linux/drivers/scsi/libsas/sas_event.c
Ahmed S. Darwish c2d0f1a65a scsi: libsas: Introduce a _gfp() variant of event notifiers
sas_alloc_event() uses in_interrupt() to decide which allocation should be
used.

The usage of in_interrupt() in drivers is phased out and Linus clearly
requested that code which changes behaviour depending on context should
either be separated or the context be conveyed in an argument passed by the
caller, which usually knows the context.

The in_interrupt() check is also only partially correct, because it fails
to choose the correct code path when just preemption or interrupts are
disabled. For example, as in the following call chain:

  mvsas/mv_sas.c: mvs_work_queue() [process context]
  spin_lock_irqsave(mvs_info::lock, )
    -> libsas/sas_event.c: sas_notify_phy_event()
      -> sas_alloc_event()
        -> in_interrupt() = false
          -> invalid GFP_KERNEL allocation
    -> libsas/sas_event.c: sas_notify_port_event()
      -> sas_alloc_event()
        -> in_interrupt() = false
          -> invalid GFP_KERNEL allocation

Introduce sas_alloc_event_gfp(), sas_notify_port_event_gfp(), and
sas_notify_phy_event_gfp(), which all behave like the non _gfp() variants
but use a caller-passed GFP mask for allocations.

For bisectability, all callers will be modified first to pass GFP context,
then the non _gfp() libsas API variants will be modified to take a gfp_t by
default.

Link: https://lore.kernel.org/r/20210118100955.1761652-4-a.darwish@linutronix.de
Fixes: 1c393b970e ("scsi: libsas: Use dynamic alloced work to avoid sas event lost")
Cc: Jason Yan <yanaijie@huawei.com>
Reviewed-by: John Garry <john.garry@huawei.com>
Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
2021-01-22 21:31:07 -05:00

219 lines
4.7 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* Serial Attached SCSI (SAS) Event processing
*
* Copyright (C) 2005 Adaptec, Inc. All rights reserved.
* Copyright (C) 2005 Luben Tuikov <luben_tuikov@adaptec.com>
*/
#include <linux/export.h>
#include <scsi/scsi_host.h>
#include "sas_internal.h"
int sas_queue_work(struct sas_ha_struct *ha, struct sas_work *sw)
{
/* it's added to the defer_q when draining so return succeed */
int rc = 1;
if (!test_bit(SAS_HA_REGISTERED, &ha->state))
return 0;
if (test_bit(SAS_HA_DRAINING, &ha->state)) {
/* add it to the defer list, if not already pending */
if (list_empty(&sw->drain_node))
list_add_tail(&sw->drain_node, &ha->defer_q);
} else
rc = queue_work(ha->event_q, &sw->work);
return rc;
}
static int sas_queue_event(int event, struct sas_work *work,
struct sas_ha_struct *ha)
{
unsigned long flags;
int rc;
spin_lock_irqsave(&ha->lock, flags);
rc = sas_queue_work(ha, work);
spin_unlock_irqrestore(&ha->lock, flags);
return rc;
}
void __sas_drain_work(struct sas_ha_struct *ha)
{
struct sas_work *sw, *_sw;
int ret;
set_bit(SAS_HA_DRAINING, &ha->state);
/* flush submitters */
spin_lock_irq(&ha->lock);
spin_unlock_irq(&ha->lock);
drain_workqueue(ha->event_q);
drain_workqueue(ha->disco_q);
spin_lock_irq(&ha->lock);
clear_bit(SAS_HA_DRAINING, &ha->state);
list_for_each_entry_safe(sw, _sw, &ha->defer_q, drain_node) {
list_del_init(&sw->drain_node);
ret = sas_queue_work(ha, sw);
if (ret != 1)
sas_free_event(to_asd_sas_event(&sw->work));
}
spin_unlock_irq(&ha->lock);
}
int sas_drain_work(struct sas_ha_struct *ha)
{
int err;
err = mutex_lock_interruptible(&ha->drain_mutex);
if (err)
return err;
if (test_bit(SAS_HA_REGISTERED, &ha->state))
__sas_drain_work(ha);
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;
struct asd_sas_phy *sas_phy;
if (!test_and_clear_bit(ev, &d->pending))
continue;
if (list_empty(&port->phy_list))
continue;
sas_phy = container_of(port->phy_list.next, struct asd_sas_phy,
port_phy_el);
sas_notify_port_event(sas_phy, PORTE_BROADCAST_RCVD);
}
mutex_unlock(&ha->disco_mutex);
}
static void sas_port_event_worker(struct work_struct *work)
{
struct asd_sas_event *ev = to_asd_sas_event(work);
sas_port_event_fns[ev->event](work);
sas_free_event(ev);
}
static void sas_phy_event_worker(struct work_struct *work)
{
struct asd_sas_event *ev = to_asd_sas_event(work);
sas_phy_event_fns[ev->event](work);
sas_free_event(ev);
}
static int __sas_notify_port_event(struct asd_sas_phy *phy,
enum port_event event,
struct asd_sas_event *ev)
{
struct sas_ha_struct *ha = phy->ha;
int ret;
BUG_ON(event >= PORT_NUM_EVENTS);
INIT_SAS_EVENT(ev, sas_port_event_worker, phy, event);
ret = sas_queue_event(event, &ev->work, ha);
if (ret != 1)
sas_free_event(ev);
return ret;
}
int sas_notify_port_event_gfp(struct asd_sas_phy *phy, enum port_event event,
gfp_t gfp_flags)
{
struct asd_sas_event *ev;
ev = sas_alloc_event_gfp(phy, gfp_flags);
if (!ev)
return -ENOMEM;
return __sas_notify_port_event(phy, event, ev);
}
EXPORT_SYMBOL_GPL(sas_notify_port_event_gfp);
int sas_notify_port_event(struct asd_sas_phy *phy, enum port_event event)
{
struct asd_sas_event *ev;
ev = sas_alloc_event(phy);
if (!ev)
return -ENOMEM;
return __sas_notify_port_event(phy, event, ev);
}
EXPORT_SYMBOL_GPL(sas_notify_port_event);
static inline int __sas_notify_phy_event(struct asd_sas_phy *phy,
enum phy_event event,
struct asd_sas_event *ev)
{
struct sas_ha_struct *ha = phy->ha;
int ret;
BUG_ON(event >= PHY_NUM_EVENTS);
INIT_SAS_EVENT(ev, sas_phy_event_worker, phy, event);
ret = sas_queue_event(event, &ev->work, ha);
if (ret != 1)
sas_free_event(ev);
return ret;
}
int sas_notify_phy_event_gfp(struct asd_sas_phy *phy, enum phy_event event,
gfp_t gfp_flags)
{
struct asd_sas_event *ev;
ev = sas_alloc_event_gfp(phy, gfp_flags);
if (!ev)
return -ENOMEM;
return __sas_notify_phy_event(phy, event, ev);
}
EXPORT_SYMBOL_GPL(sas_notify_phy_event_gfp);
int sas_notify_phy_event(struct asd_sas_phy *phy, enum phy_event event)
{
struct asd_sas_event *ev;
ev = sas_alloc_event(phy);
if (!ev)
return -ENOMEM;
return __sas_notify_phy_event(phy, event, ev);
}
EXPORT_SYMBOL_GPL(sas_notify_phy_event);