Re: [PATCH for-next v3] RDMA/rxe: Fix ib_device reference counting (again)

From: Jason Gunthorpe <jgg@nvidia.com>
To: Bob Pearson <rpearsonhpe@gmail.com>
Cc: <zyjzyj2000@gmail.com>, <linux-rdma@vger.kernel.org>
Subject: Re: [PATCH for-next v3] RDMA/rxe: Fix ib_device reference counting (again)
Date: Fri, 5 Mar 2021 14:20:31 -0400	[thread overview]
Message-ID: <20210305182031.GA1884080@nvidia.com> (raw)
In-Reply-To: <20210304192048.2958-1-rpearson@hpe.com>

On Thu, Mar 04, 2021 at 01:20:49PM -0600, Bob Pearson wrote:
> From: Bob Pearson <rpearsonhpe@gmail.com>
> 
> Three errors occurred in the fix referenced below.
> 
> 1) rxe_rcv_mcast_pkt() dropped a reference to ib_device when
> no error occurred causing an underflow on the reference counter.
> This code is cleaned up to be clearer and easier to read.
> 
> 2) Extending the reference taken by rxe_get_dev_from_net() in
> rxe_udp_encap_recv() until each skb is freed was not matched by
> a reference in the loopback path resulting in underflows.
> 
> 3) In rxe_comp.c in rxe_completer() the function free_pkt() did
> not clear skb which triggered a warning at done: and could possibly
> at exit: . The WARN_ONCE() calls are not actually needed.
> The call to free_pkt() is moved to the end to clearly show that
> all skbs are freed.
> 
> This patch fixes these errors.
> 
> Fixes: 899aba891cab ("RDMA/rxe: Fix FIXME in rxe_udp_encap_recv()")
> Signed-off-by: Bob Pearson <rpearsonhpe@gmail.com>
> Version 3:
> V2 of this patch had spelling errors and style issues which are
> fixed in this version.
> 
> Version 2:
> v1 of this patch incorrectly added a WARN_ON_ONCE in rxe_completer
> where it could be triggered for normal traffic. This version
> replaced that with a pr_warn located correctly.
> 
> v1 of this patch placed a call to kfree_skb in an if statement
> that could trigger style warnings. This version cleans that up.
> 
>  drivers/infiniband/sw/rxe/rxe_comp.c | 55 +++++++++++---------------
>  drivers/infiniband/sw/rxe/rxe_net.c  | 10 ++++-
>  drivers/infiniband/sw/rxe/rxe_recv.c | 59 +++++++++++++++++-----------
>  3 files changed, 67 insertions(+), 57 deletions(-)

I split this into three patches for-rc as is required by Linus.

It looks reasonable to me and the reorganizing make sense

Thanks,
Jason