22b9153faa
When requeuing work to a draining workqueue the last work instance may not be idle, so sas_queue_work() must not touch work->entry. Introduce sas_work with a drain_node list_head to have a private list for collecting work deferred due to drain collision. Fixes reports like: BUG: unable to handle kernel NULL pointer dereference at (null) IP: [<ffffffff810410d4>] process_one_work+0x2e/0x338 Signed-off-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
166 lines
4.2 KiB
C
166 lines
4.2 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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void sas_queue_work(struct sas_ha_struct *ha, struct sas_work *sw)
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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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/* add it to the defer list, if not already pending */
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if (list_empty(&sw->drain_node))
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list_add(&sw->drain_node, &ha->defer_q);
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} else
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scsi_queue_work(ha->core.shost, &sw->work);
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}
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static void sas_queue_event(int event, unsigned long *pending,
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struct sas_work *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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void __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 sas_work *sw, *_sw;
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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(sw, _sw, &ha->defer_q, drain_node) {
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list_del_init(&sw->drain_node);
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sas_queue_work(ha, sw);
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}
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spin_unlock_irq(&ha->state_lock);
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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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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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if (test_bit(SAS_HA_REGISTERED, &ha->state))
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__sas_drain_work(ha);
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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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void sas_disable_revalidation(struct sas_ha_struct *ha)
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{
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mutex_lock(&ha->disco_mutex);
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set_bit(SAS_HA_ATA_EH_ACTIVE, &ha->state);
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mutex_unlock(&ha->disco_mutex);
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}
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void sas_enable_revalidation(struct sas_ha_struct *ha)
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{
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int i;
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mutex_lock(&ha->disco_mutex);
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clear_bit(SAS_HA_ATA_EH_ACTIVE, &ha->state);
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for (i = 0; i < ha->num_phys; i++) {
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struct asd_sas_port *port = ha->sas_port[i];
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const int ev = DISCE_REVALIDATE_DOMAIN;
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struct sas_discovery *d = &port->disc;
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if (!test_and_clear_bit(ev, &d->pending))
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continue;
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sas_queue_event(ev, &d->pending, &d->disc_work[ev].work, ha);
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}
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mutex_unlock(&ha->disco_mutex);
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}
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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_SAS_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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