>-----Original Message-----
>From: Intel-wired-lan <intel-wired-lan-boun...@osuosl.org> On Behalf Of
>Fijalkowski, Maciej
>Sent: Thursday, January 23, 2025 8:31 PM
>To: intel-wired-...@lists.osuosl.org
>Cc: Fijalkowski, Maciej <maciej.fijalkow...@intel.com>;
>net...@vger.kernel.org; x...@redhat.com; Nguyen, Anthony L
><anthony.l.ngu...@intel.com>; Simon Horman <ho...@kernel.org>; Kitszel,
>Przemyslaw <przemyslaw.kits...@intel.com>; Keller, Jacob E
><jacob.e.kel...@intel.com>; Maxwell, Jon <jmaxw...@redhat.com>; Karlsson,
>Magnus <magnus.karls...@intel.com>
>Subject: [Intel-wired-lan] [PATCH v5 iwl-net 2/3] ice: gather page_count()'s of
>each frag right before XDP prog call
>
>If we store the pgcnt on few fragments while being in the middle of gathering
>the whole frame and we stumbled upon DD bit not being set, we terminate the
>NAPI Rx processing loop and come back later on. Then on next NAPI execution
>we work on previously stored pgcnt.
>
>Imagine that second half of page was used actively by networking stack and by
>the time we came back, stack is not busy with this page anymore and
>decremented the refcnt. The page reuse algorithm in this case should be good
>to reuse the page but given the old refcnt it will not do so and attempt to
>release the page via page_frag_cache_drain() with pagecnt_bias used as an arg.
>This in turn will result in negative refcnt on struct page, which was initially
>observed by Xu Du.
>
>Therefore, move the page count storage from ice_get_rx_buf() to a place where
>we are sure that whole frame has been collected, but before calling XDP
>program as it internally can also change the page count of fragments belonging
>to xdp_buff.
>
>Fixes: ac0753391195 ("ice: Store page count inside ice_rx_buf")
>Reported-and-tested-by: Xu Du <x...@redhat.com>
>Reviewed-by: Przemek Kitszel <przemyslaw.kits...@intel.com>
>Reviewed-by: Simon Horman <ho...@kernel.org>
>Co-developed-by: Jacob Keller <jacob.e.kel...@intel.com>
>Signed-off-by: Jacob Keller <jacob.e.kel...@intel.com>
>Signed-off-by: Maciej Fijalkowski <maciej.fijalkow...@intel.com>
>---
> drivers/net/ethernet/intel/ice/ice_txrx.c | 27 ++++++++++++++++++++++-
> 1 file changed, 26 insertions(+), 1 deletion(-)
>
Tested-by: Chandan Kumar Rout <chandanx.r...@intel.com> (A Contingent Worker at
Intel)
