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David S. Miller 72d61d3009 Merge branch 'mlxsw-Support-dcbnl_setbuffer-dcbnl_getbuffer'
Ido Schimmel says:

====================
mlxsw: Support dcbnl_setbuffer, dcbnl_getbuffer

Petr says:

On Spectrum, port buffers, also called port headroom, is where packets are
stored while they are parsed and the forwarding decision is being made. For
lossless traffic flows, in case shared buffer admission is not allowed,
headroom is also where to put the extra traffic received before the sent
PAUSE takes effect.

Linux supports two DCB interfaces related to the headroom: dcbnl_setbuffer
for configuration, and dcbnl_getbuffer for inspection. This patch set
implements them.

With dcbnl_setbuffer in place, there will be two sources of authority over
the ingress configuration: the DCB ETS hook, because ETS configuration is
mirrored to ingress, and the DCB setbuffer hook. mlxsw is in a similar
situation on the egress side, where there are two sources of the ETS
configuration: the DCB ETS hook, and the TC qdisc hooks. This is a
non-intuitive situation, because the way the ASIC ends up being configured
depends not only on the actual configured bits, but also on the order in
which they were configured.

To prevent these issues on the ingress side, two configuration modes will
exist: DCB mode and TC mode. DCB ETS will keep getting projected to ingress
in the (default) DCB mode. When a qdisc is installed on a port, it will be
switched to the TC mode, the ingress configuration will be done through the
dcbnl_setbuffer callback. The reason is that the dcbnl_setbuffer hook is
not standardized and supported by lldpad. Projecting DCB ETS configuration
to ingress is a reasonable heuristic to configure ingress especially when
PFC is in effect.

In patch #1, the toggle between the DCB and TC modes of headroom
configuration, described above, is introduced.

Patch #2 implements dcbnl_getbuffer and dcbnl_setbuffer. dcbnl_getbuffer
can be always used to determine the current port headroom configuration.
dcbnl_setbuffer is only permitted in the TC mode.

In patch #3, make the qdisc module toggle the headroom mode from DCB to TC
and back, depending on whether there is an offloaded qdisc on the port.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>
2020-09-17 17:01:38 -07:00
arch s390/cio: Helper functions to read CSSID, IID, and CHID 2020-09-15 13:21:46 -07:00
block block-5.9-2020-09-04 2020-09-04 13:04:51 -07:00
certs .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
crypto Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2020-08-30 15:53:44 -07:00
Documentation dt-bindings: marvell,prestera: Add description for device-tree bindings 2020-09-17 16:35:47 -07:00
drivers mlxsw: spectrum_qdisc: Disable port buffer autoresize with qdiscs 2020-09-17 17:01:38 -07:00
fs Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-09-04 21:28:59 -07:00
include netdev: Remove unused functions 2020-09-17 16:51:33 -07:00
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lib Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-09-04 21:28:59 -07:00
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mm Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-09-04 21:28:59 -07:00
net netlink: add spaces around '&' in netlink_recv/sendmsg() 2020-09-17 16:53:47 -07:00
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sound sound fixes for 5.9-rc4 2020-09-04 12:05:25 -07:00
tools selftests: mptcp: interpret \n as a new line 2020-09-17 16:26:09 -07:00
usr Merge branch 'work.fdpic' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-08-07 13:29:39 -07:00
virt * PAE and PKU bugfixes for x86 2020-08-22 10:03:05 -07:00
.clang-format block: add bio_for_each_bvec_all() 2020-05-25 11:25:24 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
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.gitignore .gitignore: Add ZSTD-compressed files 2020-07-31 11:50:49 +02:00
.mailmap Merge branch 'akpm' (patches from Andrew) 2020-08-21 14:44:48 -07:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Add Krzysztof Kozlowski to Samsung S3FWRN5 and remove Robert 2020-09-10 15:22:16 -07:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS MAINTAINERS: Add Krzysztof Kozlowski to Samsung S3FWRN5 and remove Robert 2020-09-10 15:22:16 -07:00
Makefile Linux 5.9-rc3 2020-08-30 16:01:54 -07:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.