lkml.org 
[lkml]   [2020]   [Feb]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH 1/3] infiniband: hw: hfi1: verbs.c: Use built-in RCU list checking
From
Date
On 2/14/2020 10:43 AM, Madhuparna Bhowmik wrote:
>
>
> On Wed, Jan 15, 2020 at 12:05 AM <madhuparnabhowmik04@gmail.com
> <mailto:madhuparnabhowmik04@gmail.com>> wrote:
>
> From: Dennis Dalessandro <dennis.dalessandro@intel.com
> <mailto:dennis.dalessandro@intel.com>>
>
> On 1/14/2020 12:00 PM, Dennis Dalessandro wrote:
> > On 1/14/2020 11:57 AM, Jason Gunthorpe wrote:
> >> On Tue, Jan 14, 2020 at 09:53:45PM +0530,
> >> madhuparnabhowmik04@gmail.com
> <mailto:madhuparnabhowmik04@gmail.com> wrote:
> >>> From: Madhuparna Bhowmik <madhuparnabhowmik04@gmail.com
> <mailto:madhuparnabhowmik04@gmail.com>>
> >>>
> >>> list_for_each_entry_rcu has built-in RCU and lock checking.
> >>> Pass cond argument to list_for_each_entry_rcu.
> >>>
> >>> Signed-off-by: Madhuparna Bhowmik
> <madhuparnabhowmik04@gmail.com <mailto:madhuparnabhowmik04@gmail.com>>
> >>>   drivers/infiniband/hw/hfi1/verbs.c | 2 +-
> >>>   1 file changed, 1 insertion(+), 1 deletion(-)
> >>>
> >>> diff --git a/drivers/infiniband/hw/hfi1/verbs.c
> >>> b/drivers/infiniband/hw/hfi1/verbs.c
> >>> index 089e201d7550..22f2d4fd2577 100644
> >>> +++ b/drivers/infiniband/hw/hfi1/verbs.c
> >>> @@ -515,7 +515,7 @@ static inline void hfi1_handle_packet(struct
> >>> hfi1_packet *packet,
> >>>                          opa_get_lid(packet->dlid, 9B));
> >>>           if (!mcast)
> >>>               goto drop;
> >>> -        list_for_each_entry_rcu(p, &mcast->qp_list, list) {
> >>> +        list_for_each_entry_rcu(p, &mcast->qp_list, list,
> >>> lockdep_is_held(&(ibp->rvp.lock))) {
> >>
> >> Okay, this looks reasonable
> >>
> >> Mike, Dennis, is this the right lock to test?
> >>
> >
> > I'm looking at that right now actually, I don't think this is
> correct.
> > Wanted to talk to Mike before I send a response though.
> >
> > -Denny
>
> That's definitely going to throw a ton of lock dep messages. It's not
> really the right lock either. Instead what we probably need to do is
> what we do in the non-multicast part of the code and take the
> rcu_read_lock().
>
> I'd say hold off on this and we'll fix it right. Same goes for the
> qib one.
>
> Alright, thank you for reviewing.
>
> The rdmavt one though looks to be OK. I'll give it a test.
>
> Hi,
> I just wanted to follow up on this.
> Any updates?
> Also, is the bug fixed now?
>
> Thank you,
> Madhuparna
>
> Thank you,
> Madhuparna
>
> -Denny
>

I've got a patch going through internal discussion and testing for
adding rcu read locking.

The RDMAVT patch, I was OK with going in, I guess I just mentioned that
in a reply rather than adding an RB tag. Let me go ahead and do that.

-Denny

\
 
 \ /
  Last update: 2020-02-14 18:25    [W:0.064 / U:1.012 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site