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From 587eb88b2177476bb5d004b0515332d7c1f3205b Mon Sep 17 00:00:00 2001 |
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From: Sasha Levin <sashal@kernel.org> |
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Date: Wed, 3 Aug 2022 10:49:23 +0300 |
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Subject: net/mlx5: Avoid false positive lockdep warning by adding |
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lock_class_key |
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|
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From: Moshe Shemesh <moshe@nvidia.com> |
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[ Upstream commit d59b73a66e5e0682442b6d7b4965364e57078b80 ] |
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|
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Add a lock_class_key per mlx5 device to avoid a false positive |
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"possible circular locking dependency" warning by lockdep, on flows |
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which lock more than one mlx5 device, such as adding SF. |
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|
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kernel log: |
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====================================================== |
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WARNING: possible circular locking dependency detected |
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5.19.0-rc8+ #2 Not tainted |
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------------------------------------------------------ |
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kworker/u20:0/8 is trying to acquire lock: |
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ffff88812dfe0d98 (&dev->intf_state_mutex){+.+.}-{3:3}, at: mlx5_init_one+0x2e/0x490 [mlx5_core] |
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|
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but task is already holding lock: |
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ffff888101aa7898 (&(¬ifier->n_head)->rwsem){++++}-{3:3}, at: blocking_notifier_call_chain+0x5a/0x130 |
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|
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which lock already depends on the new lock. |
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|
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the existing dependency chain (in reverse order) is: |
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|
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-> #1 (&(¬ifier->n_head)->rwsem){++++}-{3:3}: |
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down_write+0x90/0x150 |
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blocking_notifier_chain_register+0x53/0xa0 |
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mlx5_sf_table_init+0x369/0x4a0 [mlx5_core] |
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mlx5_init_one+0x261/0x490 [mlx5_core] |
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probe_one+0x430/0x680 [mlx5_core] |
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local_pci_probe+0xd6/0x170 |
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work_for_cpu_fn+0x4e/0xa0 |
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process_one_work+0x7c2/0x1340 |
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worker_thread+0x6f6/0xec0 |
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kthread+0x28f/0x330 |
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ret_from_fork+0x1f/0x30 |
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|
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-> #0 (&dev->intf_state_mutex){+.+.}-{3:3}: |
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__lock_acquire+0x2fc7/0x6720 |
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lock_acquire+0x1c1/0x550 |
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__mutex_lock+0x12c/0x14b0 |
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mlx5_init_one+0x2e/0x490 [mlx5_core] |
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mlx5_sf_dev_probe+0x29c/0x370 [mlx5_core] |
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auxiliary_bus_probe+0x9d/0xe0 |
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really_probe+0x1e0/0xaa0 |
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__driver_probe_device+0x219/0x480 |
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driver_probe_device+0x49/0x130 |
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__device_attach_driver+0x1b8/0x280 |
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bus_for_each_drv+0x123/0x1a0 |
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__device_attach+0x1a3/0x460 |
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bus_probe_device+0x1a2/0x260 |
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device_add+0x9b1/0x1b40 |
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__auxiliary_device_add+0x88/0xc0 |
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mlx5_sf_dev_state_change_handler+0x67e/0x9d0 [mlx5_core] |
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blocking_notifier_call_chain+0xd5/0x130 |
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mlx5_vhca_state_work_handler+0x2b0/0x3f0 [mlx5_core] |
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process_one_work+0x7c2/0x1340 |
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worker_thread+0x59d/0xec0 |
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kthread+0x28f/0x330 |
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ret_from_fork+0x1f/0x30 |
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|
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other info that might help us debug this: |
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|
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Possible unsafe locking scenario: |
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|
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CPU0 CPU1 |
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---- ---- |
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lock(&(¬ifier->n_head)->rwsem); |
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lock(&dev->intf_state_mutex); |
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lock(&(¬ifier->n_head)->rwsem); |
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lock(&dev->intf_state_mutex); |
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|
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*** DEADLOCK *** |
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|
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4 locks held by kworker/u20:0/8: |
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#0: ffff888150612938 ((wq_completion)mlx5_events){+.+.}-{0:0}, at: process_one_work+0x6e2/0x1340 |
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#1: ffff888100cafdb8 ((work_completion)(&work->work)#3){+.+.}-{0:0}, at: process_one_work+0x70f/0x1340 |
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#2: ffff888101aa7898 (&(¬ifier->n_head)->rwsem){++++}-{3:3}, at: blocking_notifier_call_chain+0x5a/0x130 |
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#3: ffff88813682d0e8 (&dev->mutex){....}-{3:3}, at:__device_attach+0x76/0x460 |
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|
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stack backtrace: |
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CPU: 6 PID: 8 Comm: kworker/u20:0 Not tainted 5.19.0-rc8+ |
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Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014 |
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Workqueue: mlx5_events mlx5_vhca_state_work_handler [mlx5_core] |
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Call Trace: |
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<TASK> |
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dump_stack_lvl+0x57/0x7d |
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check_noncircular+0x278/0x300 |
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? print_circular_bug+0x460/0x460 |
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? lock_chain_count+0x20/0x20 |
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? register_lock_class+0x1880/0x1880 |
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__lock_acquire+0x2fc7/0x6720 |
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? register_lock_class+0x1880/0x1880 |
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? register_lock_class+0x1880/0x1880 |
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lock_acquire+0x1c1/0x550 |
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? mlx5_init_one+0x2e/0x490 [mlx5_core] |
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? lockdep_hardirqs_on_prepare+0x400/0x400 |
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__mutex_lock+0x12c/0x14b0 |
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? mlx5_init_one+0x2e/0x490 [mlx5_core] |
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? mlx5_init_one+0x2e/0x490 [mlx5_core] |
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? _raw_read_unlock+0x1f/0x30 |
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? mutex_lock_io_nested+0x1320/0x1320 |
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? __ioremap_caller.constprop.0+0x306/0x490 |
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? mlx5_sf_dev_probe+0x269/0x370 [mlx5_core] |
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? iounmap+0x160/0x160 |
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mlx5_init_one+0x2e/0x490 [mlx5_core] |
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mlx5_sf_dev_probe+0x29c/0x370 [mlx5_core] |
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? mlx5_sf_dev_remove+0x130/0x130 [mlx5_core] |
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auxiliary_bus_probe+0x9d/0xe0 |
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really_probe+0x1e0/0xaa0 |
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__driver_probe_device+0x219/0x480 |
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? auxiliary_match_id+0xe9/0x140 |
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driver_probe_device+0x49/0x130 |
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__device_attach_driver+0x1b8/0x280 |
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? driver_allows_async_probing+0x140/0x140 |
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bus_for_each_drv+0x123/0x1a0 |
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? bus_for_each_dev+0x1a0/0x1a0 |
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? lockdep_hardirqs_on_prepare+0x286/0x400 |
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? trace_hardirqs_on+0x2d/0x100 |
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__device_attach+0x1a3/0x460 |
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? device_driver_attach+0x1e0/0x1e0 |
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? kobject_uevent_env+0x22d/0xf10 |
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bus_probe_device+0x1a2/0x260 |
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device_add+0x9b1/0x1b40 |
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? dev_set_name+0xab/0xe0 |
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? __fw_devlink_link_to_suppliers+0x260/0x260 |
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? memset+0x20/0x40 |
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? lockdep_init_map_type+0x21a/0x7d0 |
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__auxiliary_device_add+0x88/0xc0 |
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? auxiliary_device_init+0x86/0xa0 |
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mlx5_sf_dev_state_change_handler+0x67e/0x9d0 [mlx5_core] |
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blocking_notifier_call_chain+0xd5/0x130 |
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mlx5_vhca_state_work_handler+0x2b0/0x3f0 [mlx5_core] |
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? mlx5_vhca_event_arm+0x100/0x100 [mlx5_core] |
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? lock_downgrade+0x6e0/0x6e0 |
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? lockdep_hardirqs_on_prepare+0x286/0x400 |
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process_one_work+0x7c2/0x1340 |
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? lockdep_hardirqs_on_prepare+0x400/0x400 |
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? pwq_dec_nr_in_flight+0x230/0x230 |
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? rwlock_bug.part.0+0x90/0x90 |
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worker_thread+0x59d/0xec0 |
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? process_one_work+0x1340/0x1340 |
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kthread+0x28f/0x330 |
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? kthread_complete_and_exit+0x20/0x20 |
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ret_from_fork+0x1f/0x30 |
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</TASK> |
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|
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Fixes: 6a3273217469 ("net/mlx5: SF, Port function state change support") |
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Signed-off-by: Moshe Shemesh <moshe@nvidia.com> |
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Reviewed-by: Shay Drory <shayd@nvidia.com> |
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Signed-off-by: Saeed Mahameed <saeedm@nvidia.com> |
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Signed-off-by: Sasha Levin <sashal@kernel.org> |
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--- |
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drivers/net/ethernet/mellanox/mlx5/core/main.c | 4 ++++ |
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include/linux/mlx5/driver.h | 1 + |
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2 files changed, 5 insertions(+) |
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|
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diff --git a/drivers/net/ethernet/mellanox/mlx5/core/main.c b/drivers/net/ethernet/mellanox/mlx5/core/main.c |
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index ba2e5232b90be..616207c3b187a 100644 |
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--- a/drivers/net/ethernet/mellanox/mlx5/core/main.c |
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+++ b/drivers/net/ethernet/mellanox/mlx5/core/main.c |
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@@ -1472,7 +1472,9 @@ int mlx5_mdev_init(struct mlx5_core_dev *dev, int profile_idx) |
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memcpy(&dev->profile, &profile[profile_idx], sizeof(dev->profile)); |
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INIT_LIST_HEAD(&priv->ctx_list); |
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spin_lock_init(&priv->ctx_lock); |
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+ lockdep_register_key(&dev->lock_key); |
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mutex_init(&dev->intf_state_mutex); |
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+ lockdep_set_class(&dev->intf_state_mutex, &dev->lock_key); |
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|
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mutex_init(&priv->bfregs.reg_head.lock); |
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mutex_init(&priv->bfregs.wc_head.lock); |
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@@ -1527,6 +1529,7 @@ int mlx5_mdev_init(struct mlx5_core_dev *dev, int profile_idx) |
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mutex_destroy(&priv->bfregs.wc_head.lock); |
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mutex_destroy(&priv->bfregs.reg_head.lock); |
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mutex_destroy(&dev->intf_state_mutex); |
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+ lockdep_unregister_key(&dev->lock_key); |
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return err; |
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} |
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|
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@@ -1545,6 +1548,7 @@ void mlx5_mdev_uninit(struct mlx5_core_dev *dev) |
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mutex_destroy(&priv->bfregs.wc_head.lock); |
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mutex_destroy(&priv->bfregs.reg_head.lock); |
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mutex_destroy(&dev->intf_state_mutex); |
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+ lockdep_unregister_key(&dev->lock_key); |
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} |
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|
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static int probe_one(struct pci_dev *pdev, const struct pci_device_id *id) |
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diff --git a/include/linux/mlx5/driver.h b/include/linux/mlx5/driver.h |
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index 5040cd774c5a3..b0b4ac92354a2 100644 |
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--- a/include/linux/mlx5/driver.h |
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+++ b/include/linux/mlx5/driver.h |
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@@ -773,6 +773,7 @@ struct mlx5_core_dev { |
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enum mlx5_device_state state; |
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/* sync interface state */ |
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struct mutex intf_state_mutex; |
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+ struct lock_class_key lock_key; |
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unsigned long intf_state; |
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struct mlx5_priv priv; |
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struct mlx5_profile profile; |
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-- |
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2.35.1 |
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