Hello, Linus.
So, safe fixes my ass. 8852aac ("workqueue: mod_delayed_work_on()
shouldn't queue timer on 0 delay") had the side-effect of performing
delayed_work sanity checks even when @delay is 0, which should be fine
for any sane use cases.
Unfortunately, megaraid was being overly ingenious. It seemingly
wanted to use cancel_delayed_work_sync() before cancel_work_sync() was
introduced, but didn't want to waste the space for full delayed_work
as it was only gonna use 0 @delay. So, it only allocated space for
struct work_struct and then casted it to struct delayed_work and
passed it into delayed_work functions - truly awesome engineering
tradeoff to save some bytes.
Xiaotian fixed it by making megraid allocate full delayed_work for
now. It should be converted to use work_struct and cancel_work_sync()
but I think we better do that after 3.7.
I added another commit to change BUG_ON()s in __queue_delayed_work()
to WARN_ON_ONCE()s so that the kernel doens't crash even if there are
more such abuses.
Please pull from the following branch to receive the two patches.
git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq.git for-3.7-fixes
----------------------------------------------------------------
Tejun Heo (1):
workqueue: convert BUG_ON()s in __queue_delayed_work() to WARN_ON_ONCE()s
Xiaotian Feng (1):
megaraid: fix BUG_ON() from incorrect use of delayed work
drivers/scsi/megaraid/megaraid_sas.h | 2 +-
drivers/scsi/megaraid/megaraid_sas_base.c | 14 ++++++--------
kernel/workqueue.c | 4 ++--
3 files changed, 9 insertions(+), 11 deletions(-)
diff --git a/drivers/scsi/megaraid/megaraid_sas.h b/drivers/scsi/megaraid/megaraid_sas.h
index 16b7a72..3b2365c 100644
--- a/drivers/scsi/megaraid/megaraid_sas.h
+++ b/drivers/scsi/megaraid/megaraid_sas.h
@@ -1276,7 +1276,7 @@ struct megasas_evt_detail {
} __attribute__ ((packed));
struct megasas_aen_event {
- struct work_struct hotplug_work;
+ struct delayed_work hotplug_work;
struct megasas_instance *instance;
};
diff --git a/drivers/scsi/megaraid/megaraid_sas_base.c b/drivers/scsi/megaraid/megaraid_sas_base.c
index d2c5366..e4f2baa 100644
--- a/drivers/scsi/megaraid/megaraid_sas_base.c
+++ b/drivers/scsi/megaraid/megaraid_sas_base.c
@@ -2060,9 +2060,9 @@ megasas_service_aen(struct megasas_instance *instance, struct megasas_cmd *cmd)
} else {
ev->instance = instance;
instance->ev = ev;
- INIT_WORK(&ev->hotplug_work, megasas_aen_polling);
- schedule_delayed_work(
- (struct delayed_work *)&ev->hotplug_work, 0);
+ INIT_DELAYED_WORK(&ev->hotplug_work,
+ megasas_aen_polling);
+ schedule_delayed_work(&ev->hotplug_work, 0);
}
}
}
@@ -4352,8 +4352,7 @@ megasas_suspend(struct pci_dev *pdev, pm_message_t state)
/* cancel the delayed work if this work still in queue */
if (instance->ev != NULL) {
struct megasas_aen_event *ev = instance->ev;
- cancel_delayed_work_sync(
- (struct delayed_work *)&ev->hotplug_work);
+ cancel_delayed_work_sync(&ev->hotplug_work);
instance->ev = NULL;
}
@@ -4545,8 +4544,7 @@ static void __devexit megasas_detach_one(struct pci_dev *pdev)
/* cancel the delayed work if this work still in queue*/
if (instance->ev != NULL) {
struct megasas_aen_event *ev = instance->ev;
- cancel_delayed_work_sync(
- (struct delayed_work *)&ev->hotplug_work);
+ cancel_delayed_work_sync(&ev->hotplug_work);
instance->ev = NULL;
}
@@ -5190,7 +5188,7 @@ static void
megasas_aen_polling(struct work_struct *work)
{
struct megasas_aen_event *ev =
- container_of(work, struct megasas_aen_event, hotplug_work);
+ container_of(work, struct megasas_aen_event, hotplug_work.work);
struct megasas_instance *instance = ev->instance;
union megasas_evt_class_locale class_locale;
struct Scsi_Host *host;
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 084aa47..1dae900 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -1361,8 +1361,8 @@ static void __queue_delayed_work(int cpu, struct workqueue_struct *wq,
WARN_ON_ONCE(timer->function != delayed_work_timer_fn ||
timer->data != (unsigned long)dwork);
- BUG_ON(timer_pending(timer));
- BUG_ON(!list_empty(&work->entry));
+ WARN_ON_ONCE(timer_pending(timer));
+ WARN_ON_ONCE(!list_empty(&work->entry));
/*
* If @delay is 0, queue @dwork->work immediately. This is for
--
To unsubscribe from this list: send the line "unsubscribe linux-scsi" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
