Hariprasad Kelam says:
====================
Priority flow control support for RVU netdev
In network congestion, instead of pausing all traffic on link
PFC allows user to selectively pause traffic according to its
class. This series of patches add support of PFC for RVU netdev
drivers.
Patch1 adds support to disable pause frames by default as
with PFC user can enable either PFC or 802.3 pause frames.
Patch2&3 adds resource management support for flow control
and configures necessary registers for PFC.
Patch4 adds dcb ops registration for netdev drivers.
V2 changes:
Fix compilation error by exporting required symbols 'otx2_config_pause_frm'
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
Data centric bridging designed to eliminate packet loss due to
queue overflow by adding enhancements to ethernet network such as
proprity flow control etc. This patch adds support for management
of Priority flow control(PFC) on Octeontx2 and CN10K interfaces.
To enable PFC for all priorities
dcb pfc set dev eth0 prio-pfc all:on/off
To enable PFC on selected priorites
dcb pfc set dev eth0 prio-pfc 0:on/off 1:on/off ..7:on/off
With the ntuple commands user can map Priority to receive queues.
On queue overflow NIX will assert backpressure such that PFC pause frames
are genarated with mapped priority.
To map priority 7 to Queue 1
ethtool -U eth0 flow-type ether dst xx:xx:xx:xx:xx:xx vlan 0xe00a
m 0x1fff queue 1
Signed-off-by: Hariprasad Kelam <hkelam@marvell.com>
Signed-off-by: Sunil Kovvuri Goutham <sgoutham@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
CN10K MAC block (RPM) and Octeontx2 MAC block (CGX) both supports
PFC flow control and 802.3X flow control pause frames.
Each MAC block supports max 4 LMACS and AF driver assigns same
(MAC,LMAC) to PF and its VFs. As PF and its share same (MAC,LMAC)
pair we need resource management to address below scenarios
1. Maintain PFC and 8023X pause frames mutually exclusive.
2. Reject disable flow control request if other PF or Vfs
enabled it.
Signed-off-by: Hariprasad Kelam <hkelam@marvell.com>
Signed-off-by: Sunil Kovvuri Goutham <sgoutham@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Prirority based flow control (802.1Qbb) mechanism is similar to
ethernet pause frames (802.3x) instead pausing all traffic on a link,
PFC allows user to selectively pause traffic according to its class.
Oceteontx2 MAC block (CGX) and CN10K Mac block (RPM) both supports
PFC. As upper layer mbox handler is same for both the MACs, this
patch configures PFC by calling apporopritate callbacks.
Signed-off-by: Sunil Kumar Kori <skori@marvell.com>
Signed-off-by: Hariprasad Kelam <hkelam@marvell.com>
Signed-off-by: Sunil Kovvuri Goutham <sgoutham@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Current implementation is such that 802.3x pause frames are
enabled by default. As CGX and RPM blocks support PFC
(priority flow control) also, instead of driver enabling one
between them enable them upon request from PF or its VFs.
Also add support to disable pause frames in driver unbind.
Signed-off-by: Hariprasad Kelam <hkelam@marvell.com>
Signed-off-by: Sunil Kovvuri Goutham <sgoutham@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Jeremy Kerr says:
====================
MCTP tag control interface
This series implements a small interface for userspace-controlled
message tag allocation for the MCTP protocol. Rather than leaving the
kernel to allocate per-message tag values, userspace can explicitly
allocate (and release) message tags through two new ioctls:
SIOCMCTPALLOCTAG and SIOCMCTPDROPTAG.
In order to do this, we first introduce some minor changes to the tag
handling, including a couple of new tests for the route input paths.
As always, any comments/queries/etc are most welcome.
v2:
- make mctp_lookup_prealloc_tag static
- minor checkpatch formatting fixes
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
This change adds a couple of new ioctls for mctp sockets:
SIOCMCTPALLOCTAG and SIOCMCTPDROPTAG. These ioctls provide facilities
for explicit allocation / release of tags, overriding the automatic
allocate-on-send/release-on-reply and timeout behaviours. This allows
userspace more control over messages that may not fit a simple
request/response model.
In order to indicate a pre-allocated tag to the sendmsg() syscall, we
introduce a new flag to the struct sockaddr_mctp.smctp_tag value:
MCTP_TAG_PREALLOC.
Additional changes from Jeremy Kerr <jk@codeconstruct.com.au>.
Contains a fix that was:
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Matt Johnston <matt@codeconstruct.com.au>
Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
Currently, we require an exact match on an incoming packet's dest
address, and the key's local_addr field.
In a future change, we may want to set up a key before packets are
routed, meaning we have no local address to match on.
This change allows key lookups to match on local_addr = MCTP_ADDR_ANY.
Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
Currently, we have a couple of paths that check that an EID matches, or
the match value is MCTP_ADDR_ANY.
Rather than open coding this, add a little helper.
Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
This change adds a few more tests to check the key/tag lookups on route
input. We add a specific entry to the keys lists, route a packet with
specific header values, and check for key match/mismatch.
Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
This is a definition for the tag-owner flag, which has TO as a standard
abbreviation. We'll want to add a helper for the actual tag value in a
future change.
Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
-queue
Tony Nguyen says:
====================
40GbE Intel Wired LAN Driver Updates 2022-02-08
Joe Damato says:
This patch set makes several updates to the i40e driver stats collection
and reporting code to help users of i40e get a better sense of how the
driver is performing and interacting with the rest of the kernel.
These patches include some new stats (like waived and busy) which were
inspired by other drivers that track stats using the same nomenclature.
The new stats and an existing stat, rx_reuse, are now accessible with
ethtool to make harvesting this data more convenient for users.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
netvsc_device_remove() calls vunmap() inside which should not be
called in the interrupt context. Current code calls hv_unmap_memory()
in the free_netvsc_device() which is rcu callback and maybe called
in the interrupt context. This will trigger BUG_ON(in_interrupt())
in the vunmap(). Fix it via moving hv_unmap_memory() to netvsc_device_
remove().
Fixes: 846da38de0 ("net: netvsc: Add Isolation VM support for netvsc driver")
Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Tony Nguyen says:
====================
1GbE Intel Wired LAN Driver Updates 2022-02-07
Corinna Vinschen says:
Fix the kernel warning "Missing unregister, handled but fix driver"
when running, e.g.,
$ ethtool -G eth0 rx 1024
on igc. Remove memset hack from igb and align igb code to igc.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
Document Gigabit Ethernet IP found on RZ/G2UL SoC. Gigabit Ethernet
Interface is identical to one found on the RZ/G2L SoC. No driver changes
are required as generic compatible string "renesas,rzg2l-gbeth" will be
used as a fallback.
Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Document Gigabit Ethernet IP found on RZ/V2L SoC. Gigabit Ethernet
Interface is identical to one found on the RZ/G2L SoC. No driver changes
are required as generic compatible string "renesas,rzg2l-gbeth" will be
used as a fallback.
Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Acked-by: Rob Herring <robh@kernel.org>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: David S. Miller <davem@davemloft.net>
The default values for hooks in the driver.pm are NULLs.
Hence drop unused pch_pm_ops.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20220207210730.75252-6-andriy.shevchenko@linux.intel.com
Acked-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This makes the error handling much more simpler than open-coding everything
and in addition makes the probe function smaller an tidier.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20220207210730.75252-5-andriy.shevchenko@linux.intel.com
Acked-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Eliminate some boilerplate code by using module_pci_driver() instead of
init/exit, and, if needed, moving the salient bits from init into probe.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20220207210730.75252-4-andriy.shevchenko@linux.intel.com
Acked-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
There is already helper functions to do 64-bit I/O on 32-bit machines or
buses, thus we don't need to reinvent the wheel.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20220207210730.75252-3-andriy.shevchenko@linux.intel.com
Acked-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
There is already helper functions to do 64-bit I/O on 32-bit machines or
buses, thus we don't need to reinvent the wheel.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20220207210730.75252-2-andriy.shevchenko@linux.intel.com
Acked-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
For some reason default_device_ops kept two exit method:
1) default_device_exit() is called for each netns being dismantled in
a cleanup_net() round. This acquires rtnl for each invocation.
2) default_device_exit_batch() is called once with the list of all netns
int the batch, allowing for a single rtnl invocation.
Get rid of the .exit() method to handle the logic from
default_device_exit_batch(), to decrease the number of rtnl acquisition
to one.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
cleanup_net() is competing with other rtnl users.
Batching bond_net_exit() factorizes all rtnl acquistions
to a single one, giving chance for cleanup_net()
to progress much faster, holding rtnl a bit longer.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Jay Vosburgh <j.vosburgh@gmail.com>
Cc: Veaceslav Falico <vfalico@gmail.com>
Cc: Andy Gospodarek <andy@greyhouse.net>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
cleanup_net() is competing with other rtnl users.
Avoiding to acquire rtnl for each netns before calling
cgw_remove_all_jobs() gives chance for cleanup_net()
to progress much faster, holding rtnl a bit longer.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Oliver Hartkopp <socketcan@hartkopp.net>
Acked-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
cleanup_net() is competing with other rtnl users.
Avoiding to acquire rtnl for each netns before calling
ipmr_rules_exit() gives chance for cleanup_net()
to progress much faster, holding rtnl a bit longer.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
cleanup_net() is competing with other rtnl users.
Avoiding to acquire rtnl for each netns before calling
ip6mr_rules_exit() gives chance for cleanup_net()
to progress much faster, holding rtnl a bit longer.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
cleanup_net() is competing with other rtnl users.
fib6_rules_net_exit() seems a good candidate for exit_batch(),
as this gives chance for cleanup_net() to progress much faster,
holding rtnl a bit longer.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
cleanup_net() is competing with other rtnl users.
Instead of acquiring rtnl at each fib_net_exit() invocation,
add fib_net_exit_batch() so that rtnl is acquired once.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
cleanup_net() is competing with other rtnl users.
nexthop_net_exit() seems a good candidate for exit_batch(),
as this gives chance for cleanup_net() to progress much faster,
holding rtnl a bit longer.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
IPv6 does not scale very well with the number of IPv6 addresses.
It uses a global (shared by all netns) hash table with 256 buckets.
Some functions like addrconf_verify_rtnl() and addrconf_ifdown()
have to iterate all addresses in the hash table.
I have seen addrconf_verify_rtnl() holding the cpu for 10ms or more.
Switch to the per netns hashtable (and spinlock) added
in prior patches.
This considerably speeds up netns dismantle times on hosts
with thousands of netns. This also has an impact
on regular (fast path) IPv6 processing.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Next step for using per netns inet6_addr_lst
is to have per netns work item to ultimately
call addrconf_verify_rtnl() and addrconf_verify()
with a new 'struct net*' argument.
Everything is still using the global inet6_addr_lst[] table.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Add a per netns hash table and a dedicated spinlock,
first step to get rid of the global inet6_addr_lst[] one.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Convert one dev_hold()/dev_put() pair in register_netdevice()
and unregister_netdevice_many() to dev_hold_track()
and dev_put_track().
This would allow to detect a rogue dev_put() a bit earlier.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/20220207184107.1401096-1-eric.dumazet@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
In some cases, pages cannot be reused by i40e because the page is busy. Add
a counter for this event.
Busy page count is accessible via ethtool.
Signed-off-by: Joe Damato <jdamato@fastly.com>
Tested-by: Dave Switzer <david.switzer@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
In some cases, pages can not be reused because they are not associated with
the correct NUMA zone. Knowing how often pages are waived helps users to
understand the interaction between the driver's memory usage and their
system.
Pass rx_stats through to i40e_can_reuse_rx_page to allow tracking when
pages are waived.
The page waive count is accessible via ethtool.
Signed-off-by: Joe Damato <jdamato@fastly.com>
Tested-by: Dave Switzer <david.switzer@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
Add a counter for new page allocations in the i40e RX path. This stat is
accessible with ethtool.
Signed-off-by: Joe Damato <jdamato@fastly.com>
Tested-by: Dave Switzer <david.switzer@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
rx page reuse was already being tracked by the i40e driver per RX ring.
Aggregate the counts and make them accessible via ethtool.
Signed-off-by: Joe Damato <jdamato@fastly.com>
Tested-by: Dave Switzer <david.switzer@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
Page reuse was being tracked from two locations:
- i40e_reuse_rx_page (via 40e_clean_rx_irq), and
- i40e_alloc_mapped_page
Remove the double count and only count reuse from i40e_alloc_mapped_page
when the page is about to be reused.
Signed-off-by: Joe Damato <jdamato@fastly.com>
Tested-by: Dave Switzer <david.switzer@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
Guillaume Nault says:
====================
inet: Separate DSCP from ECN bits using new dscp_t type
The networking stack currently doesn't clearly distinguish between DSCP
and ECN bits. The entire DSCP+ECN bits are stored in u8 variables (or
structure fields), and each part of the stack handles them in their own
way, using different macros. This has created several bugs in the past
and some uncommon code paths are still unfixed.
Such bugs generally manifest by selecting invalid routes because of ECN
bits interfering with FIB routes and rules lookups (more details in the
LPC 2021 talk[1] and in the RFC of this series[2]).
This patch series aims at preventing the introduction of such bugs (and
detecting existing ones), by introducing a dscp_t type, representing
"sanitised" DSCP values (that is, with no ECN information), as opposed
to plain u8 values that contain both DSCP and ECN information. dscp_t
makes it clear for the reader what we're working on, and Sparse can
flag invalid interactions between dscp_t and plain u8.
This series converts only a few variables and structures:
* Patch 1 converts the tclass field of struct fib6_rule. It
effectively forbids the use of ECN bits in the tos/dsfield option
of ip -6 rule. Rules now match packets solely based on their DSCP
bits, so ECN doesn't influence the result any more. This contrasts
with the previous behaviour where all 8 bits of the Traffic Class
field were used. It is believed that this change is acceptable as
matching ECN bits wasn't usable for IPv4, so only IPv6-only
deployments could be depending on it. Also the previous behaviour
made DSCP-based ip6-rules fail for packets with both a DSCP and an
ECN mark, which is another reason why any such deploy is unlikely.
* Patch 2 converts the tos field of struct fib4_rule. This one too
effectively forbids defining ECN bits, this time in ip -4 rule.
Before that, setting ECN bit 1 was accepted, while ECN bit 0 was
rejected. But even when accepted, the rule would never match, as
the packets would have their ECN bits cleared before doing the
rule lookup.
* Patch 3 converts the fc_tos field of struct fib_config. This is
equivalent to patch 2, but for IPv4 routes. Routes using a
tos/dsfield option with any ECN bit set is now rejected. Before
this patch, they were accepted but, as with ip4 rules, these routes
couldn't match any packet, since their ECN bits are cleared before
the lookup.
* Patch 4 converts the fa_tos field of struct fib_alias. This one is
pure internal u8 to dscp_t conversion. While patches 1-3 had user
facing consequences, this patch shouldn't have any side effect and
is there to give an overview of what future conversion patches will
look like. Conversions are quite mechanical, but imply some code
churn, which is the price for the extra clarity a possibility of
type checking.
To summarise, all the behaviour changes required for the dscp_t type
approach to work should be contained in patches 1-3. These changes are
edge cases of ip-route and ip-rule that don't currently work properly.
So they should be safe. Also, a kernel selftest is added for each of
them.
Finally, this work also paves the way for allowing the usage of the 3
high order DSCP bits in IPv4 (a few call paths already handle them, but
in general the stack clears them before IPv4 rule and route lookups).
References:
[1] LPC 2021 talk:
- https://linuxplumbersconf.org/event/11/contributions/943/
- Direct link to slide deck:
https://linuxplumbersconf.org/event/11/contributions/943/attachments/901/1780/inet_tos_lpc2021.pdf
[2] RFC version of this series:
- https://lore.kernel.org/netdev/cover.1638814614.git.gnault@redhat.com/
====================
Link: https://lore.kernel.org/r/cover.1643981839.git.gnault@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Use the new dscp_t type to replace the fa_tos field of fib_alias. This
ensures ECN bits are ignored and makes the field compatible with the
fc_dscp field of struct fib_config.
Converting old *tos variables and fields to dscp_t allows sparse to
flag incorrect uses of DSCP and ECN bits. This patch is entirely about
type annotation and shouldn't change any existing behaviour.
Signed-off-by: Guillaume Nault <gnault@redhat.com>
Acked-by: David Ahern <dsahern@kernel.org>
Reviewed-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Use the new dscp_t type to replace the fc_tos field of fib_config, to
ensure IPv4 routes aren't influenced by ECN bits when configured with
non-zero rtm_tos.
Before this patch, IPv4 routes specifying an rtm_tos with some of the
ECN bits set were accepted. However they wouldn't work (never match) as
IPv4 normally clears the ECN bits with IPTOS_RT_MASK before doing a FIB
lookup (although a few buggy code paths don't).
After this patch, IPv4 routes specifying an rtm_tos with any ECN bit
set is rejected.
Note: IPv6 routes ignore rtm_tos altogether, any rtm_tos is accepted,
but treated as if it were 0.
Signed-off-by: Guillaume Nault <gnault@redhat.com>
Acked-by: David Ahern <dsahern@kernel.org>
Reviewed-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Use the new dscp_t type to replace the tos field of struct fib4_rule,
so that fib4-rules consistently ignore ECN bits.
Before this patch, fib4-rules did accept rules with the high order ECN
bit set (but not the low order one). Also, it relied on its callers
masking the ECN bits of ->flowi4_tos to prevent those from influencing
the result. This was brittle and a few call paths still do the lookup
without masking the ECN bits first.
After this patch fib4-rules only compare the DSCP bits. ECN can't
influence the result anymore, even if the caller didn't mask these
bits. Also, fib4-rules now must have both ECN bits cleared or they will
be rejected.
Signed-off-by: Guillaume Nault <gnault@redhat.com>
Acked-by: David Ahern <dsahern@kernel.org>
Reviewed-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Define a dscp_t type and its appropriate helpers that ensure ECN bits
are not taken into account when handling DSCP.
Use this new type to replace the tclass field of struct fib6_rule, so
that fib6-rules don't get influenced by ECN bits anymore.
Before this patch, fib6-rules didn't make any distinction between the
DSCP and ECN bits. Therefore, rules specifying a DSCP (tos or dsfield
options in iproute2) stopped working as soon a packets had at least one
of its ECN bits set (as a work around one could create four rules for
each DSCP value to match, one for each possible ECN value).
After this patch fib6-rules only compare the DSCP bits. ECN doesn't
influence the result anymore. Also, fib6-rules now must have the ECN
bits cleared or they will be rejected.
Signed-off-by: Guillaume Nault <gnault@redhat.com>
Acked-by: David Ahern <dsahern@kernel.org>
Reviewed-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Reading the PTP clock is a simple operation requiring only 3 register
reads. Under a PREEMPT_RT kernel, protecting those reads by a spin_lock is
counter-productive: if the 2nd task preempting the 1st has a higher prio
but needs to read time as well, it will require 2 context switches, which
will pretty much always be more costly than just disabling preemption for
the duration of the reads. Moreover, with the code logic recently added
to get_systime(), disabling preemption is not even required anymore:
reads and writes just need to be protected from each other, to prevent a
clock read while the clock is being updated.
Improve the above situation by replacing the PTP spinlock by a rwlock, and
using read_lock for PTP clock reads so simultaneous reads do not block
each other.
Signed-off-by: Yannick Vignon <yannick.vignon@nxp.com>
Link: https://lore.kernel.org/r/20220204135545.2770625-1-yannick.vignon@oss.nxp.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
