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Re: [Qemu-devel] [PATCH v2 for-2.4 00/12] hw/net: Fix .can_receive() for
From: |
Stefan Hajnoczi |
Subject: |
Re: [Qemu-devel] [PATCH v2 for-2.4 00/12] hw/net: Fix .can_receive() for NICs |
Date: |
Mon, 20 Jul 2015 18:09:50 +0100 |
User-agent: |
Mutt/1.5.23 (2014-03-12) |
On Wed, Jul 15, 2015 at 06:19:01PM +0800, Fam Zheng wrote:
> v2: Don't use BH in patches 6 and 12. [Jason]
> Add Stefan's reviewed-by in all others.
> Drop trace point in patch 8 and move function body upward. [Michael]
>
> Since a90a742 "tap: Drop tap_can_send", all nics that returns false from
> .can_receive() are required to explicitly flush the incoming queue when the
> status of it is changing back to true, otherwise the backend will sop
> processing more rx packets.
>
> The purpose of this callback is to tell the peer backend (tap, socket, etc)
> "hold on until guest consumes old data because my buffer is not ready". More
> often than not NICs also do this when driver deactivated the card or disabled
> rx, causing the packets being unnessarily queued, where they should actualy be
> dropped.
>
> This series adds such missing qemu_flush_queued_packets calls for all NICs,
> and
> drops such unnecessary conditions in .can_receive(), so that NICs now:
>
> - return false from .can_receive when guest buffers are busy.
> - call qemu_flush_queued_packets when buffers are available again.
> - return -1 from .receive when rx is not enabled.
>
> e1000, ne2000, rocker and vmxnet3 are not included because they're fixed by
> other patches on the list and applied to Stefan's tree.
>
> virtio-net is covered by another series:
>
> https://lists.gnu.org/archive/html/qemu-devel/2015-06/msg07377.html ^U
>
> http://patchwork.ozlabs.org/patch/495379/ (the subject should have v2, my
> bad.)
>
> All other NICs are okay, as they already do the flush on the state transition
> points.
>
> Please review.
>
> Fam Zheng (12):
> xgmac: Drop packets with eth_can_rx is false.
> pcnet: Drop pcnet_can_receive
> eepro100: Drop nic_can_receive
> usbnet: Drop usbnet_can_receive
> etsec: Move etsec_can_receive into etsec_receive
> etsec: Flush queue when rx buffer is consumed
> mcf_fec: Drop mcf_fec_can_receive
> milkymist-minimac2: Flush queued packets when link comes up
> mipsnet: Flush queued packets when receiving is enabled
> stellaris_enet: Flush queued packets when read done
> dp8393x: Flush packets when link comes up
> axienet: Flush queued packets when rx is done
>
> hw/net/dp8393x.c | 8 ++++++++
> hw/net/eepro100.c | 11 -----------
> hw/net/fsl_etsec/etsec.c | 20 ++++++++++----------
> hw/net/fsl_etsec/etsec.h | 4 +++-
> hw/net/fsl_etsec/rings.c | 17 +++++++++++------
> hw/net/lance.c | 1 -
> hw/net/mcf_fec.c | 9 +--------
> hw/net/milkymist-minimac2.c | 33 ++++++++++++++++-----------------
> hw/net/mipsnet.c | 9 +++++++--
> hw/net/pcnet-pci.c | 1 -
> hw/net/pcnet.c | 9 ---------
> hw/net/pcnet.h | 1 -
> hw/net/stellaris_enet.c | 14 +++++---------
> hw/net/xgmac.c | 8 ++++----
> hw/net/xilinx_axienet.c | 17 +++++++++++++----
> hw/usb/dev-network.c | 20 ++++----------------
> trace-events | 1 -
> 17 files changed, 82 insertions(+), 101 deletions(-)
I can't merge this until net/hub.c is fixed. Anything that relies on
qemu_can_send_packet() will break if we drop .can_receive() functions.
At this point in the 2.4 release cycle I'm tempted to revert the
relevant qemu_set_fd_handler2() refactoring patches and stage this for
2.5 instead. That way we know networking works as before and we can
tackle all these fixups in 2.5.
pgp7KUbxkoMc2.pgp
Description: PGP signature
- [Qemu-devel] [PATCH v2 for-2.4 07/12] mcf_fec: Drop mcf_fec_can_receive, (continued)
- [Qemu-devel] [PATCH v2 for-2.4 07/12] mcf_fec: Drop mcf_fec_can_receive, Fam Zheng, 2015/07/15
- [Qemu-devel] [PATCH v2 for-2.4 09/12] mipsnet: Flush queued packets when receiving is enabled, Fam Zheng, 2015/07/15
- [Qemu-devel] [PATCH v2 for-2.4 08/12] milkymist-minimac2: Flush queued packets when link comes up, Fam Zheng, 2015/07/15
- [Qemu-devel] [PATCH v2 for-2.4 10/12] stellaris_enet: Flush queued packets when read done, Fam Zheng, 2015/07/15
- [Qemu-devel] [PATCH v2 for-2.4 11/12] dp8393x: Flush packets when link comes up, Fam Zheng, 2015/07/15
- [Qemu-devel] [PATCH v2 for-2.4 12/12] axienet: Flush queued packets when rx is done, Fam Zheng, 2015/07/15
- Re: [Qemu-devel] [PATCH v2 for-2.4 00/12] hw/net: Fix .can_receive() for NICs, Jason Wang, 2015/07/16
- Re: [Qemu-devel] [PATCH v2 for-2.4 00/12] hw/net: Fix .can_receive() for NICs,
Stefan Hajnoczi <=