Messages in this thread | | | Subject | Re: [PATCH 1/3] infiniband: hw: hfi1: verbs.c: Use built-in RCU list checking | From | Dennis Dalessandro <> | Date | Tue, 14 Jan 2020 13:24:00 -0500 |
| |
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 wrote: >>> From: Madhuparna Bhowmik <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> >>> 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.
The rdmavt one though looks to be OK. I'll give it a test.
-Denny
| |