@@ -201,14 +201,9 @@ enum {
MLX5E_RQ_STATE_POST_WQES_ENABLE,
};
-enum cq_flags {
- MLX5E_CQ_HAS_CQES = 1,
-};
-
struct mlx5e_cq {
/* data path - accessed per cqe */
struct mlx5_cqwq wq;
- unsigned long flags;
/* data path - accessed per napi poll */
struct napi_struct *napi;
@@ -194,10 +194,6 @@ bool mlx5e_poll_rx_cq(struct mlx5e_cq *cq, int budget)
struct mlx5e_rq *rq = container_of(cq, struct mlx5e_rq, cq);
int i;
- /* avoid accessing cq (dma coherent memory) if not needed */
- if (!test_and_clear_bit(MLX5E_CQ_HAS_CQES, &cq->flags))
- return false;
-
for (i = 0; i < budget; i++) {
struct mlx5e_rx_wqe *wqe;
struct mlx5_cqe64 *cqe;
@@ -243,10 +239,8 @@ wq_ll_pop:
/* ensure cq space is freed before enabling more cqes */
wmb();
- if (i == budget) {
- set_bit(MLX5E_CQ_HAS_CQES, &cq->flags);
+ if (i == budget)
return true;
- }
return false;
}
@@ -262,10 +262,6 @@ bool mlx5e_poll_tx_cq(struct mlx5e_cq *cq)
u16 sqcc;
int i;
- /* avoid accessing cq (dma coherent memory) if not needed */
- if (!test_and_clear_bit(MLX5E_CQ_HAS_CQES, &cq->flags))
- return false;
-
sq = container_of(cq, struct mlx5e_sq, cq);
npkts = 0;
@@ -341,10 +337,6 @@ bool mlx5e_poll_tx_cq(struct mlx5e_cq *cq)
netif_tx_wake_queue(sq->txq);
sq->stats.wake++;
}
- if (i == MLX5E_TX_CQ_POLL_BUDGET) {
- set_bit(MLX5E_CQ_HAS_CQES, &cq->flags);
- return true;
- }
- return false;
+ return (i == MLX5E_TX_CQ_POLL_BUDGET);
}
@@ -87,7 +87,6 @@ void mlx5e_completion_event(struct mlx5_core_cq *mcq)
{
struct mlx5e_cq *cq = container_of(mcq, struct mlx5e_cq, mcq);
- set_bit(MLX5E_CQ_HAS_CQES, &cq->flags);
set_bit(MLX5E_CHANNEL_NAPI_SCHED, &cq->channel->flags);
barrier();
napi_schedule(cq->napi);
This is a note to let you know that I have just added a patch titled net/mlx5e: Remove wrong poll CQ optimization to the linux-4.2.y-queue branch of the 4.2.y-ckt extended stable tree which can be found at: http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-4.2.y-queue This patch is scheduled to be released in version 4.2.8-ckt6. If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 4.2.y-ckt tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Kamal ---8<------------------------------------------------------------ From a6d298cbf2ac0c07479a1ca92f637474fb0268d0 Mon Sep 17 00:00:00 2001 From: Tariq Toukan <tariqt@mellanox.com> Date: Mon, 29 Feb 2016 21:17:09 +0200 Subject: net/mlx5e: Remove wrong poll CQ optimization commit 59a7c2fd336eaafb030aac9c91ac21d136a99f33 upstream. With the MLX5E_CQ_HAS_CQES optimization flag, the following buggy flow might occur: - Suppose RX is always busy, TX has a single packet every second. - We poll a single TX cqe and clear its flag. - We never arm it again as RX is always busy. - TX CQ flag is never changed, and new TX cqes are not polled. We revert this optimization. Fixes: e586b3b0baee ('net/mlx5: Ethernet Datapath files') Signed-off-by: Tariq Toukan <tariqt@mellanox.com> Signed-off-by: Saeed Mahameed <saeedm@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net> [ kamal: backport to 4.2-stable: context around mlx5e_poll_rx_cq return ] Signed-off-by: Kamal Mostafa <kamal@canonical.com> --- drivers/net/ethernet/mellanox/mlx5/core/en.h | 5 ----- drivers/net/ethernet/mellanox/mlx5/core/en_rx.c | 8 +------- drivers/net/ethernet/mellanox/mlx5/core/en_tx.c | 10 +--------- drivers/net/ethernet/mellanox/mlx5/core/en_txrx.c | 1 - 4 files changed, 2 insertions(+), 22 deletions(-) -- 2.7.0