net/mlx5e: Wrap mlx5e_trap_napi_poll into rcu_read_lock
authorMaxim Mikityanskiy <maximmi@nvidia.com>
Mon, 4 Apr 2022 18:51:15 +0000 (21:51 +0300)
committerSaeed Mahameed <saeedm@nvidia.com>
Wed, 18 May 2022 06:03:54 +0000 (23:03 -0700)
commit379169740b0a955972cebb4994b2607b264a4b41
tree2afa49e49d3e173420bd61d1760a23bba4d0e5c1
parent785d7ed295513bd3374095304b7034fd65c123b0
net/mlx5e: Wrap mlx5e_trap_napi_poll into rcu_read_lock

The body of mlx5e_napi_poll is wrapped into rcu_read_lock to be able to
read the XDP program pointer using rcu_dereference. However, the trap RQ
NAPI doesn't use rcu_read_lock, because the trap RQ works only in the
non-linear mode, and mlx5e_skb_from_cqe_nonlinear, until recently,
didn't support XDP and didn't call rcu_dereference.

Starting from the cited commit, mlx5e_skb_from_cqe_nonlinear supports
XDP and calls rcu_dereference, but mlx5e_trap_napi_poll doesn't wrap it
into rcu_read_lock. It leads to RCU-lockdep warnings like this:

    WARNING: suspicious RCU usage

This commit fixes the issue by adding an rcu_read_lock to
mlx5e_trap_napi_poll, similarly to mlx5e_napi_poll.

Fixes: ea5d49bdae8b ("net/mlx5e: Add XDP multi buffer support to the non-linear legacy RQ")
Signed-off-by: Maxim Mikityanskiy <maximmi@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
drivers/net/ethernet/mellanox/mlx5/core/en/trap.c