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Date:   Tue, 14 Jan 2020 12:57:40 -0400
From:   Jason Gunthorpe <jgg@ziepe.ca>
To:     madhuparnabhowmik04@gmail.com
Cc:     mike.marciniszyn@intel.com, dennis.dalessandro@intel.com,
        paulmck@kernel.org, joel@joelfernandes.org, frextrite@gmail.com,
        linux-kernel-mentees@lists.linuxfoundation.org,
        rcu@vger.kernel.org, linux-rdma@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/3] infiniband: hw: hfi1: verbs.c: Use built-in RCU list
 checking
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References: <20200114162345.19995-1-madhuparnabhowmik04@gmail.com>
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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?

Jason