linux_dsm_epyc7002/drivers/scsi/libsas/sas_event.c
Dan Williams 87c8331fcf [SCSI] libsas: prevent domain rediscovery competing with ata error handling
libata error handling provides for a timeout for link recovery.  libsas
must not rescan for previously known devices in this interval otherwise
it may remove a device that is simply waiting for its link to recover.
Let libata-eh make the determination of when the link is stable and
prevent libsas (host workqueue) from taking action while this
determination is pending.

Using a mutex (ha->disco_mutex) to flush and disable revalidation while
eh is running requires any discovery action that may block on eh be
moved to its own context outside the lock.  Probing ATA devices
explicitly waits on ata-eh and the cache-flush-io issued during device
removal may also pend awaiting eh completion.  Essentially any rphy
add/remove activity needs to run outside the lock.

This adds two new cleanup states for sas_unregister_domain_devices()
'allocated-but-not-probed', and 'flagged-for-destruction'.  In the
'allocated-but-not-probed' state  dev->rphy points to a rphy that is
known to have not been through a sas_rphy_add() event.  At domain
teardown check if this device is still pending probe and cleanup
accordingly.  Similarly if a device has already been queued for removal
then sas_unregister_domain_devices has nothing to do.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2012-02-19 13:52:34 -06:00

157 lines
4.0 KiB
C

/*
* Serial Attached SCSI (SAS) Event processing
*
* Copyright (C) 2005 Adaptec, Inc. All rights reserved.
* Copyright (C) 2005 Luben Tuikov <luben_tuikov@adaptec.com>
*
* This file is licensed under GPLv2.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of the
* License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*
*/
#include <linux/export.h>
#include <scsi/scsi_host.h>
#include "sas_internal.h"
#include "sas_dump.h"
static void sas_queue_work(struct sas_ha_struct *ha, struct work_struct *work)
{
if (!test_bit(SAS_HA_REGISTERED, &ha->state))
return;
if (test_bit(SAS_HA_DRAINING, &ha->state))
list_add(&work->entry, &ha->defer_q);
else
scsi_queue_work(ha->core.shost, work);
}
static void sas_queue_event(int event, unsigned long *pending,
struct work_struct *work,
struct sas_ha_struct *ha)
{
if (!test_and_set_bit(event, pending)) {
unsigned long flags;
spin_lock_irqsave(&ha->state_lock, flags);
sas_queue_work(ha, work);
spin_unlock_irqrestore(&ha->state_lock, flags);
}
}
int sas_drain_work(struct sas_ha_struct *ha)
{
struct workqueue_struct *wq = ha->core.shost->work_q;
struct work_struct *w, *_w;
int err;
err = mutex_lock_interruptible(&ha->drain_mutex);
if (err)
return err;
set_bit(SAS_HA_DRAINING, &ha->state);
/* flush submitters */
spin_lock_irq(&ha->state_lock);
spin_unlock_irq(&ha->state_lock);
drain_workqueue(wq);
spin_lock_irq(&ha->state_lock);
clear_bit(SAS_HA_DRAINING, &ha->state);
list_for_each_entry_safe(w, _w, &ha->defer_q, entry) {
list_del_init(&w->entry);
sas_queue_work(ha, w);
}
spin_unlock_irq(&ha->state_lock);
mutex_unlock(&ha->drain_mutex);
return 0;
}
EXPORT_SYMBOL_GPL(sas_drain_work);
void sas_disable_revalidation(struct sas_ha_struct *ha)
{
mutex_lock(&ha->disco_mutex);
set_bit(SAS_HA_ATA_EH_ACTIVE, &ha->state);
mutex_unlock(&ha->disco_mutex);
}
void sas_enable_revalidation(struct sas_ha_struct *ha)
{
int i;
mutex_lock(&ha->disco_mutex);
clear_bit(SAS_HA_ATA_EH_ACTIVE, &ha->state);
for (i = 0; i < ha->num_phys; i++) {
struct asd_sas_port *port = ha->sas_port[i];
const int ev = DISCE_REVALIDATE_DOMAIN;
struct sas_discovery *d = &port->disc;
if (!test_and_clear_bit(ev, &d->pending))
continue;
sas_queue_event(ev, &d->pending, &d->disc_work[ev].work, ha);
}
mutex_unlock(&ha->disco_mutex);
}
static void notify_ha_event(struct sas_ha_struct *sas_ha, enum ha_event event)
{
BUG_ON(event >= HA_NUM_EVENTS);
sas_queue_event(event, &sas_ha->pending,
&sas_ha->ha_events[event].work, sas_ha);
}
static void notify_port_event(struct asd_sas_phy *phy, enum port_event event)
{
struct sas_ha_struct *ha = phy->ha;
BUG_ON(event >= PORT_NUM_EVENTS);
sas_queue_event(event, &phy->port_events_pending,
&phy->port_events[event].work, ha);
}
static void notify_phy_event(struct asd_sas_phy *phy, enum phy_event event)
{
struct sas_ha_struct *ha = phy->ha;
BUG_ON(event >= PHY_NUM_EVENTS);
sas_queue_event(event, &phy->phy_events_pending,
&phy->phy_events[event].work, ha);
}
int sas_init_events(struct sas_ha_struct *sas_ha)
{
static const work_func_t sas_ha_event_fns[HA_NUM_EVENTS] = {
[HAE_RESET] = sas_hae_reset,
};
int i;
for (i = 0; i < HA_NUM_EVENTS; i++) {
INIT_WORK(&sas_ha->ha_events[i].work, sas_ha_event_fns[i]);
sas_ha->ha_events[i].ha = sas_ha;
}
sas_ha->notify_ha_event = notify_ha_event;
sas_ha->notify_port_event = notify_port_event;
sas_ha->notify_phy_event = notify_phy_event;
return 0;
}