From: Maxim Mikityanskiy <maximmi@mellanox.com>
To: Maciej Fijalkowski <maciej.fijalkowski@intel.com>, daniel@iogearbox.net
Cc: ast@kernel.org, netdev@vger.kernel.org, bpf@vger.kernel.org,
bjorn.topel@intel.com, magnus.karlsson@intel.com
Subject: Re: [PATCH bpf 0/3] XSK related fixes
Date: Thu, 6 Feb 2020 15:58:17 +0200 [thread overview]
Message-ID: <d843052f-e0a5-7a8c-da65-7cb15c274483@mellanox.com> (raw)
In-Reply-To: <20200205045834.56795-1-maciej.fijalkowski@intel.com>
On 2020-02-05 06:58, Maciej Fijalkowski wrote:
> Cameron reported [0] that on fresh bpf-next he could not run multiple
> xdpsock instances in Tx-only mode on single network interface with i40e
> driver.
>
> Turns out that Maxim's series [1] which was adding RCU protection around
> ndo_xsk_wakeup added check against the __I40E_CONFIG_BUSY being set on
> pf->state within i40e_xsk_wakeup() - if it's set, return -ENETDOWN.
> Since this bit is set per PF when UMEM is being enabled/disabled, the
> situation Cameron stumbled upon was that when he launched second xdpsock
> instance, second UMEM was being registered, hence set __I40E_CONFIG_BUSY
> which is now observed by first xdpsock and therefore xdpsock's kick_tx()
> gets -ENETDOWN as errno.
>
> -ENETDOWN currently is not allowed in kick_tx(), so we were exiting the
> first application. Such exit means also XDP program being unloaded and
> its dedicated resources, which caused an -ENXIO being return in the
> second xdpsock instance.
>
> Let's fix the issue from both sides - protect ourselves from future
> xdpsock crashes by allowing for -ENETDOWN errno being set in kick_tx()
> (patch 3) and from driver side, return -EAGAIN for the case where PF is
> busy (patch 1).
>
> Remove also doubled variable from xdpsock_user.c (patch 2).
>
> Note that ixgbe seems not to be affected since UMEM registration sets
> the busy/disable bit per ring, not per PF.
>
> Thanks!
> Maciej
>
> [0]: https://www.spinics.net/lists/xdp-newbies/msg01558.html
> [1]: https://lore.kernel.org/netdev/20191217162023.16011-1-maximmi@mellanox.com/
>
> Maciej Fijalkowski (3):
> i40e: Relax i40e_xsk_wakeup's return value when PF is busy
> samples: bpf: drop doubled variable declaration in xdpsock
> samples: bpf: allow for -ENETDOWN in xdpsock
>
> drivers/net/ethernet/intel/i40e/i40e_xsk.c | 2 +-
> samples/bpf/xdpsock_user.c | 4 ++--
> 2 files changed, 3 insertions(+), 3 deletions(-)
>
Acked-by: Maxim Mikityanskiy <maximmi@mellanox.com>
Though it's already merged (that was too fast).
prev parent reply other threads:[~2020-02-06 13:58 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-05 4:58 [PATCH bpf 0/3] XSK related fixes Maciej Fijalkowski
2020-02-05 4:58 ` [PATCH bpf 1/3] i40e: Relax i40e_xsk_wakeup's return value when PF is busy Maciej Fijalkowski
2020-02-05 4:58 ` [PATCH bpf 2/3] samples: bpf: drop doubled variable declaration in xdpsock Maciej Fijalkowski
2020-02-05 4:58 ` [PATCH bpf 3/3] samples: bpf: allow for -ENETDOWN " Maciej Fijalkowski
2020-02-05 21:21 ` [PATCH bpf 0/3] XSK related fixes Daniel Borkmann
2020-02-06 13:58 ` Maxim Mikityanskiy [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=d843052f-e0a5-7a8c-da65-7cb15c274483@mellanox.com \
--to=maximmi@mellanox.com \
--cc=ast@kernel.org \
--cc=bjorn.topel@intel.com \
--cc=bpf@vger.kernel.org \
--cc=daniel@iogearbox.net \
--cc=maciej.fijalkowski@intel.com \
--cc=magnus.karlsson@intel.com \
--cc=netdev@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).