING, &ha->state))
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list_add(&work->entry, &ha->defer_q);
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else
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scsi_queue_work(ha->core.shost, work);
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}
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static void sas_queue_event(int event, unsigned long *pending,
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struct work_struct *work,
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struct sas_ha_struct *ha)
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{
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if (!test_and_set_bit(event, pending)) {
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unsigned long flags;
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spin_lock_irqsave(&ha->state_lock, flags);
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sas_queue_work(ha, work);
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spin_unlock_irqrestore(&ha->state_lock, flags);
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}
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}
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int sas_drain_work(struct sas_ha_struct *ha)
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{
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struct workqueue_struct *wq = ha->core.shost->work_q;
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struct work_struct *w, *_w;
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int err;
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err = mutex_lock_interruptible(&ha->drain_mutex);
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if (err)
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return err;
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set_bit(SAS_HA_DRAINING, &ha->state);
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/* flush submitters */
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spin_lock_irq(&ha->state_lock);
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spin_unlock_irq(&ha->state_lock);
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drain_workqueue(wq);
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spin_lock_irq(&ha->state_lock);
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clear_bit(SAS_HA_DRAINING, &ha->state);
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list_for_each_entry_safe(w, _w, &ha->defer_q, entry) {
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list_del_init(&w->entry);
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sas_queue_work(ha, w);
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}
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spin_unlock_irq(&ha->state_lock);
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mutex_unlock(&ha->drain_mutex);
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return 0;
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}
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EXPORT_SYMBOL_GPL(sas_drain_work);
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static void notify_ha_event(struct sas_ha_struct *sas_ha, enum ha_event event)
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{
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BUG_ON(event >= HA_NUM_EVENTS);
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sas_queue_event(event, &sas_ha->pending,
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&sas_ha->ha_events[event].work, sas_ha);
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}
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static void notify_port_event(struct asd_sas_phy *phy, enum port_event event)
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{
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struct sas_ha_struct *ha = phy->ha;
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BUG_ON(event >= PORT_NUM_EVENTS);
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sas_queue_event(event, &phy->port_events_pending,
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&phy->port_events[event].work, ha);
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}
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static void notify_phy_event(struct asd_sas_phy *phy, enum phy_event event)
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{
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struct sas_ha_struct *ha = phy->ha;
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BUG_ON(event >= PHY_NUM_EVENTS);
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sas_queue_event(event, &phy->phy_events_pending,
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&phy->phy_events[event].work, ha);
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}
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int sas_init_events(struct sas_ha_struct *sas_ha)
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{
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static const work_func_t sas_ha_event_fns[HA_NUM_EVENTS] = {
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[HAE_RESET] = sas_hae_reset,
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};
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int i;
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for (i = 0; i < HA_NUM_EVENTS; i++) {
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INIT_WORK(&sas_ha->ha_events[i].work, sas_ha_event_fns[i]);
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sas_ha->ha_events[i].ha = sas_ha;
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}
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sas_ha->notify_ha_event = notify_ha_event;
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sas_ha->notify_port_event = notify_port_event;
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sas_ha->notify_phy_event = notify_phy_event;
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return 0;
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}
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