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2024-11-11net/mlx5e: SHAMPO, Fix page_index calculation inconsistencyDragos Tatulea
When calculating the index for the next frag page slot, the divisor is incorrect: it should be the number of pages per queue not the number of headers per queue. This is currently harmless because frag pages are not used directly, but they are intermediated through the info array. But it needs to be fixed as an upcoming patch will get rid of the info array. This patch introduces a new pages per queue variable and plugs it in the formula. Now that this variable exists, additional code can be simplified in the SHAMPO initialization code. Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com> Signed-off-by: Tariq Toukan <tariqt@nvidia.com> Link: https://patch.msgid.link/20241107194357.683732-10-tariqt@nvidia.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-11-11net/mlx5e: SHAMPO, Simplify UMR allocation for headersDragos Tatulea
Allocating page fragments for header data split is currently more complicated than it should be. That's because the number of KSM entries allocated is not aligned to the number of headers per page. This leads to having leftovers in the next allocation which require additional accounting and needlessly complicated code. This patch aligns (down) the number of KSM entries in the UMR WQE to the number of headers per page by: 1) Aligning the max number of entries allocated per UMR WQE (max_ksm_entries) to MLX5E_SHAMPO_WQ_HEADER_PER_PAGE. 2) Aligning the total number of free headers to MLX5E_SHAMPO_WQ_HEADER_PER_PAGE. ... and then it drops the extra accounting code from mlx5e_build_shampo_hd_umr(). Although the number of entries allocated per UMR WQE is slightly smaller due to aligning down, no performance impact was observed. Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com> Signed-off-by: Tariq Toukan <tariqt@nvidia.com> Link: https://patch.msgid.link/20241107194357.683732-9-tariqt@nvidia.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-11-11net/mlx5: Make vport QoS enablement more flexible for future extensionsCarolina Jubran
Refactor esw_qos_vport_enable to support more generic configurations, allowing it to be reused for new vport node types in future patches. This refactor includes a new way to change the vport parent node by disabling the current setup and re-enabling it with the new parent. This change sets the foundation for adapting configuration based on the parent type in future patches. Signed-off-by: Carolina Jubran <cjubran@nvidia.com> Reviewed-by: Cosmin Ratiu <cratiu@nvidia.com> Signed-off-by: Tariq Toukan <tariqt@nvidia.com> Link: https://patch.msgid.link/20241107194357.683732-8-tariqt@nvidia.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-11-11net/mlx5: Integrate esw_qos_vport_enable logic into rate operationsCarolina Jubran
Fold the esw_qos_vport_enable function into operations for configuring maximum and minimum rates, simplifying QoS logic. This change consolidates enabling and updating the scheduling element configuration, streamlining how vport QoS is initialized and adjusted. Signed-off-by: Carolina Jubran <cjubran@nvidia.com> Reviewed-by: Cosmin Ratiu <cratiu@nvidia.com> Signed-off-by: Tariq Toukan <tariqt@nvidia.com> Link: https://patch.msgid.link/20241107194357.683732-7-tariqt@nvidia.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-11-11net/mlx5: Generalize scheduling element operationsCarolina Jubran
Introduce helper functions to create and destroy scheduling elements, allowing flexible configuration for different scheduling element types. The new helper functions streamline the process by centralizing error handling and logging through esw_qos_sched_elem_op_warn, which now accepts the operation type (create, destroy, or modify). The changes also adjust the esw_qos_vport_enable and mlx5_esw_qos_vport_disable functions to leverage the new generalized create/destroy helpers. The destroy functions now log errors with esw_warn without returning them. This prevents unnecessary error handling since the node was already destroyed and no further action is required from callers. Signed-off-by: Carolina Jubran <cjubran@nvidia.com> Reviewed-by: Cosmin Ratiu <cratiu@nvidia.com> Signed-off-by: Tariq Toukan <tariqt@nvidia.com> Link: https://patch.msgid.link/20241107194357.683732-6-tariqt@nvidia.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-11-11net/mlx5: Refactor scheduling element configuration bitmasksCarolina Jubran
Refactor esw_qos_sched_elem_config to set bitmasks only when max_rate or bw_share values change, allowing the function to configure nodes with only one of these parameters. This enables more flexible usage for nodes where only one parameter requires configuration. Remove scattered assignments and checks to centralize them within this function, removing the now redundant esw_qos_set_node_max_rate entirely. With this refactor, also remove the assignment of the vport scheduling node max rate to the parent max rate for unlimited vports (where max rate is set to zero), as firmware already handles this behavior. Signed-off-by: Carolina Jubran <cjubran@nvidia.com> Reviewed-by: Cosmin Ratiu <cratiu@nvidia.com> Signed-off-by: Tariq Toukan <tariqt@nvidia.com> Link: https://patch.msgid.link/20241107194357.683732-5-tariqt@nvidia.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-11-11net/mlx5: Generalize max_rate and min_rate setting for nodesCarolina Jubran
Refactor max_rate and min_rate setting functions to operate on mlx5_esw_sched_node, allowing for generalized handling of both vports and nodes. Signed-off-by: Carolina Jubran <cjubran@nvidia.com> Reviewed-by: Cosmin Ratiu <cratiu@nvidia.com> Signed-off-by: Tariq Toukan <tariqt@nvidia.com> Link: https://patch.msgid.link/20241107194357.683732-4-tariqt@nvidia.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-11-11net/mlx5: Simplify QoS normalization by removing error handlingCarolina Jubran
This change updates esw_qos_normalize_min_rate to not return errors, significantly simplifying the code. Normalization failures are software bugs, and it's unnecessary to handle them with rollback mechanisms. Instead, `esw_qos_update_sched_node_bw_share` and `esw_qos_normalize_min_rate` now return void, with any errors logged as warnings to indicate potential software issues. This approach avoids compensating for hidden bugs and removes error handling from all places that perform normalization, streamlining future patches. Signed-off-by: Carolina Jubran <cjubran@nvidia.com> Reviewed-by: Cosmin Ratiu <cratiu@nvidia.com> Signed-off-by: Tariq Toukan <tariqt@nvidia.com> Link: https://patch.msgid.link/20241107194357.683732-3-tariqt@nvidia.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-11-11net/mlx5: E-switch, refactor eswitch mode changePatrisious Haddad
The E-switch mode was previously updated before removing and re-adding the IB device, which could cause a temporary mismatch between the E-switch mode and the IB device configuration. To prevent this discrepancy, the IB device is now removed first, then the E-switch mode is updated, and finally, the IB device is re-added. This sequence ensures consistent alignment between the E-switch mode and the IB device whenever the mode changes, regardless of the new mode value. Signed-off-by: Patrisious Haddad <phaddad@nvidia.com> Reviewed-by: Mark Bloch <mbloch@nvidia.com> Signed-off-by: Tariq Toukan <tariqt@nvidia.com> Link: https://patch.msgid.link/20241107194357.683732-2-tariqt@nvidia.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-11-11Merge branch 'mlx5-misc-fixes-2024-11-07'Jakub Kicinski
Tariq Toukan says: ==================== mlx5 misc fixes 2024-11-07 This patchset provides misc bug fixes from the team to the mlx5 core and Eth drivers. ==================== Link: https://patch.msgid.link/20241107183527.676877-1-tariqt@nvidia.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-11-11net/mlx5e: Disable loopback self-test on multi-PF netdevCarolina Jubran
In Multi-PF (Socket Direct) configurations, when a loopback packet is sent through one of the secondary devices, it will always be received on the primary device. This causes the loopback layer to fail in identifying the loopback packet as the devices are different. To avoid false test failures, disable the loopback self-test in Multi-PF configurations. Fixes: ed29705e4ed1 ("net/mlx5: Enable SD feature") Signed-off-by: Carolina Jubran <cjubran@nvidia.com> Signed-off-by: Tariq Toukan <tariqt@nvidia.com> Link: https://patch.msgid.link/20241107183527.676877-8-tariqt@nvidia.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-11-11net/mlx5e: CT: Fix null-ptr-deref in add rule err flowMoshe Shemesh
In error flow of mlx5_tc_ct_entry_add_rule(), in case ct_rule_add() callback returns error, zone_rule->attr is used uninitiated. Fix it to use attr which has the needed pointer value. Kernel log: BUG: kernel NULL pointer dereference, address: 0000000000000110 RIP: 0010:mlx5_tc_ct_entry_add_rule+0x2b1/0x2f0 [mlx5_core] … Call Trace: <TASK> ? __die+0x20/0x70 ? page_fault_oops+0x150/0x3e0 ? exc_page_fault+0x74/0x140 ? asm_exc_page_fault+0x22/0x30 ? mlx5_tc_ct_entry_add_rule+0x2b1/0x2f0 [mlx5_core] ? mlx5_tc_ct_entry_add_rule+0x1d5/0x2f0 [mlx5_core] mlx5_tc_ct_block_flow_offload+0xc6a/0xf90 [mlx5_core] ? nf_flow_offload_tuple+0xd8/0x190 [nf_flow_table] nf_flow_offload_tuple+0xd8/0x190 [nf_flow_table] flow_offload_work_handler+0x142/0x320 [nf_flow_table] ? finish_task_switch.isra.0+0x15b/0x2b0 process_one_work+0x16c/0x320 worker_thread+0x28c/0x3a0 ? __pfx_worker_thread+0x10/0x10 kthread+0xb8/0xf0 ? __pfx_kthread+0x10/0x10 ret_from_fork+0x2d/0x50 ? __pfx_kthread+0x10/0x10 ret_from_fork_asm+0x1a/0x30 </TASK> Fixes: 7fac5c2eced3 ("net/mlx5: CT: Avoid reusing modify header context for natted entries") Signed-off-by: Moshe Shemesh <moshe@nvidia.com> Reviewed-by: Cosmin Ratiu <cratiu@nvidia.com> Reviewed-by: Yevgeny Kliteynik <kliteyn@nvidia.com> Signed-off-by: Tariq Toukan <tariqt@nvidia.com> Link: https://patch.msgid.link/20241107183527.676877-7-tariqt@nvidia.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-11-11net/mlx5e: clear xdp features on non-uplink representorsWilliam Tu
Non-uplink representor port does not support XDP. The patch clears the xdp feature by checking the net_device_ops.ndo_bpf is set or not. Verify using the netlink tool: $ tools/net/ynl/cli.py --spec Documentation/netlink/specs/netdev.yaml --dump dev-get Representor netdev before the patch: {'ifindex': 8, 'xdp-features': {'basic', 'ndo-xmit', 'ndo-xmit-sg', 'redirect', 'rx-sg', 'xsk-zerocopy'}, 'xdp-rx-metadata-features': set(), 'xdp-zc-max-segs': 1, 'xsk-features': set()}, With the patch: {'ifindex': 8, 'xdp-features': set(), 'xdp-rx-metadata-features': set(), 'xsk-features': set()}, Fixes: 4d5ab0ad964d ("net/mlx5e: take into account device reconfiguration for xdp_features flag") Signed-off-by: William Tu <witu@nvidia.com> Signed-off-by: Tariq Toukan <tariqt@nvidia.com> Link: https://patch.msgid.link/20241107183527.676877-6-tariqt@nvidia.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-11-11net/mlx5e: kTLS, Fix incorrect page refcountingDragos Tatulea
The kTLS tx handling code is using a mix of get_page() and page_ref_inc() APIs to increment the page reference. But on the release path (mlx5e_ktls_tx_handle_resync_dump_comp()), only put_page() is used. This is an issue when using pages from large folios: the get_page() references are stored on the folio page while the page_ref_inc() references are stored directly in the given page. On release the folio page will be dereferenced too many times. This was found while doing kTLS testing with sendfile() + ZC when the served file was read from NFS on a kernel with NFS large folios support (commit 49b29a573da8 ("nfs: add support for large folios")). Fixes: 84d1bb2b139e ("net/mlx5e: kTLS, Limit DUMP wqe size") Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com> Signed-off-by: Tariq Toukan <tariqt@nvidia.com> Link: https://patch.msgid.link/20241107183527.676877-5-tariqt@nvidia.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-11-11net/mlx5: fs, lock FTE when checking if activeMark Bloch
The referenced commits introduced a two-step process for deleting FTEs: - Lock the FTE, delete it from hardware, set the hardware deletion function to NULL and unlock the FTE. - Lock the parent flow group, delete the software copy of the FTE, and remove it from the xarray. However, this approach encounters a race condition if a rule with the same match value is added simultaneously. In this scenario, fs_core may set the hardware deletion function to NULL prematurely, causing a panic during subsequent rule deletions. To prevent this, ensure the active flag of the FTE is checked under a lock, which will prevent the fs_core layer from attaching a new steering rule to an FTE that is in the process of deletion. [ 438.967589] MOSHE: 2496 mlx5_del_flow_rules del_hw_func [ 438.968205] ------------[ cut here ]------------ [ 438.968654] refcount_t: decrement hit 0; leaking memory. [ 438.969249] WARNING: CPU: 0 PID: 8957 at lib/refcount.c:31 refcount_warn_saturate+0xfb/0x110 [ 438.970054] Modules linked in: act_mirred cls_flower act_gact sch_ingress openvswitch nsh mlx5_vdpa vringh vhost_iotlb vdpa mlx5_ib mlx5_core xt_conntrack xt_MASQUERADE nf_conntrack_netlink nfnetlink xt_addrtype iptable_nat nf_nat br_netfilter rpcsec_gss_krb5 auth_rpcgss oid_registry overlay rpcrdma rdma_ucm ib_iser libiscsi scsi_transport_iscsi ib_umad rdma_cm ib_ipoib iw_cm ib_cm ib_uverbs ib_core zram zsmalloc fuse [last unloaded: cls_flower] [ 438.973288] CPU: 0 UID: 0 PID: 8957 Comm: tc Not tainted 6.12.0-rc1+ #8 [ 438.973888] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014 [ 438.974874] RIP: 0010:refcount_warn_saturate+0xfb/0x110 [ 438.975363] Code: 40 66 3b 82 c6 05 16 e9 4d 01 01 e8 1f 7c a0 ff 0f 0b c3 cc cc cc cc 48 c7 c7 10 66 3b 82 c6 05 fd e8 4d 01 01 e8 05 7c a0 ff <0f> 0b c3 cc cc cc cc 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 90 [ 438.976947] RSP: 0018:ffff888124a53610 EFLAGS: 00010286 [ 438.977446] RAX: 0000000000000000 RBX: ffff888119d56de0 RCX: 0000000000000000 [ 438.978090] RDX: ffff88852c828700 RSI: ffff88852c81b3c0 RDI: ffff88852c81b3c0 [ 438.978721] RBP: ffff888120fa0e88 R08: 0000000000000000 R09: ffff888124a534b0 [ 438.979353] R10: 0000000000000001 R11: 0000000000000001 R12: ffff888119d56de0 [ 438.979979] R13: ffff888120fa0ec0 R14: ffff888120fa0ee8 R15: ffff888119d56de0 [ 438.980607] FS: 00007fe6dcc0f800(0000) GS:ffff88852c800000(0000) knlGS:0000000000000000 [ 438.983984] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 438.984544] CR2: 00000000004275e0 CR3: 0000000186982001 CR4: 0000000000372eb0 [ 438.985205] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 438.985842] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 438.986507] Call Trace: [ 438.986799] <TASK> [ 438.987070] ? __warn+0x7d/0x110 [ 438.987426] ? refcount_warn_saturate+0xfb/0x110 [ 438.987877] ? report_bug+0x17d/0x190 [ 438.988261] ? prb_read_valid+0x17/0x20 [ 438.988659] ? handle_bug+0x53/0x90 [ 438.989054] ? exc_invalid_op+0x14/0x70 [ 438.989458] ? asm_exc_invalid_op+0x16/0x20 [ 438.989883] ? refcount_warn_saturate+0xfb/0x110 [ 438.990348] mlx5_del_flow_rules+0x2f7/0x340 [mlx5_core] [ 438.990932] __mlx5_eswitch_del_rule+0x49/0x170 [mlx5_core] [ 438.991519] ? mlx5_lag_is_sriov+0x3c/0x50 [mlx5_core] [ 438.992054] ? xas_load+0x9/0xb0 [ 438.992407] mlx5e_tc_rule_unoffload+0x45/0xe0 [mlx5_core] [ 438.993037] mlx5e_tc_del_fdb_flow+0x2a6/0x2e0 [mlx5_core] [ 438.993623] mlx5e_flow_put+0x29/0x60 [mlx5_core] [ 438.994161] mlx5e_delete_flower+0x261/0x390 [mlx5_core] [ 438.994728] tc_setup_cb_destroy+0xb9/0x190 [ 438.995150] fl_hw_destroy_filter+0x94/0xc0 [cls_flower] [ 438.995650] fl_change+0x11a4/0x13c0 [cls_flower] [ 438.996105] tc_new_tfilter+0x347/0xbc0 [ 438.996503] ? ___slab_alloc+0x70/0x8c0 [ 438.996929] rtnetlink_rcv_msg+0xf9/0x3e0 [ 438.997339] ? __netlink_sendskb+0x4c/0x70 [ 438.997751] ? netlink_unicast+0x286/0x2d0 [ 438.998171] ? __pfx_rtnetlink_rcv_msg+0x10/0x10 [ 438.998625] netlink_rcv_skb+0x54/0x100 [ 438.999020] netlink_unicast+0x203/0x2d0 [ 438.999421] netlink_sendmsg+0x1e4/0x420 [ 438.999820] __sock_sendmsg+0xa1/0xb0 [ 439.000203] ____sys_sendmsg+0x207/0x2a0 [ 439.000600] ? copy_msghdr_from_user+0x6d/0xa0 [ 439.001072] ___sys_sendmsg+0x80/0xc0 [ 439.001459] ? ___sys_recvmsg+0x8b/0xc0 [ 439.001848] ? generic_update_time+0x4d/0x60 [ 439.002282] __sys_sendmsg+0x51/0x90 [ 439.002658] do_syscall_64+0x50/0x110 [ 439.003040] entry_SYSCALL_64_after_hwframe+0x76/0x7e Fixes: 718ce4d601db ("net/mlx5: Consolidate update FTE for all removal changes") Fixes: cefc23554fc2 ("net/mlx5: Fix FTE cleanup") Signed-off-by: Mark Bloch <mbloch@nvidia.com> Reviewed-by: Maor Gottlieb <maorg@nvidia.com> Signed-off-by: Tariq Toukan <tariqt@nvidia.com> Link: https://patch.msgid.link/20241107183527.676877-4-tariqt@nvidia.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-11-11net/mlx5: Fix msix vectors to respect platform limitParav Pandit
The number of PCI vectors allocated by the platform (which may be fewer than requested) is currently not honored when creating the SF pool; only the PCI MSI-X capability is considered. As a result, when a platform allocates fewer vectors (in non-dynamic mode) than requested, the PF and SF pools end up with an invalid vector range. This causes incorrect SF vector accounting, which leads to the following call trace when an invalid IRQ vector is allocated. This issue is resolved by ensuring that the platform's vector limit is respected for both the SF and PF pools. Workqueue: mlx5_vhca_event0 mlx5_sf_dev_add_active_work [mlx5_core] RIP: 0010:pci_irq_vector+0x23/0x80 RSP: 0018:ffffabd5cebd7248 EFLAGS: 00010246 RAX: ffff980880e7f308 RBX: ffff9808932fb880 RCX: 0000000000000001 RDX: 00000000000001ff RSI: 0000000000000200 RDI: ffff980880e7f308 RBP: 0000000000000200 R08: 0000000000000010 R09: ffff97a9116f0860 R10: 0000000000000002 R11: 0000000000000228 R12: ffff980897cd0160 R13: 0000000000000000 R14: ffff97a920fec0c0 R15: ffffabd5cebd72d0 FS: 0000000000000000(0000) GS:ffff97c7ff9c0000(0000) knlGS:0000000000000000 ? rescuer_thread+0x350/0x350 kthread+0x11b/0x140 ? __kthread_bind_mask+0x60/0x60 ret_from_fork+0x22/0x30 mlx5_core 0000:a1:00.0: mlx5_irq_alloc:321:(pid 6781): Failed to request irq. err = -22 mlx5_core 0000:a1:00.0: mlx5_irq_alloc:321:(pid 6781): Failed to request irq. err = -22 mlx5_core.sf mlx5_core.sf.6: MLX5E: StrdRq(1) RqSz(8) StrdSz(2048) RxCqeCmprss(0 enhanced) mlx5_core.sf mlx5_core.sf.7: firmware version: 32.43.356 mlx5_core.sf mlx5_core.sf.6 enpa1s0f0s4: renamed from eth0 mlx5_core.sf mlx5_core.sf.7: Rate limit: 127 rates are supported, range: 0Mbps to 195312Mbps mlx5_core 0000:a1:00.0: mlx5_irq_alloc:321:(pid 6781): Failed to request irq. err = -22 mlx5_core 0000:a1:00.0: mlx5_irq_alloc:321:(pid 6781): Failed to request irq. err = -22 mlx5_core 0000:a1:00.0: mlx5_irq_alloc:321:(pid 6781): Failed to request irq. err = -22 Fixes: 3354822cde5a ("net/mlx5: Use dynamic msix vectors allocation") Signed-off-by: Parav Pandit <parav@nvidia.com> Signed-off-by: Amir Tzin <amirtz@nvidia.com> Signed-off-by: Tariq Toukan <tariqt@nvidia.com> Link: https://patch.msgid.link/20241107183527.676877-3-tariqt@nvidia.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-11-11net/mlx5: E-switch, unload IB representors when unloading ETH representorsChiara Meiohas
IB representors depend on ETH representors, so the IB representors should not exist without the ETH ones. When unloading the ETH representors, the corresponding IB representors should be also unloaded. The commit 8d159eb2117b ("RDMA/mlx5: Use IB set_netdev and get_netdev functions") introduced the use of the ib_device_set_netdev API in IB repsresentors. ib_device_set_netdev() increments the refcount of the representor's netdev when loading an IB representor and decrements it when unloading. Without the unloading of the IB representor, the refcount of the representor's netdev remains greater than 0, preventing it from being unregistered. The patch uncovered an underlying bug where the eth representor is unloaded, without unloading the IB representor. This issue happened when using multiport E-switch and rebooting, causing the shutdown to hang when unloading the ETH representor because the refcount of the representor's netdevice was greater than 0. Call trace: unregister_netdevice: waiting for eth3 to become free. Usage count = 2 ref_tracker: eth%d@00000000661d60f7 has 1/1 users at ib_device_set_netdev+0x160/0x2d0 [ib_core] mlx5_ib_vport_rep_load+0x104/0x3f0 [mlx5_ib] mlx5_eswitch_reload_ib_reps+0xfc/0x110 [mlx5_core] mlx5_mpesw_work+0x236/0x330 [mlx5_core] process_one_work+0x169/0x320 worker_thread+0x288/0x3a0 kthread+0xb8/0xe0 ret_from_fork+0x2d/0x50 ret_from_fork_asm+0x11/0x20 Fixes: 8d159eb2117b ("RDMA/mlx5: Use IB set_netdev and get_netdev functions") Signed-off-by: Chiara Meiohas <cmeiohas@nvidia.com> Reviewed-by: Mark Bloch <mbloch@nvidia.com> Signed-off-by: Tariq Toukan <tariqt@nvidia.com> Link: https://patch.msgid.link/20241107183527.676877-2-tariqt@nvidia.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-11-11net: ipv4: Cache pmtu for all packet paths if multipath enabledVladimir Vdovin
Check number of paths by fib_info_num_path(), and update_or_create_fnhe() for every path. Problem is that pmtu is cached only for the oif that has received icmp message "need to frag", other oifs will still try to use "default" iface mtu. An example topology showing the problem: | host1 +---------+ | dummy0 | 10.179.20.18/32 mtu9000 +---------+ +-----------+----------------+ +---------+ +---------+ | ens17f0 | 10.179.2.141/31 | ens17f1 | 10.179.2.13/31 +---------+ +---------+ | (all here have mtu 9000) | +------+ +------+ | ro1 | 10.179.2.140/31 | ro2 | 10.179.2.12/31 +------+ +------+ | | ---------+------------+-------------------+------ | +-----+ | ro3 | 10.10.10.10 mtu1500 +-----+ | ======================================== some networks ======================================== | +-----+ | eth0| 10.10.30.30 mtu9000 +-----+ | host2 host1 have enabled multipath and sysctl net.ipv4.fib_multipath_hash_policy = 1: default proto static src 10.179.20.18 nexthop via 10.179.2.12 dev ens17f1 weight 1 nexthop via 10.179.2.140 dev ens17f0 weight 1 When host1 tries to do pmtud from 10.179.20.18/32 to host2, host1 receives at ens17f1 iface an icmp packet from ro3 that ro3 mtu=1500. And host1 caches it in nexthop exceptions cache. Problem is that it is cached only for the iface that has received icmp, and there is no way that ro3 will send icmp msg to host1 via another path. Host1 now have this routes to host2: ip r g 10.10.30.30 sport 30000 dport 443 10.10.30.30 via 10.179.2.12 dev ens17f1 src 10.179.20.18 uid 0 cache expires 521sec mtu 1500 ip r g 10.10.30.30 sport 30033 dport 443 10.10.30.30 via 10.179.2.140 dev ens17f0 src 10.179.20.18 uid 0 cache So when host1 tries again to reach host2 with mtu>1500, if packet flow is lucky enough to be hashed with oif=ens17f1 its ok, if oif=ens17f0 it blackholes and still gets icmp msgs from ro3 to ens17f1, until lucky day when ro3 will send it through another flow to ens17f0. Signed-off-by: Vladimir Vdovin <deliran@verdict.gg> Reviewed-by: Ido Schimmel <idosch@nvidia.com> Link: https://patch.msgid.link/20241108093427.317942-1-deliran@verdict.gg Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-11-11Merge branch 'mptcp-fix-a-couple-of-races'Jakub Kicinski
Paolo Abeni says: ==================== mptcp: fix a couple of races The first patch addresses a division by zero issue reported by Eric, the second one solves a similar issue found by code inspection while investigating the former. ==================== Link: https://patch.msgid.link/cover.1731060874.git.pabeni@redhat.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-11-11mptcp: cope racing subflow creation in mptcp_rcv_space_adjustPaolo Abeni
Additional active subflows - i.e. created by the in kernel path manager - are included into the subflow list before starting the 3whs. A racing recvmsg() spooling data received on an already established subflow would unconditionally call tcp_cleanup_rbuf() on all the current subflows, potentially hitting a divide by zero error on the newly created ones. Explicitly check that the subflow is in a suitable state before invoking tcp_cleanup_rbuf(). Fixes: c76c6956566f ("mptcp: call tcp_cleanup_rbuf on subflows") Signed-off-by: Paolo Abeni <pabeni@redhat.com> Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Link: https://patch.msgid.link/02374660836e1b52afc91966b7535c8c5f7bafb0.1731060874.git.pabeni@redhat.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-11-11mptcp: error out earlier on disconnectPaolo Abeni
Eric reported a division by zero splat in the MPTCP protocol: Oops: divide error: 0000 [#1] PREEMPT SMP KASAN PTI CPU: 1 UID: 0 PID: 6094 Comm: syz-executor317 Not tainted 6.12.0-rc5-syzkaller-00291-g05b92660cdfe #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 RIP: 0010:__tcp_select_window+0x5b4/0x1310 net/ipv4/tcp_output.c:3163 Code: f6 44 01 e3 89 df e8 9b 75 09 f8 44 39 f3 0f 8d 11 ff ff ff e8 0d 74 09 f8 45 89 f4 e9 04 ff ff ff e8 00 74 09 f8 44 89 f0 99 <f7> 7c 24 14 41 29 d6 45 89 f4 e9 ec fe ff ff e8 e8 73 09 f8 48 89 RSP: 0018:ffffc900041f7930 EFLAGS: 00010293 RAX: 0000000000017e67 RBX: 0000000000017e67 RCX: ffffffff8983314b RDX: 0000000000000000 RSI: ffffffff898331b0 RDI: 0000000000000004 RBP: 00000000005d6000 R08: 0000000000000004 R09: 0000000000017e67 R10: 0000000000003e80 R11: 0000000000000000 R12: 0000000000003e80 R13: ffff888031d9b440 R14: 0000000000017e67 R15: 00000000002eb000 FS: 00007feb5d7f16c0(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007feb5d8adbb8 CR3: 0000000074e4c000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> __tcp_cleanup_rbuf+0x3e7/0x4b0 net/ipv4/tcp.c:1493 mptcp_rcv_space_adjust net/mptcp/protocol.c:2085 [inline] mptcp_recvmsg+0x2156/0x2600 net/mptcp/protocol.c:2289 inet_recvmsg+0x469/0x6a0 net/ipv4/af_inet.c:885 sock_recvmsg_nosec net/socket.c:1051 [inline] sock_recvmsg+0x1b2/0x250 net/socket.c:1073 __sys_recvfrom+0x1a5/0x2e0 net/socket.c:2265 __do_sys_recvfrom net/socket.c:2283 [inline] __se_sys_recvfrom net/socket.c:2279 [inline] __x64_sys_recvfrom+0xe0/0x1c0 net/socket.c:2279 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7feb5d857559 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 51 18 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007feb5d7f1208 EFLAGS: 00000246 ORIG_RAX: 000000000000002d RAX: ffffffffffffffda RBX: 00007feb5d8e1318 RCX: 00007feb5d857559 RDX: 000000800000000e RSI: 0000000000000000 RDI: 0000000000000003 RBP: 00007feb5d8e1310 R08: 0000000000000000 R09: ffffffff81000000 R10: 0000000000000100 R11: 0000000000000246 R12: 00007feb5d8e131c R13: 00007feb5d8ae074 R14: 000000800000000e R15: 00000000fffffdef and provided a nice reproducer. The root cause is the current bad handling of racing disconnect. After the blamed commit below, sk_wait_data() can return (with error) with the underlying socket disconnected and a zero rcv_mss. Catch the error and return without performing any additional operations on the current socket. Reported-by: Eric Dumazet <edumazet@google.com> Fixes: 419ce133ab92 ("tcp: allow again tcp_disconnect() when threads are waiting") Signed-off-by: Paolo Abeni <pabeni@redhat.com> Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Link: https://patch.msgid.link/8c82ecf71662ecbc47bf390f9905de70884c9f2d.1731060874.git.pabeni@redhat.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-11-11net: netconsole: selftests: Check if netdevsim is availableBreno Leitao
The netconsole selftest relies on the availability of the netdevsim module. To ensure the test can run correctly, we need to check if the netdevsim module is either loaded or built-in before proceeding. Update the netconsole selftest to check for the existence of the /sys/bus/netdevsim/new_device file before running the test. If the file is not found, the test is skipped with an explanation that the CONFIG_NETDEVSIM kernel config option may not be enabled. Signed-off-by: Breno Leitao <leitao@debian.org> Reviewed-by: Simon Horman <horms@kernel.org> Link: https://patch.msgid.link/20241108-netcon_selftest_deps-v1-1-1789cbf3adcd@debian.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-11-11Merge branch 'net-phylink-phylink_resolve-cleanups'Jakub Kicinski
Russell King says: ==================== net: phylink: phylink_resolve() cleanups This series does a bit of clean-up in phylink_resolve() to make the code a little easier to follow. Patch 1 moves the manual flow control setting in two of the switch cases to after the switch(). Patch 2 changes the MLO_AN_FIXED case to be a simple if() statement, reducing its indentation. Patch 3 changes the MLO_AN_PHY case to also be a simple if() statment, also reducing its indentation. Patch 4 does the same for the last case. Patch 5 reformats the code and comments for the reduced indentation, making it easier to read. ==================== Link: https://patch.msgid.link/Zy411lVWe2SikuOs@shell.armlinux.org.uk Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-11-11net: phylink: clean up phylink_resolve()Russell King (Oracle)
Now that we have reduced the indentation level, clean up the code formatting. Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk> Link: https://patch.msgid.link/E1t9RQz-002Ff5-EA@rmk-PC.armlinux.org.uk Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-11-11net: phylink: remove switch() statement in resolve handlingRussell King (Oracle)
The switch() statement doesn't sit very well with the preceeding if() statements, so let's just convert everything to if()s. As a result of the two preceding commits, there is now only one case in the switch() statement. Remove the switch statement and reduce the code indentation. Code reformatting will be in the following commit. Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk> Link: https://patch.msgid.link/E1t9RQu-002Fez-AA@rmk-PC.armlinux.org.uk Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-11-11net: phylink: move MLO_AN_PHY resolve handling to if() statementRussell King (Oracle)
The switch() statement doesn't sit very well with the preceeding if() statements, and results in excessive indentation that spoils code readability. Continue cleaning this up by converting the MLO_AN_PHY case to use an if() statmeent. Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk> Link: https://patch.msgid.link/E1t9RQp-002Fet-5W@rmk-PC.armlinux.org.uk Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-11-11net: phylink: move MLO_AN_FIXED resolve handling to if() statementRussell King (Oracle)
The switch() statement doesn't sit very well with the preceeding if() statements, and results in excessive indentation that spoils code readability. Begin cleaning this up by converting the MLO_AN_FIXED case to an if() statement. Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk> Link: https://patch.msgid.link/E1t9RQk-002Fen-1A@rmk-PC.armlinux.org.uk Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-11-11net: phylink: move manual flow control settingRussell King (Oracle)
Move the handling of manual flow control configuration to a common location during resolve. We currently evaluate this for all but fixed links. Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk> Link: https://patch.msgid.link/E1t9RQe-002Feh-T1@rmk-PC.armlinux.org.uk Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-11-11Merge branch 'suspend-irqs-during-application-busy-periods'Jakub Kicinski
Joe Damato says: ==================== Suspend IRQs during application busy periods This series introduces a new mechanism, IRQ suspension, which allows network applications using epoll to mask IRQs during periods of high traffic while also reducing tail latency (compared to existing mechanisms, see below) during periods of low traffic. In doing so, this balances CPU consumption with network processing efficiency. Martin Karsten (CC'd) and I have been collaborating on this series for several months and have appreciated the feedback from the community on our RFC [1]. We've updated the cover letter and kernel documentation in an attempt to more clearly explain how this mechanism works, how applications can use it, and how it compares to existing mechanisms in the kernel. I briefly mentioned this idea at netdev conf 2024 (for those who were there) and Martin described this idea in an earlier paper presented at Sigmetrics 2024 [2]. ~ The short explanation (TL;DR) We propose adding a new napi config parameter: irq_suspend_timeout to help balance CPU usage and network processing efficiency when using IRQ deferral and napi busy poll. If this parameter is set to a non-zero value *and* a user application has enabled preferred busy poll on a busy poll context (via the EPIOCSPARAMS ioctl introduced in commit 18e2bf0edf4d ("eventpoll: Add epoll ioctl for epoll_params")), then application calls to epoll_wait for that context will cause device IRQs and softirq processing to be suspended as long as epoll_wait successfully retrieves data from the NAPI. Each time data is retrieved, the irq_suspend_timeout is deferred. If/when network traffic subsides and epoll_wait returns no data, IRQ suspension is immediately reverted back to the existing napi_defer_hard_irqs and gro_flush_timeout mechanism which was introduced in commit 6f8b12d661d0 ("net: napi: add hard irqs deferral feature")). The irq_suspend_timeout serves as a safety mechanism. If userland takes a long time processing data, irq_suspend_timeout will fire and restart normal NAPI processing. For a more in depth explanation, please continue reading. ~ Comparison with existing mechanisms Interrupt mitigation can be accomplished in napi software, by setting napi_defer_hard_irqs and gro_flush_timeout, or via interrupt coalescing in the NIC. This can be quite efficient, but in both cases, a fixed timeout (or packet count) needs to be configured. However, a fixed timeout cannot effectively support both low- and high-load situations: At low load, an application typically processes a few requests and then waits to receive more input data. In this scenario, a large timeout will cause unnecessary latency. At high load, an application typically processes many requests before being ready to receive more input data. In this case, a small timeout will likely fire prematurely and trigger irq/softirq processing, which interferes with the application's execution. This causes overhead, most likely due to cache contention. While NICs attempt to provide adaptive interrupt coalescing schemes, these cannot properly take into account application-level processing. An alternative packet delivery mechanism is busy-polling, which results in perfect alignment of application processing and network polling. It delivers optimal performance (throughput and latency), but results in 100% cpu utilization and is thus inefficient for below-capacity workloads. We propose to add a new packet delivery mode that properly alternates between busy polling and interrupt-based delivery depending on busy and idle periods of the application. During a busy period, the system operates in busy-polling mode, which avoids interference. During an idle period, the system falls back to interrupt deferral, but with a small timeout to avoid excessive latencies. This delivery mode can also be viewed as an extension of basic interrupt deferral, but alternating between a small and a very large timeout. This delivery mode is efficient, because it avoids softirq execution interfering with application processing during busy periods. It can be used with blocking epoll_wait to conserve cpu cycles during idle periods. The effect of alternating between busy and idle periods is that performance (throughput and latency) is very close to full busy polling, while cpu utilization is lower and very close to interrupt mitigation. ~ Usage details IRQ suspension is introduced via a per-NAPI configuration parameter that controls the maximum time that IRQs can be suspended. Here's how it is intended to work: - The user application (or system administrator) uses the netdev-genl netlink interface to set the pre-existing napi_defer_hard_irqs and gro_flush_timeout NAPI config parameters to enable IRQ deferral. - The user application (or system administrator) sets the proposed irq_suspend_timeout parameter via the netdev-genl netlink interface to a larger value than gro_flush_timeout to enable IRQ suspension. - The user application issues the existing epoll ioctl to set the prefer_busy_poll flag on the epoll context. - The user application then calls epoll_wait to busy poll for network events, as it normally would. - If epoll_wait returns events to userland, IRQs are suspended for the duration of irq_suspend_timeout. - If epoll_wait finds no events and the thread is about to go to sleep, IRQ handling using napi_defer_hard_irqs and gro_flush_timeout is resumed. As long as epoll_wait is retrieving events, IRQs (and softirq processing) for the NAPI being polled remain disabled. When network traffic reduces, eventually a busy poll loop in the kernel will retrieve no data. When this occurs, regular IRQ deferral using gro_flush_timeout for the polled NAPI is re-enabled. Unless IRQ suspension is continued by subsequent calls to epoll_wait, it automatically times out after the irq_suspend_timeout timer expires. Regular deferral is also immediately re-enabled when the epoll context is destroyed. ~ Usage scenario The target scenario for IRQ suspension as packet delivery mode is a system that runs a dominant application with substantial network I/O. The target application can be configured to receive input data up to a certain batch size (via epoll_wait maxevents parameter) and this batch size determines the worst-case latency that application requests might experience. Because packet delivery is suspended during the target application's processing, the batch size also determines the worst-case latency of concurrent applications using the same RX queue(s). gro_flush_timeout should be set as small as possible, but large enough to make sure that a single request is likely not being interfered with. irq_suspend_timeout is largely a safety mechanism against misbehaving applications. It should be set large enough to cover the processing of an entire application batch, i.e., the factor between gro_flush_timeout and irq_suspend_timeout should roughly correspond to the maximum batch size that the target application would process in one go. ~ Important call out in the implementation - Enabling per epoll-context preferred busy poll will now effectively lead to a nonblocking iteration through napi_busy_loop, even when busy_poll_usecs is 0. See patch 4. ~ Benchmark configs & descriptions The changes were benchmarked with memcached [3] using the benchmarking tool mutilate [4]. To facilitate benchmarking, a small patch [5] was applied to memcached 1.6.29 to allow setting per-epoll context preferred busy poll and other settings via environment variables. Another small patch [6] was applied to libevent to enable full busy-polling. Multiple scenarios were benchmarked as described below and the scripts used for producing these results can be found on github [7] (note: all scenarios use NAPI-based traffic splitting via SO_INCOMING_ID by passing -N to memcached): - base: - no other options enabled - deferX: - set defer_hard_irqs to 100 - set gro_flush_timeout to X,000 - napibusy: - set defer_hard_irqs to 100 - set gro_flush_timeout to 200,000 - enable busy poll via the existing ioctl (busy_poll_usecs = 64, busy_poll_budget = 64, prefer_busy_poll = true) - fullbusy: - set defer_hard_irqs to 100 - set gro_flush_timeout to 5,000,000 - enable busy poll via the existing ioctl (busy_poll_usecs = 1000, busy_poll_budget = 64, prefer_busy_poll = true) - change memcached's nonblocking epoll_wait invocation (via libevent) to using a 1 ms timeout - suspend0: - set defer_hard_irqs to 0 - set gro_flush_timeout to 0 - set irq_suspend_timeout to 20,000,000 - enable busy poll via the existing ioctl (busy_poll_usecs = 0, busy_poll_budget = 64, prefer_busy_poll = true) - suspendX: - set defer_hard_irqs to 100 - set gro_flush_timeout to X,000 - set irq_suspend_timeout to 20,000,000 - enable busy poll via the existing ioctl (busy_poll_usecs = 0, busy_poll_budget = 64, prefer_busy_poll = true) ~ Benchmark results Tested on: Single socket AMD EPYC 7662 64-Core Processor Hyperthreading disabled 4 NUMA Zones (NPS=4) 16 CPUs per NUMA zone (64 cores total) 2 x Dual port 100gbps Mellanox Technologies ConnectX-5 Ex EN NIC The test machine is configured such that a single interface has 8 RX queues. The queues' IRQs and memcached are pinned to CPUs that are NUMA-local to the interface which is under test. The NIC's interrupt coalescing configuration is left at boot-time defaults. Results: Results are shown below. The mechanism added by this series is represented by the 'suspend' cases. Data presented shows a summary over nearly 10 runs of each test case [8] using the scripts on github [7]. For latency, the median is shown. For throughput and CPU utilization, the average is shown. The results also include cycles-per-query (cpq) and instruction-per-query (ipq) metrics, following the methodology proposed in [2], to augment the CPU utilization numbers, which could be skewed due to frequency scaling. We find that this does not appear to be the case as CPU utilization and low-level metrics show similar trends. These results were captured using the scripts on github [7] to illustrate how this approach compares with other pre-existing mechanisms. This data is not to be interpreted as scientific data captured in a fully isolated lab setting, but instead as best effort, illustrative information comparing and contrasting tradeoffs. The absolute QPS results shift between submissions, but the relative differences are equivalent. As patches are rebased, several factors likely influence overall performance. Compare: - Throughput (MAX) and latencies of base vs suspend. - CPU usage of napibusy and fullbusy during lower load (200K, 400K for example) vs suspend. - Latency of the defer variants vs suspend as timeout and load increases. - suspend0, which sets defer_hard_irqs and gro_flush_timeout to 0, has nearly the same performance as the base case (this is FAQ item #1). The overall takeaway is that the suspend variants provide a superior combination of high throughput, low latency, and low cpu utilization compared to all other variants. Each of the suspend variants works very well, but some fine-tuning between latency and cpu utilization is still possible by tuning the small timeout (gro_flush_timeout). Note: we've reorganized the results to make comparison among testcases with the same load easier. testcase load qps avglat 95%lat 99%lat cpu cpq ipq base 200K 199946 112 239 416 26 12973 11343 defer10 200K 199971 54 124 142 29 19412 17460 defer20 200K 199986 60 130 153 26 15644 14095 defer50 200K 200025 79 144 182 23 12122 11632 defer200 200K 199999 164 254 309 19 8923 9635 fullbusy 200K 199998 46 118 133 100 43658 23133 napibusy 200K 199983 100 237 277 56 24840 24716 suspend0 200K 200020 105 249 432 30 14264 11796 suspend10 200K 199950 53 123 141 32 19518 16903 suspend20 200K 200037 58 126 151 30 16426 14736 suspend50 200K 199961 73 136 177 26 13310 12633 suspend200 200K 199998 149 251 306 21 9566 10203 testcase load qps avglat 95%lat 99%lat cpu cpq ipq base 400K 400014 139 269 707 41 9476 9343 defer10 400K 400016 59 133 166 53 13991 12989 defer20 400K 399952 67 140 172 47 12063 11644 defer50 400K 400007 87 162 198 39 9384 9880 defer200 400K 399979 181 274 330 31 7089 8430 fullbusy 400K 399987 50 123 156 100 21827 16037 napibusy 400K 400014 76 222 272 83 18185 16529 suspend0 400K 400015 127 350 776 47 10699 9603 suspend10 400K 400023 57 129 164 54 13758 13178 suspend20 400K 400043 62 135 169 49 12071 11826 suspend50 400K 400071 76 149 186 42 10011 10301 suspend200 400K 399961 154 269 327 34 7827 8774 testcase load qps avglat 95%lat 99%lat cpu cpq ipq base 600K 599951 149 266 574 61 9265 8876 defer10 600K 600006 71 147 203 76 11866 10936 defer20 600K 600123 76 152 203 66 10430 10342 defer50 600K 600162 95 172 217 54 8526 9142 defer200 600K 599942 200 301 357 46 6977 8212 fullbusy 600K 599990 55 127 177 100 14551 13983 napibusy 600K 600035 63 160 250 96 13937 14140 suspend0 600K 599903 127 320 732 68 10166 8963 suspend10 600K 599908 63 137 192 69 10902 11100 suspend20 600K 599961 66 141 194 65 9976 10370 suspend50 600K 599973 80 159 204 57 8678 9381 suspend200 600K 600010 157 277 346 48 7133 8381 testcase load qps avglat 95%lat 99%lat cpu cpq ipq base 800K 800039 181 300 536 87 9585 8304 defer10 800K 800038 181 530 939 96 10564 8970 defer20 800K 800029 112 225 329 90 10056 8935 defer50 800K 799999 120 208 296 82 9234 8562 defer200 800K 800066 227 338 401 63 7117 8129 fullbusy 800K 800040 61 134 190 100 10913 12608 napibusy 800K 799944 64 141 214 99 10828 12588 suspend0 800K 799911 126 248 509 85 9346 8498 suspend10 800K 800006 69 143 200 83 9410 9845 suspend20 800K 800120 74 150 207 78 8786 9454 suspend50 800K 799989 87 168 224 71 7946 8833 suspend200 800K 799987 160 292 357 62 6923 8229 testcase load qps avglat 95%lat 99%lat cpu cpq ipq base 1000K 906879 4079 5751 6216 98 9496 7904 defer10 1000K 860849 3643 6274 6730 99 10040 8676 defer20 1000K 896063 3298 5840 6349 98 9620 8237 defer50 1000K 919782 2962 5513 5807 97 9284 7951 defer200 1000K 970941 3059 5348 5984 95 8593 7959 fullbusy 1000K 999950 70 150 207 100 8732 10777 napibusy 1000K 999996 78 154 223 100 8722 10656 suspend0 1000K 949706 2666 5770 6660 99 9071 8046 suspend10 1000K 1000024 80 160 220 92 8137 9035 suspend20 1000K 1000059 83 165 226 89 7850 8804 suspend50 1000K 999955 95 180 240 84 7411 8459 suspend200 1000K 999914 163 299 366 77 6833 8078 testcase load qps avglat 95%lat 99%lat cpu cpq ipq base MAX 1037654 4184 5453 5810 100 8411 7938 defer10 MAX 905607 4840 6151 6380 100 9639 8431 defer20 MAX 986463 4455 5594 5796 100 8848 8110 defer50 MAX 1077030 4000 5073 5299 100 8104 7920 defer200 MAX 1040728 4152 5385 5765 100 8379 7849 fullbusy MAX 1247536 3518 3935 3984 100 6998 7930 napibusy MAX 1136310 3799 7756 9964 100 7670 7877 suspend0 MAX 1057509 4132 5724 6185 100 8253 7918 suspend10 MAX 1215147 3580 3957 4041 100 7185 7944 suspend20 MAX 1216469 3576 3953 3988 100 7175 7950 suspend50 MAX 1215871 3577 3961 4075 100 7181 7949 suspend200 MAX 1216882 3556 3951 3988 100 7175 7955 ~ FAQ - Why is a new parameter needed? Does irq_suspend_timeout override gro_flush_timeout? Using the suspend mechanism causes the system to alternate between polling mode and irq-driven packet delivery. During busy periods, irq_suspend_timeout overrides gro_flush_timeout and keeps the system busy polling, but when epoll finds no events, the setting of gro_flush_timeout and napi_defer_hard_irqs determine the next step. There are essentially three possible loops for network processing and packet delivery: 1) hardirq -> softirq -> napi poll; basic interrupt delivery 2) timer -> softirq -> napi poll; deferred irq processing 3) epoll -> busy-poll -> napi poll; busy looping Loop 2 can take control from Loop 1, if gro_flush_timeout and napi_defer_hard_irqs are set. If gro_flush_timeout and napi_defer_hard_irqs are set, Loops 2 and 3 "wrestle" with each other for control. During busy periods, irq_suspend_timeout is used as timer in Loop 2, which essentially tilts this in favour of Loop 3. If gro_flush_timeout and napi_defer_hard_irqs are not set, Loop 3 cannot take control from Loop 1. Therefore, setting gro_flush_timeout and napi_defer_hard_irqs is the recommended usage, because otherwise setting irq_suspend_timeout might not have any discernible effect. This is shown in the results above: compare suspend0 with the base case. Note that the lack of napi_defer_hard_irqs and gro_flush_timeout produce similar results for both, which encourages the use of napi_defer_hard_irqs and gro_flush_timeout in addition to irq_suspend_timeout. - Can the new timeout value be threaded through the new epoll ioctl ? It is possible, but presents challenges for userspace. User applications must ensure that the file descriptors added to epoll contexts have the same NAPI ID to support busy polling. An epoll context is not permanently tied to any particular NAPI ID. So, a user application could decide to clear the file descriptors from the context and add a new set of file descriptors with a different NAPI ID to the context. Busy polling would work as expected, but the meaning of the suspend timeout becomes ambiguous because IRQs are not inherently associated with epoll contexts, but rather with the NAPI. The user program would need to reissue the ioctl to set the irq_suspend_timeout, but the napi_defer_hard_irqs and gro_flush_timeout settings would come from the NAPI's napi_config (which are set either by sysfs or by netlink). Such an interface seems awkard to use from a user perspective. Further, IRQs are related to NAPIs, which is why they are stored in the napi_config space. Putting the irq_suspend_timeout in the epoll context while other IRQ deferral mechanisms remain in the NAPI's napi_config space seems like an odd design choice. We've opted to keep all of the IRQ deferral parameters together and place the irq_suspend_timeout in napi_config. This has nice benefits for userspace: if a user app were to remove all file descriptors from an epoll context and add new file descriptors with a new NAPI ID, the correct suspend timeout for that NAPI ID would be used automatically without the user application needing to do anything (like re-issuing an ioctl, for example). All IRQ deferral related parameters are in one place and can all be set the same way: with netlink. - Can irq suspend be built by combining NIC coalescing and gro_flush_timeout ? No. The problem is that the long timeout must engage if and only if prefer-busy is active. When using NIC coalescing for the short timeout (without napi_defer_hard_irqs/gro_flush_timeout), an interrupt after an idle period will trigger softirq, which will run napi polling. At this point, prefer-busy is not active, so NIC interrupts would be re-enabled. Then it is not possible for the longer timeout to interject to switch control back to polling. In other words, only by using the software timer for the short timeout, it is possible to extend the timeout without having to reprogram the NIC timer or reach down directly and disable interrupts. Using gro_flush_timeout for the long timeout also has problems, for the same underlying reason. In the current napi implementation, gro_flush_timeout is not tied to prefer-busy. We'd either have to change that and in the process modify the existing deferral mechanism, or introduce a state variable to determine whether gro_flush_timeout is used as long timeout for irq suspend or whether it is used for its default purpose. In an earlier version, we did try something similar to the latter and made it work, but it ends up being a lot more convoluted than our current proposal. - Isn't it already possible to combine busy looping with irq deferral? Yes, in fact enabling irq deferral via napi_defer_hard_irqs and gro_flush_timeout is a precondition for prefer_busy_poll to have an effect. If the application also uses a tight busy loop with essentially nonblocking epoll_wait (accomplished with a very short timeout parameter), this is the fullbusy case shown in the results. An application using blocking epoll_wait is shown as the napibusy case in the results. It's a hybrid approach that provides limited latency benefits compared to the base case and plain irq deferral, but not as good as fullbusy or suspend. ~ Special thanks Several people were involved in earlier stages of the development of this mechanism whom we'd like to thank: - Peter Cai (CC'd), for the initial kernel patch and his contributions to the paper. - Mohammadamin Shafie (CC'd), for testing various versions of the kernel patch and providing helpful feedback. Thanks, Martin and Joe [1]: https://lore.kernel.org/netdev/20240812125717.413108-1-jdamato@fastly.com/ [2]: https://doi.org/10.1145/3626780 [3]: https://github.com/memcached/memcached/blob/master/doc/napi_ids.txt [4]: https://github.com/leverich/mutilate [5]: https://raw.githubusercontent.com/martinkarsten/irqsuspend/main/patches/memcached.patch [6]: https://raw.githubusercontent.com/martinkarsten/irqsuspend/main/patches/libevent.patch [7]: https://github.com/martinkarsten/irqsuspend [8]: https://github.com/martinkarsten/irqsuspend/tree/main/results v8: https://lore.kernel.org/20241108045337.292905-1-jdamato@fastly.com v7: https://lore.kernel.org/20241108023912.98416-1-jdamato@fastly.com v6: https://lore.kernel.org/20241104215542.215919-1-jdamato@fastly.com v5: https://lore.kernel.org/20241103052421.518856-1-jdamato@fastly.com v4: https://lore.kernel.org/20241102005214.32443-1-jdamato@fastly.com v3: https://lore.kernel.org/20241101004846.32532-1-jdamato@fastly.com v2: https://lore.kernel.org/20241021015311.95468-1-jdamato@fastly.com ==================== Link: https://patch.msgid.link/20241109050245.191288-1-jdamato@fastly.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-11-11docs: networking: Describe irq suspensionJoe Damato
Describe irq suspension, the epoll ioctls, and the tradeoffs of using different gro_flush_timeout values. Signed-off-by: Joe Damato <jdamato@fastly.com> Co-developed-by: Martin Karsten <mkarsten@uwaterloo.ca> Signed-off-by: Martin Karsten <mkarsten@uwaterloo.ca> Reviewed-by: Sridhar Samudrala <sridhar.samudrala@intel.com> Reviewed-by: Bagas Sanjaya <bagasdotme@gmail.com> Link: https://patch.msgid.link/20241109050245.191288-7-jdamato@fastly.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-11-11selftests: net: Add busy_poll_testJoe Damato
Add an epoll busy poll test using netdevsim. This test is comprised of: - busy_poller (via busy_poller.c) - busy_poll_test.sh which loads netdevsim, sets up network namespaces, and runs busy_poller to receive data and socat to send data. The selftest tests two different scenarios: - busy poll (the pre-existing version in the kernel) - busy poll with suspend enabled (what this series adds) The data transmit is a 1MiB temporary file generated from /dev/urandom and the test is considered passing if the md5sum of the input file to socat matches the md5sum of the output file from busy_poller. netdevsim was chosen instead of veth due to netdevsim's support for netdev-genl. For now, this test uses the functionality that netdevsim provides. In the future, perhaps netdevsim can be extended to emulate device IRQs to more thoroughly test all pre-existing kernel options (like defer_hard_irqs) and suspend. Signed-off-by: Joe Damato <jdamato@fastly.com> Co-developed-by: Martin Karsten <mkarsten@uwaterloo.ca> Signed-off-by: Martin Karsten <mkarsten@uwaterloo.ca> Acked-by: Stanislav Fomichev <sdf@fomichev.me> Reviewed-by: Willem de Bruijn <willemb@google.com> Link: https://patch.msgid.link/20241109050245.191288-6-jdamato@fastly.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-11-11eventpoll: Control irq suspension for prefer_busy_pollMartin Karsten
When events are reported to userland and prefer_busy_poll is set, irqs are temporarily suspended using napi_suspend_irqs. If no events are found and ep_poll would go to sleep, irq suspension is cancelled using napi_resume_irqs. Signed-off-by: Martin Karsten <mkarsten@uwaterloo.ca> Co-developed-by: Joe Damato <jdamato@fastly.com> Signed-off-by: Joe Damato <jdamato@fastly.com> Tested-by: Joe Damato <jdamato@fastly.com> Tested-by: Martin Karsten <mkarsten@uwaterloo.ca> Acked-by: Stanislav Fomichev <sdf@fomichev.me> Reviewed-by: Sridhar Samudrala <sridhar.samudrala@intel.com> Link: https://patch.msgid.link/20241109050245.191288-5-jdamato@fastly.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-11-11eventpoll: Trigger napi_busy_loop, if prefer_busy_poll is setMartin Karsten
Setting prefer_busy_poll now leads to an effectively nonblocking iteration though napi_busy_loop, even when busy_poll_usecs is 0. Signed-off-by: Martin Karsten <mkarsten@uwaterloo.ca> Co-developed-by: Joe Damato <jdamato@fastly.com> Signed-off-by: Joe Damato <jdamato@fastly.com> Tested-by: Joe Damato <jdamato@fastly.com> Tested-by: Martin Karsten <mkarsten@uwaterloo.ca> Acked-by: Stanislav Fomichev <sdf@fomichev.me> Reviewed-by: Sridhar Samudrala <sridhar.samudrala@intel.com> Link: https://patch.msgid.link/20241109050245.191288-4-jdamato@fastly.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-11-11net: Add control functions for irq suspensionMartin Karsten
The napi_suspend_irqs routine bootstraps irq suspension by elongating the defer timeout to irq_suspend_timeout. The napi_resume_irqs routine effectively cancels irq suspension by forcing the napi to be scheduled immediately. Signed-off-by: Martin Karsten <mkarsten@uwaterloo.ca> Co-developed-by: Joe Damato <jdamato@fastly.com> Signed-off-by: Joe Damato <jdamato@fastly.com> Tested-by: Joe Damato <jdamato@fastly.com> Tested-by: Martin Karsten <mkarsten@uwaterloo.ca> Acked-by: Stanislav Fomichev <sdf@fomichev.me> Reviewed-by: Sridhar Samudrala <sridhar.samudrala@intel.com> Link: https://patch.msgid.link/20241109050245.191288-3-jdamato@fastly.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-11-11net: Add napi_struct parameter irq_suspend_timeoutMartin Karsten
Add a per-NAPI IRQ suspension parameter, which can be get/set with netdev-genl. This patch doesn't change any behavior but prepares the code for other changes in the following commits which use irq_suspend_timeout as a timeout for IRQ suspension. Signed-off-by: Martin Karsten <mkarsten@uwaterloo.ca> Co-developed-by: Joe Damato <jdamato@fastly.com> Signed-off-by: Joe Damato <jdamato@fastly.com> Tested-by: Joe Damato <jdamato@fastly.com> Tested-by: Martin Karsten <mkarsten@uwaterloo.ca> Acked-by: Stanislav Fomichev <sdf@fomichev.me> Reviewed-by: Sridhar Samudrala <sridhar.samudrala@intel.com> Link: https://patch.msgid.link/20241109050245.191288-2-jdamato@fastly.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-11-11net: clarify SO_DEVMEM_DONTNEED behavior in documentationMina Almasry
Document new behavior when the number of frags passed is too big. Signed-off-by: Mina Almasry <almasrymina@google.com> Link: https://patch.msgid.link/20241107210331.3044434-2-almasrymina@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-11-11net: fix SO_DEVMEM_DONTNEED looping too longMina Almasry
Exit early if we're freeing more than 1024 frags, to prevent looping too long. Also minor code cleanups: - Flip checks to reduce indentation. - Use sizeof(*tokens) everywhere for consistentcy. Cc: Yi Lai <yi1.lai@linux.intel.com> Signed-off-by: Mina Almasry <almasrymina@google.com> Acked-by: Stanislav Fomichev <sdf@fomichev.me> Link: https://patch.msgid.link/20241107210331.3044434-1-almasrymina@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-11-11bnxt_en: add unlocked version of bnxt_refclk_readVadim Fedorenko
Serialization of PHC read with FW reset mechanism uses ptp_lock which also protects timecounter updates. This means we cannot grab it when called from bnxt_cc_read(). Let's move locking into different function. Fixes: 6c0828d00f07 ("bnxt_en: replace PTP spinlock with seqlock") Signed-off-by: Vadim Fedorenko <vadfed@meta.com> Reviewed-by: Pavan Chebbi <pavan.chebbi@broadcom.com> Link: https://patch.msgid.link/20241107214917.2980976-1-vadfed@meta.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-11-11Merge branch 'rtnetlink-convert-rtnl_newlink-to-per-netns-rtnl'Jakub Kicinski
Kuniyuki Iwashima says: ==================== rtnetlink: Convert rtnl_newlink() to per-netns RTNL. Patch 1 - 3 removes __rtnl_link_unregister and protect link_ops by its dedicated mutex to move synchronize_srcu() out of RTNL scope. Patch 4 introduces struct rtnl_nets and helper functions to acquire multiple per-netns RTNL in rtnl_newlink(). Patch 5 - 8 are to prefetch the peer device's netns in rtnl_newlink(). Patch 9 converts rtnl_newlink() to per-netns RTNL. Patch 10 pushes RTNL down to rtnl_dellink() and rtnl_setlink(), but the conversion will not be completed unless we support cases with peer/upper/lower devices. I confirmed v3 survived ./rtnetlink.sh; rmmod netdevsim.ko; without lockdep splat. v3: https://lore.kernel.org/20241107022900.70287-1-kuniyu@amazon.com v2: https://lore.kernel.org/20241106022432.13065-1-kuniyu@amazon.com v1: https://lore.kernel.org/20241105020514.41963-1-kuniyu@amazon.com ==================== Link: https://patch.msgid.link/20241108004823.29419-1-kuniyu@amazon.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-11-11rtnetlink: Register rtnl_dellink() and rtnl_setlink() with ↵Kuniyuki Iwashima
RTNL_FLAG_DOIT_PERNET_WIP. Currently, rtnl_setlink() and rtnl_dellink() cannot be fully converted to per-netns RTNL due to a lack of handling peer/lower/upper devices in different netns. For example, when we change a device in rtnl_setlink() and need to propagate that to its upper devices, we want to avoid acquiring all netns locks, for which we do not know the upper limit. The same situation happens when we remove a device. rtnl_dellink() could be transformed to remove a single device in the requested netns and delegate other devices to per-netns work, and rtnl_setlink() might be ? Until we come up with a better idea, let's use a new flag RTNL_FLAG_DOIT_PERNET_WIP for rtnl_dellink() and rtnl_setlink(). This will unblock converting RTNL users where such devices are not related. Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/20241108004823.29419-11-kuniyu@amazon.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-11-11rtnetlink: Convert RTM_NEWLINK to per-netns RTNL.Kuniyuki Iwashima
Now, we are ready to convert rtnl_newlink() to per-netns RTNL; rtnl_link_ops is protected by SRCU and netns is prefetched in rtnl_newlink(). Let's register rtnl_newlink() with RTNL_FLAG_DOIT_PERNET and push RTNL down as rtnl_nets_lock(). Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org> Link: https://patch.msgid.link/20241108004823.29419-10-kuniyu@amazon.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-11-11netkit: Set IFLA_NETKIT_PEER_INFO to netkit_link_ops.peer_type.Kuniyuki Iwashima
For per-netns RTNL, we need to prefetch the peer device's netns. Let's set rtnl_link_ops.peer_type and accordingly remove duplicated validation in ->newlink(). Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Acked-by: Nikolay Aleksandrov <razor@blackwall.org> Link: https://patch.msgid.link/20241108004823.29419-9-kuniyu@amazon.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-11-11vxcan: Set VXCAN_INFO_PEER to vxcan_link_ops.peer_type.Kuniyuki Iwashima
For per-netns RTNL, we need to prefetch the peer device's netns. Let's set rtnl_link_ops.peer_type and accordingly remove duplicated validation in ->newlink(). Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org> Link: https://patch.msgid.link/20241108004823.29419-8-kuniyu@amazon.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-11-11veth: Set VETH_INFO_PEER to veth_link_ops.peer_type.Kuniyuki Iwashima
For per-netns RTNL, we need to prefetch the peer device's netns. Let's set rtnl_link_ops.peer_type and accordingly remove duplicated validation in ->newlink(). Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org> Link: https://patch.msgid.link/20241108004823.29419-7-kuniyu@amazon.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-11-11rtnetlink: Add peer_type in struct rtnl_link_ops.Kuniyuki Iwashima
In ops->newlink(), veth, vxcan, and netkit call rtnl_link_get_net() with a net pointer, which is the first argument of ->newlink(). rtnl_link_get_net() could return another netns based on IFLA_NET_NS_PID and IFLA_NET_NS_FD in the peer device's attributes. We want to get it and fill rtnl_nets->nets[] in advance in rtnl_newlink() for per-netns RTNL. All of the three get the peer netns in the same way: 1. Call rtnl_nla_parse_ifinfomsg() 2. Call ops->validate() (vxcan doesn't have) 3. Call rtnl_link_get_net_tb() Let's add a new field peer_type to struct rtnl_link_ops and prefetch netns in the peer ifla to add it to rtnl_nets in rtnl_newlink(). Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org> Link: https://patch.msgid.link/20241108004823.29419-6-kuniyu@amazon.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-11-11rtnetlink: Introduce struct rtnl_nets and helpers.Kuniyuki Iwashima
rtnl_newlink() needs to hold 3 per-netns RTNL: 2 for a new device and 1 for its peer. We will add rtnl_nets_lock() later, which performs the nested locking based on struct rtnl_nets, which has an array of struct net pointers. rtnl_nets_add() adds a net pointer to the array and sorts it so that rtnl_nets_lock() can simply acquire per-netns RTNL from array[0] to [2]. Before calling rtnl_nets_add(), get_net() must be called for the net, and rtnl_nets_destroy() will call put_net() for each. Let's apply the helpers to rtnl_newlink(). When CONFIG_DEBUG_NET_SMALL_RTNL is disabled, we do not call rtnl_net_lock() thus do not care about the array order, so rtnl_net_cmp_locks() returns -1 so that the loop in rtnl_nets_add() can be optimised to NOP. Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org> Link: https://patch.msgid.link/20241108004823.29419-5-kuniyu@amazon.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-11-11rtnetlink: Remove __rtnl_link_register()Kuniyuki Iwashima
link_ops is protected by link_ops_mutex and no longer needs RTNL, so we have no reason to have __rtnl_link_register() separately. Let's remove it and call rtnl_link_register() from ifb.ko and dummy.ko. Note that both modules' init() work on init_net only, so we need not export pernet_ops_rwsem and can use rtnl_net_lock() there. Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Link: https://patch.msgid.link/20241108004823.29419-4-kuniyu@amazon.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-11-11rtnetlink: Protect link_ops by mutex.Kuniyuki Iwashima
rtnl_link_unregister() holds RTNL and calls synchronize_srcu(), but rtnl_newlink() will acquire SRCU frist and then RTNL. Then, we need to unlink ops and call synchronize_srcu() outside of RTNL to avoid the deadlock. rtnl_link_unregister() rtnl_newlink() ---- ---- lock(rtnl_mutex); lock(&ops->srcu); lock(rtnl_mutex); sync(&ops->srcu); Let's move as such and add a mutex to protect link_ops. Now, link_ops is protected by its dedicated mutex and rtnl_link_register() no longer needs to hold RTNL. While at it, we move the initialisation of ops->dellink and ops->srcu out of the mutex scope. Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Link: https://patch.msgid.link/20241108004823.29419-3-kuniyu@amazon.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-11-11rtnetlink: Remove __rtnl_link_unregister().Kuniyuki Iwashima
rtnl_link_unregister() holds RTNL and calls __rtnl_link_unregister(), where we call synchronize_srcu() to wait inflight RTM_NEWLINK requests for per-netns RTNL. We put synchronize_srcu() in __rtnl_link_unregister() due to ifb.ko and dummy.ko. However, rtnl_newlink() will acquire SRCU before RTNL later in this series. Then, lockdep will detect the deadlock: rtnl_link_unregister() rtnl_newlink() ---- ---- lock(rtnl_mutex); lock(&ops->srcu); lock(rtnl_mutex); sync(&ops->srcu); To avoid the problem, we must call synchronize_srcu() before RTNL in rtnl_link_unregister(). As a preparation, let's remove __rtnl_link_unregister(). Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Link: https://patch.msgid.link/20241108004823.29419-2-kuniyu@amazon.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-11-11nommu: pass NULL argument to vma_iter_prealloc()Hajime Tazaki
When deleting a vma entry from a maple tree, it has to pass NULL to vma_iter_prealloc() in order to calculate internal state of the tree, but it passed a wrong argument. As a result, nommu kernels crashed upon accessing a vma iterator, such as acct_collect() reading the size of vma entries after do_munmap(). This commit fixes this issue by passing a right argument to the preallocation call. Link: https://lkml.kernel.org/r/20241108222834.3625217-1-thehajime@gmail.com Fixes: b5df09226450 ("mm: set up vma iterator for vma_iter_prealloc() calls") Signed-off-by: Hajime Tazaki <thehajime@gmail.com> Reviewed-by: Liam R. Howlett <Liam.Howlett@Oracle.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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