- 16 Feb, 2022 4 commits
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Vladimir Oltean authored
Currently there is a very subtle aspect to the behavior of __vlan_add_flags(): it changes the struct net_bridge_vlan flags and pvid, yet it returns true ("changed") even if none of those changed, just a transition of br_vlan_is_brentry(v) took place from false to true. This can be seen in br_vlan_add_existing(), however we do not actually rely on this subtle behavior, since the "if" condition that checks that the vlan wasn't a brentry before had a useless (until now) assignment: *changed = true; Make things more obvious by actually making __vlan_add_flags() do what's written on the box, and be more specific about what is actually written on the box. This is needed because further transformations will be done to __vlan_add_flags(). Signed-off-by:
Vladimir Oltean <vladimir.oltean@nxp.com> Acked-by:
Nikolay Aleksandrov <nikolay@nvidia.com> Signed-off-by:
David S. Miller <davem@davemloft.net>
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Vladimir Oltean authored
When a VLAN is added to a bridge port and it doesn't exist on the bridge device yet, it gets created for the multicast context, but it is 'hidden', since it doesn't have the BRENTRY flag yet: ip link add br0 type bridge && ip link set swp0 master br0 bridge vlan add dev swp0 vid 100 # the master VLAN 100 gets created bridge vlan add dev br0 vid 100 self # that VLAN becomes brentry just now All switchdev drivers ignore switchdev notifiers for VLAN entries which have the BRENTRY unset, and for good reason: these are merely private data structures used by the bridge driver. So we might just as well not notify those at all. Cleanup in the switchdev drivers that check for the BRENTRY flag is now possible, and will be handled separately, since those checks just became dead code. Signed-off-by:
Vladimir Oltean <vladimir.oltean@nxp.com> Acked-by:
Nikolay Aleksandrov <nikolay@nvidia.com> Signed-off-by:
David S. Miller <davem@davemloft.net>
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Vladimir Oltean authored
When a VLAN is added to a bridge port, a master VLAN gets created on the bridge for context, but it doesn't have the BRENTRY flag. Then, when the same VLAN is added to the bridge itself, that enters through the br_vlan_add_existing() code path and gains the BRENTRY flag, thus it becomes "existing". It seems natural to check for this condition early, because the current code flow is to notify switchdev of the addition of a VLAN that isn't a brentry, just to delete it immediately afterwards. Signed-off-by:
Vladimir Oltean <vladimir.oltean@nxp.com> Acked-by:
Nikolay Aleksandrov <nikolay@nvidia.com> Signed-off-by:
David S. Miller <davem@davemloft.net>
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Haiyue Wang authored
The commit a5886ef4 ("gve: Introduce per netdev `enum gve_queue_format`") introduces three queue format type, only GVE_GQI_QPL_FORMAT queue has page list. So it should use the queue page list number to detect the zero size queue page list. Correct the design logic. Using the 'queue_format == GVE_GQI_RDA_FORMAT' may lead to request zero sized memory allocation, like if the queue format is GVE_DQO_RDA_FORMAT. The kernel memory subsystem will return ZERO_SIZE_PTR, which is not NULL address, so the driver can run successfully. Also the code still checks the queue page list number firstly, then accesses the allocated memory, so zero number queue page list allocation will not lead to access fault. Signed-off-by:
Haiyue Wang <haiyue.wang@intel.com> Reviewed-by:
Bailey Forrest <bcf@google.com> Link: https://lore.kernel.org/r/20220215051751.260866-1-haiyue.wang@intel.comSigned-off-by:
Jakub Kicinski <kuba@kernel.org>
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- 15 Feb, 2022 22 commits
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Colin Ian King authored
There are spelling mistakes in debug messages. Fix them. Signed-off-by:
Colin Ian King <colin.i.king@gmail.com> Signed-off-by:
David S. Miller <davem@davemloft.net>
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Yang Li authored
Fix the following coccicheck warnings: ./drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c:1199:42-47: WARNING: conversion to bool not needed here ./drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c:1218:54-59: WARNING: conversion to bool not needed here Reported-by:
Abaci Robot <abaci@linux.alibaba.com> Signed-off-by:
Yang Li <yang.lee@linux.alibaba.com> Signed-off-by:
David S. Miller <davem@davemloft.net>
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Vladimir Oltean authored
If the following call path returns an error from switchdev: nbp_vlan_flush -> __vlan_del -> __vlan_vid_del -> br_switchdev_port_vlan_del -> __vlan_group_free -> WARN_ON(!list_empty(&vg->vlan_list)); then the deletion of the net_bridge_vlan is silently halted, which will trigger the WARN_ON from __vlan_group_free(). The WARN_ON is rather unhelpful, because nothing about the source of the error is printed. Add a print to catch errors from __vlan_del. Signed-off-by:
Vladimir Oltean <vladimir.oltean@nxp.com> Signed-off-by:
David S. Miller <davem@davemloft.net>
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Christophe JAILLET authored
hso_create_device() is only called from function that already use GFP_KERNEL. And all the callers are called from the probe function. So there is no need here to explicitly require a GFP_ATOMIC when allocating memory. Use GFP_KERNEL instead. Signed-off-by:
Christophe JAILLET <christophe.jaillet@wanadoo.fr> Signed-off-by:
David S. Miller <davem@davemloft.net>
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Michael Catanzaro authored
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>
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git://git.kernel.org/pub/scm/linux/kernel/git/saeed/linuxDavid S. Miller authored
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 846d6da1 ("net/mlx5e: Fix division by 0 in mlx5e_select_queue") and commit 84c8a874 ("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>
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Maxim Mikityanskiy authored
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>
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Maxim Mikityanskiy authored
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>
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Maxim Mikityanskiy authored
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>
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Maxim Mikityanskiy authored
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>
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Maxim Mikityanskiy authored
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>
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Maxim Mikityanskiy authored
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>
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Maxim Mikityanskiy authored
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>
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Maxim Mikityanskiy authored
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>
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Maxim Mikityanskiy authored
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>
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Maxim Mikityanskiy authored
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>
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Maxim Mikityanskiy authored
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>
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Maxim Mikityanskiy authored
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>
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Aya Levin authored
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>
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Aya Levin authored
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>
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Tariq Toukan authored
Remove tstamp pointer in mlx5e_txqsq as it's no longer used after commit 7c39afb3 ("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>
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Tobias Waldekranz authored
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: 2ee84cfe ("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.comSigned-off-by:
Jakub Kicinski <kuba@kernel.org>
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- 14 Feb, 2022 14 commits
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Colin Ian King authored
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>
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Volodymyr Mytnyk authored
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>
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David S. Miller authored
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>
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M Chetan Kumar authored
Post debugfs use call wwan_put_debugfs_dir()to drop debugfs dev reference. Signed-off-by:
M Chetan Kumar <m.chetan.kumar@linux.intel.com> Signed-off-by:
David S. Miller <davem@davemloft.net>
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M Chetan Kumar authored
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>
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David S. Miller authored
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>
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Luiz Angelo Daros de Luca authored
Some devices, like the switch in Banana Pi BPI R64 only starts to answer after a HW reset. It is the same reset code from realtek-smi. Reported-by:
Frank Wunderlich <frank-w@public-files.de> Signed-off-by:
Luiz Angelo Daros de Luca <luizluca@gmail.com> Tested-by:
Frank Wunderlich <frank-w@public-files.de> Reviewed-by:
Linus Walleij <linus.walleij@linaro.org> Reviewed-by:
Alvin Šipraga <alsi@bang-olufsen.dk> Acked-by:
Arınç ÜNAL <arinc.unal@arinc9.com> Signed-off-by:
David S. Miller <davem@davemloft.net>
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Luiz Angelo Daros de Luca authored
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>
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Ido Schimmel authored
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: e5f80fcf ("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>
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Luiz Angelo Daros de Luca authored
The macro was missed while renaming realtek-smi.h to realtek.h. Fixes: f5f11907 (net: dsa: realtek: rename realtek_smi to) Signed-off-by:
Luiz Angelo Daros de Luca <luizluca@gmail.com> Reviewed-by:
Florian Fainelli <f.fainelli@gmail.com> Reviewed-by:
Linus Walleij <linus.walleij@linaro.org> Reviewed-by:
Andrew Lunn <andrew@lunn.ch> Reviewed-by:
Alvin Šipraga <alsi@bang-olufsen.dk> Acked-by:
Arınç ÜNAL <arinc.unal@arinc9.com> Signed-off-by:
David S. Miller <davem@davemloft.net>
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David S. Miller authored
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>
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Sebastian Andrzej Siewior authored
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>
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Sebastian Andrzej Siewior authored
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.netSigned-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>
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Sebastian Andrzej Siewior authored
The preempt_disable() () section was introduced in commit cece1945 ("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 b0e28f1e ("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 e30b38c2 ("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 (b0e28f1e) should not have been applied only the latter (e30b38c2). 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.netSigned-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>
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