kernel-doc is reporting some warnings, so fix them:
% scripts/kernel-doc -Wall -Werror -none include/net/mac80211.h
include/net/mac80211.h:2056: warning: No description found for return value of 'wdev_to_ieee80211_vif'
include/net/mac80211.h:2066: warning: No description found for return value of 'ieee80211_vif_to_wdev'
include/net/mac80211.h:5603: warning: No description found for return value of 'ieee80211_beacon_cntdwn_is_complete'
include/net/mac80211.h:5968: warning: No description found for return value of 'ieee80211_gtk_rekey_add'
include/net/mac80211.h:6350: warning: No description found for return value of 'ieee80211_find_sta_by_link_addrs'
include/net/mac80211.h:6478: warning: No description found for return value of 'ieee80211_txq_airtime_check'
include/net/mac80211.h:6981: warning: No description found for return value of 'rate_control_set_rates'
include/net/mac80211.h:7142: warning: No description found for return value of 'ieee80211_tx_prepare_skb'
include/net/mac80211.h:7156: warning: No description found for return value of 'ieee80211_parse_tx_radiotap'
include/net/mac80211.h:7277: warning: No description found for return value of 'ieee80211_tx_dequeue'
include/net/mac80211.h:7292: warning: No description found for return value of 'ieee80211_tx_dequeue_ni'
include/net/mac80211.h:7324: warning: No description found for return value of 'ieee80211_next_txq'
include/net/mac80211.h:7405: warning: No description found for return value of 'ieee80211_txq_may_transmit'
include/net/mac80211.h:7466: warning: No description found for return value of 'ieee80211_calc_rx_airtime'
include/net/mac80211.h:7480: warning: No description found for return value of 'ieee80211_calc_tx_airtime'
include/net/mac80211.h:7528: warning: No description found for return value of 'ieee80211_is_tx_data'
include/net/mac80211.h:7562: warning: No description found for return value of 'ieee80211_set_active_links'
17 warnings as Errors
Signed-off-by: Jeff Johnson <quic_jjohnson@quicinc.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Tested-by: Randy Dunlap <rdunlap@infradead.org>
Link: https://msgid.link/20240329-mac80211-kdoc-retval-v1-2-5e4d1ad6c250@quicinc.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Kalle Valo says:
====================
wireless-next patches for v6.10
The first "new features" pull request for v6.10 with changes both in
stack and in drivers. The big thing in this pull request is that
wireless subsystem is now almost free of sparse warnings. There's only
one warning left in ath11k which was introduced in v6.9-rc1 and will
be fixed via the wireless tree.
Realtek drivers continue to improve, now we have support for RTL8922AE
and RTL8723CS devices. ath11k also has long waited support for P2P.
This time we have a small conflict in iwlwifi, Stephen has an example
merge resolution which should help with fixing the conflict:
https://lore.kernel.org/all/20240326100945.765b8caf@canb.auug.org.au/
Major changes:
rtw89
* RTL8922AE Wi-Fi 7 PCI device support
rtw88
* RTL8723CS SDIO device support
iwlwifi
* don't support puncturing in 5 GHz
* support monitor mode on passive channels
* BZ-W device support
* P2P with HE/EHT support
ath11k
* P2P support for QCA6390, WCN6855 and QCA2066
* tag 'wireless-next-2024-04-03' of git://git.kernel.org/pub/scm/linux/kernel/git/wireless/wireless-next: (122 commits)
wifi: mt76: mt7915: workaround dubious x | !y warning
wifi: mwl8k: Avoid -Wflex-array-member-not-at-end warnings
wifi: ti: Avoid a hundred -Wflex-array-member-not-at-end warnings
wifi: iwlwifi: mvm: fix check in iwl_mvm_sta_fw_id_mask
net: rfkill: gpio: Convert to platform remove callback returning void
wifi: mac80211: use kvcalloc() for codel vars
wifi: iwlwifi: reconfigure TLC during HW restart
wifi: iwlwifi: mvm: don't change BA sessions during restart
wifi: iwlwifi: mvm: select STA mask only for active links
wifi: iwlwifi: mvm: set wider BW OFDMA ignore correctly
wifi: iwlwifi: Add support for LARI_CONFIG_CHANGE_CMD cmd v9
wifi: iwlwifi: mvm: Declare HE/EHT capabilities support for P2P interfaces
wifi: iwlwifi: mvm: Remove outdated comment
wifi: iwlwifi: add support for BZ_W
wifi: iwlwifi: Print a specific device name.
wifi: iwlwifi: remove wrong CRF_IDs
wifi: iwlwifi: remove devices that never came out
wifi: iwlwifi: mvm: mark EMLSR disabled in cleanup iterator
wifi: iwlwifi: mvm: fix active link counting during recovery
wifi: iwlwifi: mvm: assign link STA ID lookups during restart
...
====================
Link: https://lore.kernel.org/r/20240403093625.CF515C433C7@smtp.kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Some PHYs can recognize during a cable test if the impedance in the cable
is okay. They can detect reflections caused by impedance discontinuity
between a regular 100 Ohm cable and an abnormal part with a higher or
lower impedance.
This commit introduces a new result code:
ETHTOOL_A_CABLE_RESULT_CODE_IMPEDANCE_MISMATCH,
which represents the results of a cable test indicating issues with
impedance integrity.
Signed-off-by: Pawel Dembicki <paweldembicki@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://lore.kernel.org/r/20240402201123.2961909-2-paweldembicki@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
In the previous GC implementation, the shape of the inflight socket
graph was not expected to change while GC was in progress.
MSG_PEEK was tricky because it could install inflight fd silently
and transform the graph.
Let's say we peeked a fd, which was a listening socket, and accept()ed
some embryo sockets from it. The garbage collection algorithm would
have been confused because the set of sockets visited in scan_inflight()
would change within the same GC invocation.
That's why we placed spin_lock(&unix_gc_lock) and spin_unlock() in
unix_peek_fds() with a fat comment.
In the new GC implementation, we no longer garbage-collect the socket
if it exists in another queue, that is, if it has a bridge to another
SCC. Also, accept() will require the lock if it has edges.
Thus, we need not do the complicated lock dance.
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://lore.kernel.org/r/20240401173125.92184-3-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Prior to this patch, what we can see by enabling trace_tcp_send is
only happening under two circumstances:
1) active rst mode
2) non-active rst mode and based on the full socket
That means the inconsistency occurs if we use tcpdump and trace
simultaneously to see how rst happens.
It's necessary that we should take into other cases into considerations,
say:
1) time-wait socket
2) no socket
...
By parsing the incoming skb and reversing its 4-tuple can
we know the exact 'flow' which might not exist.
Samples after applied this patch:
1. tcp_send_reset: skbaddr=XXX skaddr=XXX src=ip:port dest=ip:port
state=TCP_ESTABLISHED
2. tcp_send_reset: skbaddr=000...000 skaddr=XXX src=ip:port dest=ip:port
state=UNKNOWN
Note:
1) UNKNOWN means we cannot extract the right information from skb.
2) skbaddr/skaddr could be 0
Signed-off-by: Jason Xing <kernelxing@tencent.com>
Link: https://lore.kernel.org/r/20240401073605.37335-3-kerneljasonxing@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
For short netdev holds within a function there are still a lot of
users of dev_put() rather than netdev_put(). Add DEFINE_FREE() to
allow making those safer.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
The new guard/scoped_gard can be useful for the RTNL as well,
so add a guard definition for it. It gets used like
{
guard(rtnl)();
// RTNL held until end of block
}
or
scoped_guard(rtnl) {
// RTNL held in this block
}
as with any other guard/scoped_guard.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Since we have pool->p.napi (Jakub) and pool->cpuid (Lorenzo) to check
whether it's safe to use direct recycling, we can use both globally for
each page instead of relying solely on @allow_direct argument.
Let's assume that @allow_direct means "I'm sure it's local, don't waste
time rechecking this" and when it's false, try the mentioned params to
still recycle the page directly. If neither is true, we'll lose some
CPU cycles, but then it surely won't be hotpath. On the other hand,
paths where it's possible to use direct cache, but not possible to
safely set @allow_direct, will benefit from this move.
The whole propagation of @napi_safe through a dozen of skb freeing
functions can now go away, which saves us some stack space.
Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com>
Link: https://lore.kernel.org/r/20240329165507.3240110-2-aleksander.lobakin@intel.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
genetlink.h is a shell of what used to be a combined uAPI
and kernel header over a decade ago. It has fewer than
10 lines of code. Merge it into net/genetlink.h.
In some ways it'd be better to keep the combined header
under linux/ but it would make looking through git history
harder.
Acked-by: Sven Eckelmann <sven@narfation.org>
Link: https://lore.kernel.org/r/20240329175710.291749-4-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
There are things in linux/genetlink.h which are only used
under net/netlink/. Move them to a new local header.
A new header with just 2 externs isn't great, but alternative
would be to include af_netlink.h in genetlink.c which feels
even worse.
Link: https://lore.kernel.org/r/20240329175710.291749-2-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Commit 14d898f3c1 ("dev: Move received_rps counter next
to RPS members in softnet data") was unfortunate:
received_rps is dirtied by a cpu and never read by other
cpus in fast path.
Its presence in the hot RPS cache line (shared by many cpus)
is hurting RPS/RFS performance.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
process_backlog() can batch increments of sd->input_queue_head,
saving some memory bandwidth.
Also add READ_ONCE()/WRITE_ONCE() annotations around
sd->input_queue_head accesses.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
input_queue_tail_incr_save() is incrementing the sd queue_tail
and save it in the flow last_qtail.
Two issues here :
- no lock protects the write on last_qtail, we should use appropriate
annotations.
- We can perform this write after releasing the per-cpu backlog lock,
to decrease this lock hold duration (move away the cache line miss)
Also move input_queue_head_incr() and rps helpers to include/net/rps.h,
while adding rps_ prefix to better reflect their role.
v2: Fixed a build issue (Jakub and kernel build bots)
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
If under extreme cpu backlog pressure enqueue_to_backlog() has
to drop a packet, it could do this without dirtying a cache line
and potentially slowing down the target cpu.
Move sd->dropped into a separate cache line, and make it atomic.
In non pressure mode, this field is not touched, no need to consume
valuable space in a hot cache line.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Move dev_xmit_recursion() and friends to net/core/dev.h
They are only used from net/core/dev.c and net/core/filter.c.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
kick_defer_list_purge() is defined in net/core/dev.c
and used from net/core/skubff.c
Because we need softnet_data, include <linux/netdevice.h>
from net/core/dev.h
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Packet Forwarding Control Protocol (PFCP) is a 3GPP Protocol
used between the control plane and the user plane function.
It is specified in TS 29.244[1].
Note that this module is not designed to support this Protocol
in the kernel space. There is no support for parsing any PFCP messages.
There is no API that could be used by any userspace daemon.
Basically it does not support PFCP. This protocol is sophisticated
and there is no need for implementing it in the kernel. The purpose
of this module is to allow users to setup software and hardware offload
of PFCP packets using tc tool.
When user requests to create a PFCP device, a new socket is created.
The socket is set up with port number 8805 which is specific for
PFCP [29.244 4.2.2]. This allow to receive PFCP request messages,
response messages use other ports.
Note that only one PFCP netdev can be created.
Only IPv4 is supported at this time.
[1] https://portal.3gpp.org/desktopmodules/Specifications/SpecificationDetails.aspx?specificationId=3111
Signed-off-by: Wojciech Drewek <wojciech.drewek@intel.com>
Signed-off-by: Marcin Szycik <marcin.szycik@linux.intel.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Historically, tunnel flags like TUNNEL_CSUM or TUNNEL_ERSPAN_OPT
have been defined as __be16. Now all of those 16 bits are occupied
and there's no more free space for new flags.
It can't be simply switched to a bigger container with no
adjustments to the values, since it's an explicit Endian storage,
and on LE systems (__be16)0x0001 equals to
(__be64)0x0001000000000000.
We could probably define new 64-bit flags depending on the
Endianness, i.e. (__be64)0x0001 on BE and (__be64)0x00010000... on
LE, but that would introduce an Endianness dependency and spawn a
ton of Sparse warnings. To mitigate them, all of those places which
were adjusted with this change would be touched anyway, so why not
define stuff properly if there's no choice.
Define IP_TUNNEL_*_BIT counterparts as a bit number instead of the
value already coded and a fistful of <16 <-> bitmap> converters and
helpers. The two flags which have a different bit position are
SIT_ISATAP_BIT and VTI_ISVTI_BIT, as they were defined not as
__cpu_to_be16(), but as (__force __be16), i.e. had different
positions on LE and BE. Now they both have strongly defined places.
Change all __be16 fields which were used to store those flags, to
IP_TUNNEL_DECLARE_FLAGS() -> DECLARE_BITMAP(__IP_TUNNEL_FLAG_NUM) ->
unsigned long[1] for now, and replace all TUNNEL_* occurrences to
their bitmap counterparts. Use the converters in the places which talk
to the userspace, hardware (NFP) or other hosts (GRE header). The rest
must explicitly use the new flags only. This must be done at once,
otherwise there will be too many conversions throughout the code in
the intermediate commits.
Finally, disable the old __be16 flags for use in the kernel code
(except for the two 'irregular' flags mentioned above), to prevent
any accidental (mis)use of them. For the userspace, nothing is
changed, only additions were made.
Most noticeable bloat-o-meter difference (.text):
vmlinux: 307/-1 (306)
gre.ko: 62/0 (62)
ip_gre.ko: 941/-217 (724) [*]
ip_tunnel.ko: 390/-900 (-510) [**]
ip_vti.ko: 138/0 (138)
ip6_gre.ko: 534/-18 (516) [*]
ip6_tunnel.ko: 118/-10 (108)
[*] gre_flags_to_tnl_flags() grew, but still is inlined
[**] ip_tunnel_find() got uninlined, hence such decrease
The average code size increase in non-extreme case is 100-200 bytes
per module, mostly due to sizeof(long) > sizeof(__be16), as
%__IP_TUNNEL_FLAG_NUM is less than %BITS_PER_LONG and the compilers
are able to expand the majority of bitmap_*() calls here into direct
operations on scalars.
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Unlike IPv6 tunnels which use purely-kernel __ip6_tnl_parm structure
to store params inside the kernel, IPv4 tunnel code uses the same
ip_tunnel_parm which is being used to talk with the userspace.
This makes it difficult to alter or add any fields or use a
different format for whatever data.
Define struct ip_tunnel_parm_kern, a 1:1 copy of ip_tunnel_parm for
now, and use it throughout the code. Define the pieces, where the copy
user <-> kernel happens, as standalone functions, and copy the data
there field-by-field, so that the kernel-side structure could be easily
modified later on and the users wouldn't have to care about this.
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Now that we have generic bitmap_read() and bitmap_write(), which are
inline and try to take care of non-bound-crossing and aligned cases
to keep them optimized, collapse bitmap_{get,set}_value8() into
simple wrappers around the former ones.
bloat-o-meter shows no difference in vmlinux and -2 bytes for
gpio-pca953x.ko, which says the optimization didn't suffer due to
that change. The converted helpers have the value width embedded
and always compile-time constant and that helps a lot.
Suggested-by: Yury Norov <yury.norov@gmail.com>
Signed-off-by: Yury Norov <yury.norov@gmail.com>
Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The number of times yet another open coded
`BITS_TO_LONGS(nbits) * sizeof(long)` can be spotted is huge.
Some generic helper is long overdue.
Add one, bitmap_size(), but with one detail.
BITS_TO_LONGS() uses DIV_ROUND_UP(). The latter works well when both
divident and divisor are compile-time constants or when the divisor
is not a pow-of-2. When it is however, the compilers sometimes tend
to generate suboptimal code (GCC 13):
48 83 c0 3f add $0x3f,%rax
48 c1 e8 06 shr $0x6,%rax
48 8d 14 c5 00 00 00 00 lea 0x0(,%rax,8),%rdx
%BITS_PER_LONG is always a pow-2 (either 32 or 64), but GCC still does
full division of `nbits + 63` by it and then multiplication by 8.
Instead of BITS_TO_LONGS(), use ALIGN() and then divide by 8. GCC:
8d 50 3f lea 0x3f(%rax),%edx
c1 ea 03 shr $0x3,%edx
81 e2 f8 ff ff 1f and $0x1ffffff8,%edx
Now it shifts `nbits + 63` by 3 positions (IOW performs fast division
by 8) and then masks bits[2:0]. bloat-o-meter:
add/remove: 0/0 grow/shrink: 20/133 up/down: 156/-773 (-617)
Clang does it better and generates the same code before/after starting
from -O1, except that with the ALIGN() approach it uses %edx and thus
still saves some bytes:
add/remove: 0/0 grow/shrink: 9/133 up/down: 18/-538 (-520)
Note that we can't expand DIV_ROUND_UP() by adding a check and using
this approach there, as it's used in array declarations where
expressions are not allowed.
Add this helper to tools/ as well.
Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@intel.com>
Acked-by: Yury Norov <yury.norov@gmail.com>
Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Since commit b03fc1173c ("bitops: let optimize out non-atomic bitops
on compile-time constants"), the non-atomic bitops are macros which can
be expanded by the compilers into compile-time expressions, which will
result in better optimized object code. Unfortunately, turned out that
passing `volatile` to those macros discards any possibility of
optimization, as the compilers then don't even try to look whether
the passed bitmap is known at compilation time. In addition to that,
the mentioned linkmode helpers are marked with `inline`, not
`__always_inline`, meaning that it's not guaranteed some compiler won't
uninline them for no reason, which will also effectively prevent them
from being optimized (it's a well-known thing the compilers sometimes
uninline `2 + 2`).
Convert linkmode_*_bit() from inlines to macros. Their calling
convention are 1:1 with the corresponding bitops, so that it's not even
needed to enumerate and map the arguments, only the names. No changes in
vmlinux' object code (compiled by LLVM for x86_64) whatsoever, but that
doesn't necessarily means the change is meaningless.
Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@intel.com>
Acked-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Yury Norov <yury.norov@gmail.com>
Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Since commit b03fc1173c ("bitops: let optimize out non-atomic bitops
on compile-time constants"), the compilers are able to expand inline
bitmap operations to compile-time initializers when possible.
However, during the round of replacement if-__set-else-__clear with
__assign_bit() as per Andy's advice, bloat-o-meter showed +1024 bytes
difference in object code size for one module (even one function),
where the pattern:
DECLARE_BITMAP(foo) = { }; // on the stack, zeroed
if (a)
__set_bit(const_bit_num, foo);
if (b)
__set_bit(another_const_bit_num, foo);
...
is heavily used, although there should be no difference: the bitmap is
zeroed, so the second half of __assign_bit() should be compiled-out as
a no-op.
I either missed the fact that __assign_bit() has bitmap pointer marked
as `volatile` (as we usually do for bitops) or was hoping that the
compilers would at least try to look past the `volatile` for
__always_inline functions. Anyhow, due to that attribute, the compilers
were always compiling the whole expression and no mentioned compile-time
optimizations were working.
Convert __assign_bit() to a macro since it's a very simple if-else and
all of the checks are performed inside __set_bit() and __clear_bit(),
thus that wrapper has to be as transparent as possible. After that
change, despite it showing only -20 bytes change for vmlinux (due to
that it's still relatively unpopular), no drastic code size changes
happen when replacing if-set-else-clear for onstack bitmaps with
__assign_bit(), meaning the compiler now expands them to the actual
operations will all the expected optimizations.
Atomic assign_bit() is less affected due to its nature, but let's
convert it to a macro as well to keep the code consistent and not
leave a place for possible suboptimal codegen. Moreover, with certain
kernel configuration it actually gives some saves (x86):
do_ip_setsockopt 4154 4099 -55
Suggested-by: Yury Norov <yury.norov@gmail.com> # assign_bit(), too
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@intel.com>
Acked-by: Yury Norov <yury.norov@gmail.com>
Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Avoid open-coding that simple expression each time by moving
BYTES_TO_BITS() from the probes code to <linux/bitops.h> to export
it to the rest of the kernel.
Simplify the macro while at it. `BITS_PER_LONG / sizeof(long)` always
equals to %BITS_PER_BYTE, regardless of the target architecture.
Do the same for the tools ecosystem as well (incl. its version of
bitops.h). The previous implementation had its implicit type of long,
while the new one is int, so adjust the format literal accordingly in
the perf code.
Suggested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@intel.com>
Acked-by: Yury Norov <yury.norov@gmail.com>
Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Commit 8238b45798 ("wait_on_bit: add an acquire memory barrier") added
a new bitop, test_bit_acquire(), with proper wrapping in order to try to
optimize it at compile-time, but missed the list of bitops used for
checking their prototypes a bit below.
The functions added have consistent prototypes, so that no more changes
are required and no functional changes take place.
Fixes: 8238b45798 ("wait_on_bit: add an acquire memory barrier")
Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@intel.com>
Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
There are, especially with multi-attr arrays, many cases
of needing to iterate all attributes of a specific type
in a netlink message or a nested attribute. Add specific
macros to support that case.
Also convert many instances using this spatch:
@@
iterator nla_for_each_attr;
iterator name nla_for_each_attr_type;
identifier nla;
expression head, len, rem;
expression ATTR;
type T;
identifier x;
@@
-nla_for_each_attr(nla, head, len, rem)
+nla_for_each_attr_type(nla, ATTR, head, len, rem)
{
<... T x; ...>
-if (nla_type(nla) == ATTR) {
...
-}
}
@@
identifier nla;
iterator nla_for_each_nested;
iterator name nla_for_each_nested_type;
expression attr, rem;
expression ATTR;
type T;
identifier x;
@@
-nla_for_each_nested(nla, attr, rem)
+nla_for_each_nested_type(nla, ATTR, attr, rem)
{
<... T x; ...>
-if (nla_type(nla) == ATTR) {
...
-}
}
@@
iterator nla_for_each_attr;
iterator name nla_for_each_attr_type;
identifier nla;
expression head, len, rem;
expression ATTR;
type T;
identifier x;
@@
-nla_for_each_attr(nla, head, len, rem)
+nla_for_each_attr_type(nla, ATTR, head, len, rem)
{
<... T x; ...>
-if (nla_type(nla) != ATTR) continue;
...
}
@@
identifier nla;
iterator nla_for_each_nested;
iterator name nla_for_each_nested_type;
expression attr, rem;
expression ATTR;
type T;
identifier x;
@@
-nla_for_each_nested(nla, attr, rem)
+nla_for_each_nested_type(nla, ATTR, attr, rem)
{
<... T x; ...>
-if (nla_type(nla) != ATTR) continue;
...
}
Although I had to undo one bad change this made, and
I also adjusted some other code for whitespace and to
use direct variable initialization now.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Link: https://lore.kernel.org/r/20240328203144.b5a6c895fb80.I1869b44767379f204998ff44dd239803f39c23e0@changeid
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
While looking at UDP receive performance, I saw sk_wake_async()
was no longer inlined.
This matters at least on AMD Zen1-4 platforms (see SRSO)
This might be because rcu_read_lock() and rcu_read_unlock()
are no longer nops in recent kernels ?
Add sk_wake_async_rcu() variant, which must be called from
contexts already holding rcu lock.
As SOCK_FASYNC is deprecated in modern days, use unlikely()
to give a hint to the compiler.
sk_wake_async_rcu() is properly inlined from
__udp_enqueue_schedule_skb() and sock_def_readable().
Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/20240328144032.1864988-5-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
The definition of the lowlink in Tarjan's algorithm is the
smallest index of a vertex that is reachable with at most one
back-edge in SCC. This is not useful for a cross-edge.
If we start traversing from A in the following graph, the final
lowlink of D is 3. The cross-edge here is one between D and C.
A -> B -> D D = (4, 3) (index, lowlink)
^ | | C = (3, 1)
| V | B = (2, 1)
`--- C <--' A = (1, 1)
This is because the lowlink of D is updated with the index of C.
In the following patch, we detect a dead SCC by checking two
conditions for each vertex.
1) vertex has no edge directed to another SCC (no bridge)
2) vertex's out_degree is the same as the refcount of its file
If 1) is false, there is a receiver of all fds of the SCC and
its ancestor SCC.
To evaluate 1), we need to assign a unique index to each SCC and
assign it to all vertices in the SCC.
This patch changes the lowlink update logic for cross-edge so
that in the example above, the lowlink of D is updated with the
lowlink of C.
A -> B -> D D = (4, 1) (index, lowlink)
^ | | C = (3, 1)
| V | B = (2, 1)
`--- C <--' A = (1, 1)
Then, all vertices in the same SCC have the same lowlink, and we
can quickly find the bridge connecting to different SCC if exists.
However, it is no longer called lowlink, so we rename it to
scc_index. (It's sometimes called lowpoint.)
Also, we add a global variable to hold the last index used in DFS
so that we do not reset the initial index in each DFS.
This patch can be squashed to the SCC detection patch but is
split deliberately for anyone wondering why lowlink is not used
as used in the original Tarjan's algorithm and many reference
implementations.
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Acked-by: Paolo Abeni <pabeni@redhat.com>
Link: https://lore.kernel.org/r/20240325202425.60930-13-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Before starting Tarjan's algorithm, we need to mark all vertices
as unvisited. We can save this O(n) setup by reserving two special
indices (0, 1) and using two variables.
The first time we link a vertex to unix_unvisited_vertices, we set
unix_vertex_unvisited_index to index.
During DFS, we can see that the index of unvisited vertices is the
same as unix_vertex_unvisited_index.
When we finalise SCC later, we set unix_vertex_grouped_index to each
vertex's index.
Then, we can know (i) that the vertex is on the stack if the index
of a visited vertex is >= 2 and (ii) that it is not on the stack and
belongs to a different SCC if the index is unix_vertex_grouped_index.
After the whole algorithm, all indices of vertices are set as
unix_vertex_grouped_index.
Next time we start DFS, we know that all unvisited vertices have
unix_vertex_grouped_index, and we can use unix_vertex_unvisited_index
as the not-on-stack marker.
To use the same variable in __unix_walk_scc(), we can swap
unix_vertex_(grouped|unvisited)_index at the end of Tarjan's
algorithm.
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Acked-by: Paolo Abeni <pabeni@redhat.com>
Link: https://lore.kernel.org/r/20240325202425.60930-10-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
To garbage collect inflight AF_UNIX sockets, we must define the
cyclic reference appropriately. This is a bit tricky if the loop
consists of embryo sockets.
Suppose that the fd of AF_UNIX socket A is passed to D and the fd B
to C and that C and D are embryo sockets of A and B, respectively.
It may appear that there are two separate graphs, A (-> D) and
B (-> C), but this is not correct.
A --. .-- B
X
C <-' `-> D
Now, D holds A's refcount, and C has B's refcount, so unix_release()
will never be called for A and B when we close() them. However, no
one can call close() for D and C to free skbs holding refcounts of A
and B because C/D is in A/B's receive queue, which should have been
purged by unix_release() for A and B.
So, here's another type of cyclic reference. When a fd of an AF_UNIX
socket is passed to an embryo socket, the reference is indirectly held
by its parent listening socket.
.-> A .-> B
| `- sk_receive_queue | `- sk_receive_queue
| `- skb | `- skb
| `- sk == C | `- sk == D
| `- sk_receive_queue | `- sk_receive_queue
| `- skb +---------' `- skb +-.
| |
`---------------------------------------------------------'
Technically, the graph must be denoted as A <-> B instead of A (-> D)
and B (-> C) to find such a cyclic reference without touching each
socket's receive queue.
.-> A --. .-- B <-.
| X | == A <-> B
`-- C <-' `-> D --'
We apply this fixup during GC by fetching the real successor by
unix_edge_successor().
When we call accept(), we clear unix_sock.listener under unix_gc_lock
not to confuse GC.
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Acked-by: Paolo Abeni <pabeni@redhat.com>
Link: https://lore.kernel.org/r/20240325202425.60930-9-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This is a prep patch for the following change, where we need to
fetch the listening socket from the successor embryo socket
during GC.
We add a new field to struct unix_sock to save a pointer to a
listening socket.
We set it when connect() creates a new socket, and clear it when
accept() is called.
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Acked-by: Paolo Abeni <pabeni@redhat.com>
Link: https://lore.kernel.org/r/20240325202425.60930-8-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
In the new GC, we use a simple graph algorithm, Tarjan's Strongly
Connected Components (SCC) algorithm, to find cyclic references.
The algorithm visits every vertex exactly once using depth-first
search (DFS).
DFS starts by pushing an input vertex to a stack and assigning it
a unique number. Two fields, index and lowlink, are initialised
with the number, but lowlink could be updated later during DFS.
If a vertex has an edge to an unvisited inflight vertex, we visit
it and do the same processing. So, we will have vertices in the
stack in the order they appear and number them consecutively in
the same order.
If a vertex has a back-edge to a visited vertex in the stack,
we update the predecessor's lowlink with the successor's index.
After iterating edges from the vertex, we check if its index
equals its lowlink.
If the lowlink is different from the index, it shows there was a
back-edge. Then, we go backtracking and propagate the lowlink to
its predecessor and resume the previous edge iteration from the
next edge.
If the lowlink is the same as the index, we pop vertices before
and including the vertex from the stack. Then, the set of vertices
is SCC, possibly forming a cycle. At the same time, we move the
vertices to unix_visited_vertices.
When we finish the algorithm, all vertices in each SCC will be
linked via unix_vertex.scc_entry.
Let's take an example. We have a graph including five inflight
vertices (F is not inflight):
A -> B -> C -> D -> E (-> F)
^ |
`---------'
Suppose that we start DFS from C. We will visit C, D, and B first
and initialise their index and lowlink. Then, the stack looks like
this:
> B = (3, 3) (index, lowlink)
D = (2, 2)
C = (1, 1)
When checking B's edge to C, we update B's lowlink with C's index
and propagate it to D.
B = (3, 1) (index, lowlink)
> D = (2, 1)
C = (1, 1)
Next, we visit E, which has no edge to an inflight vertex.
> E = (4, 4) (index, lowlink)
B = (3, 1)
D = (2, 1)
C = (1, 1)
When we leave from E, its index and lowlink are the same, so we
pop E from the stack as single-vertex SCC. Next, we leave from
B and D but do nothing because their lowlink are different from
their index.
B = (3, 1) (index, lowlink)
D = (2, 1)
> C = (1, 1)
Then, we leave from C, whose index and lowlink are the same, so
we pop B, D and C as SCC.
Last, we do DFS for the rest of vertices, A, which is also a
single-vertex SCC.
Finally, each unix_vertex.scc_entry is linked as follows:
A -. B -> C -> D E -.
^ | ^ | ^ |
`--' `---------' `--'
We use SCC later to decide whether we can garbage-collect the
sockets.
Note that we still cannot detect SCC properly if an edge points
to an embryo socket. The following two patches will sort it out.
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Acked-by: Paolo Abeni <pabeni@redhat.com>
Link: https://lore.kernel.org/r/20240325202425.60930-7-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
The new GC will use a depth first search graph algorithm to find
cyclic references. The algorithm visits every vertex exactly once.
Here, we implement the DFS part without recursion so that no one
can abuse it.
unix_walk_scc() marks every vertex unvisited by initialising index
as UNIX_VERTEX_INDEX_UNVISITED and iterates inflight vertices in
unix_unvisited_vertices and call __unix_walk_scc() to start DFS from
an arbitrary vertex.
__unix_walk_scc() iterates all edges starting from the vertex and
explores the neighbour vertices with DFS using edge_stack.
After visiting all neighbours, __unix_walk_scc() moves the visited
vertex to unix_visited_vertices so that unix_walk_scc() will not
restart DFS from the visited vertex.
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Acked-by: Paolo Abeni <pabeni@redhat.com>
Link: https://lore.kernel.org/r/20240325202425.60930-6-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
