On Tue, 2013-10-29 at 11:09 -0500, scameron@xxxxxxxxxxxxxxxxxx wrote:
> On Tue, Oct 29, 2013 at 02:43:56PM +0800, Wei Yongjun wrote:
> > From: Wei Yongjun <yongjun_wei@xxxxxxxxxxxxxxxxx>
> >
> > In case of error, the function kthread_run() returns ERR_PTR()
> > and never returns NULL. The NULL test in the return value check
> > should be replaced with IS_ERR().
> >
> > Signed-off-by: Wei Yongjun <yongjun_wei@xxxxxxxxxxxxxxxxx>
> > ---
> > drivers/scsi/hpsa.c | 3 ++-
> > 1 file changed, 2 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/scsi/hpsa.c b/drivers/scsi/hpsa.c
> > index 891c86b..f413b14 100644
> > --- a/drivers/scsi/hpsa.c
> > +++ b/drivers/scsi/hpsa.c
> > @@ -4757,7 +4757,8 @@ static void start_controller_lockup_detector(struct ctlr_info *h)
> > kthread_run(detect_controller_lockup_thread,
> > NULL, HPSA);
> > }
> > - if (!hpsa_lockup_detector) {
> > + if (IS_ERR(hpsa_lockup_detector)) {
> > + hpsa_lockup_detector = NULL;
> > dev_warn(&h->pdev->dev,
> > "Could not start lockup detector thread\n");
> > return;
>
> Ack.
Hmm, this whole lockup thread start/stop thing is horribly racy with
hotplug (and bind and unbind).
Firstly, why do you need an actual thread, why not just use a workqueue?
That way you don't need a list or a lock, you can just schedule work for
each instance? since they don't interfere, no global list and no lock.
If you insist on a thread, it should probably start at module insertion
and be shut down at module removal, so no races. You can have it sleep
forever on list_empty(&hpsa_ctlr_list) and wake it when you add a
controller.
James
--
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
