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authorMaxim Mikityanskiy <maximmi@nvidia.com>2022-04-04 21:51:15 +0300
committerSaeed Mahameed <saeedm@nvidia.com>2022-05-17 23:03:54 -0700
commit379169740b0a955972cebb4994b2607b264a4b41 (patch)
tree2afa49e49d3e173420bd61d1760a23bba4d0e5c1 /drivers
parent785d7ed295513bd3374095304b7034fd65c123b0 (diff)
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>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/net/ethernet/mellanox/mlx5/core/en/trap.c13
1 files changed, 10 insertions, 3 deletions
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/trap.c b/drivers/net/ethernet/mellanox/mlx5/core/en/trap.c
index a55b066746cb..857840ab1e91 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en/trap.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en/trap.c
@@ -14,19 +14,26 @@ static int mlx5e_trap_napi_poll(struct napi_struct *napi, int budget)
bool busy = false;
int work_done = 0;
+ rcu_read_lock();
+
ch_stats->poll++;
work_done = mlx5e_poll_rx_cq(&rq->cq, budget);
busy |= work_done == budget;
busy |= rq->post_wqes(rq);
- if (busy)
- return budget;
+ if (busy) {
+ work_done = budget;
+ goto out;
+ }
if (unlikely(!napi_complete_done(napi, work_done)))
- return work_done;
+ goto out;
mlx5e_cq_arm(&rq->cq);
+
+out:
+ rcu_read_unlock();
return work_done;
}