Clang static analysis reports this representative problem
dpaa2-switch-flower.c:616:24: warning: The right operand of '=='
is a garbage value
tmp->cfg.vlan_id == vlan) {
^ ~~~~
vlan is set in dpaa2_switch_flower_parse_mirror_key(). However
this function can return success without setting vlan. So
change the default return to -EOPNOTSUPP.
Fixes: 0f3faece58 ("dpaa2-switch: add VLAN based mirroring")
Signed-off-by: Tom Rix <trix@redhat.com>
Reviewed-by: Ioana Ciornei <ioana.ciornei@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
When multiple containers are running in the environment and multiple
macvlan network port are configured in each container, a lot of martian
source prints will appear after martian_log is enabled. they are almost
the same, and printed by net_warn_ratelimited. Each arp message will
trigger this print on each network port.
Such as:
IPv4: martian source 173.254.95.16 from 173.254.100.109,
on dev eth0
ll header: 00000000: ff ff ff ff ff ff 40 00 ad fe 64 6d
08 06 ......@...dm..
IPv4: martian source 173.254.95.16 from 173.254.100.109,
on dev eth1
ll header: 00000000: ff ff ff ff ff ff 40 00 ad fe 64 6d
08 06 ......@...dm..
There is no description of this kind of source in the RFC1812.
Signed-off-by: Zhang Yunkai <zhang.yunkai@zte.com.cn>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch fixes the checkpatch.pl warning:
ERROR: code indent should use tabs where possible #3453: FILE: drivers/net/virtio_net.c:3453: ret = register_virtio_driver(&virtio_net_driver);$
Uneccessary newline was also removed making line 3453 now 3452.
Signed-off-by: Michael Catanzaro <mcatanzaro.kernel@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Stefan Schmidt says:
====================
Only a single fix this time.
Miquel Raynal fixed the lifs/sifs periods in the ca82010 to take the actual
symbol duration time into account.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
The function mt7531_phy_mode_supported in the DSA driver set supported
mode to PHY_INTERFACE_MODE_GMII instead of PHY_INTERFACE_MODE_INTERNAL
for the internal PHY, so this check breaks the PHY initialization:
mt7530 mdio-bus:00 wan (uninitialized): failed to connect to PHY: -EINVAL
Remove the check to make it work again.
Reported-by: Hauke Mehrtens <hauke@hauke-m.de>
Fixes: e40d2cca01 ("net: phy: add MediaTek Gigabit Ethernet PHY driver")
Signed-off-by: DENG Qingfang <dqfext@gmail.com>
Acked-by: Arınç ÜNAL <arinc.unal@arinc9.com>
Tested-by: Hauke Mehrtens <hauke@hauke-m.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
Saeed Mahameed says:
====================
mlx5-updates-2022-02-14
mlx5 TX routines improvements
1) From Aya and Tariq, first 3 patches, Use the Max size of the TX descriptor
as advertised by the device and not the fixed value of 16 that the driver
always assumed, this is not a bug fix as all existing devices have Max value
larger than 16, but the series is necessary for future proofing the driver.
2) TX Synchronization improvements from Maxim, last 12 patches
Maxim Mikityanskiy Says:
=======================
mlx5e: Synchronize ndo_select_queue with configuration changes
The kernel can call ndo_select_queue at any time, and there is no direct
way to block it. The implementation of ndo_select_queue in mlx5e expects
the parameters to be consistent and may crash (invalid pointer, division
by zero) if they aren't.
There were attempts to partially fix some of the most frequent crashes,
see commit 846d6da1fc ("net/mlx5e: Fix division by 0 in
mlx5e_select_queue") and commit 84c8a87402 ("net/mlx5e: Fix division
by 0 in mlx5e_select_queue for representors"). However, they don't
address the issue completely.
This series introduces the proper synchronization mechanism between
mlx5e configuration and TX data path:
1. txq2sq updates are synchronized properly with ndo_start_xmit
(mlx5e_xmit). The TX queue is stopped when it configuration is being
updated, and memory barriers ensure the changes are visible before
restarting.
2. The set of parameters needed for mlx5e_select_queue is reduced, and
synchronization using RCU is implemented. This way, changes are
atomic, and the state in mlx5e_select_queue is always consistent.
3. A few optimizations are applied to the new implementation of
mlx5e_select_queue.
=======================
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
Check all booleans for special queues at once, when deciding whether to
go to the fast path in mlx5e_select_queue. Pack them into bitfields to
have some room for extensibility.
Signed-off-by: Maxim Mikityanskiy <maximmi@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
To improve the performance of the modulo operation (%), it's replaced by
a subtracting the divisor in a loop. The modulo is used to fix up an
out-of-bounds value that might be returned by netdev_pick_tx or to
convert the queue number to the channel number when num_tcs > 1. Both
situations are unlikely, because XPS is configured not to pick higher
queues (qid >= num_channels) by default, so under normal circumstances
the flow won't go inside the loop, and it will be faster than %.
num_tcs == 8 adds at most 7 iterations to the loop. PTP adds at most 1
iteration to the loop. HTB would add at most 256 iterations (when
num_channels == 1), so there is an additional boundary check in the HTB
flow, which falls back to % if more than 7 iterations are expected.
Signed-off-by: Maxim Mikityanskiy <maximmi@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
This commit optimizes mlx5e_select_queue for HTB and PTP cases by
short-cutting some checks, without sacrificing performance of the common
non-HTB non-PTP flow.
1. The HTB flow uses the fact that num_tcs == 1 to drop these checks
(it's not possible to attach both mqprio and htb as the root qdisc).
It's also enough to calculate `txq_ix % num_channels` only once, instead
of twice.
2. The PTP flow drops the check for HTB and the second calculation of
`txq_ix % num_channels`.
Signed-off-by: Maxim Mikityanskiy <maximmi@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
trust_state can be written while mlx5e_select_queue() is reading it. To
avoid inconsistencies, use READ_ONCE and WRITE_ONCE for access and
updates, and touch the variable only once per operation.
Signed-off-by: Maxim Mikityanskiy <maximmi@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
Both mlx5e_select_queue and mlx5e_select_ptpsq contain the same logic to
get user priority of a packet, according to the current trust state
settings. This commit moves this repeating code to its own function.
Signed-off-by: Maxim Mikityanskiy <maximmi@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
Start using the select queue parameters introduced in the previous
commit to have proper synchronization with changing the configuration
(such as number of channels and queues). It ensures that the state that
mlx5e_select_queue() sees is always consistent and stays the same while
the function is running. Also it allows mlx5e_select_queue to stop using
data structures that weren't synchronized properly: txq2sq,
channel_tc2realtxq, port_ptp_tc2realtxq. The last two are removed
completely, as they were used only in mlx5e_select_queue.
Signed-off-by: Maxim Mikityanskiy <maximmi@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
This commit moves mlx5e_select_queue and all stuff related to
ndo_select_queue to en/selq.c to put all stuff working with selq into a
separate file.
Signed-off-by: Maxim Mikityanskiy <maximmi@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
ndo_select_queue can be called at any time, and there is no way to stop
the kernel from calling it to synchronize with configuration changes
(real_num_tx_queues, num_tc). This commit introduces an internal way in
mlx5e to sync mlx5e_select_queue() with these changes. The configuration
needed by this function is stored in a struct mlx5e_selq_params, which
is modified and accessed in an atomic way using RCU methods. The whole
ndo_select_queue is called under an RCU lock, providing the necessary
guarantees.
The parameters stored in the new struct mlx5e_selq_params should only be
used from inside mlx5e_select_queue. It's the minimal set of parameters
needed for mlx5e_select_queue to do its job efficiently, derived from
parameters stored elsewhere. That means that when the configuration
change, mlx5e_selq_params may need to be updated. In such cases, the
mlx5e_selq_prepare/mlx5e_selq_apply API should be used.
struct mlx5e_selq contains two slots for the params: active and standby.
mlx5e_selq_prepare updates the standby slot, and mlx5e_selq_apply swaps
the slots in a safe atomic way using the RCU API. It integrates well
with the open/activate stages of the configuration change flow.
Signed-off-by: Maxim Mikityanskiy <maximmi@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
This commit makes necessary changes to guarantee that txq2sq remains
stable while mlx5e_xmit is running. Proper synchronization is added for
HTB TX queues.
All updates to txq2sq are performed while the corresponding queue is
disabled (i.e. mlx5e_xmit doesn't run on that queue). smp_wmb after each
change guarantees that mlx5e_xmit can see the updated value after the
queue is enabled. Comments explaining this mechanism are added to
mlx5e_xmit.
When an HTB SQ can be deleted (after deleting an HTB node), synchronize
with RCU to wait for mlx5e_select_queue to finish and stop selecting
that queue, before we re-enable it to avoid TX timeout watchdog alarms.
Signed-off-by: Maxim Mikityanskiy <maximmi@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
mlx5e_build_txq_maps updates txq2sq while TX queues are stopped. Add a
barrier to ensure that these changes are visible before the queues are
started and mlx5e_xmit reads from txq2sq.
This commit handles regular TX queues. Synchronization between HTB TX
queues and mlx5e_xmit is handled in the following commit.
Signed-off-by: Maxim Mikityanskiy <maximmi@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
Normally, the queues are disabled when the channels are deactivated, and
enabled when the channels are activated. However, on register, the
channels are not active, but the queues are enabled by default. This
change fixes it, preventing mlx5e_xmit from running when the channels
are deactivated in the beginning.
Signed-off-by: Maxim Mikityanskiy <maximmi@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
mlx5e_activate_priv_channels() and mlx5e_deactivate_priv_channels()
start and stop all netdev TX queues. This commit removes the unneeded
call to netif_tx_stop_all_queues and adds explanatory comments why these
operations are needed.
netif_tx_disable() does the same thing that netif_tx_stop_all_queues(),
but taking the TX lock, thus guaranteeing that ndo_start_xmit is not
running after return. That means that the netif_tx_stop_all_queues()
call is not really necessary.
The comments are improved: the TX watchdog timeout explanation is moved
to the start stage where it really belongs (it used to be in both
places, but was lost during some old refactoring) and rephrased in more
details; the explanation for stopping all TX queues is added.
Signed-off-by: Maxim Mikityanskiy <maximmi@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
Calculate maximal count of MPW WQEBBs on SQ's creation and store it
there. Remove MLX5E_TX_MPW_MAX_NUM_DS and MLX5E_TX_MPW_MAX_WQEBBS.
Update mlx5e_tx_mpwqe_is_full() and mlx5e_xdp_mpqwe_is_full() .
Signed-off-by: Aya Levin <ayal@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
Prior to this patch the maximal value for max WQEBBs (WQE Basic Blocks,
where WQE is a Work Queue Element) on the TX side was assumed to be 16
(fixed value). All firmware versions till today comply to this. In order
to be more flexible and resilient, read from FW the corresponding:
max_wqe_sz_sq. This value describes the maximum WQE size given in bytes,
thus max WQEBBs is given by the division in WQEBB's byte size. The
driver uses the top between 16 and the division result. This ensures
synchronization between driver and firmware and avoids unexpected
behavior. Store this value on the different SQs (Send Queues) for easy
access.
Signed-off-by: Aya Levin <ayal@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
Remove tstamp pointer in mlx5e_txqsq as it's no longer used after
commit 7c39afb394 ("net/mlx5: PTP code migration to driver core section").
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
Reviewed-by: Aya Levin <ayal@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
When a link comes up we add its presence to the name table to make it
possible for users to subscribe for link up/down events. However, after
a previous call signature change the binding is wrongly published with
the peer node as publishing node, instead of the own node as it should
be. This has the effect that the command 'tipc name table show' will
list the link binding (service type 2) with node scope and a peer node
as originator, something that obviously is impossible.
We correct this bug here.
Fixes: 50a3499ab8 ("tipc: simplify signature of tipc_namtbl_publish()")
Signed-off-by: Jon Maloy <jmaloy@redhat.com>
Link: https://lore.kernel.org/r/20220214013852.2803940-1-jmaloy@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
These chips have 8 built-in FE PHYs and 3 SERDES interfaces that can
run at 1G. With the blamed commit, the built-in PHYs could no longer
be connected to, using an MII PHY interface mode.
Create a separate .phylink_get_caps callback for these chips, which
takes the FE/GE split into consideration.
Fixes: 2ee84cfefb ("net: dsa: mv88e6xxx: convert to phylink_generic_validate()")
Signed-off-by: Tobias Waldekranz <tobias@waldekranz.com>
Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Link: https://lore.kernel.org/r/20220213185154.3262207-1-tobias@waldekranz.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Pull regulator fix from Mark Brown:
"One fix here, for initialisation of regulators that don't have an
in_enabled() operation which would mainly impact cases where they
aren't otherwise used during early setup for some reason"
* tag 'regulator-fix-v5.17-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/regulator:
regulator: core: fix false positive in regulator_late_cleanup()
On newer AMD platforms with SFH, it is observed that random interrupts
get generated on the SFH hardware and until this is cleared the firmware
sensor processing is stalled, resulting in no data been received to
driver side.
Add routines to handle these interrupts, so that firmware operations are
not stalled.
Signed-off-by: Basavaraj Natikar <Basavaraj.Natikar@amd.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Newer AMD platforms with SFH may generate interrupts on some events
which are unwarranted. Until this is cleared the actual MP2 data
processing maybe stalled in some cases.
Add a mechanism to clear the pending interrupts (if any) during the
driver initialization and sensor command operations.
Signed-off-by: Basavaraj Natikar <Basavaraj.Natikar@amd.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Sensor data is processed in polling mode. Hence disable the interrupt
for all sensor command.
Signed-off-by: Basavaraj Natikar <Basavaraj.Natikar@amd.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Misinterpreted intr_enable field name. Hence correct the structure
field name accordingly to reflect the functionality.
Fixes: f264481ad6 ("HID: amd_sfh: Extend driver capabilities for multi-generation support")
Signed-off-by: Basavaraj Natikar <Basavaraj.Natikar@amd.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Since in the current amd_sfh design the sensor data is periodically
obtained in the form of poll data, during the suspend/resume cycle,
scheduling a delayed work adds no value.
So, cancel the work and restart back during the suspend/resume cycle
respectively.
Signed-off-by: Basavaraj Natikar <Basavaraj.Natikar@amd.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
I'm leaving NVIDIA and my email account will stop working in a week, update
it with my personal account.
Signed-off-by: Nikolay Aleksandrov <nikolay@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
There is a spelling mistake in an error message. Fix it.
Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add support of rule offloading added to the non-zero index chain,
which was previously forbidden. Also, goto action is offloaded
allowing to jump for processing of desired chain.
Note that only implicit chain 0 is bound to the device port(s) for
processing. The rest of chains have to be jumped by actions.
Signed-off-by: Volodymyr Mytnyk <vmytnyk@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
M Chetan Kumar says:
====================
net: wwan: debugfs dev reference not dropped
This patch series contains WWAN subsystem & IOSM Driver changes to
drop dev reference obtained as part of wwan debugfs dir entry retrieval.
PATCH1: A new debugfs interface is introduced in wwan subsystem so
that wwan driver can drop the obtained dev reference post debugfs use.
PATCH2: IOSM Driver uses new debugfs interface to drop dev reference.
Please refer to commit messages for details.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
WWAN driver call's wwan_get_debugfs_dir() to obtain
WWAN debugfs dir entry. As part of this procedure it
returns a reference to a found device.
Since there is no debugfs interface available at WWAN
subsystem, it is not possible to drop dev reference post
debugfs use. This leads to side effects like post wwan
driver load and reload the wwan instance gets increment
from wwanX to wwanX+1.
A new debugfs interface is added in wwan subsystem so that
wwan driver can drop the obtained dev reference post debugfs
use.
void wwan_put_debugfs_dir(struct dentry *dir)
Signed-off-by: M Chetan Kumar <m.chetan.kumar@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Luiz Angelo Daros de Luca says:
====================
net: dsa: realtek: realtek-mdio: reset before setup
This patch series cleans the realtek-smi reset code and copy that to the
realtek-mdio.
v1-v2)
- do not run reset code block if GPIO is missing. It was printing "RESET
deasserted" even when there is no GPIO configured.
- reset switch after dsa_unregister_switch()
- demote reset messages to debug
v2-v3)
- do not assert the reset on gpiod_get. Do it explicitly aferwards.
- split the commit into two (one for each module)
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
When reset GPIO was missing, the driver was still printing an info
message and still trying to assert the reset. Although gpiod_set_value()
will silently ignore calls with NULL gpio_desc, it is better to make it
clear the driver might allow gpio_desc to be NULL.
The initial value for the reset pin was changed to GPIOD_OUT_LOW,
followed by a gpiod_set_value() asserting the reset. This way, it will
be easier to spot if and where the reset really happens.
A new "asserted RESET" message was added just after the reset is
asserted, similar to the existing "deasserted RESET" message. Both
messages were demoted to dbg. The code comment is not needed anymore.
Signed-off-by: Luiz Angelo Daros de Luca <luizluca@gmail.com>
Acked-by: Arınç ÜNAL <arinc.unal@arinc9.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Whenever rt6_uncached_list_flush_dev() swaps rt->rt6_idev
to the blackhole device, parts of IPv6 stack might still need
to increment one SNMP counter.
Root cause, patch from Ido, changelog from Eric :)
This bug suggests that we need to audit rt->rt6_idev usages
and make sure they are properly using RCU protection.
Fixes: e5f80fcf86 ("ipv6: give an IPv6 dev to blackhole_netdev")
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Fixes return value documentation of kernel_getsockname()
and kernel_getpeername() functions.
The previous documentation wrongly specified that the return
value is 0 in case of success, however sock->ops->getname returns
the length of the address in bytes in case of success.
Signed-off-by: Alex Maydanik <alexander.maydanik@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Sebastian Andrzej Siewior says:
====================
net: dev: PREEMPT_RT fixups.
this series removes or replaces preempt_disable() and local_irq_save()
sections which are problematic on PREEMPT_RT.
Patch 2 makes netif_rx() work from any context after I found suggestions
for it in an old thread. Should that work, then the context-specific
variants could be removed.
v2…v3:
- #2
- Export __netif_rx() so it can be used by everyone.
- Add a lockdep assert to check for interrupt context.
- Update the kernel doc and mention that the skb is posted to
backlog NAPI.
- Use __netif_rx() also in drivers/net/*.c.
- Added Toke''s review tag and kept Eric's desptite the changes
made.
v1…v2:
- #1 and #2
- merge patch 1 und 2 from the series (as per Toke).
- updated patch description and corrected the first commit number (as
per Eric).
- #2
- Provide netif_rx() as in v1 and additionally __netif_rx() without
local_bh disable()+enable() for the loopback driver. __netif_rx() is
not exported (loopback is built-in only) so it won't be used
drivers. If this doesn't work then we can still export/ define a
wrapper as Eric suggested.
- Added a comment that netif_rx() considered legacy.
- #3
- Moved ____napi_schedule() into rps_ipi_queued() and
renamed it napi_schedule_rps().
https://lore.kernel.org/all/20220204201259.1095226-1-bigeasy@linutronix.de/
v1:
https://lore.kernel.org/all/20220202122848.647635-1-bigeasy@linutronix.de
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
Disabling interrupts and in the RPS case locking input_pkt_queue is
split into local_irq_disable() and optional spin_lock().
This breaks on PREEMPT_RT because the spinlock_t typed lock can not be
acquired with disabled interrupts.
The sections in which the lock is acquired is usually short in a sense that it
is not causing long und unbounded latiencies. One exception is the
skb_flow_limit() invocation which may invoke a BPF program (and may
require sleeping locks).
By moving local_irq_disable() + spin_lock() into rps_lock(), we can keep
interrupts disabled on !PREEMPT_RT and enabled on PREEMPT_RT kernels.
Without RPS on a PREEMPT_RT kernel, the needed synchronisation happens
as part of local_bh_disable() on the local CPU.
____napi_schedule() is only invoked if sd is from the local CPU. Replace
it with __napi_schedule_irqoff() which already disables interrupts on
PREEMPT_RT as needed. Move this call to rps_ipi_queued() and rename the
function to napi_schedule_rps as suggested by Jakub.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Dave suggested a while ago (eleven years by now) "Let's make netif_rx()
work in all contexts and get rid of netif_rx_ni()". Eric agreed and
pointed out that modern devices should use netif_receive_skb() to avoid
the overhead.
In the meantime someone added another variant, netif_rx_any_context(),
which behaves as suggested.
netif_rx() must be invoked with disabled bottom halves to ensure that
pending softirqs, which were raised within the function, are handled.
netif_rx_ni() can be invoked only from process context (bottom halves
must be enabled) because the function handles pending softirqs without
checking if bottom halves were disabled or not.
netif_rx_any_context() invokes on the former functions by checking
in_interrupts().
netif_rx() could be taught to handle both cases (disabled and enabled
bottom halves) by simply disabling bottom halves while invoking
netif_rx_internal(). The local_bh_enable() invocation will then invoke
pending softirqs only if the BH-disable counter drops to zero.
Eric is concerned about the overhead of BH-disable+enable especially in
regard to the loopback driver. As critical as this driver is, it will
receive a shortcut to avoid the additional overhead which is not needed.
Add a local_bh_disable() section in netif_rx() to ensure softirqs are
handled if needed.
Provide __netif_rx() which does not disable BH and has a lockdep assert
to ensure that interrupts are disabled. Use this shortcut in the
loopback driver and in drivers/net/*.c.
Make netif_rx_ni() and netif_rx_any_context() invoke netif_rx() so they
can be removed once they are no more users left.
Link: https://lkml.kernel.org/r/20100415.020246.218622820.davem@davemloft.net
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The preempt_disable() () section was introduced in commit
cece1945bf ("net: disable preemption before call smp_processor_id()")
and adds it in case this function is invoked from preemtible context and
because get_cpu() later on as been added.
The get_cpu() usage was added in commit
b0e28f1eff ("net: netif_rx() must disable preemption")
because ip_dev_loopback_xmit() invoked netif_rx() with enabled preemption
causing a warning in smp_processor_id(). The function netif_rx() should
only be invoked from an interrupt context which implies disabled
preemption. The commit
e30b38c298 ("ip: Fix ip_dev_loopback_xmit()")
was addressing this and replaced netif_rx() with in netif_rx_ni() in
ip_dev_loopback_xmit().
Based on the discussion on the list, the former patch (b0e28f1eff)
should not have been applied only the latter (e30b38c298).
Remove get_cpu() and preempt_disable() since the function is supposed to
be invoked from context with stable per-CPU pointers. Bottom halves have
to be disabled at this point because the function may raise softirqs
which need to be processed.
Link: https://lkml.kernel.org/r/20100415.013347.98375530.davem@davemloft.net
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
